ios_client

ios_client 0.8.5/ARCHITECTURE.md

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+# Kecalek iOS — Architecture & Features
+
+**Version:** 0.8.5
+**Platform:** iOS 26+ / Swift 6
+**Files:** 57 Swift source files
+
+---
+
+## Project Structure
+
+```
+Kecalek/
+├── KecalekApp.swift          # App entry point, tab navigation
+├── AppState.swift             # Login state, connection monitoring, reconnection
+├── Core/
+│   ├── ChatClient.swift       # Main actor — all server communication & crypto (3400+ lines)
+│   ├── KeyStorage.swift       # Persistent key storage (RSA, Ed25519, sessions, TOFU)
+│   ├── KeychainService.swift  # Secure credential storage (biometric auth)
+│   └── MessageCache.swift     # Encrypted message cache (per-conversation)
+├── Crypto/
+│   ├── CryptoUtils.swift      # AES-256-GCM, HKDF, chain KDF, local encryption
+│   ├── DoubleRatchet.swift    # Signal Double Ratchet (DM encryption)
+│   ├── X3DH.swift             # Extended Triple Diffie-Hellman (session init)
+│   ├── SenderKeyState.swift   # Sender Key chains (group encryption)
+│   ├── Ed25519Crypto.swift    # Identity key generation & signing
+│   ├── X25519Crypto.swift     # DH key agreement & Ed25519↔X25519 conversion
+│   ├── RSACrypto.swift        # RSA-2048 key generation, PKCS#1/PKCS#8
+│   ├── KeyEncryption.swift    # ECP1 format: PBKDF2 600K + AES-GCM key encryption
+│   ├── FieldArithmetic.swift  # GF(2^255-19) for Ed25519→X25519 conversion
+│   ├── MessagePadding.swift   # Bucket-based padding (64B–64KB) for metadata privacy
+│   ├── ContactVerification.swift # Fingerprints, safety numbers, QR codes
+│   └── CryptoErrors.swift     # Error types
+├── Network/
+│   ├── ConnectionManager.swift # TCP/TLS via Network.framework (actor)
+│   └── ProtocolHandler.swift   # Newline-delimited JSON encoding/decoding
+├── Models/
+│   ├── Message.swift          # Message, reactions, replies, pins, files, images
+│   ├── Conversation.swift     # Conversation, members, group detection
+│   ├── User.swift             # User, UserProfile
+│   ├── DeviceBundle.swift     # X3DH key bundle per device
+│   └── Invitation.swift       # Group invitation
+├── ViewModels/
+│   ├── AuthViewModel.swift    # Login, register, pairing, biometrics
+│   ├── ChatViewModel.swift    # Messages, sending, search, reactions, pins
+│   ├── ConversationListVM.swift # Conversations, online users, favorites, avatars
+│   ├── ProfileViewModel.swift # Profile editing, avatar upload
+│   └── VerificationVM.swift   # Safety numbers, QR verification
+├── Views/
+│   ├── Auth/                  # LoginView, RegisterView, PairingView, AuthorizeDeviceView
+│   ├── Chat/                  # ChatView, MessageBubbleView, MessageInputView, etc.
+│   ├── Components/            # CircularAvatarView, ConnectionIndicator, OnlineDotOverlay
+│   ├── Conversations/         # ConversationListView, ConversationRowView, NewConversationSheet
+│   ├── Groups/                # GroupInfoView, InvitationBanner, CreateGroupSheet
+│   ├── Profile/               # ProfileView, EditProfileView
+│   └── Verification/          # SafetyNumberView, QRCodeScannerView, VerificationStatusView
+└── Utilities/
+    ├── Constants.swift        # Version, limits, timeouts, server defaults, crypto params
+    └── Extensions.swift       # Data hex/base64, DateParsing, Dictionary helpers
+```
+
+---
+
+## Architecture
+
+### Pattern: MVVM + Actor Isolation
+
+- **Views** — SwiftUI, declarative UI, bind to `@Observable` ViewModels
+- **ViewModels** — `@Observable final class`, business logic, async operations
+- **ChatClient** — `actor`, single source of truth for all crypto & network ops
+- **Models** — plain `struct`s with `Identifiable`, `Codable`
+
+### Concurrency Model
+
+- `ChatClient` is an **actor** — all crypto state (keys, sessions, ratchets) is thread-safe
+- All network calls use `async/await`
+- Real-time notifications via `AsyncStream<ChatNotification>` (multiple subscribers)
+- Background tasks: avatar loading, reconnection, notification listening
+
+### Connection Lifecycle
+
+```
+App Launch → Login (RSA challenge-response) → TCP/TLS connected
+         → Background listener loop reads messages continuously
+         → Notifications broadcast via AsyncStream to all subscribers
+         → On disconnect: exponential backoff reconnect (1s → 30s, 5 attempts)
+         → On auth failure: immediate logout (keys rotated)
+         → On foreground: check connection health, reconnect if stale (>30s)
+```
+
+---
+
+## Encryption (Signal Protocol)
+
+### Key Types
+
+| Key | Algorithm | Size | Purpose |
+|-----|-----------|------|---------|
+| RSA | RSA-2048 | 256B | Login authentication (challenge-response) |
+| Identity Key (IK) | Ed25519 | 32B | Long-term identity, signs SPK |
+| Signed Pre-Key (SPK) | X25519 | 32B | Medium-term, rotated every 7 days |
+| One-Time Pre-Keys (OPKs) | X25519 | 32B each | Single-use, batch of 50, replenish at 20 |
+| Ratchet Keys | X25519 | 32B | Ephemeral per DH ratchet step |
+| Sender Keys | Random | 32B | Per-group, per-sender chain key |
+
+### DM Encryption (X3DH + Double Ratchet)
+
+1. **Session Init (X3DH):**
+   - Alice computes: DH(IK_A, SPK_B) || DH(EK_A, IK_B) || DH(EK_A, SPK_B) || DH(EK_A, OPK_B)
+   - HKDF-SHA256 derives 32-byte shared secret
+   - Double Ratchet initialized
+
+2. **Message Encryption (Double Ratchet):**
+   - Root key → chain key → message key (HKDF chain)
+   - DH ratchet step on each direction change
+   - AES-256-GCM with derived message key
+   - AAD: ratchet header (dh_pub, n, pn)
+   - Max skip: 256 messages
+
+3. **Message Format:**
+   ```
+   plaintext → MessagePadding.pad() → AES-256-GCM encrypt → base64 → JSON
+   ```
+
+### Group Encryption (Sender Keys)
+
+1. Each member maintains own sender key chain
+2. Sender key distributed to all members via pairwise Double Ratchet DMs
+3. Messages encrypted with AES-256-GCM using derived chain key
+4. Chain ID = SHA-256(sender_key) for verification
+5. Max skip: 256 messages per chain
+
+### Message Padding
+
+Bucket sizes: `64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536` bytes
+
+```
+Format: 0x01 | plaintext | random_padding | pad_length (4B big-endian)
+```
+
+All messages padded to nearest bucket size — prevents metadata analysis of message lengths.
+
+### Self-Encryption
+
+- Derived from identity private key via HKDF
+- Encrypts own message copies for multi-device access
+- Static key — same across all user's devices
+
+### Contact Verification (TOFU)
+
+- **Fingerprint:** Iterated SHA-512 (5200 rounds) over identity key
+- **Safety Number:** 60 digits (12 groups of 5), deterministic ordering by userId
+- **QR Code:** Binary `version(1B) + uid_len(1B) + uid + identity_key(32B)`
+- **TOFU Registry:** Track first-seen identity keys, alert on change
+- **Verification Status:** unverified → trusted (TOFU) → verified (manual/QR)
+
+---
+
+## Features
+
+### Authentication & Accounts
+
+- [x] **Registration** — email + password + verification code
+- [x] **Login** — RSA challenge-response authentication
+- [x] **Biometric Login** — Face ID / Touch ID via Keychain
+- [x] **PoW Challenge** — SHA-256 proof-of-work during registration surge
+- [x] **Brute-Force Lockout** — exponential backoff (2^n seconds, max 300s)
+- [x] **Change Username** — update display name
+- [x] **Change Password** — re-encrypt RSA + Ed25519 keys with new PBKDF2 password
+- [x] **Key Rotation** — regenerate all keys with grace period for in-flight sessions
+- [x] **Logout** — clean disconnect, clear session
+
+### Multi-Device
+
+- [x] **Device Pairing** — authorize new device via pairing flow
+- [x] **Device List** — view all authorized devices
+- [x] **Device Removal** — revoke device authorization
+- [x] **Self-Encryption** — own messages readable on all devices
+
+### Messaging
+
+- [x] **Text Messages** — encrypted DM and group messages
+- [x] **Message Replies** — reply-to with visual indicator
+- [x] **Reactions** — 6 emoji reactions (👍❤️😂😮😢👎) with toggle
+- [x] **Message Pinning** — pin/unpin with pinned messages sheet
+- [x] **Message Deletion** — soft delete with "Message deleted" indicator
+- [x] **Message Forwarding** — forward to any conversation with source attribution
+- [x] **Message Search** — full-text search with result navigation (prev/next)
+- [x] **Read Receipts** — track who read each message
+- [x] **Delivery Receipts** — sent → delivered → read indicators (checkmarks)
+- [x] **Incremental Sync** — fetch only new messages via `after_ts`
+- [x] **Deleted Sync** — `get_deleted_since` for incremental deletion sync
+- [x] **Message Padding** — metadata privacy via bucket-based padding
+
+### Media & Files
+
+- [x] **Image Upload** — encrypt + chunked upload (24KB chunks)
+- [x] **Image Thumbnails** — base64 JPEG preview inline
+- [x] **Image Viewer** — full-screen with pinch zoom
+- [x] **File Upload** — any file type with mime detection
+- [x] **File Download** — decrypt + share via system share sheet
+- [x] **File Icons** — type-based system icons (PDF, DOC, ZIP, etc.)
+
+### Conversations
+
+- [x] **Direct Messages** — 1-on-1 encrypted chat
+- [x] **Group Conversations** — multi-member with Sender Keys
+- [x] **Create Conversation** — new DM or group
+- [x] **Rename Conversation** — group rename (creator only)
+- [x] **Delete Conversation** — remove DM or delete group
+- [x] **Favorites** — pin conversations to top with star icon
+- [x] **Unread Counts** — per-conversation badge
+- [x] **Online Status** — real-time presence (green dot)
+
+### Group Management
+
+- [x] **Add Member** — by email
+- [x] **Remove Member** — creator only
+- [x] **Leave Group** — with confirmation
+- [x] **Group Avatar** — upload/change group photo
+- [x] **Group Rename** — change group name
+- [x] **Group Invitations** — accept/decline with banner UI
+
+### Profile
+
+- [x] **User Profile** — username, email, phone, location
+- [x] **Avatar** — upload/change profile photo
+- [x] **Field Visibility** — toggle phone/location visibility
+- [x] **View Other Profiles** — see other users' info (respects visibility)
+
+### Contact Verification
+
+- [x] **Safety Numbers** — 60-digit verification code per contact pair
+- [x] **Fingerprints** — identity key fingerprints
+- [x] **QR Code Generation** — generate scannable verification QR
+- [x] **QR Code Scanning** — camera-based QR scan for verification
+- [x] **Verification Status** — verified (green) / trusted (blue) / unverified (gray)
+- [x] **TOFU Registry** — track identity key first-seen, detect changes
+- [x] **Shield Icon** — verification badge in chat toolbar
+
+### Connection & Reliability
+
+- [x] **TCP/TLS** — Network.framework with optional TLS
+- [x] **Configurable Server** — host, port, TLS toggle in login screen
+- [x] **Connection Indicator** — visual status (disconnected/connecting/connected)
+- [x] **Auto-Reconnect** — exponential backoff (1s → 30s, 5 attempts)
+- [x] **Background/Foreground Handling** — reconnect when returning from background
+- [x] **Auth Failure Detection** — immediate logout on key rotation
+
+### Caching & Storage
+
+- [x] **Message Cache** — encrypted per-conversation cache on disk
+- [x] **Avatar Cache** — disk + in-memory cache
+- [x] **Conversation Cache** — cached list for instant UI
+- [x] **Session Persistence** — Double Ratchet states saved encrypted
+- [x] **Sender Key Persistence** — group key chains saved encrypted
+- [x] **Device Bundle Cache** — 5-minute TTL in-memory
+- [x] **Keychain Storage** — biometric-protected credentials
+
+---
+
+## Network Protocol
+
+### Transport
+
+```
+TCP → optional TLS → Newline-delimited JSON (\n terminated)
+```
+
+### Message Format
+
+```json
+{"type": "send_message", "request_id": "uuid", "conversation_id": "...", "ciphertext": "base64..."}
+```
+
+### API Methods (36 endpoints)
+
+**Auth:** `register`, `register_confirm`, `login_start`, `login_finish`, `change_username`, `change_password`
+
+**Keys:** `get_key_bundle`, `ensure_prekeys`, `get_prekey_count`, `rotate_keys`, `reset_session`
+
+**Messaging:** `send_message`, `get_messages`, `delete_message`, `mark_read`, `mark_conversation_read`, `react_message`, `pin_message`, `get_pinned_messages`, `get_deleted_since`, `forward_message`, `confirm_delivery`, `search_messages`
+
+**Conversations:** `list_conversations`, `create_conversation`, `find_conversation`, `delete_conversation`, `rename_conversation`, `add_member`, `remove_member`, `leave_group`, `accept_invitation`, `decline_invitation`, `list_invitations`
+
+**Profiles:** `get_profile`, `update_profile`, `update_avatar`, `get_avatar`, `update_group_avatar`, `get_group_avatar`
+
+**Files:** `upload_file`, `download_file`
+
+**Devices:** `list_devices`, `remove_device`, `pairing_start`, `pairing_wait`, `authorize_device`
+
+### Notification Types (17 real-time events)
+
+```
+new_message, messages_read, message_deleted, message_reacted,
+message_pinned, message_unpinned, message_delivered,
+conversation_created, conversation_renamed, conversation_deleted,
+member_added, member_removed, group_invitation,
+user_online, user_offline, online_users,
+session_reset, keys_updated
+```
+
+---
+
+## Storage Layout
+
+```
+~/Library/Application Support/EncryptedChat/{email}/
+├── private.pem                    # RSA private key (password-protected)
+├── public.pem                     # RSA public key
+├── identity_private.bin           # Ed25519 private (ECP1: PBKDF2 + AES-GCM)
+├── identity_public.bin            # Ed25519 public
+├── spk_private.bin                # Current signed pre-key (X25519)
+├── spk_id.txt                     # SPK ID
+├── prevspk_private.bin            # Previous SPK (grace period)
+├── prevspk_id.txt
+├── opk_{id}.bin                   # One-time pre-keys
+├── sessions/
+│   └── {userId}_{deviceId}.bin    # Double Ratchet state (encrypted)
+├── sender_keys/
+│   └── {convId}_{senderId}_{deviceId}.bin  # Sender Key chain (encrypted)
+├── message_cache/
+│   └── {convId}.json              # Message cache (encrypted)
+├── conversations_cache.json       # Conversation list cache (encrypted)
+├── avatars/
+│   └── {convId}.bin               # Avatar image data (encrypted)
+├── known_identity_keys.bin        # TOFU registry (encrypted)
+├── verified_contacts.bin          # Verified contacts (encrypted)
+└── favorites.bin                  # Favorite conversation IDs (encrypted)
+```
+
+---
+
+## Build
+
+```bash
+# Xcode build
+open /Users/filip/Desktop/kecalek_ios/Kecalek/Kecalek.xcodeproj
+
+# Command-line build
+DEVELOPER_DIR=/Applications/Xcode.app/Contents/Developer \
+xcodebuild -scheme Kecalek \
+  -destination 'platform=iOS Simulator,name=iPhone 17 Pro' \
+  build
+```
+
+**Result:** 57 files, 0 errors, 0 warnings.

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+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
+				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
+				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNGUARDED_AVAILABILITY = YES_AGGRESSIVE;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				COPY_PHASE_STRIP = NO;
+				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
+				DEVELOPMENT_TEAM = J26GZ5AW57;
+				ENABLE_NS_ASSERTIONS = NO;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				ENABLE_USER_SCRIPT_SANDBOXING = YES;
+				GCC_C_LANGUAGE_STANDARD = gnu17;
+				GCC_NO_COMMON_BLOCKS = YES;
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
+				IPHONEOS_DEPLOYMENT_TARGET = 26.0;
+				LOCALIZATION_PREFERS_STRING_CATALOGS = YES;
+				MTL_ENABLE_DEBUG_INFO = NO;
+				MTL_FAST_MATH = YES;
+				SDKROOT = iphoneos;
+				STRING_CATALOG_GENERATE_SYMBOLS = YES;
+				SWIFT_COMPILATION_MODE = wholemodule;
+				VALIDATE_PRODUCT = YES;
+			};
+			name = Release;
+		};
+		DC2D11DF2F3CE6FF009F93FA /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
+				CODE_SIGN_IDENTITY = "Apple Development";
+				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 1;
+				DEVELOPMENT_TEAM = J26GZ5AW57;
+				ENABLE_PREVIEWS = YES;
+				GENERATE_INFOPLIST_FILE = YES;
+				INFOPLIST_KEY_CFBundleDisplayName = Kecalek;
+				INFOPLIST_KEY_LSApplicationCategoryType = "public.app-category.social-networking";
+				INFOPLIST_KEY_NSCameraUsageDescription = "Scan QR codes for contact verification";
+				INFOPLIST_KEY_NSFaceIDUsageDescription = "Sign in with Face ID";
+				INFOPLIST_KEY_NSPhotoLibraryUsageDescription = "Share photos in chat";
+				INFOPLIST_KEY_UIApplicationSceneManifest_Generation = YES;
+				INFOPLIST_KEY_UIApplicationSupportsIndirectInputEvents = YES;
+				INFOPLIST_KEY_UILaunchScreen_Generation = YES;
+				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPad = "UIInterfaceOrientationPortrait UIInterfaceOrientationPortraitUpsideDown UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
+				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPhone = "UIInterfaceOrientationPortrait UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+				);
+				MARKETING_VERSION = 1.0;
+				PRODUCT_BUNDLE_IDENTIFIER = Kecalek.lockmseg.com2;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
+				STRING_CATALOG_GENERATE_SYMBOLS = YES;
+				SWIFT_APPROACHABLE_CONCURRENCY = YES;
+				SWIFT_EMIT_LOC_STRINGS = YES;
+				SWIFT_UPCOMING_FEATURE_MEMBER_IMPORT_VISIBILITY = YES;
+				SWIFT_VERSION = 5.0;
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Debug;
+		};
+		DC2D11E02F3CE6FF009F93FA /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
+				CODE_SIGN_IDENTITY = "Apple Development";
+				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 1;
+				DEVELOPMENT_TEAM = J26GZ5AW57;
+				ENABLE_PREVIEWS = YES;
+				GENERATE_INFOPLIST_FILE = YES;
+				INFOPLIST_KEY_CFBundleDisplayName = Kecalek;
+				INFOPLIST_KEY_LSApplicationCategoryType = "public.app-category.social-networking";
+				INFOPLIST_KEY_NSCameraUsageDescription = "Scan QR codes for contact verification";
+				INFOPLIST_KEY_NSFaceIDUsageDescription = "Sign in with Face ID";
+				INFOPLIST_KEY_NSPhotoLibraryUsageDescription = "Share photos in chat";
+				INFOPLIST_KEY_UIApplicationSceneManifest_Generation = YES;
+				INFOPLIST_KEY_UIApplicationSupportsIndirectInputEvents = YES;
+				INFOPLIST_KEY_UILaunchScreen_Generation = YES;
+				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPad = "UIInterfaceOrientationPortrait UIInterfaceOrientationPortraitUpsideDown UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
+				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPhone = "UIInterfaceOrientationPortrait UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
+				LD_RUNPATH_SEARCH_PATHS = (
+					"$(inherited)",
+					"@executable_path/Frameworks",
+				);
+				MARKETING_VERSION = 1.0;
+				PRODUCT_BUNDLE_IDENTIFIER = Kecalek.lockmseg.com2;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
+				STRING_CATALOG_GENERATE_SYMBOLS = YES;
+				SWIFT_APPROACHABLE_CONCURRENCY = YES;
+				SWIFT_EMIT_LOC_STRINGS = YES;
+				SWIFT_UPCOMING_FEATURE_MEMBER_IMPORT_VISIBILITY = YES;
+				SWIFT_VERSION = 5.0;
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Release;
+		};
+/* End XCBuildConfiguration section */
+
+/* Begin XCConfigurationList section */
+		DC2D11CE2F3CE6FD009F93FA /* Build configuration list for PBXProject "Kecalek" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				DC2D11DC2F3CE6FF009F93FA /* Debug */,
+				DC2D11DD2F3CE6FF009F93FA /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+		DC2D11DE2F3CE6FF009F93FA /* Build configuration list for PBXNativeTarget "Kecalek" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				DC2D11DF2F3CE6FF009F93FA /* Debug */,
+				DC2D11E02F3CE6FF009F93FA /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+/* End XCConfigurationList section */
+	};
+	rootObject = DC2D11CB2F3CE6FD009F93FA /* Project object */;
+}

ios_client 0.8.5/Kecalek.xcodeproj/project.xcworkspace/contents.xcworkspacedata

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "self:">
+   </FileRef>
+</Workspace>

ios_client 0.8.5/Kecalek.xcodeproj/project.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict/>
+</plist>

ios_client 0.8.5/Kecalek.xcodeproj/project.xcworkspace/xcuserdata/filip.xcuserdatad/WorkspaceSettings.xcsettings

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>BuildLocationStyle</key>
+	<string>UseAppPreferences</string>
+	<key>CompilationCachingSetting</key>
+	<string>Default</string>
+	<key>CustomBuildLocationType</key>
+	<string>RelativeToDerivedData</string>
+	<key>DerivedDataLocationStyle</key>
+	<string>Default</string>
+	<key>ShowSharedSchemesAutomaticallyEnabled</key>
+	<true/>
+</dict>
+</plist>

ios_client 0.8.5/Kecalek.xcodeproj/xcuserdata/filip.xcuserdatad/xcschemes/xcschememanagement.plist

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>SchemeUserState</key>
+	<dict>
+		<key>Kecalek.xcscheme_^#shared#^_</key>
+		<dict>
+			<key>orderHint</key>
+			<integer>0</integer>
+		</dict>
+	</dict>
+</dict>
+</plist>

ios_client 0.8.5/Kecalek/AppState.swift

@@ -0,0 +1,161 @@
+import Foundation
+import SwiftUI
+
+enum ConnectionStatus: Equatable {
+    case disconnected
+    case connecting
+    case connected
+    case reconnecting
+}
+
+@Observable
+final class AppState {
+    var isLoggedIn = false
+    var currentUser: User?
+    var connectionStatus: ConnectionStatus = .disconnected
+    var email: String = ""
+
+    let chatClient = ChatClient()
+
+    private var reconnectTask: Task<Void, Never>?
+    private var notificationTask: Task<Void, Never>?
+    private var isReconnecting = false
+    private var backgroundedAt: Date?
+
+    /// Start listening for connection state changes (call after login)
+    func startConnectionMonitor() {
+        notificationTask?.cancel()
+        notificationTask = Task { [weak self] in
+            guard let self else { return }
+            let stream = await chatClient.makeNotificationStream()
+            for await notification in stream {
+                guard !Task.isCancelled else { break }
+                if case .connectionStateChanged(let connected) = notification {
+                    await MainActor.run {
+                        if connected {
+                            self.connectionStatus = .connected
+                            self.isReconnecting = false
+                            self.reconnectTask?.cancel()
+                            self.reconnectTask = nil
+                        } else if self.isLoggedIn, !self.isReconnecting {
+                            // Only start reconnect if not already reconnecting
+                            // (reconnect() internally calls disconnect() which fires this)
+                            self.connectionStatus = .disconnected
+                            self.attemptReconnect()
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    /// Attempt reconnect with exponential backoff; immediate logout on auth failure
+    @MainActor
+    private func attemptReconnect() {
+        reconnectTask?.cancel()
+        isReconnecting = true
+        reconnectTask = Task { [weak self] in
+            guard let self else { return }
+            let maxAttempts = 5
+            var delay: TimeInterval = Constants.reconnectBaseDelay
+
+            for attempt in 1...maxAttempts {
+                guard !Task.isCancelled, self.isLoggedIn else { return }
+
+                self.connectionStatus = .reconnecting
+                #if DEBUG
+                print("DEBUG AppState: reconnect attempt \(attempt)/\(maxAttempts), delay=\(delay)s")
+                #endif
+
+                try? await Task.sleep(nanoseconds: UInt64(delay * 1_000_000_000))
+                guard !Task.isCancelled, self.isLoggedIn else { return }
+
+                let result = await self.chatClient.reconnect()
+                switch result {
+                case .success:
+                    self.connectionStatus = .connected
+                    self.isReconnecting = false
+                    #if DEBUG
+                    print("DEBUG AppState: reconnected on attempt \(attempt)")
+                    #endif
+                    return
+                case .authFailed:
+                    // Keys rotated or invalid — logout immediately, don't retry
+                    self.isReconnecting = false
+                    #if DEBUG
+                    print("DEBUG AppState: auth failed (keys likely rotated), logging out immediately")
+                    #endif
+                    await self.logout()
+                    return
+                case .networkError:
+                    // Network issue — retry with backoff
+                    delay = min(delay * 2, Constants.reconnectMaxDelay)
+                }
+            }
+
+            // All network retries exhausted → force logout
+            self.isReconnecting = false
+            guard !Task.isCancelled, self.isLoggedIn else { return }
+            #if DEBUG
+            print("DEBUG AppState: reconnect failed after \(maxAttempts) attempts, logging out")
+            #endif
+            await self.logout()
+        }
+    }
+
+    // MARK: - App Lifecycle
+
+    func handleEnteredBackground() {
+        backgroundedAt = Date()
+    }
+
+    @MainActor
+    func handleBecameActive() {
+        guard isLoggedIn, !isReconnecting else { return }
+        let wasInBackground = backgroundedAt.map { Date().timeIntervalSince($0) } ?? 0
+        backgroundedAt = nil
+
+        Task {
+            let alive = await chatClient.isConnectionAlive()
+            if !alive {
+                #if DEBUG
+                print("DEBUG AppState: foreground — connection dead, reconnecting")
+                #endif
+                await MainActor.run {
+                    guard !self.isReconnecting else { return }
+                    self.connectionStatus = .reconnecting
+                    self.attemptReconnect()
+                }
+            } else if wasInBackground > 30 {
+                // Connection appears alive but was backgrounded a long time —
+                // force reconnect to ensure fresh state
+                #if DEBUG
+                print("DEBUG AppState: foreground — stale connection (\(Int(wasInBackground))s), reconnecting")
+                #endif
+                await MainActor.run {
+                    guard !self.isReconnecting else { return }
+                    self.connectionStatus = .reconnecting
+                    self.attemptReconnect()
+                }
+            } else {
+                #if DEBUG
+                print("DEBUG AppState: foreground — connection alive (\(Int(wasInBackground))s in bg)")
+                #endif
+            }
+        }
+    }
+
+    func logout() async {
+        isReconnecting = false
+        reconnectTask?.cancel()
+        reconnectTask = nil
+        notificationTask?.cancel()
+        notificationTask = nil
+        await chatClient.disconnect()
+        KeychainService.deleteCredentials()
+        isLoggedIn = false
+        currentUser = nil
+        connectionStatus = .disconnected
+        email = ""
+    }
+}

ios_client 0.8.5/Kecalek/Assets.xcassets/AccentColor.colorset/Contents.json

@@ -0,0 +1,11 @@
+{
+  "colors" : [
+    {
+      "idiom" : "universal"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

ios_client 0.8.5/Kecalek/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -0,0 +1,38 @@
+{
+  "images" : [
+    {
+      "filename" : "AppIcon.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "AppIcon.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "tinted"
+        }
+      ],
+      "filename" : "AppIcon.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

ios_client 0.8.5/Kecalek/Assets.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

ios_client 0.8.5/Kecalek/Core/KeyStorage.swift

@@ -0,0 +1,485 @@
+import Foundation
+import CryptoKit
+
+/// Local file storage for keys, sessions, and sender keys.
+/// Matches Python: chat_core.py key storage functions.
+///
+/// Base directory: Application Support / EncryptedChat / {email}
+/// Same file names as Python client for cross-platform compatibility.
+enum KeyStorage {
+
+    // MARK: - Base Directory
+
+    /// Get or create the key storage directory for a user
+    static func getKeyDir(email: String) throws -> URL {
+        let appSupport = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask).first!
+        let dir = appSupport.appendingPathComponent("EncryptedChat").appendingPathComponent(email)
+        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+        // iOS file protection
+        try (dir as NSURL).setResourceValue(URLFileProtection.complete, forKey: .fileProtectionKey)
+        return dir
+    }
+
+    // MARK: - RSA Keys
+
+    /// Save RSA keypair
+    static func saveRSAKeys(email: String, privateKey: SecKey, publicKey: SecKey, password: Data? = nil) throws {
+        let dir = try getKeyDir(email: email)
+        let privData = try RSACrypto.serializePrivateKey(privateKey, password: password)
+        let pubData = try RSACrypto.serializePublicKey(publicKey)
+        try writeProtected(privData, to: dir.appendingPathComponent("private.pem"))
+        try writeProtected(pubData, to: dir.appendingPathComponent("public.pem"))
+    }
+
+    /// Load RSA keypair. Returns (private, public, error).
+    static func loadRSAKeys(email: String, password: Data? = nil) -> (SecKey?, SecKey?, String?) {
+        guard let dir = try? getKeyDir(email: email) else {
+            return (nil, nil, "Cannot access key directory")
+        }
+        let privPath = dir.appendingPathComponent("private.pem")
+        let pubPath = dir.appendingPathComponent("public.pem")
+
+        guard FileManager.default.fileExists(atPath: privPath.path) else {
+            return (nil, nil, "No local keys found.")
+        }
+
+        guard let privData = try? Data(contentsOf: privPath),
+              let pubData = try? Data(contentsOf: pubPath) else {
+            return (nil, nil, "Cannot read key files.")
+        }
+
+        do {
+            let privateKey = try RSACrypto.loadPrivateKey(privData, password: password)
+            let publicKey = try RSACrypto.loadPublicKey(pubData)
+            return (privateKey, publicKey, nil)
+        } catch {
+            // Try without password (unencrypted)
+            do {
+                let privateKey = try RSACrypto.loadPrivateKey(privData, password: nil)
+                let publicKey = try RSACrypto.loadPublicKey(pubData)
+                // Re-save with password if provided
+                if let password = password {
+                    try? saveRSAKeys(email: email, privateKey: privateKey, publicKey: publicKey, password: password)
+                }
+                return (privateKey, publicKey, nil)
+            } catch {
+                return (nil, nil, "Invalid or missing password.")
+            }
+        }
+    }
+
+    // MARK: - Identity Keys (Ed25519)
+
+    static func saveIdentityKeys(
+        email: String,
+        privateKey: Curve25519.Signing.PrivateKey,
+        publicKey: Curve25519.Signing.PublicKey,
+        password: Data? = nil
+    ) throws {
+        let dir = try getKeyDir(email: email)
+        let privData = try Ed25519Crypto.serializePrivate(privateKey, password: password)
+        let pubData = Ed25519Crypto.serializePublic(publicKey)
+        try writeProtected(privData, to: dir.appendingPathComponent("identity_private.bin"))
+        try writeProtected(pubData, to: dir.appendingPathComponent("identity_public.bin"))
+    }
+
+    static func loadIdentityKeys(
+        email: String,
+        password: Data? = nil
+    ) -> (Curve25519.Signing.PrivateKey?, Curve25519.Signing.PublicKey?) {
+        guard let dir = try? getKeyDir(email: email) else { return (nil, nil) }
+        let privPath = dir.appendingPathComponent("identity_private.bin")
+        let pubPath = dir.appendingPathComponent("identity_public.bin")
+
+        guard FileManager.default.fileExists(atPath: privPath.path),
+              let privData = try? Data(contentsOf: privPath),
+              let pubData = try? Data(contentsOf: pubPath) else {
+            return (nil, nil)
+        }
+
+        do {
+            let priv = try Ed25519Crypto.loadPrivate(privData, password: password)
+            let pub = try Ed25519Crypto.loadPublic(pubData)
+            return (priv, pub)
+        } catch {
+            return (nil, nil)
+        }
+    }
+
+    // MARK: - Signed Pre-Key
+
+    static func saveSPK(email: String, privateKey: Curve25519.KeyAgreement.PrivateKey, spkId: String) throws {
+        let dir = try getKeyDir(email: email)
+        try writeProtected(X25519Crypto.serializePrivate(privateKey), to: dir.appendingPathComponent("spk_private.bin"))
+        try writeProtected(Data(spkId.utf8), to: dir.appendingPathComponent("spk_id.txt"))
+    }
+
+    static func loadSPK(email: String) -> (Curve25519.KeyAgreement.PrivateKey?, String?) {
+        guard let dir = try? getKeyDir(email: email) else { return (nil, nil) }
+        let privPath = dir.appendingPathComponent("spk_private.bin")
+        let idPath = dir.appendingPathComponent("spk_id.txt")
+
+        guard FileManager.default.fileExists(atPath: privPath.path),
+              let privData = try? Data(contentsOf: privPath),
+              let priv = try? X25519Crypto.loadPrivate(privData) else {
+            return (nil, nil)
+        }
+        let spkId = (try? String(data: Data(contentsOf: idPath), encoding: .utf8))?.trimmed ?? ""
+        return (priv, spkId)
+    }
+
+    // MARK: - Previous SPK (Grace Period)
+
+    static func savePrevSPK(email: String, privateKey: Curve25519.KeyAgreement.PrivateKey, spkId: String) throws {
+        let dir = try getKeyDir(email: email)
+        try writeProtected(X25519Crypto.serializePrivate(privateKey), to: dir.appendingPathComponent("prev_spk_private.bin"))
+        try writeProtected(Data(spkId.utf8), to: dir.appendingPathComponent("prev_spk_id.txt"))
+    }
+
+    static func loadPrevSPK(email: String) -> (Curve25519.KeyAgreement.PrivateKey?, String?) {
+        guard let dir = try? getKeyDir(email: email) else { return (nil, nil) }
+        let privPath = dir.appendingPathComponent("prev_spk_private.bin")
+        let idPath = dir.appendingPathComponent("prev_spk_id.txt")
+
+        guard FileManager.default.fileExists(atPath: privPath.path),
+              let privData = try? Data(contentsOf: privPath),
+              let priv = try? X25519Crypto.loadPrivate(privData) else {
+            return (nil, nil)
+        }
+        let spkId = (try? String(data: Data(contentsOf: idPath), encoding: .utf8))?.trimmed ?? ""
+        return (priv, spkId)
+    }
+
+    // MARK: - One-Time Pre-Keys
+
+    static func saveOPKPrivate(email: String, opkId: String, privateKey: Curve25519.KeyAgreement.PrivateKey) throws {
+        let dir = try getKeyDir(email: email).appendingPathComponent("opk_private")
+        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+        try writeProtected(X25519Crypto.serializePrivate(privateKey), to: dir.appendingPathComponent("\(opkId).bin"))
+    }
+
+    static func loadOPKPrivate(email: String, opkId: String) -> Curve25519.KeyAgreement.PrivateKey? {
+        guard let dir = try? getKeyDir(email: email) else { return nil }
+        let path = dir.appendingPathComponent("opk_private").appendingPathComponent("\(opkId).bin")
+        guard let data = try? Data(contentsOf: path) else { return nil }
+        return try? X25519Crypto.loadPrivate(data)
+    }
+
+    static func deleteOPKPrivate(email: String, opkId: String) {
+        guard let dir = try? getKeyDir(email: email) else { return }
+        let path = dir.appendingPathComponent("opk_private").appendingPathComponent("\(opkId).bin")
+        try? FileManager.default.removeItem(at: path)
+    }
+
+    // MARK: - Device ID
+
+    static func saveDeviceId(email: String, deviceId: String) throws {
+        let dir = try getKeyDir(email: email)
+        try writeProtected(Data(deviceId.utf8), to: dir.appendingPathComponent("device_id.txt"))
+    }
+
+    static func loadDeviceId(email: String) -> String? {
+        guard let dir = try? getKeyDir(email: email) else { return nil }
+        let path = dir.appendingPathComponent("device_id.txt")
+        guard let data = try? Data(contentsOf: path) else { return nil }
+        let str = String(data: data, encoding: .utf8)?.trimmed
+        return (str?.isEmpty ?? true) ? nil : str
+    }
+
+    // MARK: - Sessions (Double Ratchet)
+
+    static func saveSession(
+        email: String,
+        peerUserId: String,
+        ratchet: DoubleRatchet,
+        localKey: Data? = nil,
+        peerDeviceId: String? = nil
+    ) throws {
+        let dir = try getKeyDir(email: email).appendingPathComponent("sessions")
+        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+
+        let filename: String
+        if let deviceId = peerDeviceId {
+            filename = "\(peerUserId)_\(deviceId).bin"
+        } else {
+            filename = "\(peerUserId).bin"
+        }
+
+        let exported = try ratchet.exportState()
+        guard let localKey = localKey else {
+            throw CryptoError.encryptionFailed("localKey required for session storage")
+        }
+        let data = try CryptoUtils.encryptLocal(exported, key: localKey)
+        try writeProtected(data, to: dir.appendingPathComponent(filename))
+    }
+
+    static func loadSession(
+        email: String,
+        peerUserId: String,
+        localKey: Data? = nil,
+        peerDeviceId: String? = nil
+    ) -> DoubleRatchet? {
+        guard let dir = try? getKeyDir(email: email) else { return nil }
+        let sessionsDir = dir.appendingPathComponent("sessions")
+
+        let filename: String
+        if let deviceId = peerDeviceId {
+            filename = "\(peerUserId)_\(deviceId).bin"
+        } else {
+            filename = "\(peerUserId).bin"
+        }
+
+        let path = sessionsDir.appendingPathComponent(filename)
+        return loadSessionFile(path, localKey: localKey)
+    }
+
+    static func deleteSession(email: String, peerUserId: String, peerDeviceId: String? = nil) {
+        guard let dir = try? getKeyDir(email: email) else { return }
+        let sessionsDir = dir.appendingPathComponent("sessions")
+
+        if let deviceId = peerDeviceId {
+            let path = sessionsDir.appendingPathComponent("\(peerUserId)_\(deviceId).bin")
+            try? FileManager.default.removeItem(at: path)
+        } else {
+            // Delete all sessions for this user
+            if let files = try? FileManager.default.contentsOfDirectory(atPath: sessionsDir.path) {
+                for file in files where file.hasPrefix(peerUserId) {
+                    try? FileManager.default.removeItem(at: sessionsDir.appendingPathComponent(file))
+                }
+            }
+        }
+    }
+
+    private static func loadSessionFile(_ path: URL, localKey: Data?) -> DoubleRatchet? {
+        guard let raw = try? Data(contentsOf: path) else { return nil }
+
+        if let localKey = localKey {
+            // Try encrypted first
+            if let decrypted = try? CryptoUtils.decryptLocal(raw, key: localKey) {
+                return try? DoubleRatchet.importState(decrypted)
+            }
+            // Migration: try plaintext, immediately re-encrypt
+            if let ratchet = try? DoubleRatchet.importState(raw) {
+                try? writeProtected(CryptoUtils.encryptLocal(try ratchet.exportState(), key: localKey), to: path)
+                return ratchet
+            }
+            // Corrupted — delete
+            try? FileManager.default.removeItem(at: path)
+            return nil
+        }
+
+        // No localKey — refuse to load plaintext sessions
+        return nil
+    }
+
+    // MARK: - Sender Keys
+
+    static func saveSenderKeyState(
+        email: String,
+        convId: String,
+        state: SenderKeyState,
+        localKey: Data? = nil
+    ) throws {
+        let dir = try getKeyDir(email: email).appendingPathComponent("sender_keys")
+        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+
+        guard let localKey = localKey else {
+            throw CryptoError.encryptionFailed("localKey required for sender key storage")
+        }
+        let data = try CryptoUtils.encryptLocal(state.exportState(), key: localKey)
+        try writeProtected(data, to: dir.appendingPathComponent("\(convId).bin"))
+    }
+
+    static func loadSenderKeyState(
+        email: String,
+        convId: String,
+        localKey: Data? = nil
+    ) -> SenderKeyState? {
+        guard let dir = try? getKeyDir(email: email) else { return nil }
+        let path = dir.appendingPathComponent("sender_keys").appendingPathComponent("\(convId).bin")
+        guard let raw = try? Data(contentsOf: path) else { return nil }
+
+        if let localKey = localKey {
+            if let decrypted = try? CryptoUtils.decryptLocal(raw, key: localKey) {
+                return try? SenderKeyState.importState(decrypted)
+            }
+            // Migration: try plaintext, immediately re-encrypt
+            if let state = try? SenderKeyState.importState(raw) {
+                try? writeProtected(CryptoUtils.encryptLocal(state.exportState(), key: localKey), to: path)
+                return state
+            }
+            try? FileManager.default.removeItem(at: path)
+            return nil
+        }
+
+        return nil
+    }
+
+    static func deleteSenderKeyState(email: String, convId: String) {
+        guard let dir = try? getKeyDir(email: email) else { return }
+        let path = dir.appendingPathComponent("sender_keys").appendingPathComponent("\(convId).bin")
+        try? FileManager.default.removeItem(at: path)
+    }
+
+    // MARK: - Received Sender Keys
+
+    static func saveRecvSenderKey(
+        email: String,
+        convId: String,
+        senderId: String,
+        senderDeviceId: String,
+        state: SenderKeyState,
+        localKey: Data? = nil
+    ) throws {
+        let dir = try getKeyDir(email: email).appendingPathComponent("sender_keys_recv")
+        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+
+        guard let localKey = localKey else {
+            throw CryptoError.encryptionFailed("localKey required for sender key storage")
+        }
+        let data = try CryptoUtils.encryptLocal(state.exportState(), key: localKey)
+        try writeProtected(data, to: dir.appendingPathComponent("\(convId)_\(senderId)_\(senderDeviceId).bin"))
+    }
+
+    static func loadRecvSenderKey(
+        email: String,
+        convId: String,
+        senderId: String,
+        senderDeviceId: String,
+        localKey: Data? = nil
+    ) -> SenderKeyState? {
+        guard let dir = try? getKeyDir(email: email) else { return nil }
+        let path = dir.appendingPathComponent("sender_keys_recv").appendingPathComponent("\(convId)_\(senderId)_\(senderDeviceId).bin")
+        guard let raw = try? Data(contentsOf: path) else { return nil }
+
+        if let localKey = localKey {
+            if let decrypted = try? CryptoUtils.decryptLocal(raw, key: localKey) {
+                return try? SenderKeyState.importState(decrypted)
+            }
+            // Migration: try plaintext, immediately re-encrypt
+            if let state = try? SenderKeyState.importState(raw) {
+                try? writeProtected(CryptoUtils.encryptLocal(state.exportState(), key: localKey), to: path)
+                return state
+            }
+            try? FileManager.default.removeItem(at: path)
+            return nil
+        }
+
+        return nil
+    }
+
+    static func deleteRecvSenderKeys(email: String, convId: String) {
+        guard let dir = try? getKeyDir(email: email) else { return }
+        let recvDir = dir.appendingPathComponent("sender_keys_recv")
+        guard let files = try? FileManager.default.contentsOfDirectory(atPath: recvDir.path) else { return }
+        for file in files where file.hasPrefix(convId) {
+            try? FileManager.default.removeItem(at: recvDir.appendingPathComponent(file))
+        }
+    }
+
+    // MARK: - Favorites
+
+    static func saveFavorites(email: String, favorites: Set<String>, localKey: Data? = nil) throws {
+        let dir = try getKeyDir(email: email)
+        let jsonData = try JSONSerialization.data(withJSONObject: Array(favorites))
+        let dataToWrite: Data
+        if let localKey = localKey {
+            dataToWrite = try CryptoUtils.encryptLocal(jsonData, key: localKey)
+        } else {
+            dataToWrite = jsonData
+        }
+        try writeProtected(dataToWrite, to: dir.appendingPathComponent("favorites.json"))
+    }
+
+    static func loadFavorites(email: String, localKey: Data? = nil) -> Set<String> {
+        guard let dir = try? getKeyDir(email: email) else { return [] }
+        let path = dir.appendingPathComponent("favorites.json")
+        guard let raw = try? Data(contentsOf: path) else { return [] }
+        let jsonData: Data
+        if let localKey = localKey {
+            if let decrypted = try? CryptoUtils.decryptLocal(raw, key: localKey) {
+                jsonData = decrypted
+            } else {
+                jsonData = raw  // migration fallback
+            }
+        } else {
+            jsonData = raw
+        }
+        guard let array = try? JSONSerialization.jsonObject(with: jsonData) as? [String] else {
+            return []
+        }
+        return Set(array)
+    }
+
+    // MARK: - TOFU Identity Key Registry
+
+    static func saveKnownIdentityKeys(email: String, keys: [String: [String: String]], localKey: Data?) throws {
+        let dir = try getKeyDir(email: email)
+        let jsonObj: [String: Any] = ["version": 1, "keys": keys]
+        let jsonData = try JSONSerialization.data(withJSONObject: jsonObj)
+        guard let localKey = localKey else {
+            try writeProtected(jsonData, to: dir.appendingPathComponent("known_identity_keys.bin"))
+            return
+        }
+        let encrypted = try CryptoUtils.encryptLocal(jsonData, key: localKey)
+        try writeProtected(encrypted, to: dir.appendingPathComponent("known_identity_keys.bin"))
+    }
+
+    static func loadKnownIdentityKeys(email: String, localKey: Data?) -> [String: [String: String]] {
+        guard let dir = try? getKeyDir(email: email) else { return [:] }
+        let path = dir.appendingPathComponent("known_identity_keys.bin")
+        guard let raw = try? Data(contentsOf: path) else { return [:] }
+        do {
+            let jsonData: Data
+            if let localKey = localKey {
+                jsonData = try CryptoUtils.decryptLocal(raw, key: localKey)
+            } else {
+                jsonData = raw
+            }
+            guard let obj = try JSONSerialization.jsonObject(with: jsonData) as? [String: Any],
+                  let keys = obj["keys"] as? [String: [String: String]] else { return [:] }
+            return keys
+        } catch {
+            return [:]
+        }
+    }
+
+    // MARK: - Verified Contacts
+
+    static func saveVerifiedContacts(email: String, contacts: [String: [String: String]], localKey: Data?) throws {
+        let dir = try getKeyDir(email: email)
+        let jsonObj: [String: Any] = ["version": 1, "contacts": contacts]
+        let jsonData = try JSONSerialization.data(withJSONObject: jsonObj)
+        guard let localKey = localKey else {
+            try writeProtected(jsonData, to: dir.appendingPathComponent("verified_contacts.bin"))
+            return
+        }
+        let encrypted = try CryptoUtils.encryptLocal(jsonData, key: localKey)
+        try writeProtected(encrypted, to: dir.appendingPathComponent("verified_contacts.bin"))
+    }
+
+    static func loadVerifiedContacts(email: String, localKey: Data?) -> [String: [String: String]] {
+        guard let dir = try? getKeyDir(email: email) else { return [:] }
+        let path = dir.appendingPathComponent("verified_contacts.bin")
+        guard let raw = try? Data(contentsOf: path) else { return [:] }
+        do {
+            let jsonData: Data
+            if let localKey = localKey {
+                jsonData = try CryptoUtils.decryptLocal(raw, key: localKey)
+            } else {
+                jsonData = raw
+            }
+            guard let obj = try JSONSerialization.jsonObject(with: jsonData) as? [String: Any],
+                  let contacts = obj["contacts"] as? [String: [String: String]] else { return [:] }
+            return contacts
+        } catch {
+            return [:]
+        }
+    }
+
+    // MARK: - Helpers
+
+    private static func writeProtected(_ data: Data, to url: URL) throws {
+        try data.write(to: url, options: .completeFileProtection)
+    }
+}

ios_client 0.8.5/Kecalek/Core/KeychainService.swift

@@ -0,0 +1,132 @@
+import Foundation
+import Security
+import LocalAuthentication
+
+enum KeychainService {
+    private static let service = "com.encryptedchat.credentials"
+    private static let account = "userCredentials"
+
+    struct Credentials: Codable {
+        let email: String
+        let password: String
+        let host: String
+        let port: UInt16
+    }
+
+    /// Check if saved credentials exist without triggering biometric prompt.
+    static func hasSavedCredentials() -> Bool {
+        let context = LAContext()
+        context.interactionNotAllowed = true
+
+        let query: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: account,
+            kSecMatchLimit as String: kSecMatchLimitOne,
+            kSecReturnAttributes as String: true,
+            kSecUseAuthenticationContext as String: context
+        ]
+        var result: AnyObject?
+        let status = SecItemCopyMatching(query as CFDictionary, &result)
+        // errSecInteractionNotAllowed means item exists but needs biometric
+        return status == errSecSuccess || status == errSecInteractionNotAllowed
+    }
+
+    /// Save credentials to Keychain with biometric protection.
+    static func saveCredentials(email: String, password: String, host: String, port: UInt16) throws {
+        // Delete any existing entry first
+        deleteCredentials()
+
+        let credentials = Credentials(email: email, password: password, host: host, port: port)
+        let data = try JSONEncoder().encode(credentials)
+
+        var accessError: Unmanaged<CFError>?
+        guard let accessControl = SecAccessControlCreateWithFlags(
+            kCFAllocatorDefault,
+            kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly,
+            .biometryAny,
+            &accessError
+        ) else {
+            throw KeychainError.accessControlCreationFailed
+        }
+
+        let query: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: account,
+            kSecValueData as String: data,
+            kSecAttrAccessControl as String: accessControl
+        ]
+
+        let status = SecItemAdd(query as CFDictionary, nil)
+        guard status == errSecSuccess else {
+            throw KeychainError.saveFailed(status)
+        }
+    }
+
+    /// Load credentials from Keychain. Triggers biometric prompt.
+    static func loadCredentials() throws -> Credentials {
+        let context = LAContext()
+        context.localizedReason = "Unlock to log in"
+
+        let query: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: account,
+            kSecReturnData as String: true,
+            kSecMatchLimit as String: kSecMatchLimitOne,
+            kSecUseAuthenticationContext as String: context
+        ]
+
+        var result: AnyObject?
+        let status = SecItemCopyMatching(query as CFDictionary, &result)
+
+        guard status == errSecSuccess, let data = result as? Data else {
+            if status == errSecUserCanceled || status == errSecAuthFailed {
+                throw KeychainError.biometricFailed
+            }
+            throw KeychainError.loadFailed(status)
+        }
+
+        return try JSONDecoder().decode(Credentials.self, from: data)
+    }
+
+    /// Delete stored credentials from Keychain.
+    @discardableResult
+    static func deleteCredentials() -> Bool {
+        let query: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: service,
+            kSecAttrAccount as String: account
+        ]
+        let status = SecItemDelete(query as CFDictionary)
+        return status == errSecSuccess || status == errSecItemNotFound
+    }
+
+    /// Check if biometric authentication is available on this device.
+    static func isBiometricAvailable() -> Bool {
+        let context = LAContext()
+        var error: NSError?
+        return context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error)
+    }
+
+    enum KeychainError: LocalizedError {
+        case accessControlCreationFailed
+        case saveFailed(OSStatus)
+        case loadFailed(OSStatus)
+        case biometricFailed
+
+        var errorDescription: String? {
+            switch self {
+            case .accessControlCreationFailed:
+                return "Failed to create biometric access control"
+            case .saveFailed(let status):
+                return "Failed to save credentials (error \(status))"
+            case .loadFailed(let status):
+                return "Failed to load credentials (error \(status))"
+            case .biometricFailed:
+                return "Biometric authentication failed or was cancelled"
+            }
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Core/MessageCache.swift

@@ -0,0 +1,200 @@
+import Foundation
+
+/// Encrypted local message cache.
+/// Matches Python: chat_core.py message cache (message_cache/{conv_id}.json)
+enum MessageCache {
+
+    /// Save messages for a conversation (encrypted with local storage key)
+    static func save(email: String, convId: String, messages: [[String: Any]], cacheKey: Data?) throws {
+        let dir = try KeyStorage.getKeyDir(email: email).appendingPathComponent("message_cache")
+        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+
+        let jsonData = try JSONSerialization.data(withJSONObject: messages)
+
+        guard let cacheKey = cacheKey else {
+            return  // Refuse to save plaintext message cache
+        }
+        let dataToWrite = try CryptoUtils.encryptLocal(jsonData, key: cacheKey)
+        try dataToWrite.write(to: dir.appendingPathComponent("\(convId).json"), options: .completeFileProtection)
+    }
+
+    /// Load messages for a conversation
+    static func load(email: String, convId: String, cacheKey: Data?) -> [[String: Any]]? {
+        guard let dir = try? KeyStorage.getKeyDir(email: email) else { return nil }
+        let path = dir.appendingPathComponent("message_cache").appendingPathComponent("\(convId).json")
+        guard let raw = try? Data(contentsOf: path) else { return nil }
+
+        let jsonData: Data
+        if let cacheKey = cacheKey {
+            if let decrypted = try? CryptoUtils.decryptLocal(raw, key: cacheKey) {
+                jsonData = decrypted
+            } else if let parsed = try? JSONSerialization.jsonObject(with: raw) as? [[String: Any]] {
+                // Migration: re-encrypt plaintext cache and return
+                try? save(email: email, convId: convId, messages: parsed, cacheKey: cacheKey)
+                return parsed
+            } else {
+                // Corrupted — delete stale cache
+                try? FileManager.default.removeItem(at: path)
+                return nil
+            }
+        } else {
+            jsonData = raw
+        }
+
+        return try? JSONSerialization.jsonObject(with: jsonData) as? [[String: Any]]
+    }
+
+    /// Search messages in a conversation
+    static func search(email: String, convId: String, query: String, cacheKey: Data?) -> [[String: Any]] {
+        guard let messages = load(email: email, convId: convId, cacheKey: cacheKey) else {
+            return []
+        }
+        let lowerQuery = query.lowercased()
+        return messages.filter { msg in
+            if let text = msg["text"] as? String, text.lowercased().contains(lowerQuery) {
+                return true
+            }
+            return false
+        }
+    }
+
+    /// Delete cache for a conversation
+    static func delete(email: String, convId: String) {
+        guard let dir = try? KeyStorage.getKeyDir(email: email) else { return }
+        let path = dir.appendingPathComponent("message_cache").appendingPathComponent("\(convId).json")
+        try? FileManager.default.removeItem(at: path)
+    }
+
+    // MARK: - Per-Message Cache (for Double Ratchet - messages can only be decrypted once)
+
+    /// Cache a decrypted message by its ID
+    static func cacheDecryptedMessage(email: String, convId: String, messageId: String, plaintext: Data, cacheKey: Data?) {
+        guard let dir = try? KeyStorage.getKeyDir(email: email) else { return }
+        let cacheDir = dir.appendingPathComponent("decrypted_messages").appendingPathComponent(convId)
+        try? FileManager.default.createDirectory(at: cacheDir, withIntermediateDirectories: true)
+
+        let path = cacheDir.appendingPathComponent("\(messageId).bin")
+        do {
+            guard let cacheKey = cacheKey else { return }  // Refuse plaintext
+            let dataToWrite = try CryptoUtils.encryptLocal(plaintext, key: cacheKey)
+            try dataToWrite.write(to: path, options: .completeFileProtection)
+        } catch {
+            #if DEBUG
+            print("DEBUG MessageCache: failed to cache message \(messageId): \(error)")
+            #endif
+        }
+    }
+
+    /// Load all cached decrypted messages for a conversation.
+    /// Returns array of (messageId, plaintext) tuples.
+    static func loadAllCachedMessages(email: String, convId: String, cacheKey: Data?) -> [(String, Data)] {
+        guard let dir = try? KeyStorage.getKeyDir(email: email) else { return [] }
+        let cacheDir = dir.appendingPathComponent("decrypted_messages").appendingPathComponent(convId)
+        guard let files = try? FileManager.default.contentsOfDirectory(at: cacheDir, includingPropertiesForKeys: nil) else { return [] }
+
+        var result: [(String, Data)] = []
+        for file in files where file.pathExtension == "bin" {
+            let messageId = file.deletingPathExtension().lastPathComponent
+            guard let raw = try? Data(contentsOf: file) else { continue }
+            if let cacheKey = cacheKey,
+               let decrypted = try? CryptoUtils.decryptLocal(raw, key: cacheKey) {
+                result.append((messageId, decrypted))
+            } else if cacheKey == nil {
+                result.append((messageId, raw))
+            }
+        }
+        return result
+    }
+
+    /// Get a cached decrypted message by ID
+    static func getCachedMessage(email: String, convId: String, messageId: String, cacheKey: Data?) -> Data? {
+        guard let dir = try? KeyStorage.getKeyDir(email: email) else { return nil }
+        let path = dir.appendingPathComponent("decrypted_messages").appendingPathComponent(convId).appendingPathComponent("\(messageId).bin")
+        guard let raw = try? Data(contentsOf: path) else { return nil }
+
+        if let cacheKey = cacheKey {
+            if let decrypted = try? CryptoUtils.decryptLocal(raw, key: cacheKey) {
+                return decrypted
+            }
+            // Migration: try as plaintext, re-encrypt
+            if let _ = try? JSONSerialization.jsonObject(with: raw) {
+                cacheDecryptedMessage(email: email, convId: convId, messageId: messageId, plaintext: raw, cacheKey: cacheKey)
+                return raw
+            }
+            // Corrupted — delete
+            try? FileManager.default.removeItem(at: path)
+            return nil
+        }
+        return raw
+    }
+
+    // MARK: - Conversation List Cache
+
+    /// Save conversation list to disk (encrypted with local key)
+    static func saveConversations(email: String, conversations: [Conversation], cacheKey: Data?) {
+        guard let cacheKey = cacheKey else { return }
+        guard let dir = try? KeyStorage.getKeyDir(email: email) else { return }
+        do {
+            let jsonData = try JSONEncoder().encode(conversations)
+            let encrypted = try CryptoUtils.encryptLocal(jsonData, key: cacheKey)
+            try encrypted.write(to: dir.appendingPathComponent("conversation_cache.json"), options: .completeFileProtection)
+        } catch {
+            #if DEBUG
+            print("DEBUG MessageCache: failed to save conversations: \(error)")
+            #endif
+        }
+    }
+
+    /// Load conversation list from disk
+    static func loadConversations(email: String, cacheKey: Data?) -> [Conversation]? {
+        guard let cacheKey = cacheKey else { return nil }
+        guard let dir = try? KeyStorage.getKeyDir(email: email) else { return nil }
+        let path = dir.appendingPathComponent("conversation_cache.json")
+        guard let raw = try? Data(contentsOf: path) else { return nil }
+        guard let decrypted = try? CryptoUtils.decryptLocal(raw, key: cacheKey) else { return nil }
+        return try? JSONDecoder().decode([Conversation].self, from: decrypted)
+    }
+
+    // MARK: - Avatar Disk Cache
+
+    /// Save avatar data to disk (encrypted with local key)
+    static func saveAvatar(email: String, key: String, data: Data, cacheKey: Data?) {
+        guard let cacheKey = cacheKey else { return }
+        guard let dir = try? KeyStorage.getKeyDir(email: email) else { return }
+        let cacheDir = dir.appendingPathComponent("avatar_cache")
+        try? FileManager.default.createDirectory(at: cacheDir, withIntermediateDirectories: true)
+        do {
+            let encrypted = try CryptoUtils.encryptLocal(data, key: cacheKey)
+            try encrypted.write(to: cacheDir.appendingPathComponent("\(key).dat"), options: .completeFileProtection)
+        } catch {
+            #if DEBUG
+            print("DEBUG MessageCache: failed to save avatar \(key): \(error)")
+            #endif
+        }
+    }
+
+    /// Load avatar data from disk
+    static func loadAvatar(email: String, key: String, cacheKey: Data?) -> Data? {
+        guard let cacheKey = cacheKey else { return nil }
+        guard let dir = try? KeyStorage.getKeyDir(email: email) else { return nil }
+        let path = dir.appendingPathComponent("avatar_cache").appendingPathComponent("\(key).dat")
+        guard let raw = try? Data(contentsOf: path) else { return nil }
+        return try? CryptoUtils.decryptLocal(raw, key: cacheKey)
+    }
+
+    /// Load all cached avatars from disk
+    static func loadAllAvatars(email: String, cacheKey: Data?) -> [String: Data] {
+        guard let cacheKey = cacheKey else { return [:] }
+        guard let dir = try? KeyStorage.getKeyDir(email: email) else { return [:] }
+        let cacheDir = dir.appendingPathComponent("avatar_cache")
+        guard let files = try? FileManager.default.contentsOfDirectory(at: cacheDir, includingPropertiesForKeys: nil) else { return [:] }
+        var result: [String: Data] = [:]
+        for file in files where file.pathExtension == "dat" {
+            let key = file.deletingPathExtension().lastPathComponent
+            guard let raw = try? Data(contentsOf: file),
+                  let decrypted = try? CryptoUtils.decryptLocal(raw, key: cacheKey) else { continue }
+            result[key] = decrypted
+        }
+        return result
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/ContactVerification.swift

@@ -0,0 +1,162 @@
+import Foundation
+import CryptoKit
+
+/// Contact key verification: fingerprints, safety numbers, QR codes.
+/// Matches Python: crypto_utils.py compute_fingerprint, compute_safety_number, etc.
+enum ContactVerification {
+
+    /// Version byte for fingerprint computation (Signal's NumericFingerprint).
+    private static let fingerprintVersion: UInt16 = 0
+
+    /// Number of SHA-512 iterations for fingerprint computation.
+    private static let fingerprintIterations = 5200
+
+    // MARK: - Fingerprint
+
+    /// Compute a 32-byte fingerprint for a user's identity key.
+    ///
+    /// Uses iterated SHA-512 (Signal's NumericFingerprint algorithm).
+    /// Seed: version(2B big-endian) + identity_key(32B) + user_id(UTF-8).
+    /// Each iteration: SHA-512(previous_hash + identity_key).
+    /// Output: first 32 bytes of final hash.
+    static func computeFingerprint(userId: String, identityKey: Data, iterations: Int = fingerprintIterations) -> Data {
+        let versionBytes = fingerprintVersion.bigEndianData
+        var data = versionBytes + identityKey + Data(userId.utf8)
+        for _ in 0..<iterations {
+            var hasher = SHA512()
+            hasher.update(data: data)
+            hasher.update(data: identityKey)
+            let digest = hasher.finalize()
+            data = Data(digest)
+        }
+        return Data(data.prefix(32))
+    }
+
+    /// Format 32-byte fingerprint as 6 groups of 5 zero-padded digits (30 digits).
+    ///
+    /// Each group: int(bytes[i*5:(i+1)*5], big-endian) % 100000.
+    /// Output: two lines of 3 groups each, space-separated.
+    static func formatFingerprint(_ fpBytes: Data) -> String {
+        var groups: [String] = []
+        for i in 0..<6 {
+            let start = i * 5
+            let end = min(start + 5, fpBytes.count)
+            let slice = fpBytes[fpBytes.startIndex + start ..< fpBytes.startIndex + end]
+            let num = bigEndianUInt64(slice) % 100000
+            groups.append(String(format: "%05d", num))
+        }
+        return groups[0..<3].joined(separator: " ") + "\n" + groups[3..<6].joined(separator: " ")
+    }
+
+    // MARK: - Safety Number
+
+    /// Compute a 60-digit safety number for a pair of users.
+    ///
+    /// Both users see the same number regardless of who computes it.
+    /// Lower user_id's fingerprint comes first (deterministic ordering).
+    /// Output: 12 groups of 5 digits, formatted as 3 lines of 4 groups.
+    static func computeSafetyNumber(
+        myUserId: String, myIdentityKey: Data,
+        theirUserId: String, theirIdentityKey: Data
+    ) -> String {
+        let fpMine = computeFingerprint(userId: myUserId, identityKey: myIdentityKey)
+        let fpTheirs = computeFingerprint(userId: theirUserId, identityKey: theirIdentityKey)
+
+        let combined: Data
+        if myUserId < theirUserId {
+            combined = fpMine + fpTheirs
+        } else {
+            combined = fpTheirs + fpMine
+        }
+
+        // 64 bytes -> 12 groups of 5 digits
+        var groups: [String] = []
+        for i in 0..<12 {
+            let start = i * 5
+            let end = min(start + 5, combined.count)
+            let slice = combined[combined.startIndex + start ..< combined.startIndex + end]
+            let num = bigEndianUInt64(slice) % 100000
+            groups.append(String(format: "%05d", num))
+        }
+
+        return [
+            groups[0..<4].joined(separator: " "),
+            groups[4..<8].joined(separator: " "),
+            groups[8..<12].joined(separator: " "),
+        ].joined(separator: "\n")
+    }
+
+    // MARK: - QR Code
+
+    /// Encode user identity for QR code verification.
+    ///
+    /// Format: version(1B=0x01) + uid_len(1B) + uid(UTF-8) + identity_key(32B).
+    static func encodeVerificationQR(userId: String, identityKey: Data) -> Data {
+        let uidBytes = Data(userId.utf8)
+        var data = Data([0x01, UInt8(uidBytes.count)])
+        data.append(uidBytes)
+        data.append(identityKey)
+        return data
+    }
+
+    /// Decode QR code verification payload.
+    ///
+    /// Returns (userId, identityKey).
+    /// Throws on invalid format.
+    static func decodeVerificationQR(_ data: Data) throws -> (userId: String, identityKey: Data) {
+        guard data.count >= 3 else {
+            throw VerificationError.qrDataTooShort
+        }
+        guard data[data.startIndex] == 0x01 else {
+            throw VerificationError.unknownQRVersion(data[data.startIndex])
+        }
+        let uidLen = Int(data[data.startIndex + 1])
+        guard data.count >= 2 + uidLen + 32 else {
+            throw VerificationError.qrDataTruncated
+        }
+        let uidData = data[data.startIndex + 2 ..< data.startIndex + 2 + uidLen]
+        guard let userId = String(data: uidData, encoding: .utf8) else {
+            throw VerificationError.invalidUTF8
+        }
+        let identityKey = Data(data[data.startIndex + 2 + uidLen ..< data.startIndex + 2 + uidLen + 32])
+        return (userId, identityKey)
+    }
+
+    // MARK: - Helpers
+
+    /// Convert up to 8 bytes to UInt64, big-endian.
+    private static func bigEndianUInt64(_ data: Data) -> UInt64 {
+        var result: UInt64 = 0
+        for byte in data {
+            result = result << 8 | UInt64(byte)
+        }
+        return result
+    }
+}
+
+// MARK: - UInt16 Big-Endian
+
+private extension UInt16 {
+    var bigEndianData: Data {
+        var value = self.bigEndian
+        return Data(bytes: &value, count: 2)
+    }
+}
+
+// MARK: - Verification Errors
+
+enum VerificationError: Error, LocalizedError {
+    case qrDataTooShort
+    case unknownQRVersion(UInt8)
+    case qrDataTruncated
+    case invalidUTF8
+
+    var errorDescription: String? {
+        switch self {
+        case .qrDataTooShort: return "QR data too short"
+        case .unknownQRVersion(let v): return "Unknown QR version: \(v)"
+        case .qrDataTruncated: return "QR data truncated"
+        case .invalidUTF8: return "Invalid UTF-8 in QR data"
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/CryptoErrors.swift

@@ -0,0 +1,95 @@
+import Foundation
+
+enum CryptoError: Error, LocalizedError {
+    case invalidBase64
+    case invalidHex
+    case invalidKeyData(String)
+    case invalidSignature
+    case signatureVerificationFailed
+    case encryptionFailed(String)
+    case decryptionFailed(String)
+    case invalidECP1Format
+    case pbkdf2Failed
+    case rsaKeyGenerationFailed
+    case rsaOperationFailed(String)
+    case x3dhFailed(String)
+    case ratchetError(String)
+    case senderKeyError(String)
+    case maxSkipExceeded
+    case duplicateMessage
+    case invalidHeader(String)
+    case stateImportFailed(String)
+    case keyConversionFailed(String)
+
+    var errorDescription: String? {
+        switch self {
+        case .invalidBase64: return "Invalid base64 encoding"
+        case .invalidHex: return "Invalid hex encoding"
+        case .invalidKeyData(let msg): return "Invalid key data: \(msg)"
+        case .invalidSignature: return "Invalid signature format"
+        case .signatureVerificationFailed: return "Signature verification failed"
+        case .encryptionFailed(let msg): return "Encryption failed: \(msg)"
+        case .decryptionFailed(let msg): return "Decryption failed: \(msg)"
+        case .invalidECP1Format: return "Invalid ECP1 key format"
+        case .pbkdf2Failed: return "PBKDF2 key derivation failed"
+        case .rsaKeyGenerationFailed: return "RSA key generation failed"
+        case .rsaOperationFailed(let msg): return "RSA operation failed: \(msg)"
+        case .x3dhFailed(let msg): return "X3DH failed: \(msg)"
+        case .ratchetError(let msg): return "Ratchet error: \(msg)"
+        case .senderKeyError(let msg): return "Sender key error: \(msg)"
+        case .maxSkipExceeded: return "Maximum message skip exceeded"
+        case .duplicateMessage: return "Duplicate message detected"
+        case .invalidHeader(let msg): return "Invalid header: \(msg)"
+        case .stateImportFailed(let msg): return "State import failed: \(msg)"
+        case .keyConversionFailed(let msg): return "Key conversion failed: \(msg)"
+        }
+    }
+}
+
+enum NetworkError: Error, LocalizedError {
+    case notConnected
+    case connectionFailed(String)
+    case timeout
+    case serverError(String)
+    case protocolError(String)
+    case messageTooLarge
+    case invalidResponse(String)
+    case authenticationFailed(String)
+    case alreadyConnected
+
+    var errorDescription: String? {
+        switch self {
+        case .notConnected: return "Not connected to server"
+        case .connectionFailed(let msg): return "Connection failed: \(msg)"
+        case .timeout: return "Request timed out"
+        case .serverError(let msg): return "Server error: \(msg)"
+        case .protocolError(let msg): return "Protocol error: \(msg)"
+        case .messageTooLarge: return "Message exceeds maximum size"
+        case .invalidResponse(let msg): return "Invalid response: \(msg)"
+        case .authenticationFailed(let msg): return "Authentication failed: \(msg)"
+        case .alreadyConnected: return "Already connected"
+        }
+    }
+}
+
+enum ChatError: Error, LocalizedError {
+    case notLoggedIn
+    case conversationNotFound
+    case membershipRequired
+    case permissionDenied(String)
+    case operationFailed(String)
+    case fileError(String)
+    case invalidData(String)
+
+    var errorDescription: String? {
+        switch self {
+        case .notLoggedIn: return "Not logged in"
+        case .conversationNotFound: return "Conversation not found"
+        case .membershipRequired: return "Must be a member of this conversation"
+        case .permissionDenied(let msg): return "Permission denied: \(msg)"
+        case .operationFailed(let msg): return "Operation failed: \(msg)"
+        case .fileError(let msg): return "File error: \(msg)"
+        case .invalidData(let msg): return "Invalid data: \(msg)"
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/CryptoUtils.swift

@@ -0,0 +1,196 @@
+import Foundation
+import CryptoKit
+
+/// Core cryptographic utilities: AES-GCM, HKDF, KDF helpers
+enum CryptoUtils {
+
+    // MARK: - AES-256-GCM
+
+    /// Encrypt with AES-256-GCM. Returns (key, nonce, ciphertext, tag) — all as Data.
+    /// If key is nil, generates a random 256-bit key.
+    /// Matches Python: aes_encrypt(plaintext, key=None)
+    static func aesEncrypt(_ plaintext: Data, key: Data? = nil) throws -> (key: Data, nonce: Data, ciphertext: Data, tag: Data) {
+        let keyData = key ?? Data.randomBytes(32)
+        let symmetricKey = SymmetricKey(data: keyData)
+        let nonceData = Data.randomBytes(12)
+        let gcmNonce = try AES.GCM.Nonce(data: nonceData)
+
+        let sealedBox = try AES.GCM.seal(plaintext, using: symmetricKey, nonce: gcmNonce)
+
+        return (
+            key: keyData,
+            nonce: nonceData,
+            ciphertext: Data(sealedBox.ciphertext),
+            tag: Data(sealedBox.tag)
+        )
+    }
+
+    /// Decrypt with AES-256-GCM.
+    /// Matches Python: aes_decrypt(key, nonce, ciphertext, tag)
+    static func aesDecrypt(key: Data, nonce: Data, ciphertext: Data, tag: Data) throws -> Data {
+        let symmetricKey = SymmetricKey(data: key)
+        let gcmNonce = try AES.GCM.Nonce(data: nonce)
+
+        let sealedBox = try AES.GCM.SealedBox(
+            nonce: gcmNonce,
+            ciphertext: ciphertext,
+            tag: tag
+        )
+
+        do {
+            return try AES.GCM.open(sealedBox, using: symmetricKey)
+        } catch {
+            throw CryptoError.decryptionFailed("AES-GCM decryption failed")
+        }
+    }
+
+    /// Encrypt with AES-256-GCM using AAD. Returns ciphertext with tag appended.
+    /// Used by Double Ratchet and Sender Keys.
+    static func aesGcmEncrypt(_ plaintext: Data, key: Data, nonce: Data, aad: Data) throws -> Data {
+        let symmetricKey = SymmetricKey(data: key)
+        let gcmNonce = try AES.GCM.Nonce(data: nonce)
+
+        let sealedBox = try AES.GCM.seal(
+            plaintext,
+            using: symmetricKey,
+            nonce: gcmNonce,
+            authenticating: aad
+        )
+
+        // Return ciphertext + tag concatenated (matches Python AESGCM.encrypt)
+        return Data(sealedBox.ciphertext) + Data(sealedBox.tag)
+    }
+
+    /// Decrypt AES-256-GCM with AAD. Input ciphertext has tag appended (last 16 bytes).
+    static func aesGcmDecrypt(_ ctWithTag: Data, key: Data, nonce: Data, aad: Data) throws -> Data {
+        guard ctWithTag.count >= 16 else {
+            throw CryptoError.decryptionFailed("Ciphertext too short")
+        }
+
+        let ct = ctWithTag.prefix(ctWithTag.count - 16)
+        let tag = ctWithTag.suffix(16)
+
+        let symmetricKey = SymmetricKey(data: key)
+        let gcmNonce = try AES.GCM.Nonce(data: nonce)
+
+        let sealedBox = try AES.GCM.SealedBox(
+            nonce: gcmNonce,
+            ciphertext: ct,
+            tag: tag
+        )
+
+        do {
+            return try AES.GCM.open(sealedBox, using: symmetricKey, authenticating: aad)
+        } catch {
+            throw CryptoError.decryptionFailed("AES-GCM decryption with AAD failed")
+        }
+    }
+
+    // MARK: - HKDF
+
+    /// HKDF-SHA256 key derivation.
+    /// Matches Python: hkdf_derive(input_key, salt, info, length=32)
+    static func hkdfDerive(inputKey: Data, salt: Data, info: Data, length: Int = 32) -> Data {
+        let symmetricKey = SymmetricKey(data: inputKey)
+        let derived = HKDF<SHA256>.deriveKey(
+            inputKeyMaterial: symmetricKey,
+            salt: salt,
+            info: info,
+            outputByteCount: length
+        )
+        return derived.withUnsafeBytes { Data($0) }
+    }
+
+    // MARK: - KDF for Double Ratchet
+
+    /// Root key KDF. Returns (newRootKey, chainKey).
+    /// HKDF with rootKey as salt and DH output as input. Derives 64 bytes, split in half.
+    /// Matches Python: kdf_rk(root_key, dh_output)
+    static func kdfRK(rootKey: Data, dhOutput: Data) -> (newRootKey: Data, chainKey: Data) {
+        let derived = hkdfDerive(
+            inputKey: dhOutput,
+            salt: rootKey,
+            info: Data(Constants.rootKeyInfo.utf8),
+            length: 64
+        )
+        return (derived.prefix(32), Data(derived.suffix(32)))
+    }
+
+    /// Chain key KDF. Returns (newChainKey, messageKey).
+    /// HMAC-SHA256: messageKey = HMAC(chainKey, 0x01), newChainKey = HMAC(chainKey, 0x02)
+    /// Matches Python: kdf_ck(chain_key)
+    static func kdfCK(chainKey: Data) -> (newChainKey: Data, messageKey: Data) {
+        let symmetricKey = SymmetricKey(data: chainKey)
+        let messageKey = Data(HMAC<SHA256>.authenticationCode(for: Data([0x01]), using: symmetricKey))
+        let newChainKey = Data(HMAC<SHA256>.authenticationCode(for: Data([0x02]), using: symmetricKey))
+        return (newChainKey, messageKey)
+    }
+
+    // MARK: - Self-Encryption Key
+
+    /// Derive static AES-256 key from identity key for self-encrypted message copies.
+    /// Matches Python: derive_self_encryption_key(identity_private)
+    static func deriveSelfEncryptionKey(identityPrivateRaw: Data) -> Data {
+        hkdfDerive(
+            inputKey: identityPrivateRaw,
+            salt: Data(Constants.selfEncryptionSalt.utf8),
+            info: Data(Constants.selfEncryptionInfo.utf8),
+            length: 32
+        )
+    }
+
+    // MARK: - Local Storage Key
+
+    /// Derive AES-256 key for encrypting local session/sender key files.
+    /// Matches Python: derive_local_storage_key(identity_private)
+    static func deriveLocalStorageKey(identityPrivateRaw: Data) -> Data {
+        hkdfDerive(
+            inputKey: identityPrivateRaw,
+            salt: Data(Constants.localStorageSalt.utf8),
+            info: Data(Constants.localStorageInfo.utf8),
+            length: 32
+        )
+    }
+
+    // MARK: - Local File Encryption
+
+    /// Encrypt data for local storage. Format: nonce(12) + tag(16) + ciphertext
+    /// Matches Python: _encrypt_local(data, key)
+    static func encryptLocal(_ data: Data, key: Data) throws -> Data {
+        let symmetricKey = SymmetricKey(data: key)
+        let sealedBox = try AES.GCM.seal(data, using: symmetricKey)
+
+        var result = Data()
+        result.append(Data(sealedBox.nonce))       // 12 bytes
+        result.append(Data(sealedBox.tag))          // 16 bytes
+        result.append(Data(sealedBox.ciphertext))   // N bytes
+        return result
+    }
+
+    /// Decrypt locally stored data. Format: nonce(12) + tag(16) + ciphertext
+    /// Matches Python: _decrypt_local(raw, key)
+    static func decryptLocal(_ raw: Data, key: Data) throws -> Data {
+        guard raw.count >= 28 else {  // 12 + 16 minimum
+            throw CryptoError.decryptionFailed("Local encrypted data too short")
+        }
+
+        let nonce = raw[0..<12]
+        let tag = raw[12..<28]
+        let ct = raw[28...]
+
+        let symmetricKey = SymmetricKey(data: key)
+        let gcmNonce = try AES.GCM.Nonce(data: nonce)
+
+        let sealedBox = try AES.GCM.SealedBox(
+            nonce: gcmNonce,
+            ciphertext: ct,
+            tag: tag
+        )
+
+        do {
+            return try AES.GCM.open(sealedBox, using: symmetricKey)
+        } catch {
+            throw CryptoError.decryptionFailed("Local storage decryption failed")
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/DoubleRatchet.swift

@@ -0,0 +1,393 @@
+import Foundation
+import CryptoKit
+
+/// Ratchet header sent with each message
+struct RatchetHeader {
+    let dhPub: Data   // sender's current ratchet public key (32 bytes)
+    let n: Int        // message number in current sending chain
+    let pn: Int       // number of messages in previous sending chain
+
+    /// Serialize header to JSON bytes for use as AAD.
+    /// Matches Python: RatchetHeader.serialize()
+    /// IMPORTANT: Must match Python's json.dumps() format exactly (with spaces after : and ,)
+    func serialize() -> Data {
+        // Python json.dumps produces: {"dh_pub": "...", "n": 0, "pn": 0}
+        // Note the spaces after colons and commas - this is critical for AAD matching
+        let jsonString = "{\"dh_pub\": \"\(dhPub.hexString)\", \"n\": \(n), \"pn\": \(pn)}"
+        return jsonString.data(using: .utf8)!
+    }
+
+    /// Convert to dictionary for protocol.
+    /// Matches Python: RatchetHeader.to_dict()
+    func toDict() -> [String: Any] {
+        [
+            "dh_pub": dhPub.hexString,
+            "n": n,
+            "pn": pn,
+        ]
+    }
+
+    /// Parse from dictionary.
+    /// Matches Python: RatchetHeader.from_dict(d)
+    static func fromDict(_ d: [String: Any]) throws -> RatchetHeader {
+        guard let dhPubHex = d["dh_pub"] as? String,
+              let dhPub = Data(hexString: dhPubHex),
+              let n = d["n"] as? Int,
+              let pn = d["pn"] as? Int else {
+            throw CryptoError.invalidHeader("Missing or invalid header fields")
+        }
+        return RatchetHeader(dhPub: dhPub, n: n, pn: pn)
+    }
+}
+
+/// Signal Double Ratchet implementation.
+/// Matches Python: DoubleRatchet class in crypto_utils.py
+class DoubleRatchet {
+
+    private(set) var dhPair: (privateKey: Curve25519.KeyAgreement.PrivateKey,
+                               publicKey: Curve25519.KeyAgreement.PublicKey)?
+    private(set) var dhRemote: Curve25519.KeyAgreement.PublicKey?
+    private(set) var rootKey: Data = Data()
+    private(set) var sendChainKey: Data?
+    private(set) var recvChainKey: Data?
+    private(set) var sendN: Int = 0
+    private(set) var recvN: Int = 0
+    private(set) var prevSendN: Int = 0
+    // Skipped message keys: "dh_pub_hex:n" → message_key
+    private(set) var skipped: [String: Data] = [:]
+
+    /// Attached X3DH header — set when creating a new session, consumed on first send.
+    /// Matches Python: ratchet._x3dh_header
+    var x3dhHeader: [String: Any]?
+
+    init() {}
+
+    // MARK: - Initialization
+
+    /// Initialize as initiator (Alice) after X3DH.
+    /// Matches Python: DoubleRatchet.init_alice(shared_secret, bob_spk_pub)
+    static func initAlice(sharedSecret: Data, bobSpkPub: Curve25519.KeyAgreement.PublicKey) throws -> DoubleRatchet {
+        let ratchet = DoubleRatchet()
+        let (priv, pub) = X25519Crypto.generateKeypair()
+        ratchet.dhPair = (priv, pub)
+        ratchet.dhRemote = bobSpkPub
+
+        // Debug: print ratchet inputs (matching Python _dh_ratchet)
+        #if DEBUG
+        print("DEBUG initAlice: shared_secret (root_key) = \(sharedSecret.hexString)")
+        print("DEBUG initAlice: my_dh_pub = \(X25519Crypto.serializePublic(pub).hexString)")
+        print("DEBUG initAlice: remote_dh_pub (bob_spk) = \(X25519Crypto.serializePublic(bobSpkPub).hexString)")
+        #endif
+
+        // Perform DH ratchet to derive send chain
+        let dhOutput = try X25519Crypto.dh(priv, bobSpkPub)
+        let (newRK, sendCK) = CryptoUtils.kdfRK(rootKey: sharedSecret, dhOutput: dhOutput)
+        #if DEBUG
+        print("DEBUG initAlice: dh_output = \(dhOutput.hexString)")
+        print("DEBUG initAlice: new_root_key = \(newRK.hexString)")
+        print("DEBUG initAlice: send_chain_key = \(sendCK.hexString)")
+        #endif
+        ratchet.rootKey = newRK
+        ratchet.sendChainKey = sendCK
+        ratchet.recvChainKey = nil
+        ratchet.sendN = 0
+        ratchet.recvN = 0
+        ratchet.prevSendN = 0
+        return ratchet
+    }
+
+    /// Initialize as responder (Bob) after X3DH.
+    /// Matches Python: DoubleRatchet.init_bob(shared_secret, spk_pair)
+    static func initBob(
+        sharedSecret: Data,
+        spkPair: (privateKey: Curve25519.KeyAgreement.PrivateKey, publicKey: Curve25519.KeyAgreement.PublicKey)
+    ) -> DoubleRatchet {
+        let ratchet = DoubleRatchet()
+        ratchet.dhPair = spkPair
+        ratchet.rootKey = sharedSecret
+        ratchet.sendChainKey = nil
+        ratchet.recvChainKey = nil
+        ratchet.sendN = 0
+        ratchet.recvN = 0
+        ratchet.prevSendN = 0
+        return ratchet
+    }
+
+    // MARK: - Encrypt
+
+    /// Encrypt a message.
+    /// Returns (header dict, ciphertext with tag, nonce).
+    /// Matches Python: DoubleRatchet.encrypt(plaintext)
+    func encrypt(_ plaintext: Data) throws -> (header: [String: Any], ciphertext: Data, nonce: Data) {
+        guard sendChainKey != nil else {
+            throw CryptoError.ratchetError("Send chain not initialized")
+        }
+        guard let dhPair = dhPair else {
+            throw CryptoError.ratchetError("DH pair not set")
+        }
+
+        let (newCK, messageKey) = CryptoUtils.kdfCK(chainKey: sendChainKey!)
+        sendChainKey = newCK
+
+        let header = RatchetHeader(
+            dhPub: X25519Crypto.serializePublic(dhPair.publicKey),
+            n: sendN,
+            pn: prevSendN
+        )
+
+        let nonce = Data.randomBytes(12)
+        let aad = header.serialize()
+
+        // Debug: print encrypt values (matching Python decrypt)
+        #if DEBUG
+        print("DEBUG encrypt: message_key = \(messageKey.hexString)")
+        print("DEBUG encrypt: aad = \(aad.hexString)")
+        print("DEBUG encrypt: aad_str = \(String(data: aad, encoding: .utf8) ?? "nil")")
+        print("DEBUG encrypt: nonce = \(nonce.hexString)")
+        #endif
+
+        let ctWithTag = try CryptoUtils.aesGcmEncrypt(plaintext, key: messageKey, nonce: nonce, aad: aad)
+        #if DEBUG
+        print("DEBUG encrypt: ciphertext_len = \(ctWithTag.count)")
+        #endif
+
+        sendN += 1
+
+        return (header.toDict(), ctWithTag, nonce)
+    }
+
+    // MARK: - Decrypt
+
+    /// Decrypt a message. Handles DH ratchet step if new dh_pub.
+    /// State is snapshotted before modification and restored on failure (M9 fix).
+    /// Matches Python: DoubleRatchet.decrypt(header_dict, ciphertext, nonce)
+    func decrypt(headerDict: [String: Any], ciphertext: Data, nonce: Data) throws -> Data {
+        let header = try RatchetHeader.fromDict(headerDict)
+        let remoteDhPubBytes = header.dhPub
+
+        // Check if this is from a skipped message
+        let skipKey = "\(remoteDhPubBytes.hexString):\(header.n)"
+        if let mk = skipped[skipKey] {
+            skipped.removeValue(forKey: skipKey)
+            let aad = header.serialize()
+            do {
+                return try CryptoUtils.aesGcmDecrypt(ciphertext, key: mk, nonce: nonce, aad: aad)
+            } catch {
+                // Restore skipped key on failure
+                skipped[skipKey] = mk
+                throw error
+            }
+        }
+
+        // Snapshot state before modifications
+        let snap = snapshot()
+
+        do {
+            let remoteDhPub = try X25519Crypto.loadPublic(remoteDhPubBytes)
+            let currentRemoteBytes: Data? = dhRemote.map { X25519Crypto.serializePublic($0) }
+
+            if currentRemoteBytes == nil || remoteDhPubBytes != currentRemoteBytes {
+                // New DH ratchet step
+                try skipMessages(until: header.pn)
+                try dhRatchet(remoteDhPub: remoteDhPub)
+            }
+
+            try skipMessages(until: header.n)
+
+            // Derive message key from receive chain
+            guard recvChainKey != nil else {
+                throw CryptoError.ratchetError("Receive chain key is nil")
+            }
+            let (newCK, mk) = CryptoUtils.kdfCK(chainKey: recvChainKey!)
+            recvChainKey = newCK
+            recvN += 1
+
+            let aad = header.serialize()
+            return try CryptoUtils.aesGcmDecrypt(ciphertext, key: mk, nonce: nonce, aad: aad)
+        } catch {
+            restore(snap)
+            throw error
+        }
+    }
+
+    // MARK: - State Snapshot/Restore (M9)
+
+    private struct Snapshot {
+        let dhPairPriv: Data?
+        let dhPairPub: Data?
+        let dhRemote: Data?
+        let rootKey: Data
+        let sendChainKey: Data?
+        let recvChainKey: Data?
+        let sendN: Int
+        let recvN: Int
+        let prevSendN: Int
+        let skipped: [String: Data]
+    }
+
+    private func snapshot() -> Snapshot {
+        Snapshot(
+            dhPairPriv: dhPair.map { X25519Crypto.serializePrivate($0.privateKey) },
+            dhPairPub: dhPair.map { X25519Crypto.serializePublic($0.publicKey) },
+            dhRemote: dhRemote.map { X25519Crypto.serializePublic($0) },
+            rootKey: rootKey,
+            sendChainKey: sendChainKey,
+            recvChainKey: recvChainKey,
+            sendN: sendN,
+            recvN: recvN,
+            prevSendN: prevSendN,
+            skipped: skipped
+        )
+    }
+
+    private func restore(_ snap: Snapshot) {
+        if let privData = snap.dhPairPriv, let pubData = snap.dhPairPub,
+           let priv = try? X25519Crypto.loadPrivate(privData),
+           let pub = try? X25519Crypto.loadPublic(pubData) {
+            dhPair = (priv, pub)
+        } else {
+            dhPair = nil
+        }
+        if let remoteData = snap.dhRemote, let remote = try? X25519Crypto.loadPublic(remoteData) {
+            dhRemote = remote
+        } else {
+            dhRemote = nil
+        }
+        rootKey = snap.rootKey
+        sendChainKey = snap.sendChainKey
+        recvChainKey = snap.recvChainKey
+        sendN = snap.sendN
+        recvN = snap.recvN
+        prevSendN = snap.prevSendN
+        skipped = snap.skipped
+    }
+
+    // MARK: - Internal Ratchet Operations
+
+    private func skipMessages(until: Int) throws {
+        guard recvChainKey != nil else { return }
+        if until - recvN > Constants.maxSkip {
+            throw CryptoError.maxSkipExceeded
+        }
+        while recvN < until {
+            let (newCK, mk) = CryptoUtils.kdfCK(chainKey: recvChainKey!)
+            recvChainKey = newCK
+            let remoteHex = dhRemote.map { X25519Crypto.serializePublic($0).hexString } ?? ""
+            skipped["\(remoteHex):\(recvN)"] = mk
+            recvN += 1
+        }
+    }
+
+    private func dhRatchet(remoteDhPub: Curve25519.KeyAgreement.PublicKey) throws {
+        prevSendN = sendN
+        sendN = 0
+        recvN = 0
+        dhRemote = remoteDhPub
+
+        // Derive new receive chain key
+        guard let dhPair = dhPair else {
+            throw CryptoError.ratchetError("DH pair not set")
+        }
+        let dhOutput1 = try X25519Crypto.dh(dhPair.privateKey, remoteDhPub)
+        let (newRK1, recvCK) = CryptoUtils.kdfRK(rootKey: rootKey, dhOutput: dhOutput1)
+        rootKey = newRK1
+        recvChainKey = recvCK
+
+        // Generate new DH pair and derive new send chain key
+        let (newPriv, newPub) = X25519Crypto.generateKeypair()
+        self.dhPair = (newPriv, newPub)
+        let dhOutput2 = try X25519Crypto.dh(newPriv, remoteDhPub)
+        let (newRK2, sendCK) = CryptoUtils.kdfRK(rootKey: rootKey, dhOutput: dhOutput2)
+        rootKey = newRK2
+        sendChainKey = sendCK
+    }
+
+    // MARK: - State Export/Import
+
+    /// Serialize full ratchet state for persistent storage.
+    /// Produces JSON matching Python's DoubleRatchet.export_state() exactly.
+    func exportState() throws -> Data {
+        var state: [String: Any] = [:]
+
+        if let pair = dhPair {
+            state["dh_priv"] = X25519Crypto.serializePrivate(pair.privateKey).hexString
+            state["dh_pub"] = X25519Crypto.serializePublic(pair.publicKey).hexString
+        } else {
+            state["dh_priv"] = NSNull()
+            state["dh_pub"] = NSNull()
+        }
+
+        if let remote = dhRemote {
+            state["dh_remote"] = X25519Crypto.serializePublic(remote).hexString
+        } else {
+            state["dh_remote"] = NSNull()
+        }
+
+        state["root_key"] = rootKey.hexString
+        state["send_ck"] = sendChainKey?.hexString ?? NSNull()
+        state["recv_ck"] = recvChainKey?.hexString ?? NSNull()
+        state["send_n"] = sendN
+        state["recv_n"] = recvN
+        state["prev_send_n"] = prevSendN
+
+        // Skipped keys: Python format is "dh_pub_hex:n" -> message_key_hex
+        var skippedDict: [String: String] = [:]
+        for (key, value) in skipped {
+            skippedDict[key] = value.hexString
+        }
+        state["skipped"] = skippedDict
+
+        return try JSONSerialization.data(withJSONObject: state)
+    }
+
+    /// Deserialize ratchet state.
+    /// Matches Python: DoubleRatchet.import_state(data)
+    static func importState(_ data: Data) throws -> DoubleRatchet {
+        guard let state = try JSONSerialization.jsonObject(with: data) as? [String: Any] else {
+            throw CryptoError.stateImportFailed("Invalid JSON")
+        }
+
+        let r = DoubleRatchet()
+
+        if let dhPrivHex = state["dh_priv"] as? String,
+           let dhPubHex = state["dh_pub"] as? String,
+           let privData = Data(hexString: dhPrivHex),
+           let pubData = Data(hexString: dhPubHex) {
+            let priv = try X25519Crypto.loadPrivate(privData)
+            let pub = try X25519Crypto.loadPublic(pubData)
+            r.dhPair = (priv, pub)
+        }
+
+        if let dhRemoteHex = state["dh_remote"] as? String,
+           let remoteData = Data(hexString: dhRemoteHex) {
+            r.dhRemote = try X25519Crypto.loadPublic(remoteData)
+        }
+
+        guard let rootKeyHex = state["root_key"] as? String,
+              let rootKey = Data(hexString: rootKeyHex) else {
+            throw CryptoError.stateImportFailed("Missing root_key")
+        }
+        r.rootKey = rootKey
+
+        if let sendCKHex = state["send_ck"] as? String, let ck = Data(hexString: sendCKHex) {
+            r.sendChainKey = ck
+        }
+        if let recvCKHex = state["recv_ck"] as? String, let ck = Data(hexString: recvCKHex) {
+            r.recvChainKey = ck
+        }
+
+        r.sendN = state["send_n"] as? Int ?? 0
+        r.recvN = state["recv_n"] as? Int ?? 0
+        r.prevSendN = state["prev_send_n"] as? Int ?? 0
+
+        if let skippedDict = state["skipped"] as? [String: String] {
+            for (key, valueHex) in skippedDict {
+                if let value = Data(hexString: valueHex) {
+                    r.skipped[key] = value
+                }
+            }
+        }
+
+        return r
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/Ed25519Crypto.swift

@@ -0,0 +1,73 @@
+import Foundation
+import CryptoKit
+
+/// Ed25519 signing operations — Identity Key management
+enum Ed25519Crypto {
+
+    // MARK: - Key Generation
+
+    /// Generate Ed25519 keypair
+    static func generateKeypair() -> (privateKey: Curve25519.Signing.PrivateKey, publicKey: Curve25519.Signing.PublicKey) {
+        let privateKey = Curve25519.Signing.PrivateKey()
+        return (privateKey, privateKey.publicKey)
+    }
+
+    // MARK: - Serialization
+
+    /// Serialize Ed25519 private key. With password: raw 32B → ECP1. Without: raw 32B.
+    /// Matches Python: serialize_ed25519_private(key, password=None)
+    static func serializePrivate(_ key: Curve25519.Signing.PrivateKey, password: Data? = nil) throws -> Data {
+        let raw = key.rawData  // 32 bytes
+        if let password = password {
+            return try KeyEncryption.encrypt(raw, password: password)
+        }
+        return raw
+    }
+
+    /// Serialize Ed25519 public key to 32 raw bytes.
+    /// Matches Python: serialize_ed25519_public(key)
+    static func serializePublic(_ key: Curve25519.Signing.PublicKey) -> Data {
+        key.rawData  // 32 bytes
+    }
+
+    // MARK: - Loading
+
+    /// Load Ed25519 private key. Auto-detects ECP1 / raw 32B.
+    /// Matches Python: load_ed25519_private(data, password=None)
+    static func loadPrivate(_ data: Data, password: Data? = nil) throws -> Curve25519.Signing.PrivateKey {
+        if KeyEncryption.isECP1Format(data) {
+            guard let pwd = password else {
+                throw CryptoError.invalidKeyData("ECP1 key requires password")
+            }
+            let raw = try KeyEncryption.decrypt(data, password: pwd)
+            return try Curve25519.Signing.PrivateKey(rawRepresentation: raw)
+        }
+        if data.count == 32 {
+            return try Curve25519.Signing.PrivateKey(rawRepresentation: data)
+        }
+        throw CryptoError.invalidKeyData("Cannot parse Ed25519 private key (\(data.count) bytes)")
+    }
+
+    /// Load Ed25519 public key from 32 raw bytes.
+    /// Matches Python: load_ed25519_public(data)
+    static func loadPublic(_ data: Data) throws -> Curve25519.Signing.PublicKey {
+        guard data.count == 32 else {
+            throw CryptoError.invalidKeyData("Ed25519 public key must be 32 bytes, got \(data.count)")
+        }
+        return try Curve25519.Signing.PublicKey(rawRepresentation: data)
+    }
+
+    // MARK: - Sign / Verify
+
+    /// Sign data with Ed25519. Returns 64-byte signature.
+    /// Matches Python: ed25519_sign(private_key, data)
+    static func sign(_ privateKey: Curve25519.Signing.PrivateKey, data: Data) throws -> Data {
+        Data(try privateKey.signature(for: data))
+    }
+
+    /// Verify Ed25519 signature.
+    /// Matches Python: ed25519_verify(public_key, signature, data)
+    static func verify(_ publicKey: Curve25519.Signing.PublicKey, signature: Data, data: Data) -> Bool {
+        publicKey.isValidSignature(signature, for: data)
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/FieldArithmetic.swift

@@ -0,0 +1,231 @@
+import Foundation
+
+/// Pure Swift GF(2^255-19) arithmetic for Ed25519 → X25519 public key conversion.
+///
+/// The conversion formula is: u = (1 + y) / (1 - y) mod p
+/// where p = 2^255 - 19, and y is the Ed25519 public key's y-coordinate.
+///
+/// Uses 4-limb UInt64 representation (little-endian).
+enum FieldArithmetic {
+
+    // p = 2^255 - 19
+    static let p: [UInt64] = [
+        0xFFFF_FFFF_FFFF_FFED,  // limb 0 (least significant)
+        0xFFFF_FFFF_FFFF_FFFF,  // limb 1
+        0xFFFF_FFFF_FFFF_FFFF,  // limb 2
+        0x7FFF_FFFF_FFFF_FFFF,  // limb 3 (most significant, 2^63 - 1 accounting for -19)
+    ]
+
+    /// Load a 256-bit little-endian byte array into 4 UInt64 limbs
+    static func load(_ bytes: Data) -> [UInt64] {
+        precondition(bytes.count == 32)
+        var limbs = [UInt64](repeating: 0, count: 4)
+        for i in 0..<4 {
+            var val: UInt64 = 0
+            for j in 0..<8 {
+                val |= UInt64(bytes[i * 8 + j]) << (j * 8)
+            }
+            limbs[i] = val
+        }
+        return limbs
+    }
+
+    /// Store 4 UInt64 limbs as 32 little-endian bytes
+    static func store(_ limbs: [UInt64]) -> Data {
+        var bytes = Data(count: 32)
+        for i in 0..<4 {
+            for j in 0..<8 {
+                bytes[i * 8 + j] = UInt8((limbs[i] >> (j * 8)) & 0xFF)
+            }
+        }
+        return bytes
+    }
+
+    /// a + b mod p
+    static func add(_ a: [UInt64], _ b: [UInt64]) -> [UInt64] {
+        var result = [UInt64](repeating: 0, count: 4)
+        var carry: UInt64 = 0
+        for i in 0..<4 {
+            let (sum1, c1) = a[i].addingReportingOverflow(b[i])
+            let (sum2, c2) = sum1.addingReportingOverflow(carry)
+            result[i] = sum2
+            carry = (c1 ? 1 : 0) + (c2 ? 1 : 0)
+        }
+        // Reduce mod p
+        return reduceOnce(result, carry: carry)
+    }
+
+    /// a - b mod p
+    static func sub(_ a: [UInt64], _ b: [UInt64]) -> [UInt64] {
+        var result = [UInt64](repeating: 0, count: 4)
+        var borrow: UInt64 = 0
+        for i in 0..<4 {
+            let (diff1, b1) = a[i].subtractingReportingOverflow(b[i])
+            let (diff2, b2) = diff1.subtractingReportingOverflow(borrow)
+            result[i] = diff2
+            borrow = (b1 ? 1 : 0) + (b2 ? 1 : 0)
+        }
+        if borrow > 0 {
+            // Add p back
+            var c: UInt64 = 0
+            for i in 0..<4 {
+                let (s1, c1) = result[i].addingReportingOverflow(p[i])
+                let (s2, c2) = s1.addingReportingOverflow(c)
+                result[i] = s2
+                c = (c1 ? 1 : 0) + (c2 ? 1 : 0)
+            }
+        }
+        return result
+    }
+
+    /// Multiply two 256-bit numbers mod p using schoolbook multiplication
+    static func mul(_ a: [UInt64], _ b: [UInt64]) -> [UInt64] {
+        // Full 512-bit product in 8 limbs
+        var product = [UInt64](repeating: 0, count: 8)
+
+        for i in 0..<4 {
+            var carry: UInt64 = 0
+            for j in 0..<4 {
+                let (hi, lo) = a[i].multipliedFullWidth(by: b[j])
+                let (sum1, c1) = product[i + j].addingReportingOverflow(lo)
+                let (sum2, c2) = sum1.addingReportingOverflow(carry)
+                product[i + j] = sum2
+                carry = hi + (c1 ? 1 : 0) + (c2 ? 1 : 0)
+            }
+            product[i + 4] = carry
+        }
+
+        // Reduce mod p using Barrett-like reduction
+        // Since p = 2^255 - 19, for a 512-bit number we can use:
+        // x mod p = (x_low + x_high * 2^256) mod p
+        // Since 2^255 ≡ 19 (mod p), 2^256 ≡ 38 (mod p)
+        return reduceFull(product)
+    }
+
+    /// Reduce 512-bit product mod p using 2^256 ≡ 38 (mod p)
+    private static func reduceFull(_ product: [UInt64]) -> [UInt64] {
+        // Split: low = product[0..3], high = product[4..7]
+        // result = low + high * 38
+        var result = [UInt64](repeating: 0, count: 5)
+
+        // Start with low part
+        for i in 0..<4 {
+            result[i] = product[i]
+        }
+
+        // Add high * 38
+        var carry: UInt64 = 0
+        for i in 0..<4 {
+            let (hi, lo) = product[i + 4].multipliedFullWidth(by: 38)
+            let (sum1, c1) = result[i].addingReportingOverflow(lo)
+            let (sum2, c2) = sum1.addingReportingOverflow(carry)
+            result[i] = sum2
+            carry = hi + (c1 ? 1 : 0) + (c2 ? 1 : 0)
+        }
+        result[4] = carry
+
+        // The result might still be >= p, so reduce once more
+        // result[4] * 2^256 ≡ result[4] * 38 (mod p)
+        let extra: UInt64 = result[4]
+        result[4] = 0
+        if extra > 0 {
+            let (hi, lo) = extra.multipliedFullWidth(by: 38)
+            let (sum1, c1) = result[0].addingReportingOverflow(lo)
+            result[0] = sum1
+            var c = hi + (c1 ? 1 : 0)
+            for i in 1..<4 {
+                let (s, cf) = result[i].addingReportingOverflow(c)
+                result[i] = s
+                c = cf ? 1 : 0
+            }
+            // One more round if carry
+            if c > 0 {
+                let (s, _) = result[0].addingReportingOverflow(c * 38)
+                result[0] = s
+            }
+        }
+
+        var out = Array(result[0..<4])
+        // Final reduction: if >= p, subtract p
+        out = reduceOnce(out, carry: 0)
+        return out
+    }
+
+    /// If the number >= p, subtract p
+    private static func reduceOnce(_ val: [UInt64], carry: UInt64) -> [UInt64] {
+        if carry > 0 || isGreaterOrEqual(val, p) {
+            var result = [UInt64](repeating: 0, count: 4)
+            var borrow: UInt64 = 0
+            for i in 0..<4 {
+                let (diff1, b1) = val[i].subtractingReportingOverflow(p[i])
+                let (diff2, b2) = diff1.subtractingReportingOverflow(borrow)
+                result[i] = diff2
+                borrow = (b1 ? 1 : 0) + (b2 ? 1 : 0)
+            }
+            // If borrow after subtracting p, the original was fine (shouldn't happen with carry)
+            if borrow > 0 && carry == 0 {
+                return val
+            }
+            return result
+        }
+        return val
+    }
+
+    /// Compare a >= b
+    private static func isGreaterOrEqual(_ a: [UInt64], _ b: [UInt64]) -> Bool {
+        for i in stride(from: 3, through: 0, by: -1) {
+            if a[i] > b[i] { return true }
+            if a[i] < b[i] { return false }
+        }
+        return true  // equal
+    }
+
+    /// Modular inverse using Fermat's little theorem: a^(-1) = a^(p-2) mod p
+    static func inverse(_ a: [UInt64]) -> [UInt64] {
+        // p - 2 = 2^255 - 21
+        let pMinus2 = sub(p, [2, 0, 0, 0])
+        return power(a, pMinus2)
+    }
+
+    /// Modular exponentiation using square-and-multiply
+    static func power(_ base: [UInt64], _ exp: [UInt64]) -> [UInt64] {
+        var result: [UInt64] = [1, 0, 0, 0]  // 1
+        var b = base
+
+        for i in 0..<4 {
+            var limb = exp[i]
+            let bits = (i == 3) ? 63 : 64  // top limb has 63 bits for p-2
+            for _ in 0..<bits {
+                if limb & 1 == 1 {
+                    result = mul(result, b)
+                }
+                b = mul(b, b)
+                limb >>= 1
+            }
+        }
+        return result
+    }
+
+    // MARK: - Ed25519 → X25519 Public Key Conversion
+
+    /// Convert Ed25519 public key (32 bytes) to X25519 public key (32 bytes).
+    /// Formula: u = (1 + y) * inverse(1 - y) mod p
+    static func ed25519PublicToX25519(_ ed25519Pub: Data) -> Data {
+        precondition(ed25519Pub.count == 32)
+
+        // Ed25519 public key is the y-coordinate with sign bit in the top bit of byte 31
+        var keyBytes = ed25519Pub
+        // Clear the sign bit
+        keyBytes[31] &= 0x7F
+
+        let y = load(keyBytes)
+        let one: [UInt64] = [1, 0, 0, 0]
+
+        let onePlusY = add(one, y)
+        let oneMinusY = sub(one, y)
+        let inv = inverse(oneMinusY)
+        let u = mul(onePlusY, inv)
+
+        return store(u)
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/KeyEncryption.swift

@@ -0,0 +1,106 @@
+import Foundation
+import CryptoKit
+import CommonCrypto
+
+/// ECP1 key encryption format: PBKDF2-HMAC-SHA256 (600k iterations) + AES-256-GCM
+/// Wire format: magic(4) + salt(16) + nonce(12) + ciphertext_with_tag(N+16)
+enum KeyEncryption {
+
+    /// Encrypt raw key bytes with password using ECP1 format
+    static func encrypt(_ rawBytes: Data, password: Data) throws -> Data {
+        let salt = Data.randomBytes(16)
+        let derivedKey = try pbkdf2(password: password, salt: salt)
+
+        let nonce = Data.randomBytes(12)
+        let symmetricKey = SymmetricKey(data: derivedKey)
+        let gcmNonce = try AES.GCM.Nonce(data: nonce)
+
+        // AAD = ECP1 magic bytes (matching Python)
+        let sealedBox = try AES.GCM.seal(
+            rawBytes,
+            using: symmetricKey,
+            nonce: gcmNonce,
+            authenticating: Constants.ecp1Magic
+        )
+
+        // ciphertext + tag concatenated (matches Python's AESGCM.encrypt output)
+        var result = Data()
+        result.append(Constants.ecp1Magic)    // 4 bytes
+        result.append(salt)                    // 16 bytes
+        result.append(nonce)                   // 12 bytes
+        result.append(sealedBox.ciphertext)    // N bytes
+        result.append(sealedBox.tag)           // 16 bytes
+        return result
+    }
+
+    /// Decrypt ECP1-encrypted key bytes with password
+    static func decrypt(_ data: Data, password: Data) throws -> Data {
+        guard data.count >= 48 else {  // 4 + 16 + 12 + 16 minimum
+            throw CryptoError.invalidECP1Format
+        }
+        guard data.prefix(4) == Constants.ecp1Magic else {
+            throw CryptoError.invalidECP1Format
+        }
+
+        let salt = data[4..<20]
+        let nonce = data[20..<32]
+        let ctWithTag = data[32...]
+
+        guard ctWithTag.count >= 16 else {
+            throw CryptoError.invalidECP1Format
+        }
+
+        let derivedKey = try pbkdf2(password: password, salt: Data(salt))
+        let symmetricKey = SymmetricKey(data: derivedKey)
+        let gcmNonce = try AES.GCM.Nonce(data: nonce)
+
+        // Split ciphertext and tag
+        let ct = ctWithTag.prefix(ctWithTag.count - 16)
+        let tag = ctWithTag.suffix(16)
+
+        let sealedBox = try AES.GCM.SealedBox(
+            nonce: gcmNonce,
+            ciphertext: ct,
+            tag: tag
+        )
+
+        do {
+            return try AES.GCM.open(sealedBox, using: symmetricKey, authenticating: Constants.ecp1Magic)
+        } catch {
+            throw CryptoError.decryptionFailed("ECP1 decryption failed - wrong password?")
+        }
+    }
+
+    /// Check if data starts with ECP1 magic
+    static func isECP1Format(_ data: Data) -> Bool {
+        data.count >= 4 && data.prefix(4) == Constants.ecp1Magic
+    }
+
+    // MARK: - PBKDF2
+
+    /// Derive 32-byte key using PBKDF2-HMAC-SHA256 with 600k iterations
+    static func pbkdf2(password: Data, salt: Data) throws -> Data {
+        var derivedKey = Data(count: 32)
+        let status = derivedKey.withUnsafeMutableBytes { derivedKeyPtr in
+            password.withUnsafeBytes { passwordPtr in
+                salt.withUnsafeBytes { saltPtr in
+                    CCKeyDerivationPBKDF(
+                        CCPBKDFAlgorithm(kCCPBKDF2),
+                        passwordPtr.baseAddress?.assumingMemoryBound(to: Int8.self),
+                        password.count,
+                        saltPtr.baseAddress?.assumingMemoryBound(to: UInt8.self),
+                        salt.count,
+                        CCPseudoRandomAlgorithm(kCCPRFHmacAlgSHA256),
+                        Constants.pbkdf2Iterations,
+                        derivedKeyPtr.baseAddress?.assumingMemoryBound(to: UInt8.self),
+                        32
+                    )
+                }
+            }
+        }
+        guard status == kCCSuccess else {
+            throw CryptoError.pbkdf2Failed
+        }
+        return derivedKey
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/MessagePadding.swift

@@ -0,0 +1,59 @@
+import Foundation
+
+/// Message padding for metadata privacy — hides plaintext length.
+/// Matches Python: crypto_utils.py pad_plaintext / unpad_plaintext
+enum MessagePadding {
+
+    /// Magic byte prefix to distinguish padded from legacy unpadded messages.
+    private static let padMagic: UInt8 = 0x01
+
+    /// Bucket sizes for length hiding (64B to 64KB).
+    private static let padBuckets = [64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536]
+
+    /// Pad plaintext to nearest bucket size to hide message length.
+    ///
+    /// Format: `0x01 + plaintext + random_padding + pad_length(4B big-endian)`
+    /// Prefix 0x01 distinguishes padded messages from legacy unpadded (which start with '{').
+    static func pad(_ plaintext: Data) -> Data {
+        var content = Data([padMagic])
+        content.append(plaintext)
+
+        // +4 for the length suffix
+        let minSize = content.count + 4
+        let target = padBuckets.first(where: { $0 >= minSize }) ?? minSize
+        let padLen = target - content.count
+
+        // random_padding (padLen - 4 bytes) + pad_length (4 bytes big-endian)
+        var result = content
+        result.append(Data.randomBytes(padLen - 4))
+        result.append(UInt32(padLen).bigEndianData)
+        return result
+    }
+
+    /// Remove padding. Returns raw plaintext for both padded and legacy unpadded messages.
+    static func unpad(_ data: Data) -> Data {
+        guard !data.isEmpty else { return data }
+
+        // Legacy unpadded message (starts with '{' for JSON)
+        guard data[data.startIndex] == padMagic else { return data }
+
+        // Too short to be validly padded (magic + at least 4 bytes for length)
+        guard data.count >= 5 else { return data }
+
+        // Read pad_length from last 4 bytes (big-endian UInt32)
+        let padLenOffset = data.count - 4
+        let padLen = data.withUnsafeBytes { ptr -> UInt32 in
+            var value: UInt32 = 0
+            withUnsafeMutableBytes(of: &value) { dest in
+                dest.copyBytes(from: UnsafeRawBufferPointer(rebasing: ptr[padLenOffset...]))
+            }
+            return UInt32(bigEndian: value)
+        }
+
+        // Validate padding metadata
+        guard padLen >= 4, padLen <= data.count - 1 else { return data }
+
+        // Strip: skip magic byte (index 0), take up to (data.count - padLen)
+        return data[data.startIndex + 1 ..< data.startIndex + data.count - Int(padLen)]
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/RSACrypto.swift

@@ -0,0 +1,356 @@
+import Foundation
+import Security
+
+/// RSA-4096 operations — used for login challenge-response ONLY
+enum RSACrypto {
+
+    // MARK: - Key Generation
+
+    /// Generate RSA-4096 keypair
+    static func generateKeypair() throws -> (privateKey: SecKey, publicKey: SecKey) {
+        let attributes: [String: Any] = [
+            kSecAttrKeyType as String: kSecAttrKeyTypeRSA,
+            kSecAttrKeySizeInBits as String: 4096,
+        ]
+
+        var error: Unmanaged<CFError>?
+        guard let privateKey = SecKeyCreateRandomKey(attributes as CFDictionary, &error) else {
+            throw CryptoError.rsaKeyGenerationFailed
+        }
+        guard let publicKey = SecKeyCopyPublicKey(privateKey) else {
+            throw CryptoError.rsaKeyGenerationFailed
+        }
+        return (privateKey, publicKey)
+    }
+
+    // MARK: - Serialization
+
+    /// Serialize RSA private key. With password: DER → ECP1. Without: PEM PKCS#8.
+    static func serializePrivateKey(_ key: SecKey, password: Data? = nil) throws -> Data {
+        var error: Unmanaged<CFError>?
+        guard let derData = SecKeyCopyExternalRepresentation(key, &error) as Data? else {
+            throw CryptoError.rsaOperationFailed("Failed to export private key")
+        }
+
+        // SecKey exports in PKCS#1 format on iOS — wrap in PKCS#8 for Python compat
+        let pkcs8 = wrapRSAPrivateKeyPKCS8(derData)
+
+        if let password = password {
+            return try KeyEncryption.encrypt(pkcs8, password: password)
+        }
+
+        // PEM encode for Python compatibility
+        return pemEncode(pkcs8, label: "PRIVATE KEY")
+    }
+
+    /// Serialize RSA public key as PEM SubjectPublicKeyInfo (Python-compatible)
+    static func serializePublicKey(_ key: SecKey) throws -> Data {
+        var error: Unmanaged<CFError>?
+        guard let derData = SecKeyCopyExternalRepresentation(key, &error) as Data? else {
+            throw CryptoError.rsaOperationFailed("Failed to export public key")
+        }
+
+        // SecKey exports PKCS#1 on iOS — wrap in SubjectPublicKeyInfo
+        let spki = wrapRSAPublicKeySPKI(derData)
+        return pemEncode(spki, label: "PUBLIC KEY")
+    }
+
+    /// Load RSA private key. Auto-detects ECP1 vs PEM format.
+    static func loadPrivateKey(_ data: Data, password: Data? = nil) throws -> SecKey {
+        let derData: Data
+
+        if KeyEncryption.isECP1Format(data) {
+            guard let pwd = password else {
+                throw CryptoError.invalidKeyData("ECP1 key requires password")
+            }
+            let raw = try KeyEncryption.decrypt(data, password: pwd)
+            derData = unwrapPKCS8ToRSAPrivateKey(raw)
+        } else {
+            // PEM format
+            let pem = String(data: data, encoding: .utf8) ?? ""
+            derData = try pemDecode(pem, label: "PRIVATE KEY")
+                .flatMap { unwrapPKCS8ToRSAPrivateKey($0) }
+                ?? pemDecode(pem, label: "RSA PRIVATE KEY")
+                ?? { throw CryptoError.invalidKeyData("Cannot parse RSA private key PEM") }()
+        }
+
+        let attributes: [String: Any] = [
+            kSecAttrKeyType as String: kSecAttrKeyTypeRSA,
+            kSecAttrKeyClass as String: kSecAttrKeyClassPrivate,
+        ]
+
+        var error: Unmanaged<CFError>?
+        guard let key = SecKeyCreateWithData(derData as CFData, attributes as CFDictionary, &error) else {
+            throw CryptoError.invalidKeyData("Failed to create RSA private key from DER")
+        }
+        return key
+    }
+
+    /// Load RSA public key from PEM
+    static func loadPublicKey(_ pemData: Data) throws -> SecKey {
+        let pem = String(data: pemData, encoding: .utf8) ?? ""
+
+        // Try SubjectPublicKeyInfo (PUBLIC KEY), unwrap to PKCS#1
+        let derData: Data
+        if let spki = pemDecode(pem, label: "PUBLIC KEY") {
+            derData = unwrapSPKIToRSAPublicKey(spki)
+        } else if let pkcs1 = pemDecode(pem, label: "RSA PUBLIC KEY") {
+            derData = pkcs1
+        } else {
+            throw CryptoError.invalidKeyData("Cannot parse RSA public key PEM")
+        }
+
+        let attributes: [String: Any] = [
+            kSecAttrKeyType as String: kSecAttrKeyTypeRSA,
+            kSecAttrKeyClass as String: kSecAttrKeyClassPublic,
+        ]
+
+        var error: Unmanaged<CFError>?
+        guard let key = SecKeyCreateWithData(derData as CFData, attributes as CFDictionary, &error) else {
+            throw CryptoError.invalidKeyData("Failed to create RSA public key from DER")
+        }
+        return key
+    }
+
+    // MARK: - Sign / Verify
+
+    /// Sign data with RSA-PSS SHA-256.
+    /// Note: iOS uses salt_length = hash_length (32). Server must use PSS.AUTO to verify.
+    static func sign(_ privateKey: SecKey, data: Data) throws -> Data {
+        var error: Unmanaged<CFError>?
+        guard let signature = SecKeyCreateSignature(
+            privateKey,
+            .rsaSignatureMessagePSSSHA256,
+            data as CFData,
+            &error
+        ) as Data? else {
+            throw CryptoError.rsaOperationFailed("RSA signing failed")
+        }
+        return signature
+    }
+
+    /// Verify RSA-PSS SHA-256 signature
+    static func verify(_ publicKey: SecKey, signature: Data, data: Data) -> Bool {
+        SecKeyVerifySignature(
+            publicKey,
+            .rsaSignatureMessagePSSSHA256,
+            data as CFData,
+            signature as CFData,
+            nil
+        )
+    }
+
+    // MARK: - RSA-OAEP Encrypt / Decrypt (for device pairing)
+
+    /// Encrypt data with RSA-OAEP SHA-256 using a public key
+    static func encrypt(_ publicKey: SecKey, plaintext: Data) throws -> Data {
+        var error: Unmanaged<CFError>?
+        guard let encrypted = SecKeyCreateEncryptedData(
+            publicKey,
+            .rsaEncryptionOAEPSHA256,
+            plaintext as CFData,
+            &error
+        ) as Data? else {
+            throw CryptoError.rsaOperationFailed("RSA-OAEP encryption failed")
+        }
+        return encrypted
+    }
+
+    /// Decrypt data with RSA-OAEP SHA-256 using a private key
+    static func decrypt(_ privateKey: SecKey, ciphertext: Data) throws -> Data {
+        var error: Unmanaged<CFError>?
+        guard let decrypted = SecKeyCreateDecryptedData(
+            privateKey,
+            .rsaEncryptionOAEPSHA256,
+            ciphertext as CFData,
+            &error
+        ) as Data? else {
+            throw CryptoError.rsaOperationFailed("RSA-OAEP decryption failed")
+        }
+        return decrypted
+    }
+
+    /// Generate RSA-2048 keypair (for pairing temp keys — smaller for OAEP payload)
+    static func generateKeypair2048() throws -> (privateKey: SecKey, publicKey: SecKey) {
+        let attributes: [String: Any] = [
+            kSecAttrKeyType as String: kSecAttrKeyTypeRSA,
+            kSecAttrKeySizeInBits as String: 2048,
+        ]
+
+        var error: Unmanaged<CFError>?
+        guard let privateKey = SecKeyCreateRandomKey(attributes as CFDictionary, &error) else {
+            throw CryptoError.rsaKeyGenerationFailed
+        }
+        guard let publicKey = SecKeyCopyPublicKey(privateKey) else {
+            throw CryptoError.rsaKeyGenerationFailed
+        }
+        return (privateKey, publicKey)
+    }
+
+    // MARK: - PEM Helpers
+
+    private static func pemEncode(_ der: Data, label: String) -> Data {
+        let base64 = der.base64EncodedString(options: .lineLength64Characters)
+        let pem = "-----BEGIN \(label)-----\n\(base64)\n-----END \(label)-----\n"
+        return Data(pem.utf8)
+    }
+
+    private static func pemDecode(_ pem: String, label: String) -> Data? {
+        let beginMarker = "-----BEGIN \(label)-----"
+        let endMarker = "-----END \(label)-----"
+
+        guard let beginRange = pem.range(of: beginMarker),
+              let endRange = pem.range(of: endMarker) else {
+            return nil
+        }
+
+        let base64String = pem[beginRange.upperBound..<endRange.lowerBound]
+            .replacingOccurrences(of: "\n", with: "")
+            .replacingOccurrences(of: "\r", with: "")
+            .replacingOccurrences(of: " ", with: "")
+
+        return Data(base64Encoded: base64String)
+    }
+
+    // MARK: - ASN.1 PKCS#8 / SPKI Wrappers
+
+    // SecKey on iOS exports RSA keys in PKCS#1 format, but Python expects PKCS#8 / SPKI.
+    // These functions add/remove the ASN.1 wrapping.
+
+    // RSA OID: 1.2.840.113549.1.1.1
+    private static let rsaOID: [UInt8] = [0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01]
+    private static let nullParam: [UInt8] = [0x05, 0x00]
+
+    /// Wrap PKCS#1 RSA private key in PKCS#8 PrivateKeyInfo envelope
+    private static func wrapRSAPrivateKeyPKCS8(_ pkcs1: Data) -> Data {
+        // PrivateKeyInfo ::= SEQUENCE {
+        //   version INTEGER (0),
+        //   algorithm AlgorithmIdentifier,
+        //   privateKey OCTET STRING (containing PKCS#1 key)
+        // }
+        let version = Data([0x02, 0x01, 0x00]) // INTEGER 0
+        let algorithmSeq = asn1Sequence(Data(rsaOID) + Data(nullParam))
+        let privateKeyOctet = asn1OctetString(pkcs1)
+        return asn1Sequence(version + algorithmSeq + privateKeyOctet)
+    }
+
+    /// Unwrap PKCS#8 to get PKCS#1 RSA private key
+    private static func unwrapPKCS8ToRSAPrivateKey(_ pkcs8: Data) -> Data {
+        // Parse SEQUENCE, skip version + algorithm, extract OCTET STRING
+        guard pkcs8.count > 2 else { return pkcs8 }
+
+        var offset = 0
+        // Outer SEQUENCE
+        guard pkcs8[offset] == 0x30 else { return pkcs8 }
+        offset += 1
+        offset = skipASN1Length(pkcs8, offset: offset)
+
+        // Version INTEGER
+        guard offset < pkcs8.count, pkcs8[offset] == 0x02 else { return pkcs8 }
+        offset += 1
+        let versionLen = readASN1Length(pkcs8, offset: &offset)
+        offset += versionLen
+
+        // Algorithm SEQUENCE
+        guard offset < pkcs8.count, pkcs8[offset] == 0x30 else { return pkcs8 }
+        offset += 1
+        let algoLen = readASN1Length(pkcs8, offset: &offset)
+        offset += algoLen
+
+        // Private key OCTET STRING
+        guard offset < pkcs8.count, pkcs8[offset] == 0x04 else { return pkcs8 }
+        offset += 1
+        let keyLen = readASN1Length(pkcs8, offset: &offset)
+        guard offset + keyLen <= pkcs8.count else { return pkcs8 }
+        return Data(pkcs8[offset..<(offset + keyLen)])
+    }
+
+    /// Wrap PKCS#1 RSA public key in SubjectPublicKeyInfo
+    private static func wrapRSAPublicKeySPKI(_ pkcs1: Data) -> Data {
+        // SubjectPublicKeyInfo ::= SEQUENCE {
+        //   algorithm AlgorithmIdentifier,
+        //   subjectPublicKey BIT STRING (containing PKCS#1 key)
+        // }
+        let algorithmSeq = asn1Sequence(Data(rsaOID) + Data(nullParam))
+        let bitString = asn1BitString(pkcs1)
+        return asn1Sequence(algorithmSeq + bitString)
+    }
+
+    /// Unwrap SubjectPublicKeyInfo to get PKCS#1 RSA public key
+    private static func unwrapSPKIToRSAPublicKey(_ spki: Data) -> Data {
+        guard spki.count > 2 else { return spki }
+
+        var offset = 0
+        // Outer SEQUENCE
+        guard spki[offset] == 0x30 else { return spki }
+        offset += 1
+        offset = skipASN1Length(spki, offset: offset)
+
+        // Algorithm SEQUENCE
+        guard offset < spki.count, spki[offset] == 0x30 else { return spki }
+        offset += 1
+        let algoLen = readASN1Length(spki, offset: &offset)
+        offset += algoLen
+
+        // BIT STRING
+        guard offset < spki.count, spki[offset] == 0x03 else { return spki }
+        offset += 1
+        let bitLen = readASN1Length(spki, offset: &offset)
+        // Skip the unused bits byte
+        guard offset < spki.count, spki[offset] == 0x00 else { return spki }
+        offset += 1
+        let keyLen = bitLen - 1
+        guard offset + keyLen <= spki.count else { return spki }
+        return Data(spki[offset..<(offset + keyLen)])
+    }
+
+    // MARK: - ASN.1 Primitives
+
+    private static func asn1Length(_ length: Int) -> Data {
+        if length < 0x80 {
+            return Data([UInt8(length)])
+        } else if length <= 0xFF {
+            return Data([0x81, UInt8(length)])
+        } else if length <= 0xFFFF {
+            return Data([0x82, UInt8(length >> 8), UInt8(length & 0xFF)])
+        } else {
+            return Data([0x83, UInt8(length >> 16), UInt8((length >> 8) & 0xFF), UInt8(length & 0xFF)])
+        }
+    }
+
+    private static func asn1Sequence(_ content: Data) -> Data {
+        Data([0x30]) + asn1Length(content.count) + content
+    }
+
+    private static func asn1OctetString(_ content: Data) -> Data {
+        Data([0x04]) + asn1Length(content.count) + content
+    }
+
+    private static func asn1BitString(_ content: Data) -> Data {
+        // BIT STRING: tag + length + unused_bits(0) + content
+        Data([0x03]) + asn1Length(content.count + 1) + Data([0x00]) + content
+    }
+
+    private static func readASN1Length(_ data: Data, offset: inout Int) -> Int {
+        guard offset < data.count else { return 0 }
+        let first = data[offset]
+        offset += 1
+        if first < 0x80 {
+            return Int(first)
+        }
+        let numBytes = Int(first & 0x7F)
+        var length = 0
+        for _ in 0..<numBytes {
+            guard offset < data.count else { return length }
+            length = (length << 8) | Int(data[offset])
+            offset += 1
+        }
+        return length
+    }
+
+    private static func skipASN1Length(_ data: Data, offset: Int) -> Int {
+        var off = offset
+        _ = readASN1Length(data, offset: &off)
+        return off
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/SenderKeyState.swift

@@ -0,0 +1,175 @@
+import Foundation
+import CryptoKit
+
+/// Sender key chain for group messaging.
+/// Each sender in a group has their own chain. Others receive the initial key via pairwise ratchet.
+/// Matches Python: SenderKeyState class in crypto_utils.py
+class SenderKeyState {
+
+    let senderKey: Data
+    let chainId: Data
+    private(set) var chainKey: Data
+    private(set) var n: Int
+    private var knownKeys: [Int: Data]
+
+    /// Initialize with optional sender key (generates random 32B if nil).
+    /// Matches Python: SenderKeyState.__init__(sender_key=None)
+    init(senderKey: Data? = nil) {
+        let key = senderKey ?? Data.randomBytes(32)
+        self.senderKey = key
+        self.chainId = Data(SHA256.hash(data: key))
+        self.chainKey = CryptoUtils.hkdfDerive(
+            inputKey: key,
+            salt: Data(repeating: 0x00, count: 32),
+            info: Data(Constants.senderKeyChainInfo.utf8),
+            length: 32
+        )
+        self.n = 0
+        self.knownKeys = [:]
+    }
+
+    /// Private init for import
+    private init(senderKey: Data, chainId: Data, chainKey: Data, n: Int, knownKeys: [Int: Data]) {
+        self.senderKey = senderKey
+        self.chainId = chainId
+        self.chainKey = chainKey
+        self.n = n
+        self.knownKeys = knownKeys
+    }
+
+    // MARK: - Encrypt
+
+    /// Encrypt with current chain key.
+    /// Returns (chainId hex, n, ciphertext with tag, nonce).
+    /// Matches Python: SenderKeyState.encrypt(plaintext)
+    func encrypt(_ plaintext: Data) throws -> (chainIdHex: String, n: Int, ciphertext: Data, nonce: Data) {
+        let (newCK, messageKey) = CryptoUtils.kdfCK(chainKey: chainKey)
+        chainKey = newCK
+
+        let nonce = Data.randomBytes(12)
+        // AAD = chainId + bigEndian(UInt32(n))
+        let aad = chainId + UInt32(n).bigEndianData
+        let ctWithTag = try CryptoUtils.aesGcmEncrypt(plaintext, key: messageKey, nonce: nonce, aad: aad)
+
+        let result = (chainIdHex: chainId.hexString, n: n, ciphertext: ctWithTag, nonce: nonce)
+        n += 1
+        return result
+    }
+
+    // MARK: - Decrypt
+
+    /// Decrypt a group message. Fast-forwards the chain if needed.
+    /// State is snapshotted before modification and restored on failure.
+    /// Matches Python: SenderKeyState.decrypt(chain_id_hex, n, ciphertext, nonce)
+    func decrypt(chainIdHex: String, n: Int, ciphertext: Data, nonce: Data) throws -> Data {
+        guard let expectedChainId = Data(hexString: chainIdHex) else {
+            throw CryptoError.senderKeyError("Invalid chain ID hex")
+        }
+        guard expectedChainId == chainId else {
+            throw CryptoError.senderKeyError("Chain ID mismatch")
+        }
+
+        if n - self.n > Constants.maxSenderKeySkip {
+            throw CryptoError.senderKeyError("Sender key skip too large (\(n - self.n) > \(Constants.maxSenderKeySkip))")
+        }
+
+        // Snapshot before fast-forward
+        let snapChainKey = chainKey
+        let snapN = self.n
+        let snapKnown = knownKeys
+
+        do {
+            // Fast-forward the chain to reach message n
+            while self.n <= n {
+                let (newCK, mk) = CryptoUtils.kdfCK(chainKey: chainKey)
+                chainKey = newCK
+                knownKeys[self.n] = mk
+                self.n += 1
+            }
+
+            guard let mk = knownKeys.removeValue(forKey: n) else {
+                throw CryptoError.senderKeyError("Message key for n=\(n) not available")
+            }
+
+            let aad = chainId + UInt32(n).bigEndianData
+            return try CryptoUtils.aesGcmDecrypt(ciphertext, key: mk, nonce: nonce, aad: aad)
+        } catch {
+            // Restore state on failure
+            chainKey = snapChainKey
+            self.n = snapN
+            knownKeys = snapKnown
+            throw error
+        }
+    }
+
+    // MARK: - Key Export/Import
+
+    /// Export sender key for distribution to group members.
+    /// Matches Python: SenderKeyState.export_key()
+    func exportKey() -> Data {
+        let dict: [String: Any] = ["sender_key": senderKey.hexString]
+        return try! JSONSerialization.data(withJSONObject: dict)
+    }
+
+    /// Initialize a receiving SenderKeyState from an exported key.
+    /// Matches Python: SenderKeyState.from_key(exported_key)
+    static func fromKey(_ exportedKey: Data) throws -> SenderKeyState {
+        guard let dict = try JSONSerialization.jsonObject(with: exportedKey) as? [String: Any],
+              let senderKeyHex = dict["sender_key"] as? String,
+              let senderKey = Data(hexString: senderKeyHex) else {
+            throw CryptoError.stateImportFailed("Invalid sender key export")
+        }
+        return SenderKeyState(senderKey: senderKey)
+    }
+
+    // MARK: - Full State Export/Import
+
+    /// Serialize full state for persistent storage.
+    /// Matches Python: SenderKeyState.export_state()
+    func exportState() -> Data {
+        var knownKeysDict: [String: String] = [:]
+        for (k, v) in knownKeys {
+            knownKeysDict[String(k)] = v.hexString
+        }
+        let state: [String: Any] = [
+            "sender_key": senderKey.hexString,
+            "chain_id": chainId.hexString,
+            "chain_key": chainKey.hexString,
+            "n": n,
+            "known_keys": knownKeysDict,
+        ]
+        return try! JSONSerialization.data(withJSONObject: state)
+    }
+
+    /// Deserialize full state.
+    /// Matches Python: SenderKeyState.import_state(data)
+    static func importState(_ data: Data) throws -> SenderKeyState {
+        guard let state = try JSONSerialization.jsonObject(with: data) as? [String: Any],
+              let senderKeyHex = state["sender_key"] as? String,
+              let senderKey = Data(hexString: senderKeyHex),
+              let chainIdHex = state["chain_id"] as? String,
+              let chainId = Data(hexString: chainIdHex),
+              let chainKeyHex = state["chain_key"] as? String,
+              let chainKey = Data(hexString: chainKeyHex),
+              let n = state["n"] as? Int else {
+            throw CryptoError.stateImportFailed("Invalid sender key state")
+        }
+
+        var knownKeys: [Int: Data] = [:]
+        if let knownKeysDict = state["known_keys"] as? [String: String] {
+            for (k, v) in knownKeysDict {
+                if let idx = Int(k), let data = Data(hexString: v) {
+                    knownKeys[idx] = data
+                }
+            }
+        }
+
+        return SenderKeyState(
+            senderKey: senderKey,
+            chainId: chainId,
+            chainKey: chainKey,
+            n: n,
+            knownKeys: knownKeys
+        )
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/X25519Crypto.swift

@@ -0,0 +1,77 @@
+import Foundation
+import CryptoKit
+
+/// X25519 Diffie-Hellman key agreement
+enum X25519Crypto {
+
+    // MARK: - Key Generation
+
+    /// Generate X25519 keypair
+    static func generateKeypair() -> (privateKey: Curve25519.KeyAgreement.PrivateKey, publicKey: Curve25519.KeyAgreement.PublicKey) {
+        let privateKey = Curve25519.KeyAgreement.PrivateKey()
+        return (privateKey, privateKey.publicKey)
+    }
+
+    // MARK: - Serialization
+
+    /// Serialize X25519 private key to 32 raw bytes
+    static func serializePrivate(_ key: Curve25519.KeyAgreement.PrivateKey) -> Data {
+        key.rawData  // 32 bytes
+    }
+
+    /// Serialize X25519 public key to 32 raw bytes
+    static func serializePublic(_ key: Curve25519.KeyAgreement.PublicKey) -> Data {
+        key.rawData  // 32 bytes
+    }
+
+    /// Load X25519 private key from 32 raw bytes
+    static func loadPrivate(_ data: Data) throws -> Curve25519.KeyAgreement.PrivateKey {
+        guard data.count == 32 else {
+            throw CryptoError.invalidKeyData("X25519 private key must be 32 bytes")
+        }
+        return try Curve25519.KeyAgreement.PrivateKey(rawRepresentation: data)
+    }
+
+    /// Load X25519 public key from 32 raw bytes
+    static func loadPublic(_ data: Data) throws -> Curve25519.KeyAgreement.PublicKey {
+        guard data.count == 32 else {
+            throw CryptoError.invalidKeyData("X25519 public key must be 32 bytes")
+        }
+        return try Curve25519.KeyAgreement.PublicKey(rawRepresentation: data)
+    }
+
+    // MARK: - Diffie-Hellman
+
+    /// Perform X25519 DH key agreement. Returns 32-byte shared secret.
+    /// Matches Python: x25519_dh(private_key, public_key)
+    static func dh(_ privateKey: Curve25519.KeyAgreement.PrivateKey, _ publicKey: Curve25519.KeyAgreement.PublicKey) throws -> Data {
+        let sharedSecret = try privateKey.sharedSecretFromKeyAgreement(with: publicKey)
+        // Extract raw bytes from SharedSecret
+        return sharedSecret.withUnsafeBytes { Data($0) }
+    }
+
+    // MARK: - Ed25519 → X25519 Key Conversion
+
+    /// Convert Ed25519 private key to X25519 private key.
+    /// SHA-512(seed) → take first 32 bytes → clamp per RFC 7748
+    /// Matches Python: ed25519_private_to_x25519(ed_private)
+    static func fromEd25519Private(_ edPrivate: Curve25519.Signing.PrivateKey) throws -> Curve25519.KeyAgreement.PrivateKey {
+        let raw = edPrivate.rawData  // 32 bytes seed
+        // SHA-512 of the seed
+        let hash = SHA512.hash(data: raw)
+        var clamped = Data(hash.prefix(32))
+        // Clamp per RFC 7748
+        clamped[0] &= 248
+        clamped[31] &= 127
+        clamped[31] |= 64
+        return try Curve25519.KeyAgreement.PrivateKey(rawRepresentation: clamped)
+    }
+
+    /// Convert Ed25519 public key to X25519 public key.
+    /// Uses Montgomery birational map: u = (1+y)/(1-y) mod p
+    /// Matches Python: ed25519_public_to_x25519(ed_public)
+    static func fromEd25519Public(_ edPublic: Curve25519.Signing.PublicKey) throws -> Curve25519.KeyAgreement.PublicKey {
+        let x25519Bytes = FieldArithmetic.ed25519PublicToX25519(edPublic.rawData)
+        return try Curve25519.KeyAgreement.PublicKey(rawRepresentation: x25519Bytes)
+    }
+}

ios_client 0.8.5/Kecalek/Crypto/X3DH.swift

@@ -0,0 +1,139 @@
+import Foundation
+import CryptoKit
+
+/// X3DH key agreement protocol (Signal Protocol)
+enum X3DH {
+
+    // MARK: - Pre-Key Generation
+
+    /// Generate a signed pre-key (SPK).
+    /// Returns (private, public, signature, id).
+    /// Matches Python: generate_signed_prekey(identity_private)
+    static func generateSignedPrekey(
+        identityPrivate: Curve25519.Signing.PrivateKey
+    ) throws -> (privateKey: Curve25519.KeyAgreement.PrivateKey,
+                  publicKey: Curve25519.KeyAgreement.PublicKey,
+                  signature: Data,
+                  id: String) {
+        let (spkPriv, spkPub) = X25519Crypto.generateKeypair()
+        let spkPubBytes = X25519Crypto.serializePublic(spkPub)
+        let signature = try Ed25519Crypto.sign(identityPrivate, data: spkPubBytes)
+        return (spkPriv, spkPub, signature, UUID().uuidString)
+    }
+
+    /// Generate a batch of one-time pre-keys.
+    /// Matches Python: generate_one_time_prekeys(count=50)
+    static func generateOneTimePrekeys(count: Int = 50) -> [(privateKey: Curve25519.KeyAgreement.PrivateKey,
+                                                               publicKey: Curve25519.KeyAgreement.PublicKey,
+                                                               id: String)] {
+        (0..<count).map { _ in
+            let (priv, pub) = X25519Crypto.generateKeypair()
+            return (priv, pub, UUID().uuidString)
+        }
+    }
+
+    // MARK: - X3DH Initiate (Alice)
+
+    /// Initiator side of X3DH.
+    /// Returns (sharedSecret, ephemeralPrivate, ephemeralPublic).
+    /// Matches Python: x3dh_initiate(ik_private_ed, ik_public_remote_ed, spk_remote, spk_signature, opk_remote?)
+    static func initiate(
+        ikPrivateEd: Curve25519.Signing.PrivateKey,
+        ikPublicRemoteEd: Curve25519.Signing.PublicKey,
+        spkRemote: Curve25519.KeyAgreement.PublicKey,
+        spkSignature: Data,
+        opkRemote: Curve25519.KeyAgreement.PublicKey? = nil
+    ) throws -> (sharedSecret: Data,
+                  ephemeralPrivate: Curve25519.KeyAgreement.PrivateKey,
+                  ephemeralPublic: Curve25519.KeyAgreement.PublicKey) {
+        // Verify SPK signature
+        let spkRemoteBytes = X25519Crypto.serializePublic(spkRemote)
+        guard Ed25519Crypto.verify(ikPublicRemoteEd, signature: spkSignature, data: spkRemoteBytes) else {
+            throw CryptoError.x3dhFailed("Invalid SPK signature")
+        }
+
+        // Convert identity keys to X25519
+        let ikX25519Private = try X25519Crypto.fromEd25519Private(ikPrivateEd)
+        let ikX25519Remote = try X25519Crypto.fromEd25519Public(ikPublicRemoteEd)
+
+        // Generate ephemeral keypair
+        let (ekPriv, ekPub) = X25519Crypto.generateKeypair()
+
+        // Debug: print key inputs (matching Python x3dh_respond)
+        #if DEBUG
+        print("DEBUG x3dh_initiate: ik_remote_ed = \(Ed25519Crypto.serializePublic(ikPublicRemoteEd).hexString)")
+        print("DEBUG x3dh_initiate: ik_x25519_remote = \(X25519Crypto.serializePublic(ikX25519Remote).hexString)")
+        print("DEBUG x3dh_initiate: ek_pub = \(X25519Crypto.serializePublic(ekPub).hexString)")
+        print("DEBUG x3dh_initiate: spk_remote = \(spkRemoteBytes.hexString)")
+        #endif
+
+        // DH computations
+        let dh1 = try X25519Crypto.dh(ikX25519Private, spkRemote)   // IK_A, SPK_B
+        let dh2 = try X25519Crypto.dh(ekPriv, ikX25519Remote)        // EK_A, IK_B
+        let dh3 = try X25519Crypto.dh(ekPriv, spkRemote)             // EK_A, SPK_B
+
+        // Debug: print DH outputs
+        #if DEBUG
+        print("DEBUG x3dh_initiate: dh1 = \(dh1.hexString)")
+        print("DEBUG x3dh_initiate: dh2 = \(dh2.hexString)")
+        print("DEBUG x3dh_initiate: dh3 = \(dh3.hexString)")
+        #endif
+
+        var dhConcat = dh1 + dh2 + dh3
+        if let opk = opkRemote {
+            let dh4 = try X25519Crypto.dh(ekPriv, opk)               // EK_A, OPK_B
+            #if DEBUG
+            print("DEBUG x3dh_initiate: dh4 = \(dh4.hexString)")
+            #endif
+            dhConcat += dh4
+        }
+
+        // Derive shared secret
+        let sharedSecret = CryptoUtils.hkdfDerive(
+            inputKey: dhConcat,
+            salt: Data(repeating: 0x00, count: 32),
+            info: Data(Constants.x3dhInfo.utf8),
+            length: 32
+        )
+        #if DEBUG
+        print("DEBUG x3dh_initiate: shared_secret = \(sharedSecret.hexString)")
+        #endif
+
+        return (sharedSecret, ekPriv, ekPub)
+    }
+
+    // MARK: - X3DH Respond (Bob)
+
+    /// Responder side of X3DH.
+    /// Returns sharedSecret.
+    /// Matches Python: x3dh_respond(ik_private_ed, spk_private, ik_remote_ed, ek_remote, opk_private?)
+    static func respond(
+        ikPrivateEd: Curve25519.Signing.PrivateKey,
+        spkPrivate: Curve25519.KeyAgreement.PrivateKey,
+        ikRemoteEd: Curve25519.Signing.PublicKey,
+        ekRemote: Curve25519.KeyAgreement.PublicKey,
+        opkPrivate: Curve25519.KeyAgreement.PrivateKey? = nil
+    ) throws -> Data {
+        let ikX25519Private = try X25519Crypto.fromEd25519Private(ikPrivateEd)
+        let ikX25519Remote = try X25519Crypto.fromEd25519Public(ikRemoteEd)
+
+        let dh1 = try X25519Crypto.dh(spkPrivate, ikX25519Remote)   // SPK_B, IK_A
+        let dh2 = try X25519Crypto.dh(ikX25519Private, ekRemote)     // IK_B, EK_A
+        let dh3 = try X25519Crypto.dh(spkPrivate, ekRemote)          // SPK_B, EK_A
+
+        var dhConcat = dh1 + dh2 + dh3
+        if let opk = opkPrivate {
+            let dh4 = try X25519Crypto.dh(opk, ekRemote)             // OPK_B, EK_A
+            dhConcat += dh4
+        }
+
+        let sharedSecret = CryptoUtils.hkdfDerive(
+            inputKey: dhConcat,
+            salt: Data(repeating: 0x00, count: 32),
+            info: Data(Constants.x3dhInfo.utf8),
+            length: 32
+        )
+
+        return sharedSecret
+    }
+}

ios_client 0.8.5/Kecalek/KecalekApp.swift

@@ -0,0 +1,47 @@
+import SwiftUI
+
+@main
+struct KecalekApp: App {
+    @State private var appState = AppState()
+    @State private var authViewModel = AuthViewModel()
+    @Environment(\.scenePhase) private var scenePhase
+
+    var body: some Scene {
+        WindowGroup {
+            if appState.isLoggedIn {
+                MainTabView(appState: appState)
+            } else {
+                LoginView(viewModel: authViewModel, appState: appState)
+            }
+        }
+        .onChange(of: scenePhase) { _, newPhase in
+            switch newPhase {
+            case .background:
+                appState.handleEnteredBackground()
+            case .active:
+                appState.handleBecameActive()
+            default:
+                break
+            }
+        }
+    }
+}
+
+struct MainTabView: View {
+    var appState: AppState
+    @State private var convListVM = ConversationListVM()
+
+    var body: some View {
+        TabView {
+            ConversationListView(appState: appState, viewModel: convListVM)
+                .tabItem {
+                    Label("Chats", systemImage: "bubble.left.and.bubble.right.fill")
+                }
+
+            ProfileView(appState: appState, isOwnProfile: true)
+                .tabItem {
+                    Label("Profile", systemImage: "person.fill")
+                }
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Models/Conversation.swift

@@ -0,0 +1,54 @@
+import Foundation
+
+struct Conversation: Identifiable, Equatable, Hashable, Codable {
+    let id: String
+    var name: String?
+    var members: [ConversationMember]
+    var createdBy: String?
+    var avatarFile: String?
+    var unreadCount: Int
+    var isFavorite: Bool
+    var lastMessageTime: Date?
+
+    var isGroup: Bool {
+        name != nil || members.count > 2
+    }
+
+    /// Display name: group name, or DM partner username
+    func displayName(currentUserId: String) -> String {
+        if let name = name, !name.isEmpty {
+            return name
+        }
+        // DM: show the other person's name
+        if let other = members.first(where: { $0.userId != currentUserId }) {
+            return other.username
+        }
+        return "Unknown"
+    }
+
+    /// DM partner user ID (nil for groups)
+    func dmPartnerId(currentUserId: String) -> String? {
+        guard !isGroup else { return nil }
+        return members.first(where: { $0.userId != currentUserId })?.userId
+    }
+
+    static func == (lhs: Conversation, rhs: Conversation) -> Bool {
+        lhs.id == rhs.id
+        && lhs.name == rhs.name
+        && lhs.members == rhs.members
+        && lhs.avatarFile == rhs.avatarFile
+        && lhs.unreadCount == rhs.unreadCount
+    }
+
+    func hash(into hasher: inout Hasher) {
+        hasher.combine(id)
+    }
+}
+
+struct ConversationMember: Identifiable, Equatable, Codable {
+    let userId: String
+    var username: String
+    var email: String
+
+    var id: String { userId }
+}

ios_client 0.8.5/Kecalek/Models/DeviceBundle.swift

@@ -0,0 +1,69 @@
+import Foundation
+
+/// Key bundle for one device, used in X3DH
+struct DeviceBundle {
+    let deviceId: String
+    let identityKey: Data      // Ed25519 public key (32 bytes)
+    let spk: Data              // X25519 public key (32 bytes)
+    let spkSignature: Data     // Ed25519 signature (64 bytes)
+    let spkId: String
+    let opk: Data?             // X25519 public key (32 bytes), optional
+    let opkId: String?
+
+    /// Parse from server response dictionary
+    /// Server uses: signed_prekey, signed_prekey_id, one_time_prekey, one_time_prekey_id (base64)
+    static func fromDict(_ dict: [String: Any], identityKey: Data? = nil) throws -> DeviceBundle {
+        guard let deviceId = dict["device_id"] as? String else {
+            throw ChatError.invalidData("Missing device_id")
+        }
+
+        // Identity key can be passed in (from parent) or in dict
+        let ik: Data
+        if let passedIk = identityKey {
+            ik = passedIk
+        } else if let ikB64 = dict["identity_key"] as? String,
+                  let ikData = Data(base64Encoded: ikB64) {
+            ik = ikData
+        } else {
+            throw ChatError.invalidData("Missing identity_key")
+        }
+
+        // SPK - try both naming conventions, base64 encoded
+        let spkB64 = dict["signed_prekey"] as? String ?? dict["spk"] as? String
+        guard let spkB64 = spkB64,
+              let spk = Data(base64Encoded: spkB64) else {
+            throw ChatError.invalidData("Missing signed_prekey")
+        }
+
+        // SPK signature - base64 encoded
+        guard let spkSigB64 = dict["spk_signature"] as? String,
+              let spkSig = Data(base64Encoded: spkSigB64) else {
+            throw ChatError.invalidData("Missing spk_signature")
+        }
+
+        // SPK ID - try both naming conventions
+        let spkId = dict["signed_prekey_id"] as? String ?? dict["spk_id"] as? String
+        guard let spkId = spkId else {
+            throw ChatError.invalidData("Missing signed_prekey_id")
+        }
+
+        // OPK - optional, base64 encoded
+        var opk: Data?
+        var opkId: String?
+        let opkB64 = dict["one_time_prekey"] as? String ?? dict["opk"] as? String
+        if let opkB64 = opkB64, let opkData = Data(base64Encoded: opkB64) {
+            opk = opkData
+            opkId = dict["one_time_prekey_id"] as? String ?? dict["opk_id"] as? String
+        }
+
+        return DeviceBundle(
+            deviceId: deviceId,
+            identityKey: ik,
+            spk: spk,
+            spkSignature: spkSig,
+            spkId: spkId,
+            opk: opk,
+            opkId: opkId
+        )
+    }
+}

ios_client 0.8.5/Kecalek/Models/Invitation.swift

@@ -0,0 +1,9 @@
+import Foundation
+
+struct Invitation: Identifiable {
+    let id: String              // invitation id (from server) or conversationId
+    let conversationId: String
+    let conversationName: String
+    let invitedBy: String
+    let invitedByUsername: String
+}

ios_client 0.8.5/Kecalek/Models/Message.swift

@@ -0,0 +1,210 @@
+import Foundation
+
+struct MessageReaction: Equatable {
+    let userId: String
+    let reaction: String
+    let createdAt: Date
+}
+
+struct ForwardedFrom: Equatable {
+    let sender: String
+    let conversationId: String
+    let messageId: String
+}
+
+enum ReactionEmoji {
+    static let allowed = ["thumbsup", "heart", "laugh", "surprised", "sad", "thumbsdown"]
+    static let display: [String: String] = [
+        "thumbsup": "👍", "heart": "❤️", "laugh": "😂",
+        "surprised": "😮", "sad": "😢", "thumbsdown": "👎",
+    ]
+}
+
+struct Message: Identifiable, Equatable {
+    let id: String
+    let conversationId: String
+    let senderId: String
+    var senderUsername: String
+    let createdAt: Date
+    var text: String?
+    var replyTo: String?
+    var imageFileId: String?
+    var file: FileInfo?
+    var image: ImageInfo?
+    var isDeleted: Bool
+    var readBy: Set<String>
+    var reactions: [MessageReaction]
+    var forwardedFrom: ForwardedFrom?
+    var pinnedAt: Date?
+    var pinnedBy: String?
+
+    /// Whether this is a self-sent message
+    func isMine(currentUserId: String) -> Bool {
+        senderId == currentUserId
+    }
+
+    static func == (lhs: Message, rhs: Message) -> Bool {
+        lhs.id == rhs.id
+    }
+}
+
+struct FileInfo: Equatable, Codable {
+    let fileId: String
+    let aesKey: String   // base64
+    let iv: String       // base64
+    let filename: String
+    let size: Int
+    let mimeType: String
+}
+
+struct ImageInfo: Equatable {
+    let fileId: String
+    let aesKey: String   // base64
+    let iv: String       // base64
+    let thumbnail: String? // base64 JPEG thumbnail
+    let filename: String
+    let size: Int
+}
+
+// MARK: - Cache Dictionary Conversion
+
+extension Message {
+    /// Convert to dictionary matching server JSON format for MessageCache storage
+    func toCacheDict() -> [String: Any] {
+        var dict: [String: Any] = [
+            "message_id": id,
+            "conversation_id": conversationId,
+            "sender_id": senderId,
+            "sender_username": senderUsername,
+            "created_at": DateParsing.format(createdAt),
+            "is_deleted": isDeleted,
+        ]
+        if let text = text { dict["text"] = text }
+        if let replyTo = replyTo { dict["reply_to"] = replyTo }
+        if let imageFileId = imageFileId { dict["image_file_id"] = imageFileId }
+        if let file = file {
+            dict["file"] = [
+                "file_id": file.fileId,
+                "aes_key": file.aesKey,
+                "iv": file.iv,
+                "filename": file.filename,
+                "size": file.size,
+                "mime_type": file.mimeType,
+            ] as [String: Any]
+        }
+        if let image = image {
+            var imgDict: [String: Any] = [
+                "file_id": image.fileId,
+                "aes_key": image.aesKey,
+                "iv": image.iv,
+                "filename": image.filename,
+                "size": image.size,
+            ]
+            if let thumbnail = image.thumbnail { imgDict["thumbnail"] = thumbnail }
+            dict["image"] = imgDict
+        }
+        if !readBy.isEmpty { dict["read_by"] = Array(readBy) }
+        if !reactions.isEmpty {
+            dict["reactions"] = reactions.map {
+                ["user_id": $0.userId, "reaction": $0.reaction,
+                 "created_at": DateParsing.format($0.createdAt)] as [String: Any]
+            }
+        }
+        if let fwd = forwardedFrom {
+            dict["forwarded_from"] = ["sender": fwd.sender,
+                "conversation_id": fwd.conversationId,
+                "message_id": fwd.messageId] as [String: Any]
+        }
+        if let pinnedAt { dict["pinned_at"] = DateParsing.format(pinnedAt) }
+        if let pinnedBy { dict["pinned_by"] = pinnedBy }
+        return dict
+    }
+
+    /// Create Message from cache dictionary (server JSON format)
+    static func fromCacheDict(_ dict: [String: Any]) -> Message? {
+        guard let id = dict["message_id"] as? String,
+              let conversationId = dict["conversation_id"] as? String,
+              let senderId = dict["sender_id"] as? String,
+              let createdAtStr = dict["created_at"] as? String,
+              let createdAt = DateParsing.parse(createdAtStr) else {
+            return nil
+        }
+
+        let senderUsername = dict["sender_username"] as? String ?? ""
+
+        var file: FileInfo?
+        if let fileDict = dict["file"] as? [String: Any],
+           let fileId = fileDict["file_id"] as? String {
+            file = FileInfo(
+                fileId: fileId,
+                aesKey: fileDict["aes_key"] as? String ?? "",
+                iv: fileDict["iv"] as? String ?? "",
+                filename: fileDict["filename"] as? String ?? "",
+                size: fileDict["size"] as? Int ?? 0,
+                mimeType: fileDict["mime_type"] as? String ?? ""
+            )
+        }
+
+        var image: ImageInfo?
+        if let imgDict = dict["image"] as? [String: Any],
+           let imgFileId = imgDict["file_id"] as? String {
+            image = ImageInfo(
+                fileId: imgFileId,
+                aesKey: imgDict["aes_key"] as? String ?? "",
+                iv: imgDict["iv"] as? String ?? "",
+                thumbnail: imgDict["thumbnail"] as? String,
+                filename: imgDict["filename"] as? String ?? "image.jpg",
+                size: imgDict["size"] as? Int ?? 0
+            )
+        }
+
+        let readBy: Set<String>
+        if let readByArray = dict["read_by"] as? [String] {
+            readBy = Set(readByArray)
+        } else {
+            readBy = []
+        }
+
+        var reactions: [MessageReaction] = []
+        if let reactionsArr = dict["reactions"] as? [[String: Any]] {
+            reactions = reactionsArr.compactMap { r in
+                guard let userId = r["user_id"] as? String,
+                      let reaction = r["reaction"] as? String else { return nil }
+                let createdAt = (r["created_at"] as? String).flatMap { DateParsing.parse($0) } ?? Date()
+                return MessageReaction(userId: userId, reaction: reaction, createdAt: createdAt)
+            }
+        }
+
+        var forwardedFrom: ForwardedFrom?
+        if let fwd = dict["forwarded_from"] as? [String: Any],
+           let sender = fwd["sender"] as? String {
+            forwardedFrom = ForwardedFrom(
+                sender: sender,
+                conversationId: fwd["conversation_id"] as? String ?? "",
+                messageId: fwd["message_id"] as? String ?? ""
+            )
+        }
+
+        let pinnedAt = (dict["pinned_at"] as? String).flatMap { DateParsing.parse($0) }
+        let pinnedBy = dict["pinned_by"] as? String
+
+        return Message(
+            id: id,
+            conversationId: conversationId,
+            senderId: senderId,
+            senderUsername: senderUsername,
+            createdAt: createdAt,
+            text: dict["text"] as? String,
+            replyTo: dict["reply_to"] as? String,
+            imageFileId: dict["image_file_id"] as? String,
+            file: file,
+            image: image,
+            isDeleted: dict["is_deleted"] as? Bool ?? false,
+            readBy: readBy,
+            reactions: reactions,
+            forwardedFrom: forwardedFrom,
+            pinnedAt: pinnedAt,
+            pinnedBy: pinnedBy
+        )
+    }
+}

ios_client 0.8.5/Kecalek/Models/User.swift

@@ -0,0 +1,19 @@
+import Foundation
+
+struct User: Identifiable, Equatable {
+    let id: String
+    var username: String
+    var email: String
+    var identityKey: Data?  // Ed25519 public key (32 bytes)
+}
+
+struct UserProfile: Equatable {
+    var userId: String
+    var username: String?
+    var email: String?
+    var phone: String?
+    var phoneVisible: Bool
+    var location: String?
+    var locationVisible: Bool
+    var avatarFile: String?
+}

ios_client 0.8.5/Kecalek/Network/ConnectionManager.swift

@@ -0,0 +1,191 @@
+import Foundation
+import Network
+
+/// TCP connection manager using Network.framework.
+/// Handles connection lifecycle, TLS, buffered reading (newline-delimited), and writing.
+actor ConnectionManager {
+
+    enum ConnectionState: Equatable {
+        case disconnected
+        case connecting
+        case connected
+        case failed(String)
+    }
+
+    private var connection: NWConnection?
+    private var receiveBuffer = Data()
+    private(set) var state: ConnectionState = .disconnected
+    private var stateCallback: ((ConnectionState) -> Void)?
+    private var messageStream: AsyncStream<[String: Any]>.Continuation?
+
+    /// Set a callback for connection state changes
+    func onStateChange(_ callback: @escaping (ConnectionState) -> Void) {
+        stateCallback = callback
+    }
+
+    // MARK: - Connect / Disconnect
+
+    /// Connect to server
+    func connect(host: String, port: UInt16) async throws {
+        guard state == .disconnected || state != .connected else {
+            throw NetworkError.alreadyConnected
+        }
+
+        updateState(.connecting)
+
+        let nwHost = NWEndpoint.Host(host)
+        let nwPort = NWEndpoint.Port(rawValue: port)!
+
+        let tlsOptions = NWProtocolTLS.Options()
+        let params = NWParameters(tls: tlsOptions, tcp: .init())
+
+        let conn = NWConnection(host: nwHost, port: nwPort, using: params)
+        self.connection = conn
+        self.receiveBuffer = Data()
+
+        return try await withCheckedThrowingContinuation { continuation in
+            // nonisolated flag — accessed only from the stateUpdateHandler serial queue
+            // Use a class wrapper so the closure can mutate it
+            final class ResumedFlag: @unchecked Sendable {
+                var value = false
+            }
+            let resumed = ResumedFlag()
+
+            conn.stateUpdateHandler = { [weak self] newState in
+                Task { [weak self] in
+                    guard let self = self else { return }
+                    switch newState {
+                    case .ready:
+                        await self.updateState(.connected)
+                        guard !resumed.value else { return }
+                        resumed.value = true
+                        continuation.resume()
+                    case .failed(let error):
+                        await self.updateState(.failed(error.localizedDescription))
+                        guard !resumed.value else { return }
+                        resumed.value = true
+                        continuation.resume(throwing: NetworkError.connectionFailed(error.localizedDescription))
+                    case .cancelled:
+                        await self.updateState(.disconnected)
+                        guard !resumed.value else { return }
+                        resumed.value = true
+                        continuation.resume(throwing: NetworkError.connectionFailed("Connection cancelled"))
+                    case .waiting(let error):
+                        await self.updateState(.failed(error.localizedDescription))
+                        guard !resumed.value else { return }
+                        resumed.value = true
+                        continuation.resume(throwing: NetworkError.connectionFailed("Waiting: \(error.localizedDescription)"))
+                    default:
+                        break
+                    }
+                }
+            }
+            conn.start(queue: .global(qos: .userInitiated))
+        }
+    }
+
+    /// Disconnect from server
+    func disconnect() {
+        connection?.cancel()
+        connection = nil
+        receiveBuffer = Data()
+        updateState(.disconnected)
+        messageStream?.finish()
+        messageStream = nil
+    }
+
+    // MARK: - Send
+
+    /// Send raw data over the connection
+    func send(_ data: Data) async throws {
+        guard let connection = connection, state == .connected else {
+            throw NetworkError.notConnected
+        }
+
+        return try await withCheckedThrowingContinuation { continuation in
+            connection.send(content: data, completion: .contentProcessed { error in
+                if let error = error {
+                    continuation.resume(throwing: NetworkError.connectionFailed(error.localizedDescription))
+                } else {
+                    continuation.resume()
+                }
+            })
+        }
+    }
+
+    /// Send a protocol message (builds JSON + newline, sends)
+    func sendMessage(type: String, requestId: String? = nil, params: [String: Any] = [:]) async throws {
+        let data = try ProtocolHandler.buildRequest(type: type, requestId: requestId, params: params)
+        try await send(data)
+    }
+
+    // MARK: - Receive
+
+    /// Read one newline-delimited JSON message.
+    /// Returns nil on EOF / connection close.
+    func readMessage() async throws -> [String: Any]? {
+        while true {
+            // Check buffer for a complete line
+            if let newlineIndex = receiveBuffer.firstIndex(of: 0x0A) {
+                let lineData = receiveBuffer.prefix(through: newlineIndex)
+                receiveBuffer.removeSubrange(...newlineIndex)
+
+                // Check size
+                if lineData.count > Constants.maxMessageBytes {
+                    throw NetworkError.messageTooLarge
+                }
+
+                return try ProtocolHandler.parseMessage(Data(lineData))
+            }
+
+            // Buffer doesn't have a complete line — read more from the connection
+            guard let connection = connection else {
+                return nil
+            }
+
+            let chunk = try await receiveChunk(connection: connection)
+            guard let chunk = chunk else {
+                return nil  // EOF
+            }
+
+            receiveBuffer.append(chunk)
+
+            // Safety: if buffer exceeds max without a newline, drop it
+            if receiveBuffer.count > Constants.maxMessageBytes * 2 {
+                receiveBuffer = Data()
+                throw NetworkError.messageTooLarge
+            }
+        }
+    }
+
+    /// Read a chunk of data from the connection
+    private func receiveChunk(connection: NWConnection) async throws -> Data? {
+        return try await withCheckedThrowingContinuation { continuation in
+            connection.receive(minimumIncompleteLength: 1, maximumLength: 65536) { content, _, isComplete, error in
+                if let error = error {
+                    continuation.resume(throwing: NetworkError.connectionFailed(error.localizedDescription))
+                    return
+                }
+                if let content = content, !content.isEmpty {
+                    continuation.resume(returning: content)
+                } else if isComplete {
+                    continuation.resume(returning: nil)
+                } else {
+                    // No data and not complete — shouldn't happen but return nil
+                    continuation.resume(returning: nil)
+                }
+            }
+        }
+    }
+
+    // MARK: - State
+
+    var isConnected: Bool {
+        state == .connected
+    }
+
+    private func updateState(_ newState: ConnectionState) {
+        state = newState
+        stateCallback?(newState)
+    }
+}

ios_client 0.8.5/Kecalek/Network/ProtocolHandler.swift

@@ -0,0 +1,88 @@
+import Foundation
+
+/// Newline-delimited JSON protocol handler.
+/// Matches Python: protocol.py build_request, build_response, parse_message, encode_binary, decode_binary
+enum ProtocolHandler: Sendable {
+
+    /// Build a request message (newline-terminated JSON).
+    /// Matches Python: build_request(msg_type, request_id=None, **kwargs)
+    nonisolated static func buildRequest(type: String, requestId: String? = nil, params: [String: Any] = [:]) throws -> Data {
+        var msg: [String: Any] = ["type": type]
+        if let requestId = requestId {
+            msg["request_id"] = requestId
+        }
+        // Merge params into msg
+        for (key, value) in params {
+            msg[key] = value
+        }
+
+        let jsonData = try JSONSerialization.data(withJSONObject: msg)
+        guard jsonData.count < Constants.maxMessageBytes else {
+            throw NetworkError.messageTooLarge
+        }
+        return jsonData + Data([0x0A])  // newline
+    }
+
+    /// Build a response message (newline-terminated JSON).
+    nonisolated static func buildResponse(type: String, status: String, data: [String: Any]? = nil, requestId: String? = nil) throws -> Data {
+        var msg: [String: Any] = ["type": type, "status": status]
+        if let data = data {
+            msg["data"] = data
+        }
+        if let requestId = requestId {
+            msg["request_id"] = requestId
+        }
+
+        let jsonData = try JSONSerialization.data(withJSONObject: msg)
+        guard jsonData.count < Constants.maxMessageBytes else {
+            throw NetworkError.messageTooLarge
+        }
+        return jsonData + Data([0x0A])
+    }
+
+    /// Parse a single protocol message from bytes.
+    /// Matches Python: parse_message(line)
+    nonisolated static func parseMessage(_ data: Data) throws -> [String: Any] {
+        let trimmed = Self.trimmingNewlines(data)
+        guard !trimmed.isEmpty else {
+            throw NetworkError.protocolError("Empty message")
+        }
+        guard let obj = try JSONSerialization.jsonObject(with: trimmed) as? [String: Any] else {
+            throw NetworkError.protocolError("Message is not a JSON object")
+        }
+        return obj
+    }
+
+    /// Encode bytes to base64 string.
+    /// Matches Python: encode_binary(data)
+    nonisolated static func encodeBinary(_ data: Data) -> String {
+        data.base64EncodedString(options: [])
+    }
+
+    /// Decode base64 string to bytes.
+    /// Matches Python: decode_binary(data)
+    nonisolated static func decodeBinary(_ string: String) throws -> Data {
+        guard let data = Data(base64Encoded: string, options: .ignoreUnknownCharacters) else {
+            throw CryptoError.invalidBase64
+        }
+        return data
+    }
+
+    /// Generate a new request ID (UUID string).
+    nonisolated static func newRequestId() -> String {
+        UUID().uuidString
+    }
+
+    // MARK: - Helpers
+
+    private nonisolated static func trimmingNewlines(_ data: Data) -> Data {
+        var result = data
+        while let last = result.last, last == 0x0A || last == 0x0D {
+            result.removeLast()
+        }
+        while let first = result.first, first == 0x0A || first == 0x0D {
+            result.removeFirst()
+        }
+        return result
+    }
+}

ios_client 0.8.5/Kecalek/Utilities/Constants.swift

@@ -0,0 +1,38 @@
+import Foundation
+
+enum Constants: Sendable {
+    nonisolated static let version = "0.8.5"
+    nonisolated static let maxMessageBytes = 65536
+    nonisolated static let maxImageBytes = 5 * 1024 * 1024      // 5 MB
+    nonisolated static let maxFileBytes = 50 * 1024 * 1024       // 50 MB
+    nonisolated static let imageChunkSize = 32768                 // 32 KB (matches Python IMAGE_CHUNK_SIZE)
+    nonisolated static let selfDeviceId = "00000000-0000-0000-0000-000000000000"
+
+    nonisolated static let opkReplenishThreshold = 20
+    nonisolated static let opkBatchSize = 50
+    nonisolated static let spkRotationDays = 7
+
+    nonisolated static let maxSkip = 256
+    nonisolated static let maxSenderKeySkip = 256
+
+    nonisolated static let deviceBundleCacheTTL: TimeInterval = 300  // 5 minutes
+    nonisolated static let sendReceiveTimeout: TimeInterval = 30
+    nonisolated static let reconnectBaseDelay: TimeInterval = 1
+    nonisolated static let reconnectMaxDelay: TimeInterval = 30
+
+    nonisolated static let pbkdf2Iterations: UInt32 = 600_000
+    nonisolated static let ecp1Magic = Data([0x45, 0x43, 0x50, 0x31])  // "ECP1"
+
+    // HKDF info/salt strings matching Python
+    nonisolated static let x3dhInfo = "EncryptedChat_X3DH"
+    nonisolated static let rootKeyInfo = "EncryptedChat_RootKey"
+    nonisolated static let selfEncryptionSalt = "self_encryption"
+    nonisolated static let selfEncryptionInfo = "EncryptedChat_SelfKey"
+    nonisolated static let localStorageSalt = "local_storage"
+    nonisolated static let localStorageInfo = "EncryptedChat_LocalStorage"
+    nonisolated static let senderKeyChainInfo = "SenderKeyChain"
+
+    // Server connection defaults
+    nonisolated static let defaultHost = "chat.ai-tech.news"
+    nonisolated static let defaultPort: UInt16 = 9999
+}

ios_client 0.8.5/Kecalek/Utilities/Extensions.swift

@@ -0,0 +1,168 @@
+import Foundation
+import CryptoKit
+
+// MARK: - Data ↔ Hex
+
+extension Data {
+    /// Convert data to lowercase hex string
+    var hexString: String {
+        map { String(format: "%02x", $0) }.joined()
+    }
+
+    /// Initialize Data from a hex string
+    init?(hexString: String) {
+        let hex = hexString.lowercased()
+        guard hex.count % 2 == 0 else { return nil }
+        var data = Data(capacity: hex.count / 2)
+        var index = hex.startIndex
+        while index < hex.endIndex {
+            let nextIndex = hex.index(index, offsetBy: 2)
+            guard let byte = UInt8(hex[index..<nextIndex], radix: 16) else { return nil }
+            data.append(byte)
+            index = nextIndex
+        }
+        self = data
+    }
+
+    /// Generate random bytes
+    static func randomBytes(_ count: Int) -> Data {
+        var data = Data(count: count)
+        data.withUnsafeMutableBytes { ptr in
+            _ = SecRandomCopyBytes(kSecRandomDefault, count, ptr.baseAddress!)
+        }
+        return data
+    }
+}
+
+// MARK: - Data ↔ Base64 (Protocol Wire Format)
+
+extension Data {
+    /// Encode to standard base64 string (matching Python's base64.b64encode)
+    func base64EncodedString() -> String {
+        self.base64EncodedString(options: [])
+    }
+
+    /// Decode from base64 string
+    static func fromBase64(_ string: String) throws -> Data {
+        // Try standard base64 first, then URL-safe
+        if let data = Data(base64Encoded: string, options: .ignoreUnknownCharacters) {
+            return data
+        }
+        throw CryptoError.invalidBase64
+    }
+}
+
+// MARK: - UInt32 Big-Endian
+
+extension UInt32 {
+    var bigEndianData: Data {
+        var value = self.bigEndian
+        return Data(bytes: &value, count: 4)
+    }
+}
+
+// MARK: - CryptoKit Key → Data
+
+extension Curve25519.KeyAgreement.PublicKey {
+    nonisolated var rawData: Data {
+        Data(rawRepresentation)
+    }
+}
+
+extension Curve25519.KeyAgreement.PrivateKey {
+    nonisolated var rawData: Data {
+        Data(rawRepresentation)
+    }
+}
+
+extension Curve25519.Signing.PublicKey {
+    nonisolated var rawData: Data {
+        Data(rawRepresentation)
+    }
+}
+
+extension Curve25519.Signing.PrivateKey {
+    nonisolated var rawData: Data {
+        Data(rawRepresentation)
+    }
+}
+
+// MARK: - String helpers
+
+extension String {
+    /// Trim whitespace and newlines
+    var trimmed: String {
+        trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+}
+
+// MARK: - Date Parsing (server sends ISO8601 with or without timezone)
+
+enum DateParsing {
+    private static let iso8601WithTZ: ISO8601DateFormatter = {
+        let f = ISO8601DateFormatter()
+        f.formatOptions = [.withInternetDateTime, .withFractionalSeconds]
+        return f
+    }()
+
+    private static let iso8601Basic: ISO8601DateFormatter = {
+        let f = ISO8601DateFormatter()
+        f.formatOptions = [.withInternetDateTime]
+        return f
+    }()
+
+    private static let noTZ: DateFormatter = {
+        let f = DateFormatter()
+        f.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
+        f.timeZone = TimeZone(identifier: "UTC")
+        f.locale = Locale(identifier: "en_US_POSIX")
+        return f
+    }()
+
+    /// Parse ISO8601 date string — handles with/without timezone, with/without fractional seconds
+    static func parse(_ string: String) -> Date? {
+        iso8601WithTZ.date(from: string)
+            ?? iso8601Basic.date(from: string)
+            ?? noTZ.date(from: string)
+    }
+
+    /// Format Date to ISO8601 string (for after_ts / since_ts parameters)
+    static func format(_ date: Date) -> String {
+        iso8601WithTZ.string(from: date)
+    }
+}
+
+// MARK: - Dictionary merge helper
+
+extension Dictionary where Key == String, Value == Any {
+    nonisolated func string(for key: String) -> String? {
+        self[key] as? String
+    }
+
+    nonisolated func int(for key: String) -> Int? {
+        if let i = self[key] as? Int { return i }
+        if let s = self[key] as? String, let i = Int(s) { return i }
+        return nil
+    }
+
+    nonisolated func dict(for key: String) -> [String: Any]? {
+        self[key] as? [String: Any]
+    }
+
+    nonisolated func array(for key: String) -> [[String: Any]]? {
+        self[key] as? [[String: Any]]
+    }
+
+    nonisolated func data(for key: String) -> Data? {
+        if let hex = self[key] as? String {
+            return Data(hexString: hex)
+        }
+        return nil
+    }
+
+    nonisolated func bool(for key: String) -> Bool? {
+        if let b = self[key] as? Bool { return b }
+        if let i = self[key] as? Int { return i != 0 }
+        return nil
+    }
+}

ios_client 0.8.5/Kecalek/ViewModels/AuthViewModel.swift

@@ -0,0 +1,192 @@
+import Foundation
+import SwiftUI
+
+@Observable
+final class AuthViewModel {
+    var email = ""
+    var password = ""
+    var confirmPassword = ""
+    var username = ""
+    var confirmationCode = ""
+
+    var isLoading = false
+    var errorMessage: String?
+    var showConfirmation = false
+    var registrationMessage: String?
+
+    var serverHost = Constants.defaultHost
+    var serverPort = String(Constants.defaultPort)
+
+    var hasSavedCredentials = false
+    var isBiometricLoading = false
+
+    enum AuthMode {
+        case login, register, pairing
+    }
+    var mode: AuthMode = .login
+
+    func checkSavedCredentials() {
+        hasSavedCredentials = KeychainService.hasSavedCredentials() && KeychainService.isBiometricAvailable()
+    }
+
+    func login(appState: AppState) async {
+        guard !email.isEmpty, !password.isEmpty else {
+            errorMessage = "Email and password are required"
+            return
+        }
+
+        isLoading = true
+        errorMessage = nil
+
+        // Only connect if not already connected
+        if await !appState.chatClient.isConnected {
+            do {
+                let port = UInt16(serverPort) ?? Constants.defaultPort
+                try await appState.chatClient.connect(host: serverHost, port: port)
+            } catch {
+                isLoading = false
+                errorMessage = "Connection failed: \(error.localizedDescription)"
+                return
+            }
+        }
+
+        let (success, message) = await appState.chatClient.login(email: email, password: password)
+        isLoading = false
+
+        if success {
+            appState.email = email
+            appState.isLoggedIn = true
+            appState.connectionStatus = .connected
+            appState.startConnectionMonitor()
+            if let userId = await appState.chatClient.userId {
+                appState.currentUser = User(id: userId, username: await appState.chatClient.username, email: email)
+            }
+
+            // Save credentials for biometric login next time
+            if KeychainService.isBiometricAvailable() {
+                let port = UInt16(serverPort) ?? Constants.defaultPort
+                try? KeychainService.saveCredentials(
+                    email: email, password: password,
+                    host: serverHost, port: port
+                )
+            }
+
+            // Clear password from memory after successful login
+            password = ""
+            confirmPassword = ""
+        } else {
+            errorMessage = message
+        }
+    }
+
+    func biometricLogin(appState: AppState) async {
+        isBiometricLoading = true
+        errorMessage = nil
+
+        do {
+            let creds = try KeychainService.loadCredentials()
+            email = creds.email
+            password = creds.password
+            serverHost = creds.host
+            serverPort = String(creds.port)
+            isBiometricLoading = false
+
+            await login(appState: appState)
+
+            // If login failed, reset to defaults so the form isn't stuck on stale values
+            if !appState.isLoggedIn {
+                serverHost = Constants.defaultHost
+                serverPort = String(Constants.defaultPort)
+                password = ""
+                KeychainService.deleteCredentials()
+                hasSavedCredentials = false
+            }
+        } catch KeychainService.KeychainError.biometricFailed {
+            isBiometricLoading = false
+            // User cancelled — just let them type manually
+        } catch {
+            isBiometricLoading = false
+            errorMessage = error.localizedDescription
+        }
+    }
+
+    func register(appState: AppState) async {
+        guard !email.isEmpty, !password.isEmpty, !username.isEmpty else {
+            errorMessage = "All fields are required"
+            return
+        }
+        guard password == confirmPassword else {
+            errorMessage = "Passwords don't match"
+            return
+        }
+
+        isLoading = true
+        errorMessage = nil
+
+        #if DEBUG
+        print("DEBUG register: connecting to \(serverHost):\(serverPort)")
+        #endif
+        if await !appState.chatClient.isConnected {
+            do {
+                let port = UInt16(serverPort) ?? Constants.defaultPort
+                try await appState.chatClient.connect(host: serverHost, port: port)
+                #if DEBUG
+                print("DEBUG register: connected successfully")
+                #endif
+            } catch {
+                isLoading = false
+                #if DEBUG
+                print("DEBUG register: connection failed - \(error)")
+                #endif
+                errorMessage = "Connection failed: \(error.localizedDescription)"
+                return
+            }
+        }
+
+        #if DEBUG
+        print("DEBUG register: calling chatClient.register")
+        #endif
+        let (success, message) = await appState.chatClient.register(username: username, password: password, email: email)
+        isLoading = false
+
+        #if DEBUG
+        print("DEBUG AuthViewModel: register returned success=\(success), message=\(message)")
+        #endif
+
+        if success {
+            registrationMessage = message
+            showConfirmation = true
+            #if DEBUG
+            print("DEBUG AuthViewModel: showConfirmation set to true")
+            #endif
+        } else {
+            errorMessage = message
+            #if DEBUG
+            print("DEBUG AuthViewModel: errorMessage set to \(message)")
+            #endif
+        }
+    }
+
+    func confirmRegistration(appState: AppState) async {
+        guard !confirmationCode.isEmpty else {
+            errorMessage = "Enter the confirmation code"
+            return
+        }
+
+        isLoading = true
+        errorMessage = nil
+
+        let (success, message) = await appState.chatClient.confirmRegistration(
+            email: email, username: username, code: confirmationCode
+        )
+        isLoading = false
+
+        if success {
+            registrationMessage = message
+            // Auto-login after registration
+            await login(appState: appState)
+        } else {
+            errorMessage = message
+        }
+    }
+}

ios_client 0.8.5/Kecalek/ViewModels/ChatViewModel.swift

@@ -0,0 +1,356 @@
+import Foundation
+import SwiftUI
+
+@Observable
+final class ChatViewModel {
+    var messages: [Message] = []
+    var isLoading = false
+    var isSending = false
+    var errorMessage: String?
+    var searchQuery = ""
+    var searchResults: [String] = []  // message IDs matching search
+    var currentSearchIndex = 0
+
+    private var notificationTask: Task<Void, Never>?
+
+    func loadMessages(convId: String, chatClient: ChatClient) async {
+        let email = await chatClient.email
+        let cacheKey = await chatClient.cacheKey
+
+        // 1. Load from cache
+        let cachedDicts = MessageCache.load(email: email, convId: convId, cacheKey: cacheKey)
+        let cached = cachedDicts?.compactMap { Message.fromCacheDict($0) } ?? []
+
+        if !cached.isEmpty {
+            // Cache hit — show immediately, no spinner
+            messages = cached.sorted { $0.createdAt < $1.createdAt }
+        } else {
+            // No cache — show spinner (first open)
+            isLoading = true
+        }
+
+        // 2. Determine after_ts from newest cached message
+        let newestCached = messages.last
+
+        // 3. Fetch from server
+        let serverMessages: [Message]
+        if let newest = newestCached {
+            let afterTs = DateParsing.format(newest.createdAt)
+            #if DEBUG
+            print("DEBUG getMessages after_ts=\(afterTs)")
+            #endif
+            serverMessages = await chatClient.getMessages(convId: convId, limit: 50, afterTs: afterTs)
+        } else {
+            serverMessages = await chatClient.getMessages(convId: convId, limit: 50)
+        }
+
+        // 4. Merge
+        if newestCached != nil {
+            // Incremental: dedup by ID, append new, sort
+            let existingIds = Set(messages.map(\.id))
+            let newMessages = serverMessages.filter { !existingIds.contains($0.id) }
+            if !newMessages.isEmpty {
+                messages.append(contentsOf: newMessages)
+                messages.sort { $0.createdAt < $1.createdAt }
+            }
+        } else {
+            // Full fetch: replace
+            messages = serverMessages
+        }
+
+        // 5. Sync deleted (only for incremental)
+        if let newest = newestCached {
+            let afterTs = DateParsing.format(newest.createdAt)
+            #if DEBUG
+            print("DEBUG get_deleted_since since_ts=\(afterTs)")
+            #endif
+            let deletedIds = await chatClient.getDeletedSince(convId: convId, sinceTs: afterTs)
+            if !deletedIds.isEmpty {
+                messages.removeAll { deletedIds.contains($0.id) }
+            }
+        }
+
+        // 6. Loading done
+        isLoading = false
+
+        // 7. Save to cache
+        await saveCache(convId: convId, chatClient: chatClient)
+
+        // 8. Mark entire conversation as read (server-side bulk mark)
+        // This handles messages not in cache (e.g. failed to decrypt or never fetched)
+        await chatClient.markConversationRead(convId: convId)
+        // Update local readBy for cached messages so cache reflects read state
+        let currentUserId = await chatClient.userId ?? ""
+        var anyUpdated = false
+        for i in messages.indices {
+            if !messages[i].isMine(currentUserId: currentUserId) && !messages[i].readBy.contains(currentUserId) {
+                messages[i].readBy.insert(currentUserId)
+                anyUpdated = true
+            }
+        }
+        if anyUpdated {
+            await saveCache(convId: convId, chatClient: chatClient)
+        }
+    }
+
+    func loadOlderMessages(convId: String, chatClient: ChatClient) async {
+        let older = await chatClient.getMessages(convId: convId, limit: 50, offset: messages.count)
+        messages.insert(contentsOf: older, at: 0)
+        await saveCache(convId: convId, chatClient: chatClient)
+    }
+
+    func sendMessage(convId: String, text: String, members: [ConversationMember],
+                     chatClient: ChatClient, replyTo: String? = nil) async {
+        guard !text.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else { return }
+
+        isSending = true
+        errorMessage = nil
+
+        let (success, msg, sentMessage) = await chatClient.sendMessage(
+            convId: convId, text: text, members: members, replyTo: replyTo
+        )
+
+        isSending = false
+
+        if !success {
+            errorMessage = msg
+        } else if let sentMessage = sentMessage {
+            // Append locally — don't reload from server (ratchet keys are one-time)
+            if !messages.contains(where: { $0.id == sentMessage.id }) {
+                messages.append(sentMessage)
+            }
+            await saveCache(convId: convId, chatClient: chatClient)
+        }
+    }
+
+    func deleteMessage(messageId: String, convId: String, chatClient: ChatClient) async {
+        let success = await chatClient.deleteMessage(messageId: messageId, convId: convId)
+        if success {
+            messages.removeAll { $0.id == messageId }
+            await saveCache(convId: convId, chatClient: chatClient)
+        }
+    }
+
+    func saveCache(convId: String, chatClient: ChatClient) async {
+        let email = await chatClient.email
+        let cacheKey = await chatClient.cacheKey
+        let dicts = messages.map { $0.toCacheDict() }
+        try? MessageCache.save(email: email, convId: convId, messages: dicts, cacheKey: cacheKey)
+    }
+
+    func search(query: String) {
+        searchQuery = query
+        if query.isEmpty {
+            searchResults = []
+            currentSearchIndex = 0
+            return
+        }
+        let lower = query.lowercased()
+        searchResults = messages.filter { $0.text?.lowercased().contains(lower) == true }.map(\.id)
+        currentSearchIndex = searchResults.isEmpty ? 0 : searchResults.count - 1
+    }
+
+    func nextSearchResult() {
+        guard !searchResults.isEmpty else { return }
+        currentSearchIndex = (currentSearchIndex + 1) % searchResults.count
+    }
+
+    func prevSearchResult() {
+        guard !searchResults.isEmpty else { return }
+        currentSearchIndex = (currentSearchIndex - 1 + searchResults.count) % searchResults.count
+    }
+
+    func startNotificationListener(convId: String, chatClient: ChatClient) {
+        notificationTask?.cancel()
+        notificationTask = Task {
+            for await notification in await chatClient.makeNotificationStream() {
+                await handleNotification(notification, convId: convId, chatClient: chatClient)
+            }
+        }
+    }
+
+    @MainActor
+    private func handleNotification(_ notification: ChatNotification, convId: String, chatClient: ChatClient) {
+        switch notification {
+        case .newMessage(let data):
+            if data["conversation_id"] as? String == convId {
+                Task {
+                    if let message = await chatClient.decryptNotification(data) {
+                        await MainActor.run {
+                            // Deduplicate — sent messages are already appended locally
+                            if !messages.contains(where: { $0.id == message.id }) {
+                                messages.append(message)
+                            }
+                        }
+                        await saveCache(convId: convId, chatClient: chatClient)
+                        // Only mark as read if from someone else
+                        let myId = await chatClient.userId ?? ""
+                        if message.senderId != myId {
+                            await chatClient.markRead(convId: convId, messageIds: [message.id])
+                        }
+                        await chatClient.flushSelfEncrypt()
+                    }
+                }
+            }
+        case .messageDeleted(let data):
+            if let msgId = data["message_id"] as? String {
+                messages.removeAll { $0.id == msgId }
+                Task {
+                    await saveCache(convId: convId, chatClient: chatClient)
+                }
+            }
+        case .messagesRead(let data):
+            if let readUserId = data["user_id"] as? String,
+               let msgIds = data["message_ids"] as? [String] {
+                for i in messages.indices {
+                    if msgIds.contains(messages[i].id) {
+                        messages[i].readBy.insert(readUserId)
+                    }
+                }
+            }
+        case .messageReacted(let data):
+            if let msgId = data["message_id"] as? String,
+               let reactUserId = data["user_id"] as? String,
+               let reaction = data["reaction"] as? String,
+               let action = data["action"] as? String,
+               let idx = messages.firstIndex(where: { $0.id == msgId }) {
+                if action == "add" {
+                    let newReaction = MessageReaction(userId: reactUserId, reaction: reaction, createdAt: Date())
+                    if !messages[idx].reactions.contains(where: { $0.userId == reactUserId && $0.reaction == reaction }) {
+                        messages[idx].reactions.append(newReaction)
+                    }
+                } else {
+                    messages[idx].reactions.removeAll { $0.userId == reactUserId && $0.reaction == reaction }
+                }
+                Task { await saveCache(convId: convId, chatClient: chatClient) }
+            }
+        case .messagePinned(let data):
+            if let msgId = data["message_id"] as? String,
+               let pinUserId = data["user_id"] as? String,
+               let idx = messages.firstIndex(where: { $0.id == msgId }) {
+                messages[idx].pinnedAt = Date()
+                messages[idx].pinnedBy = pinUserId
+                Task { await saveCache(convId: convId, chatClient: chatClient) }
+            }
+        case .messageUnpinned(let data):
+            if let msgId = data["message_id"] as? String,
+               let idx = messages.firstIndex(where: { $0.id == msgId }) {
+                messages[idx].pinnedAt = nil
+                messages[idx].pinnedBy = nil
+                Task { await saveCache(convId: convId, chatClient: chatClient) }
+            }
+        case .messageDelivered(let data):
+            // Delivery receipt — message was successfully received by recipient
+            if let msgId = data["message_id"] as? String,
+               let idx = messages.firstIndex(where: { $0.id == msgId }) {
+                messages[idx].readBy.insert("__delivered__")
+                Task { await saveCache(convId: convId, chatClient: chatClient) }
+            }
+        default:
+            break
+        }
+    }
+
+    func reactToMessage(messageId: String, convId: String, reaction: String,
+                        currentUserId: String, chatClient: ChatClient) async {
+        guard let idx = messages.firstIndex(where: { $0.id == messageId }) else { return }
+        let existingReaction = messages[idx].reactions.first { $0.userId == currentUserId }
+        let hasSameReaction = existingReaction?.reaction == reaction
+        let savedReactions = messages[idx].reactions
+
+        // Optimistic update
+        if hasSameReaction {
+            // Tapping same emoji — remove it
+            messages[idx].reactions.removeAll { $0.userId == currentUserId }
+        } else {
+            // Remove any previous reaction from this user, then add new one
+            messages[idx].reactions.removeAll { $0.userId == currentUserId }
+            messages[idx].reactions.append(MessageReaction(userId: currentUserId, reaction: reaction, createdAt: Date()))
+        }
+
+        // If user had a different reaction, remove it on server first
+        if let old = existingReaction, old.reaction != reaction {
+            let _ = await chatClient.reactMessage(messageId: messageId, conversationId: convId,
+                                                   reaction: old.reaction, action: "remove")
+        }
+
+        // Add or remove the target reaction on server
+        let action = hasSameReaction ? "remove" : "add"
+        let success = await chatClient.reactMessage(messageId: messageId, conversationId: convId,
+                                                     reaction: reaction, action: action)
+        if !success {
+            // Revert on failure
+            messages[idx].reactions = savedReactions
+        }
+        await saveCache(convId: convId, chatClient: chatClient)
+    }
+
+    func pinMessage(messageId: String, convId: String, pin: Bool,
+                    chatClient: ChatClient) async {
+        guard let idx = messages.firstIndex(where: { $0.id == messageId }) else { return }
+
+        // Optimistic update
+        if pin {
+            messages[idx].pinnedAt = Date()
+            messages[idx].pinnedBy = await chatClient.userId
+        } else {
+            messages[idx].pinnedAt = nil
+            messages[idx].pinnedBy = nil
+        }
+
+        let success = await chatClient.pinMessage(messageId: messageId, conversationId: convId,
+                                                   action: pin ? "pin" : "unpin")
+        if !success {
+            // Revert on failure
+            if pin {
+                messages[idx].pinnedAt = nil
+                messages[idx].pinnedBy = nil
+            }
+        }
+        await saveCache(convId: convId, chatClient: chatClient)
+    }
+
+    // MARK: - Forward Message
+
+    func forwardMessage(message: Message, targetConvId: String,
+                        targetMembers: [ConversationMember], chatClient: ChatClient) async -> Bool {
+        var originalMsg: [String: Any] = [
+            "text": message.text ?? "",
+            "sender": message.senderUsername,
+            "conversation_id": message.conversationId,
+            "message_id": message.id,
+        ]
+        if let file = message.file {
+            originalMsg["file"] = [
+                "file_id": file.fileId,
+                "aes_key": file.aesKey,
+                "iv": file.iv,
+                "filename": file.filename,
+                "size": file.size,
+                "mime_type": file.mimeType,
+            ] as [String: Any]
+        }
+        if let image = message.image {
+            var imgDict: [String: Any] = [
+                "file_id": image.fileId,
+                "aes_key": image.aesKey,
+                "iv": image.iv,
+                "filename": image.filename,
+                "size": image.size,
+            ]
+            if let thumb = image.thumbnail { imgDict["thumbnail"] = thumb }
+            originalMsg["image"] = imgDict
+        }
+
+        let (success, _, _) = await chatClient.forwardMessage(
+            targetConvId: targetConvId, originalMsg: originalMsg,
+            targetMembers: targetMembers
+        )
+        return success
+    }
+
+    func stop() {
+        notificationTask?.cancel()
+        notificationTask = nil
+    }
+}

ios_client 0.8.5/Kecalek/ViewModels/ConversationListVM.swift

@@ -0,0 +1,246 @@
+import Foundation
+import SwiftUI
+
+@Observable
+final class ConversationListVM {
+    var conversations: [Conversation] = []
+    var invitations: [Invitation] = []
+    var onlineUsers: Set<String> = []
+    var unreadCounts: [String: Int] = [:]
+    var favorites: Set<String> = []
+    var avatarCache: [String: Data] = [:]  // convId -> avatar image data
+    var isLoading = false
+
+    private var notificationTask: Task<Void, Never>?
+    private var avatarTask: Task<Void, Never>?
+    private var refreshTask: Task<Void, Never>?
+    private var localKey: Data?
+    private var email: String = ""
+    private var lastRefreshTime: Date = .distantPast
+
+    func load(chatClient: ChatClient, email: String) async {
+        isLoading = true
+        self.email = email
+
+        // Load favorites from disk (encrypted with localKey)
+        localKey = await chatClient.localKey
+        favorites = KeyStorage.loadFavorites(email: email, localKey: localKey)
+
+        let currentUserId = await chatClient.userId ?? ""
+
+        // Load cached conversations immediately (show while fetching from server)
+        if let cached = MessageCache.loadConversations(email: email, cacheKey: localKey) {
+            conversations = sortConversations(cached, currentUserId: currentUserId)
+            for conv in conversations where conv.unreadCount > 0 {
+                unreadCounts[conv.id] = conv.unreadCount
+            }
+        }
+
+        // Load cached avatars from disk
+        let diskAvatars = MessageCache.loadAllAvatars(email: email, cacheKey: localKey)
+        if !diskAvatars.isEmpty {
+            avatarCache = diskAvatars
+        }
+
+        // Fetch conversations from server
+        let convs = await chatClient.listConversations()
+        if !convs.isEmpty {
+            // Sync unread counts from server (authoritative source)
+            for conv in convs {
+                unreadCounts[conv.id] = conv.unreadCount
+            }
+            conversations = sortConversations(convs, currentUserId: currentUserId)
+            // Save to cache
+            MessageCache.saveConversations(email: email, conversations: convs, cacheKey: localKey)
+        }
+
+        // Fetch invitations
+        invitations = await chatClient.listInvitations()
+
+        isLoading = false
+        lastRefreshTime = Date()
+
+        // Start notification listener
+        startNotificationListener(chatClient: chatClient, email: email)
+
+        // Read initial online users stored in ChatClient
+        // (online_users notification arrives during login before any subscriber exists)
+        onlineUsers = await chatClient.onlineUserIds
+
+        // Load avatars in background (non-blocking)
+        avatarTask?.cancel()
+        avatarTask = Task { await loadAvatars(chatClient: chatClient, currentUserId: currentUserId) }
+    }
+
+    func refresh(chatClient: ChatClient) async {
+        // Debounce: skip if refreshed < 2s ago
+        guard Date().timeIntervalSince(lastRefreshTime) > 2 else {
+            #if DEBUG
+            print("DEBUG ConversationListVM: refresh debounced")
+            #endif
+            return
+        }
+        lastRefreshTime = Date()
+
+        let currentUserId = await chatClient.userId ?? ""
+        let convs = await chatClient.listConversations()
+        if !convs.isEmpty {
+            // Sync unread counts from server (authoritative source)
+            for conv in convs {
+                unreadCounts[conv.id] = conv.unreadCount
+            }
+            conversations = sortConversations(convs, currentUserId: currentUserId)
+            // Save to cache
+            MessageCache.saveConversations(email: email, conversations: convs, cacheKey: localKey)
+        }
+        invitations = await chatClient.listInvitations()
+
+        // Refresh avatars in background
+        avatarTask?.cancel()
+        avatarTask = Task { await loadAvatars(chatClient: chatClient, currentUserId: currentUserId) }
+    }
+
+    func toggleFavorite(convId: String, email: String) {
+        if favorites.contains(convId) {
+            favorites.remove(convId)
+        } else {
+            favorites.insert(convId)
+        }
+        try? KeyStorage.saveFavorites(email: email, favorites: favorites, localKey: localKey)
+
+        // Re-sort
+        let userId = conversations.first?.createdBy ?? ""
+        conversations = sortConversations(conversations, currentUserId: userId)
+    }
+
+    func forceRefresh(chatClient: ChatClient) async {
+        lastRefreshTime = .distantPast
+        await refresh(chatClient: chatClient)
+    }
+
+    func updateAvatar(convId: String, data: Data) {
+        avatarCache[convId] = data
+        // Persist to disk so it survives load() re-reads
+        MessageCache.saveAvatar(email: email, key: convId, data: data, cacheKey: localKey)
+    }
+
+    func markConversationRead(convId: String) {
+        unreadCounts[convId] = 0
+    }
+
+    func incrementUnread(convId: String) {
+        unreadCounts[convId, default: 0] += 1
+    }
+
+    private func sortConversations(_ convs: [Conversation], currentUserId: String) -> [Conversation] {
+        var result = convs.map { conv -> Conversation in
+            var c = conv
+            c.isFavorite = favorites.contains(conv.id)
+            c.unreadCount = unreadCounts[conv.id] ?? conv.unreadCount
+            return c
+        }
+
+        result.sort { a, b in
+            // Favorites first
+            if a.isFavorite != b.isFavorite { return a.isFavorite }
+            // Online DMs next
+            let aOnline = a.dmPartnerId(currentUserId: currentUserId).map { onlineUsers.contains($0) } ?? false
+            let bOnline = b.dmPartnerId(currentUserId: currentUserId).map { onlineUsers.contains($0) } ?? false
+            if aOnline != bOnline { return aOnline }
+            // Alphabetical
+            return a.displayName(currentUserId: currentUserId).lowercased() < b.displayName(currentUserId: currentUserId).lowercased()
+        }
+
+        return result
+    }
+
+    private func startNotificationListener(chatClient: ChatClient, email: String) {
+        notificationTask?.cancel()
+        notificationTask = Task {
+            for await notification in await chatClient.makeNotificationStream() {
+                await handleNotification(notification, chatClient: chatClient, email: email)
+            }
+        }
+    }
+
+    @MainActor
+    private func handleNotification(_ notification: ChatNotification, chatClient: ChatClient, email: String) {
+        switch notification {
+        case .newMessage(let data):
+            if let convId = data["conversation_id"] as? String {
+                incrementUnread(convId: convId)
+            }
+        case .onlineUsers(let userIds):
+            onlineUsers = Set(userIds)
+        case .userOnline(let userId):
+            onlineUsers.insert(userId)
+        case .userOffline(let userId):
+            onlineUsers.remove(userId)
+        case .conversationCreated, .memberAdded, .memberRemoved, .conversationRenamed, .conversationDeleted:
+            refreshTask?.cancel()
+            refreshTask = Task { await refresh(chatClient: chatClient) }
+        case .groupInvitation:
+            Task { invitations = await chatClient.listInvitations() }
+        case .reconnected:
+            #if DEBUG
+            print("DEBUG ConversationListVM: reconnected — refreshing")
+            #endif
+            refreshTask?.cancel()
+            refreshTask = Task { await refresh(chatClient: chatClient) }
+        case .connectionStateChanged(let connected):
+            if !connected {
+                #if DEBUG
+                print("DEBUG ConversationListVM: disconnected")
+                #endif
+            }
+        default:
+            break
+        }
+    }
+
+    private func loadAvatars(chatClient: ChatClient, currentUserId: String) async {
+        await withTaskGroup(of: (String, Data?).self) { group in
+            for conv in conversations {
+                let convId = conv.id
+                // Skip if already cached in memory
+                if avatarCache[convId] != nil { continue }
+                if conv.isGroup {
+                    // Only fetch if group has an avatar file
+                    if conv.avatarFile != nil {
+                        group.addTask {
+                            let data = await chatClient.getGroupAvatar(convId: convId)
+                            return (convId, data)
+                        }
+                    }
+                } else {
+                    // DM: fetch partner's avatar
+                    if let partnerId = conv.dmPartnerId(currentUserId: currentUserId) {
+                        group.addTask {
+                            let data = await chatClient.getAvatar(userId: partnerId)
+                            return (convId, data)
+                        }
+                    }
+                }
+            }
+
+            let emailCapture = email
+            let keyCapture = localKey
+            for await (convId, data) in group {
+                if let data = data {
+                    avatarCache[convId] = data
+                    // Save to disk cache
+                    MessageCache.saveAvatar(email: emailCapture, key: convId, data: data, cacheKey: keyCapture)
+                }
+            }
+        }
+    }
+
+    func stop() {
+        notificationTask?.cancel()
+        notificationTask = nil
+        avatarTask?.cancel()
+        avatarTask = nil
+        refreshTask?.cancel()
+        refreshTask = nil
+    }
+}

ios_client 0.8.5/Kecalek/ViewModels/ProfileViewModel.swift

@@ -0,0 +1,98 @@
+import Foundation
+import SwiftUI
+
+@Observable
+final class ProfileViewModel {
+    var profile: UserProfile?
+    var avatarData: Data?
+    var isLoading = false
+    var isSaving = false
+    var errorMessage: String?
+
+    // Editable fields
+    var phone = ""
+    var phoneVisible = false
+    var location = ""
+    var locationVisible = false
+
+    func loadProfile(userId: String? = nil, chatClient: ChatClient) async {
+        isLoading = true
+        profile = await chatClient.getProfile(userId: userId)
+        isLoading = false
+
+        if let p = profile {
+            phone = p.phone ?? ""
+            phoneVisible = p.phoneVisible
+            location = p.location ?? ""
+            locationVisible = p.locationVisible
+        }
+
+        // Load avatar
+        let clientUserId = await chatClient.userId
+        let uid = userId ?? clientUserId ?? ""
+        if !uid.isEmpty {
+            avatarData = await chatClient.getAvatar(userId: uid)
+        }
+    }
+
+    @discardableResult
+    func saveProfile(chatClient: ChatClient) async -> Bool {
+        isSaving = true
+        errorMessage = nil
+
+        let success = await chatClient.updateProfile(
+            phone: phone.isEmpty ? nil : phone,
+            phoneVisible: phoneVisible,
+            location: location.isEmpty ? nil : location,
+            locationVisible: locationVisible
+        )
+
+        isSaving = false
+
+        if !success {
+            errorMessage = "Failed to update profile"
+        }
+        return success
+    }
+
+    func uploadAvatar(imageData: Data, chatClient: ChatClient) async {
+        isSaving = true
+        errorMessage = nil
+        let (success, msg) = await chatClient.updateAvatar(imageData: imageData)
+        isSaving = false
+
+        if success {
+            // Reload avatar from server (it was resized/compressed)
+            let clientUserId = await chatClient.userId ?? ""
+            avatarData = await chatClient.getAvatar(userId: clientUserId)
+        } else {
+            errorMessage = msg.isEmpty ? "Failed to upload avatar" : msg
+        }
+    }
+
+    // MARK: - Username Change
+
+    func changeUsername(newUsername: String, chatClient: ChatClient) async -> Bool {
+        isSaving = true
+        errorMessage = nil
+        let (success, msg) = await chatClient.changeUsername(newUsername: newUsername)
+        isSaving = false
+        if !success {
+            errorMessage = msg
+        }
+        return success
+    }
+
+    // MARK: - Password Change
+
+    func changePassword(oldPassword: String, newPassword: String, chatClient: ChatClient) async -> Bool {
+        isSaving = true
+        errorMessage = nil
+        let (success, msg) = await chatClient.changePassword(oldPassword: oldPassword, newPassword: newPassword)
+        isSaving = false
+        if !success {
+            errorMessage = msg
+        }
+        return success
+    }
+}

ios_client 0.8.5/Kecalek/ViewModels/VerificationVM.swift

@@ -0,0 +1,60 @@
+import Foundation
+import SwiftUI
+
+@Observable
+final class VerificationVM {
+    var safetyNumber: String?
+    var myFingerprint: String?
+    var peerFingerprint: String?
+    var verificationStatus: String = "unverified"  // "verified", "trusted", "unverified"
+    var qrCodeData: Data?
+    var scanResult: String?
+    var scanSuccess: Bool?
+    var isLoading = false
+    var errorMessage: String?
+
+    func loadVerification(peerUserId: String, chatClient: ChatClient) async {
+        isLoading = true
+
+        // Ensure peer's identity key is fetched (needed for safety number & verification)
+        _ = await chatClient.getPeerIdentityKey(userId: peerUserId)
+
+        // Get safety number
+        safetyNumber = await chatClient.getSafetyNumber(peerUserId: peerUserId)
+
+        // Get fingerprints
+        myFingerprint = await chatClient.getMyFingerprint()
+        peerFingerprint = await chatClient.getPeerFingerprint(peerUserId: peerUserId)
+
+        // Get verification status
+        verificationStatus = await chatClient.getVerificationStatus(userId: peerUserId)
+
+        // Get QR code data for display
+        qrCodeData = await chatClient.getVerificationQRData()
+
+        isLoading = false
+    }
+
+    func verifyContact(peerUserId: String, chatClient: ChatClient) async {
+        guard let peerIK = await chatClient.getPeerIdentityKey(userId: peerUserId) else {
+            errorMessage = "No identity key on record for this user."
+            return
+        }
+        await chatClient.verifyContact(userId: peerUserId, identityKey: peerIK, method: "manual")
+        verificationStatus = "verified"
+    }
+
+    func unverifyContact(peerUserId: String, chatClient: ChatClient) async {
+        await chatClient.unverifyContact(userId: peerUserId)
+        verificationStatus = "trusted"
+    }
+
+    func verifyQRCode(data: Data, chatClient: ChatClient) async {
+        let (success, _, message) = await chatClient.verifyQRCode(qrData: data)
+        scanSuccess = success
+        scanResult = message
+        if success {
+            verificationStatus = "verified"
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Auth/AuthorizeDeviceView.swift

@@ -0,0 +1,82 @@
+import SwiftUI
+
+struct AuthorizeDeviceView: View {
+    var appState: AppState
+    @State private var code = ""
+    @State private var isAuthorizing = false
+    @State private var statusMessage: String?
+    @State private var isError = false
+    @State private var isDone = false
+    @Environment(\.dismiss) private var dismiss
+
+    var body: some View {
+        NavigationStack {
+            ScrollView {
+                VStack(spacing: 24) {
+                    Image(systemName: "iphone.badge.checkmark")
+                        .font(.system(size: 48))
+                        .foregroundStyle(.blue)
+
+                    Text("Authorize New Device")
+                        .font(.title2.bold())
+
+                    Text("Enter the 8-digit pairing code shown on the new device.")
+                        .font(.subheadline)
+                        .foregroundStyle(.secondary)
+                        .multilineTextAlignment(.center)
+
+                    TextField("Pairing Code", text: $code)
+                        .font(.system(size: 24, weight: .bold, design: .monospaced))
+                        .multilineTextAlignment(.center)
+                        .keyboardType(.numberPad)
+                        .textFieldStyle(.roundedBorder)
+
+                    Button("Authorize") {
+                        Task { await authorize() }
+                    }
+                    .buttonStyle(.borderedProminent)
+                    .disabled(code.count < 8 || isAuthorizing || isDone)
+
+                    if isAuthorizing {
+                        ProgressView("Preparing history & sending keys...")
+                    }
+
+                    if let status = statusMessage {
+                        Text(status)
+                            .font(.caption)
+                            .foregroundStyle(isError ? .red : .green)
+                            .multilineTextAlignment(.center)
+                    }
+
+                    if isDone {
+                        Button("Done") { dismiss() }
+                            .buttonStyle(.bordered)
+                    }
+                }
+                .padding(32)
+            }
+            .navigationTitle("Authorize Device")
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .topBarLeading) {
+                    Button("Cancel") { dismiss() }
+                }
+            }
+        }
+    }
+
+    private func authorize() async {
+        isAuthorizing = true
+        isError = false
+        statusMessage = nil
+
+        let (success, msg) = await appState.chatClient.authorizeDevice(code: code)
+        isAuthorizing = false
+
+        statusMessage = msg
+        isError = !success
+        if success {
+            isDone = true
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Auth/LoginView.swift

@@ -0,0 +1,179 @@
+import SwiftUI
+
+struct LoginView: View {
+    @Bindable var viewModel: AuthViewModel
+    var appState: AppState
+    @State private var showPairing = false
+    @State private var didAttemptBiometric = false
+
+    var body: some View {
+        NavigationStack {
+            ScrollView {
+                VStack(spacing: 20) {
+                    Image(systemName: "lock.shield.fill")
+                        .font(.system(size: 60))
+                        .foregroundStyle(.blue)
+                        .padding(.top, 40)
+
+                    Text("Encrypted Chat")
+                        .font(.largeTitle.bold())
+
+                    Text("End-to-end encrypted messaging")
+                        .font(.subheadline)
+                        .foregroundStyle(.secondary)
+
+                    VStack(spacing: 16) {
+                        // Server config
+                        DisclosureGroup("Server") {
+                            TextField("Host", text: $viewModel.serverHost)
+                                .textContentType(.URL)
+                                .autocapitalization(.none)
+                            TextField("Port", text: $viewModel.serverPort)
+                                .keyboardType(.numberPad)
+                        }
+                        .padding(.horizontal)
+
+                        if viewModel.mode == .register {
+                            TextField("Username", text: $viewModel.username)
+                                .textContentType(.username)
+                                .autocapitalization(.none)
+                                .textFieldStyle(.roundedBorder)
+                        }
+
+                        TextField("Email", text: $viewModel.email)
+                            .textContentType(.emailAddress)
+                            .keyboardType(.emailAddress)
+                            .autocapitalization(.none)
+                            .textFieldStyle(.roundedBorder)
+
+                        SecureField("Password", text: $viewModel.password)
+                            .textContentType(viewModel.mode == .login ? .password : .oneTimeCode)
+                            .autocorrectionDisabled()
+                            .textInputAutocapitalization(.never)
+                            .textFieldStyle(.roundedBorder)
+
+                        if viewModel.mode == .register {
+                            SecureField("Confirm Password", text: $viewModel.confirmPassword)
+                                .textContentType(.oneTimeCode)
+                                .autocorrectionDisabled()
+                                .textInputAutocapitalization(.never)
+                                .textFieldStyle(.roundedBorder)
+                        }
+
+                        if let error = viewModel.errorMessage {
+                            Text(error)
+                                .foregroundStyle(.red)
+                                .font(.caption)
+                                .multilineTextAlignment(.center)
+                        }
+
+                        Button(action: {
+                            Task {
+                                if viewModel.mode == .login {
+                                    await viewModel.login(appState: appState)
+                                } else {
+                                    await viewModel.register(appState: appState)
+                                }
+                            }
+                        }) {
+                            if viewModel.isLoading {
+                                ProgressView()
+                                    .frame(maxWidth: .infinity)
+                            } else {
+                                Text(viewModel.mode == .login ? "Login" : "Register")
+                                    .frame(maxWidth: .infinity)
+                            }
+                        }
+                        .buttonStyle(.borderedProminent)
+                        .disabled(viewModel.isLoading)
+
+                        Button(viewModel.mode == .login ? "Don't have an account? Register" : "Already have an account? Login") {
+                            viewModel.mode = viewModel.mode == .login ? .register : .login
+                            viewModel.errorMessage = nil
+                        }
+                        .font(.caption)
+
+                        if viewModel.hasSavedCredentials && viewModel.mode == .login {
+                            Divider()
+                                .padding(.vertical, 4)
+
+                            Button {
+                                Task { await viewModel.biometricLogin(appState: appState) }
+                            } label: {
+                                if viewModel.isBiometricLoading {
+                                    ProgressView()
+                                        .frame(maxWidth: .infinity)
+                                } else {
+                                    Label("Sign in with Face ID", systemImage: "faceid")
+                                        .frame(maxWidth: .infinity)
+                                }
+                            }
+                            .buttonStyle(.bordered)
+                            .disabled(viewModel.isLoading || viewModel.isBiometricLoading)
+                        }
+
+                        Divider()
+                            .padding(.vertical, 4)
+
+                        Button("Pair from existing device") {
+                            showPairing = true
+                        }
+                        .font(.caption)
+                    }
+                    .padding(.horizontal, 32)
+                }
+            }
+            .task {
+                viewModel.checkSavedCredentials()
+                if viewModel.hasSavedCredentials && !didAttemptBiometric {
+                    didAttemptBiometric = true
+                    await viewModel.biometricLogin(appState: appState)
+                }
+            }
+            .sheet(isPresented: $viewModel.showConfirmation) {
+                ConfirmationSheet(viewModel: viewModel, appState: appState)
+            }
+            .sheet(isPresented: $showPairing) {
+                PairingView(appState: appState, authViewModel: viewModel)
+            }
+        }
+    }
+}
+
+struct ConfirmationSheet: View {
+    @Bindable var viewModel: AuthViewModel
+    var appState: AppState
+
+    var body: some View {
+        VStack(spacing: 20) {
+            Text("Confirm Registration")
+                .font(.title2.bold())
+
+            if let msg = viewModel.registrationMessage {
+                Text(msg)
+                    .font(.subheadline)
+                    .foregroundStyle(.secondary)
+                    .multilineTextAlignment(.center)
+            }
+
+            TextField("Confirmation Code", text: $viewModel.confirmationCode)
+                .textFieldStyle(.roundedBorder)
+                .keyboardType(.numberPad)
+
+            if let error = viewModel.errorMessage {
+                Text(error)
+                    .foregroundStyle(.red)
+                    .font(.caption)
+            }
+
+            Button("Confirm") {
+                Task {
+                    await viewModel.confirmRegistration(appState: appState)
+                }
+            }
+            .buttonStyle(.borderedProminent)
+            .disabled(viewModel.isLoading)
+        }
+        .padding(32)
+    }
+}

ios_client 0.8.5/Kecalek/Views/Auth/PairingView.swift

@@ -0,0 +1,175 @@
+import SwiftUI
+
+struct PairingView: View {
+    var appState: AppState
+    @Bindable var authViewModel: AuthViewModel
+    @State private var email = ""
+    @State private var password = ""
+    @State private var pairingCode: String?
+    @State private var isStarting = false
+    @State private var isWaiting = false
+    @State private var statusMessage: String?
+    @State private var isError = false
+    @Environment(\.dismiss) private var dismiss
+
+    var body: some View {
+        NavigationStack {
+            ScrollView {
+                VStack(spacing: 24) {
+                    Image(systemName: "iphone.and.arrow.forward")
+                        .font(.system(size: 48))
+                        .foregroundStyle(.blue)
+
+                    Text("Device Pairing")
+                        .font(.title2.bold())
+
+                    Text("Transfer your keys from an existing device to this one.")
+                        .font(.subheadline)
+                        .foregroundStyle(.secondary)
+                        .multilineTextAlignment(.center)
+
+                    if pairingCode == nil {
+                        // Phase 1: Enter email and start pairing
+                        VStack(spacing: 16) {
+                            // Server config
+                            DisclosureGroup("Server") {
+                                TextField("Host", text: $authViewModel.serverHost)
+                                    .textContentType(.URL)
+                                    .autocapitalization(.none)
+                                TextField("Port", text: $authViewModel.serverPort)
+                                    .keyboardType(.numberPad)
+                            }
+
+                            TextField("Email", text: $email)
+                                .textContentType(.emailAddress)
+                                .keyboardType(.emailAddress)
+                                .autocapitalization(.none)
+                                .textFieldStyle(.roundedBorder)
+
+                            SecureField("Password (for key encryption)", text: $password)
+                                .textContentType(.password)
+                                .autocorrectionDisabled()
+                                .textInputAutocapitalization(.never)
+                                .textFieldStyle(.roundedBorder)
+
+                            Button("Start Pairing") {
+                                Task { await startPairing() }
+                            }
+                            .buttonStyle(.borderedProminent)
+                            .disabled(email.isEmpty || password.isEmpty || isStarting)
+
+                            if isStarting {
+                                ProgressView("Connecting...")
+                            }
+                        }
+                    } else {
+                        // Phase 2: Show code and wait for authorization
+                        VStack(spacing: 16) {
+                            Text("Pairing Code")
+                                .font(.headline)
+
+                            Text(pairingCode!)
+                                .font(.system(size: 36, weight: .bold, design: .monospaced))
+                                .padding()
+                                .background(Color(.systemGray6))
+                                .clipShape(RoundedRectangle(cornerRadius: 12))
+
+                            Text("Enter this code on your already logged-in device\nto authorize this device.")
+                                .font(.caption)
+                                .foregroundStyle(.secondary)
+                                .multilineTextAlignment(.center)
+
+                            if isWaiting {
+                                ProgressView("Waiting for authorization...")
+                                    .padding()
+                            }
+                        }
+                    }
+
+                    if let status = statusMessage {
+                        Text(status)
+                            .font(.caption)
+                            .foregroundStyle(isError ? .red : .green)
+                            .multilineTextAlignment(.center)
+                    }
+                }
+                .padding(32)
+            }
+            .navigationTitle("Pair Device")
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .topBarLeading) {
+                    Button("Cancel") { dismiss() }
+                }
+            }
+        }
+    }
+
+    private func startPairing() async {
+        isStarting = true
+        isError = false
+        statusMessage = nil
+
+        // Connect to server
+        if await !appState.chatClient.isConnected {
+            do {
+                let port = UInt16(authViewModel.serverPort) ?? Constants.defaultPort
+                try await appState.chatClient.connect(
+                    host: authViewModel.serverHost, port: port
+                )
+            } catch {
+                isStarting = false
+                statusMessage = "Connection failed: \(error.localizedDescription)"
+                isError = true
+                return
+            }
+        }
+
+        let (success, codeOrMsg) = await appState.chatClient.pairingStart(email: email)
+        isStarting = false
+
+        if success {
+            pairingCode = codeOrMsg
+            // Start waiting for authorization
+            isWaiting = true
+            Task { await waitForAuthorization() }
+        } else {
+            statusMessage = codeOrMsg
+            isError = true
+        }
+    }
+
+    private func waitForAuthorization() async {
+        let (success, msg) = await appState.chatClient.pairingWait(
+            code: pairingCode!, email: email, password: password
+        )
+        isWaiting = false
+
+        if success {
+            statusMessage = msg
+            isError = false
+            // Auto-login
+            let (loginOk, loginMsg) = await appState.chatClient.login(email: email, password: password)
+            if loginOk {
+                appState.email = email
+                appState.isLoggedIn = true
+                appState.connectionStatus = .connected
+                appState.startConnectionMonitor()
+                if let userId = await appState.chatClient.userId {
+                    appState.currentUser = User(
+                        id: userId,
+                        username: await appState.chatClient.username,
+                        email: email
+                    )
+                }
+                dismiss()
+            } else {
+                statusMessage = "Keys imported but login failed: \(loginMsg)"
+                isError = true
+            }
+        } else {
+            statusMessage = msg
+            isError = true
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Auth/RegisterView.swift

@@ -0,0 +1,4 @@
+import SwiftUI
+
+// Registration is handled within LoginView via mode toggle.
+// This file exists for potential future separation.

ios_client 0.8.5/Kecalek/Views/Chat/ChatView.swift

@@ -0,0 +1,382 @@
+import SwiftUI
+
+struct ChatView: View {
+    @State private var conversation: Conversation
+    var appState: AppState
+    var conversationListVM: ConversationListVM?
+
+    init(conversation: Conversation, appState: AppState, conversationListVM: ConversationListVM? = nil) {
+        self._conversation = State(initialValue: conversation)
+        self.appState = appState
+        self.conversationListVM = conversationListVM
+    }
+    @State private var viewModel = ChatViewModel()
+    @State private var inputText = ""
+    @State private var replyTo: Message?
+    @State private var showGroupInfo = false
+    @State private var showDMInfo = false
+    @State private var showSearch = false
+    @State private var showDeleteConfirm = false
+    @State private var showError = false
+    @State private var memberListenerTask: Task<Void, Never>?
+    @State private var forwardingMessage: Message?
+    @State private var showForwardPicker = false
+    @State private var showPinnedMessages = false
+    @State private var scrollTarget: String?
+    @State private var showVerification = false
+    @State private var verificationStatus: String = "unverified"
+
+    private var currentUserId: String {
+        appState.currentUser?.id ?? ""
+    }
+
+    private var isPartnerOnline: Bool {
+        guard !conversation.isGroup,
+              let partnerId = conversation.dmPartnerId(currentUserId: currentUserId),
+              let listVM = conversationListVM else {
+            return false
+        }
+        return listVM.onlineUsers.contains(partnerId)
+    }
+
+    var body: some View {
+        VStack(spacing: 0) {
+            searchBar
+            messagesScrollView
+            replyPreview
+            inputView
+        }
+        .navigationBarTitleDisplayMode(.inline)
+        .toolbar { toolbarContent }
+        .alert("Delete Conversation?", isPresented: $showDeleteConfirm) {
+            Button("Cancel", role: .cancel) {}
+            Button("Delete", role: .destructive) {
+                Task { await appState.chatClient.deleteConversation(convId: conversation.id) }
+            }
+        } message: {
+            Text(conversation.isGroup
+                 ? "This will remove all members and delete the conversation."
+                 : "This will remove you from the conversation.")
+        }
+        .alert("Error", isPresented: $showError) {
+            Button("OK", role: .cancel) {}
+        } message: {
+            Text(viewModel.errorMessage ?? "Unknown error")
+        }
+        .sheet(isPresented: $showGroupInfo) {
+            GroupInfoView(conversation: $conversation, appState: appState, conversationListVM: conversationListVM)
+        }
+        .sheet(isPresented: $showDMInfo) {
+            if let partnerId = conversation.dmPartnerId(currentUserId: currentUserId) {
+                ProfileView(appState: appState, isOwnProfile: false, userId: partnerId)
+            }
+        }
+        .sheet(isPresented: $showForwardPicker) {
+            if let msg = forwardingMessage {
+                ForwardPickerView(message: msg, appState: appState)
+            }
+        }
+        .sheet(isPresented: $showVerification) {
+            if let partnerId = conversation.dmPartnerId(currentUserId: currentUserId) {
+                NavigationStack {
+                    SafetyNumberView(
+                        peerUserId: partnerId,
+                        peerUsername: conversation.displayName(currentUserId: currentUserId),
+                        chatClient: appState.chatClient
+                    )
+                    .toolbar {
+                        ToolbarItem(placement: .topBarLeading) {
+                            Button("Done") { showVerification = false }
+                        }
+                    }
+                }
+            }
+        }
+        .sheet(isPresented: $showPinnedMessages) {
+            PinnedMessagesView(
+                messages: viewModel.messages.filter { $0.pinnedAt != nil },
+                onScrollTo: { scrollTarget = $0 }
+            )
+        }
+        .task {
+            // Use already-loaded data from conversation list (avoid redundant list_conversations call)
+            if let updated = conversationListVM?.conversations.first(where: { $0.id == conversation.id }) {
+                conversation = updated
+            }
+            conversationListVM?.markConversationRead(convId: conversation.id)
+            await viewModel.loadMessages(convId: conversation.id, chatClient: appState.chatClient)
+            viewModel.startNotificationListener(convId: conversation.id, chatClient: appState.chatClient)
+
+            // Load verification status for DM partner
+            if !conversation.isGroup,
+               let partnerId = conversation.dmPartnerId(currentUserId: currentUserId) {
+                verificationStatus = await appState.chatClient.getVerificationStatus(userId: partnerId)
+            }
+
+            memberListenerTask = Task {
+                for await notification in await appState.chatClient.makeNotificationStream() {
+                    switch notification {
+                    case .memberAdded, .memberRemoved, .conversationRenamed:
+                        let refreshed = await appState.chatClient.listConversations()
+                        if let updated = refreshed.first(where: { $0.id == conversation.id }) {
+                            await MainActor.run { conversation = updated }
+                        }
+                    default:
+                        break
+                    }
+                }
+            }
+        }
+        .onDisappear {
+            viewModel.stop()
+            memberListenerTask?.cancel()
+            memberListenerTask = nil
+        }
+    }
+
+    // MARK: - Search Bar
+
+    @ViewBuilder
+    private var searchBar: some View {
+        if showSearch {
+            SearchOverlayView(
+                query: $viewModel.searchQuery,
+                matchCount: viewModel.searchResults.count,
+                currentIndex: viewModel.currentSearchIndex,
+                onSearch: { viewModel.search(query: $0) },
+                onNext: { viewModel.nextSearchResult() },
+                onPrev: { viewModel.prevSearchResult() },
+                onClose: { showSearch = false; viewModel.search(query: "") }
+            )
+        }
+    }
+
+    // MARK: - Messages
+
+    private var messagesScrollView: some View {
+        ScrollViewReader { proxy in
+            ScrollView {
+                LazyVStack(spacing: 8) {
+                    if viewModel.messages.count >= 50 {
+                        Button("Load older messages") {
+                            Task {
+                                await viewModel.loadOlderMessages(convId: conversation.id, chatClient: appState.chatClient)
+                            }
+                        }
+                        .font(.caption)
+                        .padding()
+                    }
+
+                    ForEach(viewModel.messages) { message in
+                        messageBubble(for: message)
+                            .id(message.id)
+                    }
+                }
+                .padding(.horizontal)
+                .padding(.vertical, 8)
+            }
+            .onChange(of: viewModel.messages.count) {
+                if let lastId = viewModel.messages.last?.id {
+                    withAnimation { proxy.scrollTo(lastId, anchor: .bottom) }
+                }
+            }
+            .onChange(of: scrollTarget) {
+                if let target = scrollTarget {
+                    withAnimation { proxy.scrollTo(target, anchor: .center) }
+                    scrollTarget = nil
+                }
+            }
+        }
+    }
+
+    private func messageBubble(for message: Message) -> some View {
+        let isCurrentSearch = viewModel.searchResults.indices.contains(viewModel.currentSearchIndex)
+            && viewModel.searchResults[viewModel.currentSearchIndex] == message.id
+        return MessageBubbleView(
+            message: message,
+            isMine: message.isMine(currentUserId: currentUserId),
+            isGroup: conversation.isGroup,
+            isHighlighted: viewModel.searchResults.contains(message.id),
+            isCurrentSearchResult: isCurrentSearch,
+            chatClient: appState.chatClient,
+            currentUserId: currentUserId,
+            onReply: { replyTo = message },
+            onReact: { reaction in
+                Task {
+                    await viewModel.reactToMessage(
+                        messageId: message.id, convId: conversation.id,
+                        reaction: reaction, currentUserId: currentUserId,
+                        chatClient: appState.chatClient
+                    )
+                }
+            },
+            onForward: {
+                forwardingMessage = message
+                showForwardPicker = true
+            },
+            onPin: { pin in
+                Task {
+                    await viewModel.pinMessage(
+                        messageId: message.id, convId: conversation.id,
+                        pin: pin, chatClient: appState.chatClient
+                    )
+                }
+            },
+            onDelete: {
+                Task {
+                    await viewModel.deleteMessage(
+                        messageId: message.id, convId: conversation.id,
+                        chatClient: appState.chatClient
+                    )
+                }
+            }
+        )
+    }
+
+    // MARK: - Reply Preview
+
+    @ViewBuilder
+    private var replyPreview: some View {
+        if let reply = replyTo {
+            HStack {
+                Rectangle()
+                    .fill(.blue)
+                    .frame(width: 3)
+                VStack(alignment: .leading) {
+                    Text(reply.senderUsername)
+                        .font(.caption.bold())
+                    Text(reply.text ?? "")
+                        .font(.caption)
+                        .lineLimit(1)
+                }
+                Spacer()
+                Button(action: { replyTo = nil }) {
+                    Image(systemName: "xmark.circle.fill")
+                        .foregroundStyle(.secondary)
+                }
+            }
+            .padding(.horizontal)
+            .padding(.vertical, 6)
+            .background(.ultraThinMaterial)
+        }
+    }
+
+    // MARK: - Input
+
+    private var inputView: some View {
+        MessageInputView(
+            text: $inputText,
+            isSending: viewModel.isSending,
+            onSend: {
+                Task {
+                    let text = inputText
+                    inputText = ""
+                    let reply = replyTo?.id
+                    replyTo = nil
+                    await viewModel.sendMessage(
+                        convId: conversation.id, text: text,
+                        members: conversation.members,
+                        chatClient: appState.chatClient, replyTo: reply
+                    )
+                }
+            },
+            onImageSelected: { imageData in
+                Task {
+                    viewModel.isSending = true
+                    let (success, msg, sentMessage) = await appState.chatClient.sendImage(
+                        convId: conversation.id, imageData: imageData,
+                        members: conversation.members
+                    )
+                    viewModel.isSending = false
+                    if success, let sentMessage {
+                        if !viewModel.messages.contains(where: { $0.id == sentMessage.id }) {
+                            viewModel.messages.append(sentMessage)
+                        }
+                        await viewModel.saveCache(convId: conversation.id, chatClient: appState.chatClient)
+                    } else if !success {
+                        viewModel.errorMessage = msg
+                        showError = true
+                    }
+                }
+            },
+            onFileSelected: { fileData, filename, mimeType in
+                Task {
+                    viewModel.isSending = true
+                    let (success, msg, sentMessage) = await appState.chatClient.sendFile(
+                        convId: conversation.id, fileData: fileData,
+                        filename: filename, mimeType: mimeType,
+                        members: conversation.members
+                    )
+                    viewModel.isSending = false
+                    if success, let sentMessage {
+                        if !viewModel.messages.contains(where: { $0.id == sentMessage.id }) {
+                            viewModel.messages.append(sentMessage)
+                        }
+                        await viewModel.saveCache(convId: conversation.id, chatClient: appState.chatClient)
+                    } else if !success {
+                        viewModel.errorMessage = msg
+                        showError = true
+                    }
+                }
+            },
+            members: conversation.members
+        )
+    }
+
+    // MARK: - Toolbar
+
+    @ToolbarContentBuilder
+    private var toolbarContent: some ToolbarContent {
+        ToolbarItem(placement: .principal) {
+            HStack(spacing: 8) {
+                CircularAvatarView(
+                    name: conversation.displayName(currentUserId: currentUserId),
+                    imageData: conversationListVM?.avatarCache[conversation.id],
+                    size: 28,
+                    isGroup: conversation.isGroup
+                )
+                Text(conversation.displayName(currentUserId: currentUserId))
+                    .font(.headline)
+                if !conversation.isGroup && verificationStatus == "verified" {
+                    Image(systemName: "checkmark.shield.fill")
+                        .font(.caption)
+                        .foregroundStyle(.green)
+                }
+                if isPartnerOnline {
+                    Circle().fill(.green).frame(width: 8, height: 8)
+                }
+            }
+        }
+
+        ToolbarItem(placement: .topBarTrailing) {
+            HStack(spacing: 16) {
+                if !conversation.isGroup {
+                    Button(action: { showVerification = true }) {
+                        Image(systemName: verificationStatus == "verified" ? "checkmark.shield.fill" : "shield")
+                            .foregroundStyle(verificationStatus == "verified" ? .green : .secondary)
+                    }
+                }
+                Button(action: { showPinnedMessages = true }) {
+                    Image(systemName: "pin")
+                }
+                Button(action: { showSearch.toggle() }) {
+                    Image(systemName: "magnifyingglass")
+                }
+                if conversation.isGroup {
+                    Button(action: { showGroupInfo = true }) {
+                        Image(systemName: "info.circle")
+                    }
+                } else {
+                    Button(action: { showDMInfo = true }) {
+                        Image(systemName: "info.circle")
+                    }
+                }
+                if !conversation.isGroup || conversation.createdBy == currentUserId {
+                    Button(action: { showDeleteConfirm = true }) {
+                        Image(systemName: "trash").foregroundStyle(.red)
+                    }
+                }
+            }
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Chat/ForwardPickerView.swift

@@ -0,0 +1,77 @@
+import SwiftUI
+
+struct ForwardPickerView: View {
+    let message: Message
+    let appState: AppState
+
+    @Environment(\.dismiss) private var dismiss
+    @State private var conversations: [Conversation] = []
+    @State private var isLoading = true
+    @State private var isSending = false
+
+    var body: some View {
+        NavigationStack {
+            Group {
+                if isLoading {
+                    ProgressView("Loading conversations...")
+                } else if conversations.isEmpty {
+                    Text("No conversations available")
+                        .foregroundStyle(.secondary)
+                } else {
+                    List(conversations) { conv in
+                        Button {
+                            forwardTo(conv)
+                        } label: {
+                            HStack {
+                                CircularAvatarView(
+                                    name: conv.displayName(currentUserId: appState.currentUser?.id ?? ""),
+                                    size: 36,
+                                    isGroup: conv.isGroup
+                                )
+                                Text(conv.displayName(currentUserId: appState.currentUser?.id ?? ""))
+                                Spacer()
+                            }
+                        }
+                        .disabled(isSending)
+                    }
+                }
+            }
+            .navigationTitle("Forward to...")
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .cancellationAction) {
+                    Button("Cancel") { dismiss() }
+                }
+            }
+        }
+        .task {
+            conversations = await appState.chatClient.listConversations()
+            isLoading = false
+        }
+    }
+
+    private func forwardTo(_ conv: Conversation) {
+        isSending = true
+        Task {
+            let forwardPayload: [String: Any] = [
+                "forwarded_from": [
+                    "sender": message.senderUsername,
+                    "conversation_id": message.conversationId,
+                    "message_id": message.id,
+                ] as [String: Any]
+            ]
+            let (success, _, _) = await appState.chatClient.sendMessage(
+                convId: conv.id,
+                text: message.text ?? "",
+                members: conv.members,
+                extraPayload: forwardPayload
+            )
+            await MainActor.run {
+                isSending = false
+                if success {
+                    dismiss()
+                }
+            }
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Chat/ImageViewerView.swift

@@ -0,0 +1,113 @@
+import SwiftUI
+import UIKit
+import Photos
+
+struct ImageViewerView: View {
+    let imageData: Data
+    @State private var scale: CGFloat = 1.0
+    @State private var saved = false
+    @State private var saveError: String?
+    @Environment(\.dismiss) private var dismiss
+
+    var body: some View {
+        NavigationStack {
+            GeometryReader { geo in
+                if let uiImage = UIImage(data: imageData) {
+                    Image(uiImage: uiImage)
+                        .resizable()
+                        .aspectRatio(contentMode: .fit)
+                        .scaleEffect(scale)
+                        .gesture(
+                            MagnifyGesture()
+                                .onChanged { value in
+                                    scale = value.magnification
+                                }
+                                .onEnded { _ in
+                                    withAnimation {
+                                        scale = max(1.0, min(scale, 5.0))
+                                    }
+                                }
+                        )
+                        .onTapGesture(count: 2) {
+                            withAnimation {
+                                scale = scale > 1 ? 1 : 2
+                            }
+                        }
+                        .frame(width: geo.size.width, height: geo.size.height)
+                }
+            }
+            .overlay(alignment: .bottom) {
+                if let error = saveError {
+                    Text(error)
+                        .font(.caption)
+                        .foregroundStyle(.white)
+                        .padding(8)
+                        .background(Capsule().fill(.red.opacity(0.8)))
+                        .padding(.bottom, 40)
+                        .transition(.move(edge: .bottom).combined(with: .opacity))
+                }
+            }
+            .toolbar {
+                ToolbarItem(placement: .topBarLeading) {
+                    Button {
+                        dismiss()
+                    } label: {
+                        Image(systemName: "xmark")
+                            .foregroundStyle(.white)
+                    }
+                }
+                ToolbarItem(placement: .topBarTrailing) {
+                    HStack(spacing: 16) {
+                        // Share
+                        if let uiImage = UIImage(data: imageData) {
+                            ShareLink(item: Image(uiImage: uiImage), preview: SharePreview("Image", image: Image(uiImage: uiImage))) {
+                                Image(systemName: "square.and.arrow.up")
+                                    .foregroundStyle(.white)
+                            }
+                        }
+
+                        // Save to Photos
+                        Button {
+                            saveToPhotos()
+                        } label: {
+                            Image(systemName: saved ? "checkmark.circle.fill" : "arrow.down.to.line")
+                                .foregroundStyle(saved ? .green : .white)
+                        }
+                    }
+                }
+            }
+            .toolbarBackground(.hidden, for: .navigationBar)
+            .background(.black)
+        }
+    }
+
+    private func saveToPhotos() {
+        guard let uiImage = UIImage(data: imageData) else {
+            withAnimation { saveError = "Invalid image data" }
+            return
+        }
+
+        PHPhotoLibrary.requestAuthorization(for: .addOnly) { status in
+            DispatchQueue.main.async {
+                switch status {
+                case .authorized, .limited:
+                    PHPhotoLibrary.shared().performChanges {
+                        PHAssetChangeRequest.creationRequestForAsset(from: uiImage)
+                    } completionHandler: { success, error in
+                        DispatchQueue.main.async {
+                            if success {
+                                withAnimation { saved = true; saveError = nil }
+                            } else {
+                                withAnimation { saveError = error?.localizedDescription ?? "Save failed" }
+                            }
+                        }
+                    }
+                case .denied, .restricted:
+                    withAnimation { saveError = "Photo library access denied. Check Settings." }
+                default:
+                    withAnimation { saveError = "Photo library access required" }
+                }
+            }
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Chat/MessageBubbleView.swift

@@ -0,0 +1,558 @@
+import SwiftUI
+import UIKit
+
+struct MessageBubbleView: View {
+    let message: Message
+    let isMine: Bool
+    var isGroup: Bool = false
+    var isHighlighted: Bool = false
+    var isCurrentSearchResult: Bool = false
+    var chatClient: ChatClient?
+    var currentUserId: String = ""
+    var onReply: (() -> Void)?
+    var onReact: ((String) -> Void)?
+    var onForward: (() -> Void)?
+    var onPin: ((Bool) -> Void)?
+    var onDelete: (() -> Void)?
+
+    @State private var fullImageData: Data?
+    @State private var showFullImage = false
+    @State private var isLoadingImage = false
+    @State private var isLoadingFile = false
+    @State private var downloadedFileURL: URL?
+    @State private var showShareSheet = false
+    @State private var imageError: String?
+
+    var body: some View {
+        HStack {
+            if isMine { Spacer(minLength: 60) }
+
+            VStack(alignment: isMine ? .trailing : .leading, spacing: 4) {
+                if !isMine && isGroup {
+                    Text(message.senderUsername)
+                        .font(.caption.bold())
+                        .foregroundStyle(.secondary)
+                }
+
+                if message.isDeleted {
+                    Text("Message deleted")
+                        .font(.body.italic())
+                        .foregroundStyle(.secondary)
+                        .padding(12)
+                        .background(Color(.systemGray6))
+                        .clipShape(RoundedRectangle(cornerRadius: 16))
+                } else {
+                    // Forwarded header
+                    if let fwd = message.forwardedFrom {
+                        HStack(spacing: 4) {
+                            Rectangle().fill(.cyan).frame(width: 3)
+                            VStack(alignment: .leading, spacing: 1) {
+                                Text("Forwarded from").font(.caption2).foregroundStyle(.secondary)
+                                Text(fwd.sender).font(.caption.bold()).foregroundStyle(.cyan)
+                            }
+                        }
+                        .padding(.horizontal, 8).padding(.top, 4)
+                    }
+
+                    // Reply reference
+                    if message.replyTo != nil {
+                        HStack(spacing: 4) {
+                            Rectangle()
+                                .fill(.blue.opacity(0.5))
+                                .frame(width: 2)
+                            Text("Reply to message")
+                                .font(.caption)
+                                .foregroundStyle(.secondary)
+                        }
+                        .padding(.horizontal, 8)
+                    }
+
+                    // Image thumbnail
+                    if let imageInfo = message.image {
+                        imageView(imageInfo: imageInfo)
+                    }
+
+                    // File card
+                    if let file = message.file {
+                        VStack(alignment: .leading, spacing: 4) {
+                            HStack {
+                                if isLoadingFile {
+                                    ProgressView()
+                                        .scaleEffect(0.8)
+                                } else {
+                                    Image(systemName: fileIcon(for: file.filename))
+                                }
+                                Text(file.filename)
+                                    .lineLimit(1)
+                            }
+                            .font(.subheadline)
+
+                            Text(formatFileSize(file.size))
+                                .font(.caption)
+                                .foregroundStyle(.secondary)
+                        }
+                        .padding(12)
+                        .background(Color(.systemGray5))
+                        .clipShape(RoundedRectangle(cornerRadius: 12))
+                        .onTapGesture {
+                            downloadAndShareFile(file: file)
+                        }
+                    }
+
+                    // Text content with link detection
+                    if let text = message.text, !text.isEmpty {
+                        LinkText(text: text, isMine: isMine)
+                            .padding(12)
+                            .background(
+                                isMine ? Color.blue : Color(.systemGray5)
+                            )
+                            .clipShape(RoundedRectangle(cornerRadius: 16))
+                    }
+
+                    // Timestamp + checkmarks + reactions — all on one line
+                    HStack(spacing: 4) {
+                        if message.pinnedAt != nil {
+                            Image(systemName: "pin.fill").font(.caption2).foregroundStyle(.orange)
+                        }
+                        Text(formatTime(message.createdAt)).font(.caption2).foregroundStyle(.secondary)
+                        if isMine {
+                            deliveryIndicator
+                        }
+                        if !message.reactions.isEmpty {
+                            inlineReactionBadges
+                        }
+                    }
+                    .frame(maxWidth: .infinity, alignment: isMine ? .trailing : .leading)
+                }
+            }
+            .padding(2)
+            .background(
+                RoundedRectangle(cornerRadius: 16)
+                    .fill(isCurrentSearchResult ? Color.orange.opacity(0.3) :
+                          isHighlighted ? Color.yellow.opacity(0.2) : Color.clear)
+            )
+            .contextMenu {
+                if !message.isDeleted {
+                    Button(action: { onReply?() }) {
+                        Label("Reply", systemImage: "arrowshape.turn.up.left")
+                    }
+
+                    Menu {
+                        ForEach(ReactionEmoji.allowed, id: \.self) { key in
+                            Button("\(ReactionEmoji.display[key] ?? "") \(key)") { onReact?(key) }
+                        }
+                    } label: {
+                        Label("React", systemImage: "face.smiling")
+                    }
+
+                    Button(action: {
+                        UIPasteboard.general.string = message.text ?? ""
+                        // Auto-clear clipboard after 30 seconds
+                        DispatchQueue.main.asyncAfter(deadline: .now() + 30) {
+                            if UIPasteboard.general.string == message.text {
+                                UIPasteboard.general.string = ""
+                            }
+                        }
+                    }) {
+                        Label("Copy", systemImage: "doc.on.doc")
+                    }
+
+                    Button(action: { onForward?() }) {
+                        Label("Forward", systemImage: "arrowshape.turn.up.right")
+                    }
+
+                    Button(action: { onPin?(message.pinnedAt == nil) }) {
+                        Label(message.pinnedAt == nil ? "Pin" : "Unpin",
+                              systemImage: message.pinnedAt == nil ? "pin" : "pin.slash")
+                    }
+
+                    if isMine {
+                        Button(role: .destructive, action: { onDelete?() }) {
+                            Label("Delete", systemImage: "trash")
+                        }
+                    }
+                }
+            }
+
+            if !isMine { Spacer(minLength: 60) }
+        }
+        .sheet(isPresented: $showFullImage) {
+            if let data = fullImageData {
+                ImageViewerView(imageData: data)
+            }
+        }
+        .sheet(isPresented: $showShareSheet, onDismiss: {
+            // Clean up decrypted temp file after sharing
+            if let fileURL = downloadedFileURL {
+                try? FileManager.default.removeItem(at: fileURL)
+                downloadedFileURL = nil
+            }
+        }) {
+            if let fileURL = downloadedFileURL {
+                ActivityViewController(activityItems: [fileURL])
+            }
+        }
+    }
+
+    // MARK: - Reaction Badges (inline — used in timestamp row)
+
+    private var inlineReactionBadges: some View {
+        let grouped = Dictionary(grouping: message.reactions, by: \.reaction)
+        return HStack(spacing: 2) {
+            ForEach(grouped.sorted(by: { $0.key < $1.key }), id: \.key) { reaction, users in
+                Button {
+                    onReact?(reaction)
+                } label: {
+                    Text(ReactionEmoji.display[reaction] ?? reaction)
+                        .font(.caption)
+                }
+                .buttonStyle(.plain)
+            }
+        }
+    }
+
+    // MARK: - Delivery Indicator (checkmarks)
+
+    @ViewBuilder
+    private var deliveryIndicator: some View {
+        let isRead = message.readBy.contains(where: { $0 != "__delivered__" && $0 != currentUserId })
+        let isDelivered = message.readBy.contains("__delivered__")
+
+        if isRead {
+            // Read: 2 green checkmarks
+            HStack(spacing: -4) {
+                Image(systemName: "checkmark").font(.system(size: 9, weight: .bold))
+                Image(systemName: "checkmark").font(.system(size: 9, weight: .bold))
+            }
+            .foregroundStyle(.green)
+        } else if isDelivered {
+            // Delivered: 2 gray checkmarks
+            HStack(spacing: -4) {
+                Image(systemName: "checkmark").font(.system(size: 9, weight: .bold))
+                Image(systemName: "checkmark").font(.system(size: 9, weight: .bold))
+            }
+            .foregroundStyle(.secondary)
+        } else {
+            // Sent: 1 gray checkmark
+            Image(systemName: "checkmark").font(.system(size: 9, weight: .bold))
+                .foregroundStyle(.secondary)
+        }
+    }
+
+    // MARK: - Image View
+
+    @ViewBuilder
+    private func imageView(imageInfo: ImageInfo) -> some View {
+        VStack(spacing: 4) {
+            if let thumbB64 = imageInfo.thumbnail,
+               let thumbData = Data(base64Encoded: thumbB64),
+               let uiImage = UIImage(data: thumbData) {
+                Image(uiImage: uiImage)
+                    .resizable()
+                    .aspectRatio(contentMode: .fit)
+                    .frame(maxWidth: 220, maxHeight: 220)
+                    .clipShape(RoundedRectangle(cornerRadius: 12))
+                    .overlay {
+                        if isLoadingImage {
+                            RoundedRectangle(cornerRadius: 12)
+                                .fill(.black.opacity(0.4))
+                            ProgressView()
+                                .tint(.white)
+                        }
+                    }
+                    .onTapGesture {
+                        downloadAndShowFullImage(imageInfo: imageInfo)
+                    }
+            } else {
+                // No thumbnail available — show placeholder
+                RoundedRectangle(cornerRadius: 12)
+                    .fill(Color(.systemGray5))
+                    .frame(width: 160, height: 120)
+                    .overlay {
+                        if isLoadingImage {
+                            ProgressView()
+                        } else {
+                            VStack(spacing: 6) {
+                                Image(systemName: "photo")
+                                    .font(.title2)
+                                Text(imageInfo.filename)
+                                    .font(.caption)
+                                    .lineLimit(1)
+                            }
+                            .foregroundStyle(.secondary)
+                        }
+                    }
+                    .onTapGesture {
+                        downloadAndShowFullImage(imageInfo: imageInfo)
+                    }
+            }
+
+            if let error = imageError {
+                Text(error)
+                    .font(.caption2)
+                    .foregroundStyle(.red)
+                    .onTapGesture {
+                        imageError = nil
+                        downloadAndShowFullImage(imageInfo: imageInfo)
+                    }
+            }
+        }
+    }
+
+    private func downloadAndShowFullImage(imageInfo: ImageInfo) {
+        guard !isLoadingImage, let client = chatClient else { return }
+        // If already downloaded, show immediately
+        if fullImageData != nil {
+            showFullImage = true
+            return
+        }
+        imageError = nil
+        isLoadingImage = true
+        Task {
+            guard let aesKey = try? ProtocolHandler.decodeBinary(imageInfo.aesKey),
+                  let iv = try? ProtocolHandler.decodeBinary(imageInfo.iv) else {
+                await MainActor.run {
+                    isLoadingImage = false
+                    imageError = "Failed to decode image keys"
+                }
+                return
+            }
+            let data = await client.downloadFile(fileId: imageInfo.fileId, aesKey: aesKey, iv: iv, conversationId: message.conversationId)
+            await MainActor.run {
+                isLoadingImage = false
+                if let data = data {
+                    fullImageData = data
+                    showFullImage = true
+                } else {
+                    imageError = "Download failed, tap to retry"
+                }
+            }
+        }
+    }
+
+    // MARK: - File Download
+
+    private func downloadAndShareFile(file: FileInfo) {
+        guard !isLoadingFile, let client = chatClient else { return }
+        // If already downloaded, show share sheet immediately
+        if downloadedFileURL != nil {
+            showShareSheet = true
+            return
+        }
+        isLoadingFile = true
+        Task {
+            guard let aesKey = try? ProtocolHandler.decodeBinary(file.aesKey),
+                  let iv = try? ProtocolHandler.decodeBinary(file.iv) else {
+                await MainActor.run { isLoadingFile = false }
+                return
+            }
+            let data = await client.downloadFile(fileId: file.fileId, aesKey: aesKey, iv: iv, conversationId: message.conversationId)
+            await MainActor.run {
+                isLoadingFile = false
+                if let data = data {
+                    // Save to temp with file protection, clean up on dismiss
+                    let tempDir = FileManager.default.temporaryDirectory
+                    let fileURL = tempDir.appendingPathComponent(file.filename)
+                    try? data.write(to: fileURL, options: .completeFileProtection)
+                    downloadedFileURL = fileURL
+                    showShareSheet = true
+                }
+            }
+        }
+    }
+
+    private func fileIcon(for filename: String) -> String {
+        let ext = (filename as NSString).pathExtension.lowercased()
+        switch ext {
+        case "pdf": return "doc.richtext"
+        case "doc", "docx": return "doc.text"
+        case "xls", "xlsx": return "tablecells"
+        case "ppt", "pptx": return "rectangle.on.rectangle"
+        case "zip", "rar", "7z": return "doc.zipper"
+        case "mp3", "wav", "m4a": return "music.note"
+        case "mp4", "mov", "avi": return "film"
+        case "txt": return "doc.plaintext"
+        default: return "paperclip"
+        }
+    }
+
+    // MARK: - Helpers
+
+    private func formatTime(_ date: Date) -> String {
+        let formatter = DateFormatter()
+        if Calendar.current.isDateInToday(date) {
+            formatter.dateFormat = "HH:mm"
+        } else {
+            formatter.dateFormat = "MMM d, HH:mm"
+        }
+        return formatter.string(from: date)
+    }
+
+    private func formatFileSize(_ bytes: Int) -> String {
+        if bytes < 1024 { return "\(bytes) B" }
+        if bytes < 1024 * 1024 { return "\(bytes / 1024) KB" }
+        return String(format: "%.1f MB", Double(bytes) / (1024 * 1024))
+    }
+}
+
+// MARK: - Link Text
+
+struct LinkText: View {
+    let text: String
+    let isMine: Bool
+
+    var body: some View {
+        Text(buildAttributedString())
+            .environment(\.openURL, OpenURLAction { url in
+                UIApplication.shared.open(url)
+                return .handled
+            })
+    }
+
+    private func buildAttributedString() -> AttributedString {
+        var result = AttributedString()
+
+        guard let detector = try? NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue) else {
+            return appendPlainWithMentions(text[text.startIndex..<text.endIndex], to: &result)
+        }
+
+        let nsRange = NSRange(text.startIndex..., in: text)
+        let matches = detector.matches(in: text, range: nsRange)
+
+        if matches.isEmpty {
+            return appendPlainWithMentions(text[text.startIndex..<text.endIndex], to: &result)
+        }
+
+        var lastEnd = text.startIndex
+
+        for match in matches {
+            guard let matchRange = Range(match.range, in: text),
+                  let url = match.url else { continue }
+
+            // Plain text before link (with mention highlighting)
+            if lastEnd < matchRange.lowerBound {
+                appendPlainWithMentions(text[lastEnd..<matchRange.lowerBound], to: &result)
+            }
+
+            // Link
+            let isSecure = url.scheme?.lowercased() == "https"
+            var link = AttributedString(text[matchRange])
+            link.link = url
+            link.underlineStyle = .single
+            if isMine {
+                link.foregroundColor = isSecure ? .cyan : .red
+            } else {
+                link.foregroundColor = isSecure ? .blue : .red
+            }
+            result.append(link)
+
+            lastEnd = matchRange.upperBound
+        }
+
+        // Remaining text
+        if lastEnd < text.endIndex {
+            appendPlainWithMentions(text[lastEnd..<text.endIndex], to: &result)
+        }
+
+        return result
+    }
+
+    private static let mentionRegex = try! NSRegularExpression(pattern: "@(\\w+)", options: [])
+
+    @discardableResult
+    private func appendPlainWithMentions(_ substring: Substring, to result: inout AttributedString) -> AttributedString {
+        let str = String(substring)
+        let nsRange = NSRange(str.startIndex..., in: str)
+        let matches = Self.mentionRegex.matches(in: str, range: nsRange)
+
+        if matches.isEmpty {
+            var plain = AttributedString(str)
+            plain.foregroundColor = isMine ? .white : .primary
+            result.append(plain)
+            return result
+        }
+
+        let mentionColor = Color(red: 0.537, green: 0.706, blue: 0.980)
+        var lastEnd = str.startIndex
+
+        for match in matches {
+            guard let matchRange = Range(match.range, in: str) else { continue }
+
+            if lastEnd < matchRange.lowerBound {
+                var plain = AttributedString(str[lastEnd..<matchRange.lowerBound])
+                plain.foregroundColor = isMine ? .white : .primary
+                result.append(plain)
+            }
+
+            var mention = AttributedString(str[matchRange])
+            mention.foregroundColor = mentionColor
+            mention.font = .body.bold()
+            result.append(mention)
+
+            lastEnd = matchRange.upperBound
+        }
+
+        if lastEnd < str.endIndex {
+            var plain = AttributedString(str[lastEnd..<str.endIndex])
+            plain.foregroundColor = isMine ? .white : .primary
+            result.append(plain)
+        }
+
+        return result
+    }
+}
+
+// MARK: - Flow Layout
+
+struct FlowLayout: Layout {
+    var spacing: CGFloat = 4
+
+    func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) -> CGSize {
+        let maxWidth = proposal.width ?? .infinity
+        var x: CGFloat = 0
+        var y: CGFloat = 0
+        var rowHeight: CGFloat = 0
+
+        for subview in subviews {
+            let size = subview.sizeThatFits(.unspecified)
+            if x + size.width > maxWidth && x > 0 {
+                x = 0
+                y += rowHeight + spacing
+                rowHeight = 0
+            }
+            x += size.width + spacing
+            rowHeight = max(rowHeight, size.height)
+        }
+        return CGSize(width: maxWidth, height: y + rowHeight)
+    }
+
+    func placeSubviews(in bounds: CGRect, proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) {
+        var x = bounds.minX
+        var y = bounds.minY
+        var rowHeight: CGFloat = 0
+
+        for subview in subviews {
+            let size = subview.sizeThatFits(.unspecified)
+            if x + size.width > bounds.maxX && x > bounds.minX {
+                x = bounds.minX
+                y += rowHeight + spacing
+                rowHeight = 0
+            }
+            subview.place(at: CGPoint(x: x, y: y), proposal: .unspecified)
+            x += size.width + spacing
+            rowHeight = max(rowHeight, size.height)
+        }
+    }
+}
+
+// MARK: - Share Sheet
+
+struct ActivityViewController: UIViewControllerRepresentable {
+    let activityItems: [Any]
+
+    func makeUIViewController(context: Context) -> UIActivityViewController {
+        UIActivityViewController(activityItems: activityItems, applicationActivities: nil)
+    }
+
+    func updateUIViewController(_ uiViewController: UIActivityViewController, context: Context) {}
+}

ios_client 0.8.5/Kecalek/Views/Chat/MessageInputView.swift

@@ -0,0 +1,215 @@
+import SwiftUI
+import PhotosUI
+import UniformTypeIdentifiers
+import UIKit
+
+struct MessageInputView: View {
+    @Binding var text: String
+    let isSending: Bool
+    let onSend: () -> Void
+    var onImageSelected: ((Data) -> Void)?
+    var onFileSelected: ((Data, String, String) -> Void)?  // data, filename, mimeType
+    var members: [ConversationMember] = []
+
+    @State private var isProcessing = false
+    @State private var showFilePicker = false
+    @State private var showPhotoPicker = false
+    @State private var showMentionPopup = false
+    @State private var mentionCandidates: [ConversationMember] = []
+
+    var body: some View {
+        VStack(spacing: 0) {
+            // Mention autocomplete popup
+            if showMentionPopup && !mentionCandidates.isEmpty {
+                ScrollView {
+                    VStack(alignment: .leading, spacing: 0) {
+                        ForEach(mentionCandidates) { member in
+                            Button {
+                                completeMention(member: member)
+                            } label: {
+                                Text("@\(member.username)")
+                                    .padding(.horizontal, 12)
+                                    .padding(.vertical, 8)
+                                    .frame(maxWidth: .infinity, alignment: .leading)
+                            }
+                            .buttonStyle(.plain)
+                            Divider()
+                        }
+                    }
+                }
+                .frame(maxHeight: 150)
+                .background(.ultraThinMaterial)
+                .clipShape(RoundedRectangle(cornerRadius: 8))
+                .padding(.horizontal)
+            }
+
+        HStack(spacing: 8) {
+            // Attach button
+            Menu {
+                Button {
+                    showPhotoPicker = true
+                } label: {
+                    Label("Photo", systemImage: "photo")
+                }
+                Button {
+                    showFilePicker = true
+                } label: {
+                    Label("File", systemImage: "doc")
+                }
+            } label: {
+                if isProcessing {
+                    ProgressView()
+                        .scaleEffect(0.8)
+                } else {
+                    Image(systemName: "plus.circle.fill")
+                        .font(.title2)
+                        .foregroundStyle(.blue)
+                }
+            }
+            .disabled(isProcessing || isSending)
+
+            // Text field
+            TextField("Message", text: $text, axis: .vertical)
+                .textFieldStyle(.roundedBorder)
+                .lineLimit(1...5)
+                .onSubmit {
+                    if !text.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
+                        onSend()
+                    }
+                }
+
+            // Send button
+            Button(action: onSend) {
+                if isSending {
+                    ProgressView()
+                        .scaleEffect(0.8)
+                } else {
+                    Image(systemName: "arrow.up.circle.fill")
+                        .font(.title2)
+                        .foregroundStyle(.blue)
+                }
+            }
+            .disabled(text.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty || isSending)
+        }
+        .padding(.horizontal)
+        .padding(.vertical, 8)
+        .background(.ultraThinMaterial)
+        .sheet(isPresented: $showPhotoPicker) {
+            ImagePickerView { data in
+                isProcessing = true
+                onImageSelected?(data)
+                isProcessing = false
+            }
+        }
+        .sheet(isPresented: $showFilePicker) {
+            DocumentPickerView { url in
+                guard url.startAccessingSecurityScopedResource() else { return }
+                defer { url.stopAccessingSecurityScopedResource() }
+                guard let data = try? Data(contentsOf: url) else { return }
+                let filename = url.lastPathComponent
+                let mimeType = UTType(filenameExtension: url.pathExtension)?.preferredMIMEType ?? "application/octet-stream"
+                onFileSelected?(data, filename, mimeType)
+            }
+        }
+        .onChange(of: text) {
+            updateMentionCandidates()
+        }
+        } // end VStack
+    }
+
+    private func updateMentionCandidates() {
+        // Look for @prefix at end of text
+        guard let atRange = text.range(of: "@\\w*$", options: .regularExpression) else {
+            showMentionPopup = false
+            mentionCandidates = []
+            return
+        }
+        let prefix = String(text[atRange]).dropFirst().lowercased() // remove @
+        mentionCandidates = members.filter { member in
+            prefix.isEmpty || member.username.lowercased().hasPrefix(prefix)
+        }
+        showMentionPopup = !mentionCandidates.isEmpty
+    }
+
+    private func completeMention(member: ConversationMember) {
+        if let atRange = text.range(of: "@\\w*$", options: .regularExpression) {
+            text.replaceSubrange(atRange, with: "@\(member.username) ")
+        }
+        showMentionPopup = false
+        mentionCandidates = []
+    }
+}
+
+// MARK: - Image Picker (UIKit PHPicker wrapper)
+
+struct ImagePickerView: UIViewControllerRepresentable {
+    let onImagePicked: (Data) -> Void
+
+    func makeCoordinator() -> Coordinator {
+        Coordinator(onImagePicked: onImagePicked)
+    }
+
+    func makeUIViewController(context: Context) -> PHPickerViewController {
+        var config = PHPickerConfiguration()
+        config.filter = .images
+        config.selectionLimit = 1
+        let picker = PHPickerViewController(configuration: config)
+        picker.delegate = context.coordinator
+        return picker
+    }
+
+    func updateUIViewController(_ uiViewController: PHPickerViewController, context: Context) {}
+
+    class Coordinator: NSObject, PHPickerViewControllerDelegate {
+        let onImagePicked: (Data) -> Void
+
+        init(onImagePicked: @escaping (Data) -> Void) {
+            self.onImagePicked = onImagePicked
+        }
+
+        func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
+            picker.dismiss(animated: true)
+            guard let provider = results.first?.itemProvider,
+                  provider.canLoadObject(ofClass: UIImage.self) else { return }
+            provider.loadObject(ofClass: UIImage.self) { [weak self] image, _ in
+                guard let uiImage = image as? UIImage,
+                      let data = uiImage.jpegData(compressionQuality: 0.9) else { return }
+                DispatchQueue.main.async {
+                    self?.onImagePicked(data)
+                }
+            }
+        }
+    }
+}
+
+// MARK: - Document Picker (UIKit wrapper)
+
+struct DocumentPickerView: UIViewControllerRepresentable {
+    let onPick: (URL) -> Void
+
+    func makeCoordinator() -> Coordinator {
+        Coordinator(onPick: onPick)
+    }
+
+    func makeUIViewController(context: Context) -> UIDocumentPickerViewController {
+        let picker = UIDocumentPickerViewController(forOpeningContentTypes: [.item])
+        picker.delegate = context.coordinator
+        picker.allowsMultipleSelection = false
+        return picker
+    }
+
+    func updateUIViewController(_ uiViewController: UIDocumentPickerViewController, context: Context) {}
+
+    class Coordinator: NSObject, UIDocumentPickerDelegate {
+        let onPick: (URL) -> Void
+
+        init(onPick: @escaping (URL) -> Void) {
+            self.onPick = onPick
+        }
+
+        func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
+            guard let url = urls.first else { return }
+            onPick(url)
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Chat/PinnedMessagesView.swift

@@ -0,0 +1,62 @@
+import SwiftUI
+
+struct PinnedMessagesView: View {
+    let messages: [Message]
+    var onScrollTo: ((String) -> Void)?
+
+    @Environment(\.dismiss) private var dismiss
+
+    var body: some View {
+        NavigationStack {
+            Group {
+                if messages.isEmpty {
+                    Text("No pinned messages")
+                        .foregroundStyle(.secondary)
+                } else {
+                    List(messages) { message in
+                        Button {
+                            dismiss()
+                            onScrollTo?(message.id)
+                        } label: {
+                            VStack(alignment: .leading, spacing: 4) {
+                                HStack {
+                                    Image(systemName: "pin.fill")
+                                        .font(.caption)
+                                        .foregroundStyle(.orange)
+                                    Text(message.senderUsername)
+                                        .font(.caption.bold())
+                                    Spacer()
+                                    Text(formatTime(message.createdAt))
+                                        .font(.caption2)
+                                        .foregroundStyle(.secondary)
+                                }
+                                Text(message.text ?? "")
+                                    .font(.body)
+                                    .lineLimit(3)
+                            }
+                            .padding(.vertical, 4)
+                        }
+                        .buttonStyle(.plain)
+                    }
+                }
+            }
+            .navigationTitle("Pinned Messages")
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .cancellationAction) {
+                    Button("Done") { dismiss() }
+                }
+            }
+        }
+    }
+
+    private func formatTime(_ date: Date) -> String {
+        let formatter = DateFormatter()
+        if Calendar.current.isDateInToday(date) {
+            formatter.dateFormat = "HH:mm"
+        } else {
+            formatter.dateFormat = "MMM d, HH:mm"
+        }
+        return formatter.string(from: date)
+    }
+}

ios_client 0.8.5/Kecalek/Views/Chat/SearchOverlayView.swift

@@ -0,0 +1,46 @@
+import SwiftUI
+
+struct SearchOverlayView: View {
+    @Binding var query: String
+    let matchCount: Int
+    let currentIndex: Int
+    let onSearch: (String) -> Void
+    let onNext: () -> Void
+    let onPrev: () -> Void
+    let onClose: () -> Void
+
+    var body: some View {
+        HStack(spacing: 8) {
+            Image(systemName: "magnifyingglass")
+                .foregroundStyle(.secondary)
+
+            TextField("Search messages", text: $query)
+                .textFieldStyle(.roundedBorder)
+                .onChange(of: query) { _, newValue in
+                    onSearch(newValue)
+                }
+
+            if matchCount > 0 {
+                Text("\(currentIndex + 1)/\(matchCount)")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+                    .fixedSize()
+
+                Button(action: onPrev) {
+                    Image(systemName: "chevron.up")
+                }
+                Button(action: onNext) {
+                    Image(systemName: "chevron.down")
+                }
+            }
+
+            Button(action: onClose) {
+                Image(systemName: "xmark.circle.fill")
+                    .foregroundStyle(.secondary)
+            }
+        }
+        .padding(.horizontal)
+        .padding(.vertical, 6)
+        .background(.ultraThinMaterial)
+    }
+}

ios_client 0.8.5/Kecalek/Views/Components/CircularAvatarView.swift

@@ -0,0 +1,46 @@
+import SwiftUI
+
+struct CircularAvatarView: View {
+    let name: String
+    var imageData: Data?
+    var size: CGFloat = 32
+    var isGroup: Bool = false
+
+    var body: some View {
+        if let imageData = imageData, let uiImage = UIImage(data: imageData) {
+            Image(uiImage: uiImage)
+                .resizable()
+                .aspectRatio(contentMode: .fill)
+                .frame(width: size, height: size)
+                .clipShape(Circle())
+        } else {
+            // Default: colored circle with initial letter
+            ZStack {
+                Circle()
+                    .fill(avatarColor)
+                    .frame(width: size, height: size)
+
+                Text(initial)
+                    .font(.system(size: size * 0.4, weight: .semibold))
+                    .foregroundStyle(.white)
+            }
+        }
+    }
+
+    private var initial: String {
+        String(name.prefix(1)).uppercased()
+    }
+
+    /// Deterministic color from name hash (matching Python gui_client behavior)
+    private var avatarColor: Color {
+        let colors: [Color] = [
+            .red, .orange, .yellow, .green, .mint,
+            .teal, .cyan, .blue, .indigo, .purple, .pink
+        ]
+        var hash = 0
+        for char in name.unicodeScalars {
+            hash = hash &* 31 &+ Int(char.value)
+        }
+        return colors[abs(hash) % colors.count]
+    }
+}

ios_client 0.8.5/Kecalek/Views/Components/ConnectionIndicator.swift

@@ -0,0 +1,36 @@
+import SwiftUI
+
+struct ConnectionIndicator: View {
+    let status: ConnectionStatus
+
+    var body: some View {
+        HStack(spacing: 4) {
+            Circle()
+                .fill(statusColor)
+                .frame(width: 8, height: 8)
+
+            if status != .connected {
+                Text(statusText)
+                    .font(.caption2)
+                    .foregroundStyle(.secondary)
+            }
+        }
+    }
+
+    private var statusColor: Color {
+        switch status {
+        case .connected: return .green
+        case .connecting, .reconnecting: return .orange
+        case .disconnected: return .red
+        }
+    }
+
+    private var statusText: String {
+        switch status {
+        case .connected: return ""
+        case .connecting: return "Connecting..."
+        case .reconnecting: return "Reconnecting..."
+        case .disconnected: return "Disconnected"
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Components/OnlineDotOverlay.swift

@@ -0,0 +1,15 @@
+import SwiftUI
+
+struct OnlineDotOverlay: View {
+    var size: CGFloat = 12
+
+    var body: some View {
+        Circle()
+            .fill(.green)
+            .frame(width: size, height: size)
+            .overlay(
+                Circle()
+                    .stroke(.white, lineWidth: 2)
+            )
+    }
+}

ios_client 0.8.5/Kecalek/Views/Conversations/ConversationListView.swift

@@ -0,0 +1,101 @@
+import SwiftUI
+
+struct ConversationListView: View {
+    var appState: AppState
+    @Bindable var viewModel: ConversationListVM
+    @State private var showNewConversation = false
+    @State private var showProfile = false
+    @State private var selectedConversation: Conversation?
+
+    var body: some View {
+        NavigationStack {
+            List {
+                // Invitations section
+                if !viewModel.invitations.isEmpty {
+                    Section {
+                        ForEach(viewModel.invitations) { invitation in
+                            InvitationBanner(
+                                invitation: invitation,
+                                onAccept: {
+                                    Task {
+                                        let (success, _) = await appState.chatClient.acceptInvitation(convId: invitation.conversationId)
+                                        if success {
+                                            await viewModel.refresh(chatClient: appState.chatClient)
+                                        }
+                                    }
+                                },
+                                onDecline: {
+                                    Task {
+                                        _ = await appState.chatClient.declineInvitation(convId: invitation.conversationId)
+                                        await viewModel.refresh(chatClient: appState.chatClient)
+                                    }
+                                }
+                            )
+                        }
+                    } header: {
+                        Text("Invitations")
+                    }
+                }
+
+                // Conversations section
+                Section {
+                    ForEach(viewModel.conversations) { conversation in
+                        NavigationLink(value: conversation) {
+                            ConversationRowView(
+                                conversation: conversation,
+                                currentUserId: appState.currentUser?.id ?? "",
+                                isOnline: conversation.dmPartnerId(currentUserId: appState.currentUser?.id ?? "")
+                                    .map { viewModel.onlineUsers.contains($0) } ?? false,
+                                unreadCount: viewModel.unreadCounts[conversation.id] ?? 0,
+                                avatarData: viewModel.avatarCache[conversation.id]
+                            )
+                        }
+                        .contextMenu {
+                            Button(conversation.isFavorite ? "Remove from Favorites" : "Add to Favorites") {
+                                viewModel.toggleFavorite(convId: conversation.id, email: appState.email)
+                            }
+                        }
+                    }
+                }
+            }
+            .navigationTitle("Chats")
+            .navigationDestination(for: Conversation.self) { conversation in
+                ChatView(
+                    conversation: conversation,
+                    appState: appState,
+                    conversationListVM: viewModel
+                )
+            }
+            .toolbar {
+                ToolbarItem(placement: .topBarLeading) {
+                    ConnectionIndicator(status: appState.connectionStatus)
+                }
+                ToolbarItem(placement: .topBarTrailing) {
+                    HStack {
+                        Button(action: { showProfile = true }) {
+                            Image(systemName: "person.circle")
+                        }
+                        Button(action: { showNewConversation = true }) {
+                            Image(systemName: "square.and.pencil")
+                        }
+                    }
+                }
+            }
+            .refreshable {
+                await viewModel.refresh(chatClient: appState.chatClient)
+            }
+            .sheet(isPresented: $showNewConversation) {
+                NewConversationSheet(appState: appState) { convId in
+                    showNewConversation = false
+                    await viewModel.refresh(chatClient: appState.chatClient)
+                }
+            }
+            .sheet(isPresented: $showProfile) {
+                ProfileView(appState: appState, isOwnProfile: true)
+            }
+            .task {
+                await viewModel.load(chatClient: appState.chatClient, email: appState.email)
+            }
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Conversations/ConversationRowView.swift

@@ -0,0 +1,60 @@
+import SwiftUI
+
+struct ConversationRowView: View {
+    let conversation: Conversation
+    let currentUserId: String
+    let isOnline: Bool
+    let unreadCount: Int
+    var avatarData: Data?
+
+    var body: some View {
+        HStack(spacing: 12) {
+            // Avatar
+            ZStack(alignment: .bottomTrailing) {
+                CircularAvatarView(
+                    name: conversation.displayName(currentUserId: currentUserId),
+                    imageData: avatarData,
+                    size: 44,
+                    isGroup: conversation.isGroup
+                )
+
+                if isOnline && !conversation.isGroup {
+                    OnlineDotOverlay(size: 12)
+                }
+            }
+
+            VStack(alignment: .leading, spacing: 2) {
+                HStack {
+                    if conversation.isFavorite {
+                        Image(systemName: "star.fill")
+                            .font(.caption2)
+                            .foregroundStyle(.yellow)
+                    }
+
+                    Text(conversation.displayName(currentUserId: currentUserId))
+                        .font(unreadCount > 0 ? .body.bold() : .body)
+                        .lineLimit(1)
+                }
+
+                if conversation.isGroup {
+                    Text("\(conversation.members.count) members")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                }
+            }
+
+            Spacer()
+
+            if unreadCount > 0 {
+                Text("\(unreadCount)")
+                    .font(.caption2.bold())
+                    .foregroundStyle(.white)
+                    .padding(.horizontal, 8)
+                    .padding(.vertical, 2)
+                    .background(Color.blue)
+                    .clipShape(Capsule())
+            }
+        }
+        .padding(.vertical, 4)
+    }
+}

ios_client 0.8.5/Kecalek/Views/Conversations/NewConversationSheet.swift

@@ -0,0 +1,100 @@
+import SwiftUI
+
+struct NewConversationSheet: View {
+    var appState: AppState
+    var onCreated: (String) async -> Void
+
+    @State private var email = ""
+    @State private var groupName = ""
+    @State private var isGroup = false
+    @State private var memberEmails: [String] = [""]
+    @State private var isLoading = false
+    @State private var errorMessage: String?
+    @Environment(\.dismiss) private var dismiss
+
+    var body: some View {
+        NavigationStack {
+            Form {
+                Section {
+                    Toggle("Create Group", isOn: $isGroup)
+
+                    if isGroup {
+                        TextField("Group Name", text: $groupName)
+                    }
+                }
+
+                Section(isGroup ? "Members" : "Recipient") {
+                    if isGroup {
+                        ForEach(memberEmails.indices, id: \.self) { index in
+                            TextField("Email", text: $memberEmails[index])
+                                .textContentType(.emailAddress)
+                                .keyboardType(.emailAddress)
+                                .autocapitalization(.none)
+                        }
+                        Button("Add Member") {
+                            memberEmails.append("")
+                        }
+                    } else {
+                        TextField("Email", text: $email)
+                            .textContentType(.emailAddress)
+                            .keyboardType(.emailAddress)
+                            .autocapitalization(.none)
+                    }
+                }
+
+                if let error = errorMessage {
+                    Section {
+                        Text(error)
+                            .foregroundStyle(.red)
+                    }
+                }
+            }
+            .navigationTitle("New Conversation")
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .cancellationAction) {
+                    Button("Cancel") { dismiss() }
+                }
+                ToolbarItem(placement: .confirmationAction) {
+                    Button("Create") {
+                        Task { await create() }
+                    }
+                    .disabled(isLoading)
+                }
+            }
+        }
+    }
+
+    private func create() async {
+        isLoading = true
+        errorMessage = nil
+
+        let emails: [String]
+        if isGroup {
+            emails = memberEmails.map { $0.trimmed }.filter { !$0.isEmpty }
+            guard !emails.isEmpty else {
+                errorMessage = "Add at least one member"
+                isLoading = false
+                return
+            }
+        } else {
+            guard !email.trimmed.isEmpty else {
+                errorMessage = "Enter an email address"
+                isLoading = false
+                return
+            }
+            emails = [email.trimmed]
+        }
+
+        let name = isGroup && !groupName.trimmed.isEmpty ? groupName.trimmed : nil
+        let (convId, message) = await appState.chatClient.createConversation(emails: emails, name: name)
+
+        isLoading = false
+
+        if let convId = convId {
+            await onCreated(convId)
+        } else {
+            errorMessage = message
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Groups/CreateGroupSheet.swift

@@ -0,0 +1,4 @@
+import SwiftUI
+
+// Group creation is handled within NewConversationSheet via the isGroup toggle.
+// This file exists for potential future separation.

ios_client 0.8.5/Kecalek/Views/Groups/GroupInfoView.swift

@@ -0,0 +1,301 @@
+import SwiftUI
+import PhotosUI
+
+struct GroupInfoView: View {
+    @Binding var conversation: Conversation
+    var appState: AppState
+    var conversationListVM: ConversationListVM?
+    @State private var showRenameSheet = false
+    @State private var showLeaveConfirm = false
+    @State private var showAddMember = false
+    @State private var showRemoveConfirm = false
+    @State private var showAvatarPicker = false
+    @State private var newName = ""
+    @State private var addMemberEmail = ""
+    @State private var memberToRemove: ConversationMember?
+    @State private var errorMessage: String?
+    @State private var showError = false
+    @State private var isUploadingAvatar = false
+    @State private var groupAvatarData: Data?
+    @Environment(\.dismiss) private var dismiss
+
+    private var isCreator: Bool {
+        conversation.createdBy == appState.currentUser?.id
+    }
+
+    private func refreshConversation() async {
+        let convs = await appState.chatClient.listConversations()
+        if let updated = convs.first(where: { $0.id == conversation.id }) {
+            conversation = updated
+        }
+        await conversationListVM?.forceRefresh(chatClient: appState.chatClient)
+    }
+
+    var body: some View {
+        NavigationStack {
+            List {
+                // Avatar section
+                Section {
+                    HStack {
+                        Spacer()
+                        VStack(spacing: 8) {
+                            CircularAvatarView(
+                                name: conversation.name ?? "Group",
+                                imageData: groupAvatarData ?? conversationListVM?.avatarCache[conversation.id],
+                                size: 64,
+                                isGroup: true
+                            )
+
+                            Text(conversation.name ?? "Group")
+                                .font(.title2.bold())
+
+                            Text("\(conversation.members.count) members")
+                                .font(.subheadline)
+                                .foregroundStyle(.secondary)
+                        }
+                        Spacer()
+                    }
+                    .listRowBackground(Color.clear)
+                }
+
+                // Actions
+                if isCreator {
+                    Section {
+                        Button("Add Member") {
+                            addMemberEmail = ""
+                            showAddMember = true
+                        }
+
+                        Button("Rename Group") {
+                            newName = conversation.name ?? ""
+                            showRenameSheet = true
+                        }
+
+                        Button {
+                            showAvatarPicker = true
+                        } label: {
+                            HStack {
+                                Text("Change Avatar")
+                                if isUploadingAvatar {
+                                    Spacer()
+                                    ProgressView()
+                                        .scaleEffect(0.8)
+                                }
+                            }
+                        }
+                        .disabled(isUploadingAvatar)
+                    }
+                }
+
+                // Members
+                Section("Members") {
+                    ForEach(conversation.members) { member in
+                        HStack {
+                            CircularAvatarView(name: member.username, size: 32, isGroup: false)
+
+                            VStack(alignment: .leading) {
+                                Text(member.username)
+                                    .font(.body)
+                                Text(member.email)
+                                    .font(.caption)
+                                    .foregroundStyle(.secondary)
+                            }
+
+                            Spacer()
+
+                            if member.userId == conversation.createdBy {
+                                Text("Admin")
+                                    .font(.caption)
+                                    .foregroundStyle(.blue)
+                            }
+                        }
+                        .contextMenu {
+                            if isCreator && member.userId != appState.currentUser?.id {
+                                Button("Remove from Group", role: .destructive) {
+                                    memberToRemove = member
+                                    showRemoveConfirm = true
+                                }
+                            }
+                        }
+                    }
+                }
+
+                // Leave / Delete
+                Section {
+                    Button("Leave Group", role: .destructive) {
+                        showLeaveConfirm = true
+                    }
+
+                    if isCreator {
+                        Button("Delete Group", role: .destructive) {
+                            Task {
+                                _ = await appState.chatClient.deleteConversation(convId: conversation.id)
+                                dismiss()
+                            }
+                        }
+                    }
+                }
+            }
+            .navigationTitle("Group Info")
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .topBarTrailing) {
+                    Button("Done") { dismiss() }
+                }
+            }
+            .alert("Leave Group?", isPresented: $showLeaveConfirm) {
+                Button("Cancel", role: .cancel) {}
+                Button("Leave", role: .destructive) {
+                    Task {
+                        _ = await appState.chatClient.leaveGroup(convId: conversation.id)
+                        dismiss()
+                    }
+                }
+            }
+            .alert("Remove Member?", isPresented: $showRemoveConfirm) {
+                Button("Cancel", role: .cancel) {}
+                Button("Remove", role: .destructive) {
+                    if let member = memberToRemove {
+                        Task {
+                            let (success, msg) = await appState.chatClient.removeMember(
+                                convId: conversation.id, userId: member.userId
+                            )
+                            if success {
+                                await refreshConversation()
+                            } else {
+                                errorMessage = msg
+                                showError = true
+                            }
+                        }
+                    }
+                }
+            } message: {
+                if let member = memberToRemove {
+                    Text("Remove \(member.username) from the group?")
+                }
+            }
+            .alert("Add Member", isPresented: $showAddMember) {
+                TextField("Email", text: $addMemberEmail)
+                    .textInputAutocapitalization(.never)
+                    .keyboardType(.emailAddress)
+                Button("Cancel", role: .cancel) {}
+                Button("Add") {
+                    let email = addMemberEmail.trimmingCharacters(in: .whitespacesAndNewlines)
+                    guard !email.isEmpty else { return }
+                    Task {
+                        let (success, msg) = await appState.chatClient.addMember(
+                            convId: conversation.id, email: email
+                        )
+                        if success {
+                            await refreshConversation()
+                        } else {
+                            errorMessage = msg
+                            showError = true
+                        }
+                    }
+                }
+            }
+            .alert("Rename Group", isPresented: $showRenameSheet) {
+                TextField("Group Name", text: $newName)
+                Button("Cancel", role: .cancel) {}
+                Button("Rename") {
+                    let trimmedName = newName.trimmingCharacters(in: .whitespacesAndNewlines)
+                    guard !trimmedName.isEmpty else { return }
+                    // Optimistic update - immediately reflect in UI
+                    conversation.name = trimmedName
+                    Task {
+                        let (success, _) = await appState.chatClient.renameConversation(convId: conversation.id, name: trimmedName)
+                        if success {
+                            await refreshConversation()
+                        } else {
+                            // Revert on failure
+                            await refreshConversation()
+                        }
+                    }
+                }
+            }
+            .alert("Error", isPresented: $showError) {
+                Button("OK") {}
+            } message: {
+                Text(errorMessage ?? "")
+            }
+            .sheet(isPresented: $showAvatarPicker) {
+                AvatarPickerView { imageData in
+                    isUploadingAvatar = true
+                    Task {
+                        let success = await appState.chatClient.updateGroupAvatar(
+                            convId: conversation.id, imageData: imageData
+                        )
+                        isUploadingAvatar = false
+                        if success {
+                            // Update local avatar cache (memory + disk)
+                            groupAvatarData = imageData
+                            conversationListVM?.updateAvatar(convId: conversation.id, data: imageData)
+                            await refreshConversation()
+                        } else {
+                            errorMessage = "Failed to update avatar"
+                            showError = true
+                        }
+                    }
+                }
+            }
+            .task {
+                // Load current group avatar
+                if groupAvatarData == nil, let cached = conversationListVM?.avatarCache[conversation.id] {
+                    groupAvatarData = cached
+                } else if groupAvatarData == nil {
+                    groupAvatarData = await appState.chatClient.getGroupAvatar(convId: conversation.id)
+                }
+                await refreshConversation()
+            }
+        }
+    }
+}
+
+// MARK: - Avatar Picker (PHPicker wrapper for avatar selection)
+
+private struct AvatarPickerView: UIViewControllerRepresentable {
+    let onImagePicked: (Data) -> Void
+
+    func makeCoordinator() -> Coordinator {
+        Coordinator(onImagePicked: onImagePicked)
+    }
+
+    func makeUIViewController(context: Context) -> PHPickerViewController {
+        var config = PHPickerConfiguration()
+        config.filter = .images
+        config.selectionLimit = 1
+        let picker = PHPickerViewController(configuration: config)
+        picker.delegate = context.coordinator
+        return picker
+    }
+
+    func updateUIViewController(_ uiViewController: PHPickerViewController, context: Context) {}
+
+    class Coordinator: NSObject, PHPickerViewControllerDelegate {
+        let onImagePicked: (Data) -> Void
+
+        init(onImagePicked: @escaping (Data) -> Void) {
+            self.onImagePicked = onImagePicked
+        }
+
+        func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
+            guard let provider = results.first?.itemProvider,
+                  provider.canLoadObject(ofClass: UIImage.self) else {
+                picker.dismiss(animated: true)
+                return
+            }
+            provider.loadObject(ofClass: UIImage.self) { [weak self] image, _ in
+                guard let uiImage = image as? UIImage,
+                      let data = uiImage.jpegData(compressionQuality: 0.8) else {
+                    DispatchQueue.main.async { picker.dismiss(animated: true) }
+                    return
+                }
+                DispatchQueue.main.async {
+                    self?.onImagePicked(data)
+                    picker.dismiss(animated: true)
+                }
+            }
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Groups/InvitationBanner.swift

@@ -0,0 +1,41 @@
+import SwiftUI
+
+struct InvitationBanner: View {
+    let invitation: Invitation
+    let onAccept: () -> Void
+    let onDecline: () -> Void
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            HStack {
+                Image(systemName: "envelope.badge")
+                    .foregroundStyle(.orange)
+
+                VStack(alignment: .leading) {
+                    Text(invitation.conversationName)
+                        .font(.body.bold())
+                    Text("Invited by \(invitation.invitedByUsername)")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                }
+
+                Spacer()
+            }
+
+            HStack(spacing: 12) {
+                Button("Accept") {
+                    onAccept()
+                }
+                .buttonStyle(.borderedProminent)
+                .controlSize(.small)
+
+                Button("Decline") {
+                    onDecline()
+                }
+                .buttonStyle(.bordered)
+                .controlSize(.small)
+            }
+        }
+        .padding(.vertical, 4)
+    }
+}

ios_client 0.8.5/Kecalek/Views/Profile/EditProfileView.swift

@@ -0,0 +1,4 @@
+import SwiftUI
+
+// Profile editing is handled within ProfileView when isOwnProfile = true.
+// This file exists for potential future separation.

ios_client 0.8.5/Kecalek/Views/Profile/ProfileView.swift

@@ -0,0 +1,277 @@
+import SwiftUI
+import PhotosUI
+import UIKit
+
+struct ProfileView: View {
+    var appState: AppState
+    var isOwnProfile: Bool
+    var userId: String?
+    @State private var viewModel = ProfileViewModel()
+    @State private var showLogoutConfirm = false
+    @State private var showAvatarPicker = false
+    @State private var showAuthorizeDevice = false
+    @State private var showRotateKeys = false
+    @State private var rotatePassword = ""
+    @State private var isRotating = false
+    @State private var rotateMessage: String?
+    @State private var rotateIsError = false
+    @State private var showChangeUsername = false
+    @State private var newUsername = ""
+    @State private var showChangePassword = false
+    @State private var oldPassword = ""
+    @State private var newPassword = ""
+    @State private var confirmNewPassword = ""
+    @State private var showVerification = false
+    @Environment(\.dismiss) private var dismiss
+
+    var body: some View {
+        NavigationStack {
+            Form {
+                // Avatar
+                Section {
+                    HStack {
+                        Spacer()
+                        VStack(spacing: 8) {
+                            if let avatarData = viewModel.avatarData,
+                               let uiImage = UIImage(data: avatarData) {
+                                Image(uiImage: uiImage)
+                                    .resizable()
+                                    .aspectRatio(contentMode: .fill)
+                                    .frame(width: 80, height: 80)
+                                    .clipShape(Circle())
+                            } else {
+                                CircularAvatarView(
+                                    name: viewModel.profile?.username ?? "?",
+                                    size: 80,
+                                    isGroup: false
+                                )
+                            }
+
+                            if isOwnProfile {
+                                Button("Change Photo") {
+                                    showAvatarPicker = true
+                                }
+                                .font(.caption)
+                            }
+                        }
+                        Spacer()
+                    }
+                    .listRowBackground(Color.clear)
+                }
+
+                // Info
+                Section("Info") {
+                    if let username = viewModel.profile?.username {
+                        LabeledContent("Username", value: username)
+                    }
+                    if let email = viewModel.profile?.email {
+                        LabeledContent("Email", value: email)
+                    }
+                }
+
+                if isOwnProfile {
+                    // Editable fields
+                    Section("Contact") {
+                        TextField("Phone", text: $viewModel.phone)
+                            .keyboardType(.phonePad)
+                        Toggle("Phone visible to contacts", isOn: $viewModel.phoneVisible)
+
+                        TextField("Location", text: $viewModel.location)
+                        Toggle("Location visible to contacts", isOn: $viewModel.locationVisible)
+                    }
+                } else {
+                    // Read-only view
+                    if let phone = viewModel.profile?.phone, viewModel.profile?.phoneVisible == true {
+                        Section("Contact") {
+                            LabeledContent("Phone", value: phone)
+                        }
+                    }
+                    if let location = viewModel.profile?.location, viewModel.profile?.locationVisible == true {
+                        Section("Location") {
+                            LabeledContent("Location", value: location)
+                        }
+                    }
+                }
+
+                if !isOwnProfile, let uid = userId {
+                    Section("Security") {
+                        NavigationLink {
+                            SafetyNumberView(
+                                peerUserId: uid,
+                                peerUsername: viewModel.profile?.username ?? "User",
+                                chatClient: appState.chatClient
+                            )
+                        } label: {
+                            Label("Verify Identity", systemImage: "checkmark.shield")
+                        }
+                    }
+                }
+
+                if let error = viewModel.errorMessage {
+                    Section {
+                        Text(error)
+                            .foregroundStyle(.red)
+                    }
+                }
+
+                if isOwnProfile {
+                    Section("Account") {
+                        Button {
+                            newUsername = viewModel.profile?.username ?? ""
+                            showChangeUsername = true
+                        } label: {
+                            Label("Change Username", systemImage: "person.text.rectangle")
+                        }
+
+                        Button {
+                            showChangePassword = true
+                        } label: {
+                            Label("Change Password", systemImage: "key")
+                        }
+                    }
+
+                    Section("Security") {
+                        Button {
+                            showAuthorizeDevice = true
+                        } label: {
+                            Label("Authorize New Device", systemImage: "iphone.badge.checkmark")
+                        }
+
+                        Button {
+                            showRotateKeys = true
+                        } label: {
+                            Label("Rotate Keys", systemImage: "arrow.triangle.2.circlepath")
+                        }
+                    }
+
+                    Section {
+                        Button(role: .destructive) {
+                            showLogoutConfirm = true
+                        } label: {
+                            HStack {
+                                Spacer()
+                                Text("Logout")
+                                Spacer()
+                            }
+                        }
+                    }
+                }
+            }
+            .navigationTitle(isOwnProfile ? "My Profile" : "Profile")
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .topBarTrailing) {
+                    if isOwnProfile {
+                        Button("Save") {
+                            Task {
+                                let success = await viewModel.saveProfile(chatClient: appState.chatClient)
+                                if success {
+                                    dismiss()
+                                }
+                            }
+                        }
+                        .disabled(viewModel.isSaving)
+                    }
+                }
+                ToolbarItem(placement: .topBarLeading) {
+                    if !isOwnProfile {
+                        Button {
+                            dismiss()
+                        } label: {
+                            Image(systemName: "xmark")
+                        }
+                    }
+                }
+            }
+            .alert("Logout", isPresented: $showLogoutConfirm) {
+                Button("Cancel", role: .cancel) {}
+                Button("Logout", role: .destructive) {
+                    Task {
+                        await appState.logout()
+                    }
+                }
+            } message: {
+                Text("Are you sure you want to logout?")
+            }
+            .sheet(isPresented: $showAvatarPicker) {
+                ImagePickerView { data in
+                    Task {
+                        await viewModel.uploadAvatar(imageData: data, chatClient: appState.chatClient)
+                    }
+                }
+            }
+            .sheet(isPresented: $showAuthorizeDevice) {
+                AuthorizeDeviceView(appState: appState)
+            }
+            .alert("Rotate Keys", isPresented: $showRotateKeys) {
+                SecureField("Password", text: $rotatePassword)
+                Button("Cancel", role: .cancel) { rotatePassword = "" }
+                Button("Rotate") {
+                    Task {
+                        isRotating = true
+                        let (success, msg) = await appState.chatClient.rotateKeys(password: rotatePassword)
+                        rotatePassword = ""
+                        isRotating = false
+                        rotateMessage = msg
+                        rotateIsError = !success
+                    }
+                }
+            } message: {
+                Text("Enter your password to generate new keys. All other devices will be disconnected.")
+            }
+            .alert(rotateIsError ? "Error" : "Success", isPresented: Binding(
+                get: { rotateMessage != nil },
+                set: { if !$0 { rotateMessage = nil } }
+            )) {
+                Button("OK") { rotateMessage = nil }
+            } message: {
+                Text(rotateMessage ?? "")
+            }
+            .alert("Change Username", isPresented: $showChangeUsername) {
+                TextField("New username", text: $newUsername)
+                Button("Cancel", role: .cancel) { newUsername = "" }
+                Button("Change") {
+                    Task {
+                        let success = await viewModel.changeUsername(newUsername: newUsername, chatClient: appState.chatClient)
+                        if success {
+                            await viewModel.loadProfile(chatClient: appState.chatClient)
+                        }
+                        newUsername = ""
+                    }
+                }
+            } message: {
+                Text("Enter a new display name.")
+            }
+            .alert("Change Password", isPresented: $showChangePassword) {
+                SecureField("Current password", text: $oldPassword)
+                SecureField("New password", text: $newPassword)
+                SecureField("Confirm new password", text: $confirmNewPassword)
+                Button("Cancel", role: .cancel) {
+                    oldPassword = ""
+                    newPassword = ""
+                    confirmNewPassword = ""
+                }
+                Button("Change") {
+                    Task {
+                        guard newPassword == confirmNewPassword else {
+                            viewModel.errorMessage = "Passwords don't match"
+                            return
+                        }
+                        _ = await viewModel.changePassword(
+                            oldPassword: oldPassword, newPassword: newPassword,
+                            chatClient: appState.chatClient
+                        )
+                        oldPassword = ""
+                        newPassword = ""
+                        confirmNewPassword = ""
+                    }
+                }
+            } message: {
+                Text("Enter your current password and a new password.")
+            }
+            .task {
+                await viewModel.loadProfile(userId: userId, chatClient: appState.chatClient)
+            }
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Verification/QRCodeScannerView.swift

@@ -0,0 +1,149 @@
+import SwiftUI
+import AVFoundation
+
+struct QRCodeScannerView: View {
+    let onScan: (Data) -> Void
+    @Environment(\.dismiss) private var dismiss
+    @State private var cameraPermission: CameraPermission = .unknown
+
+    enum CameraPermission {
+        case unknown, granted, denied
+    }
+
+    var body: some View {
+        NavigationStack {
+            ZStack {
+                switch cameraPermission {
+                case .unknown:
+                    ProgressView("Requesting camera access...")
+                case .denied:
+                    VStack(spacing: 16) {
+                        Image(systemName: "camera.fill")
+                            .font(.system(size: 48))
+                            .foregroundStyle(.secondary)
+                        Text("Camera access is required to scan QR codes.")
+                            .multilineTextAlignment(.center)
+                        Button("Open Settings") {
+                            if let url = URL(string: UIApplication.openSettingsURLString) {
+                                UIApplication.shared.open(url)
+                            }
+                        }
+                        .buttonStyle(.borderedProminent)
+                    }
+                    .padding()
+                case .granted:
+                    ScannerRepresentable(onScan: { data in
+                        onScan(data)
+                        dismiss()
+                    })
+                    .ignoresSafeArea()
+                }
+            }
+            .navigationTitle("Scan QR Code")
+            .navigationBarTitleDisplayMode(.inline)
+            .toolbar {
+                ToolbarItem(placement: .topBarLeading) {
+                    Button("Cancel") { dismiss() }
+                }
+            }
+        }
+        .task {
+            await checkCameraPermission()
+        }
+    }
+
+    private func checkCameraPermission() async {
+        let status = AVCaptureDevice.authorizationStatus(for: .video)
+        switch status {
+        case .authorized:
+            cameraPermission = .granted
+        case .notDetermined:
+            let granted = await AVCaptureDevice.requestAccess(for: .video)
+            cameraPermission = granted ? .granted : .denied
+        default:
+            cameraPermission = .denied
+        }
+    }
+}
+
+// MARK: - Scanner UIKit wrapper
+
+private struct ScannerRepresentable: UIViewControllerRepresentable {
+    let onScan: (Data) -> Void
+
+    func makeUIViewController(context: Context) -> ScannerViewController {
+        let vc = ScannerViewController()
+        vc.onScan = onScan
+        return vc
+    }
+
+    func updateUIViewController(_ uiViewController: ScannerViewController, context: Context) {}
+}
+
+final class ScannerViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
+    var onScan: ((Data) -> Void)?
+    private var captureSession: AVCaptureSession?
+    private var previewLayer: AVCaptureVideoPreviewLayer?
+    private var hasScanned = false
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        view.backgroundColor = .black
+        setupCamera()
+    }
+
+    override func viewDidLayoutSubviews() {
+        super.viewDidLayoutSubviews()
+        previewLayer?.frame = view.bounds
+    }
+
+    override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        captureSession?.stopRunning()
+    }
+
+    private func setupCamera() {
+        let session = AVCaptureSession()
+        captureSession = session
+
+        guard let device = AVCaptureDevice.default(for: .video),
+              let input = try? AVCaptureDeviceInput(device: device),
+              session.canAddInput(input) else {
+            return
+        }
+        session.addInput(input)
+
+        let output = AVCaptureMetadataOutput()
+        guard session.canAddOutput(output) else { return }
+        session.addOutput(output)
+        output.setMetadataObjectsDelegate(self, queue: .main)
+        output.metadataObjectTypes = [.qr]
+
+        let layer = AVCaptureVideoPreviewLayer(session: session)
+        layer.videoGravity = .resizeAspectFill
+        layer.frame = view.bounds
+        view.layer.addSublayer(layer)
+        previewLayer = layer
+
+        DispatchQueue.global(qos: .userInitiated).async {
+            session.startRunning()
+        }
+    }
+
+    func metadataOutput(_ output: AVCaptureMetadataOutput,
+                        didOutput metadataObjects: [AVMetadataObject],
+                        from connection: AVCaptureConnection) {
+        guard !hasScanned,
+              let object = metadataObjects.first as? AVMetadataMachineReadableCodeObject,
+              object.type == .qr else { return }
+
+        hasScanned = true
+        captureSession?.stopRunning()
+
+        // QR codes contain base64-encoded binary data (matching Python client)
+        if let stringValue = object.stringValue,
+           let data = Data(base64Encoded: stringValue) {
+            onScan?(data)
+        }
+    }
+}

ios_client 0.8.5/Kecalek/Views/Verification/SafetyNumberView.swift

@@ -0,0 +1,144 @@
+import SwiftUI
+import CoreImage.CIFilterBuiltins
+
+struct SafetyNumberView: View {
+    let peerUserId: String
+    let peerUsername: String
+    var chatClient: ChatClient
+    @State private var vm = VerificationVM()
+    @State private var showQRScanner = false
+
+    var body: some View {
+        ScrollView {
+            VStack(spacing: 24) {
+                // Verification status badge
+                VerificationStatusView(status: vm.verificationStatus)
+                    .padding(.top)
+
+                // Safety number
+                if let safetyNumber = vm.safetyNumber {
+                    VStack(spacing: 8) {
+                        Text("Safety Number")
+                            .font(.headline)
+
+                        Text("If both you and \(peerUsername) see the same number, your communication is secure.")
+                            .font(.caption)
+                            .foregroundStyle(.secondary)
+                            .multilineTextAlignment(.center)
+                            .padding(.horizontal)
+
+                        Text(safetyNumber)
+                            .font(.system(.title2, design: .monospaced))
+                            .padding()
+                            .background(.quaternary)
+                            .clipShape(RoundedRectangle(cornerRadius: 12))
+                    }
+                }
+
+                // QR Code
+                if let qrData = vm.qrCodeData {
+                    VStack(spacing: 8) {
+                        Text("Your QR Code")
+                            .font(.headline)
+
+                        if let qrImage = generateQRCode(from: qrData) {
+                            Image(uiImage: qrImage)
+                                .interpolation(.none)
+                                .resizable()
+                                .scaledToFit()
+                                .frame(width: 200, height: 200)
+                                .padding()
+                                .background(.white)
+                                .clipShape(RoundedRectangle(cornerRadius: 12))
+                        }
+                    }
+                }
+
+                // Fingerprints
+                VStack(spacing: 12) {
+                    if let myFP = vm.myFingerprint {
+                        VStack(spacing: 4) {
+                            Text("Your Fingerprint")
+                                .font(.subheadline.bold())
+                            Text(myFP)
+                                .font(.system(.caption, design: .monospaced))
+                        }
+                    }
+
+                    if let peerFP = vm.peerFingerprint {
+                        VStack(spacing: 4) {
+                            Text("\(peerUsername)'s Fingerprint")
+                                .font(.subheadline.bold())
+                            Text(peerFP)
+                                .font(.system(.caption, design: .monospaced))
+                        }
+                    }
+                }
+
+                // Actions
+                VStack(spacing: 12) {
+                    if vm.verificationStatus != "verified" {
+                        Button {
+                            Task { await vm.verifyContact(peerUserId: peerUserId, chatClient: chatClient) }
+                        } label: {
+                            Label("Mark as Verified", systemImage: "checkmark.shield.fill")
+                                .frame(maxWidth: .infinity)
+                        }
+                        .buttonStyle(.borderedProminent)
+
+                        Button {
+                            showQRScanner = true
+                        } label: {
+                            Label("Scan QR Code", systemImage: "qrcode.viewfinder")
+                                .frame(maxWidth: .infinity)
+                        }
+                        .buttonStyle(.bordered)
+                    } else {
+                        Button(role: .destructive) {
+                            Task { await vm.unverifyContact(peerUserId: peerUserId, chatClient: chatClient) }
+                        } label: {
+                            Label("Remove Verification", systemImage: "xmark.shield")
+                                .frame(maxWidth: .infinity)
+                        }
+                        .buttonStyle(.bordered)
+                    }
+                }
+                .padding(.horizontal)
+
+                // Scan result
+                if let result = vm.scanResult {
+                    Text(result)
+                        .font(.callout)
+                        .foregroundStyle(vm.scanSuccess == true ? .green : .red)
+                        .padding()
+                }
+            }
+            .padding()
+        }
+        .navigationTitle("Verify \(peerUsername)")
+        .navigationBarTitleDisplayMode(.inline)
+        .sheet(isPresented: $showQRScanner) {
+            QRCodeScannerView { scannedData in
+                showQRScanner = false
+                Task { await vm.verifyQRCode(data: scannedData, chatClient: chatClient) }
+            }
+        }
+        .task {
+            await vm.loadVerification(peerUserId: peerUserId, chatClient: chatClient)
+        }
+    }
+
+    private func generateQRCode(from data: Data) -> UIImage? {
+        let context = CIContext()
+        let filter = CIFilter.qrCodeGenerator()
+        // Base64-encode binary data — raw binary gets corrupted by QR readers (UTF-8 re-encoding)
+        let b64String = data.base64EncodedString()
+        filter.setValue(b64String.data(using: .ascii), forKey: "inputMessage")
+        filter.setValue("M", forKey: "inputCorrectionLevel")
+        guard let outputImage = filter.outputImage else { return nil }
+        let scale = 200.0 / outputImage.extent.width
+        let scaledImage = outputImage.transformed(by: CGAffineTransform(scaleX: scale, y: scale))
+        guard let cgImage = context.createCGImage(scaledImage, from: scaledImage.extent) else { return nil }
+        return UIImage(cgImage: cgImage)
+    }
+}

ios_client 0.8.5/Kecalek/Views/Verification/VerificationStatusView.swift

@@ -0,0 +1,43 @@
+import SwiftUI
+
+struct VerificationStatusView: View {
+    let status: String  // "verified", "trusted", "unverified"
+
+    var body: some View {
+        HStack(spacing: 6) {
+            Image(systemName: iconName)
+                .foregroundStyle(iconColor)
+            Text(displayText)
+                .font(.subheadline.bold())
+                .foregroundStyle(iconColor)
+        }
+        .padding(.horizontal, 12)
+        .padding(.vertical, 6)
+        .background(iconColor.opacity(0.12))
+        .clipShape(Capsule())
+    }
+
+    private var iconName: String {
+        switch status {
+        case "verified": return "checkmark.shield.fill"
+        case "trusted": return "shield.fill"
+        default: return "shield.slash"
+        }
+    }
+
+    private var iconColor: Color {
+        switch status {
+        case "verified": return .green
+        case "trusted": return .blue
+        default: return .secondary
+        }
+    }
+
+    private var displayText: String {
+        switch status {
+        case "verified": return "Verified"
+        case "trusted": return "Trusted"
+        default: return "Unverified"
+        }
+    }
+}

ios_client 0.8.5/SECURITY_REVIEW.md

@@ -0,0 +1,204 @@
+# Security Review: Kecalek iOS v0.8.5
+
+**Datum:** 14. března 2026
+**Platforma:** iOS 26+ / Swift 6
+**Architektura:** MVVM + Actor-based concurrency
+**Rozsah:** 57 Swift souborů, ~11 500 řádků kódu
+**Typ aplikace:** End-to-end encrypted messaging (Signal Protocol)
+
+---
+
+## 1. Shrnutí
+
+Kecalek je kryptograficky vyspělá messaging aplikace postavená na Signal Protocol (Double Ratchet, X3DH, Sender Keys). Využívá výhradně nativní Apple frameworky bez externích závislostí. Celková bezpečnostní úroveň je vysoká — během review byly identifikovány převážně provozní nedostatky, nikoli fundamentální architekturální chyby.
+
+---
+
+## 2. Kryptografická architektura
+
+### 2.1 Protokoly a algoritmy
+
+| Komponenta | Implementace | Hodnocení |
+|---|---|---|
+| Key Exchange | X3DH (Extended Triple Diffie-Hellman) | Odpovídá Signal specifikaci |
+| DM šifrování | Double Ratchet (AES-256-GCM) | Forward secrecy zajištěna |
+| Skupinové šifrování | Sender Keys (AES-256-GCM) | Distribuce přes pairwise DM |
+| Autentizace | RSA-4096 challenge-response (PSS-SHA256) | Silné |
+| Úložiště klíčů | PBKDF2-HMAC-SHA256 (600 000 iterací) + AES-256-GCM | Odpovídající |
+| Identity keys | Ed25519 (podepisování) + X25519 (key agreement) | Standard |
+| KDF | HKDF-SHA256 | Standard |
+| RNG | SecRandomCopyBytes | Kryptograficky bezpečný |
+| Message padding | Bucket-based (64B–64KB) | Skrývá délku zpráv |
+
+### 2.2 Správa klíčů
+
+- **Signed Pre-Key (SPK):** rotace každých 7 dní s grace periodem pro předchozí SPK
+- **One-Time Pre-Keys (OPK):** batch 50 kusů, doplnění při prahu 20
+- **Max skip:** 256 zpráv na chain (ochrana proti DoS přes vynucené přeskakování)
+- **TOFU registry:** sledování identity klíčů kontaktů s možností manuální verifikace
+- **Safety numbers:** 60místné číslo (SHA-512, 5 200 iterací) + QR kód verifikace
+
+### 2.3 Pozitivní nálezy
+
+- Žádné použití zastaralých algoritmů (MD5, SHA1, DES, RC4)
+- Žádné vlastní kryptografické primitivy — vše přes CryptoKit a Security framework
+- Správná implementace AAD (Associated Authenticated Data) v AES-GCM
+- Snapshot/restore mechanismus pro atomické ratchet operace (M9 fix)
+- Self-encryption pro multi-device synchronizaci vlastních zpráv
+
+---
+
+## 3. Nalezené zranitelnosti a nápravná opatření
+
+### 3.1 KRITICKÉ — Opraveno
+
+#### 3.1.1 Únik kryptografických klíčů přes debug výpisy
+
+**Popis:** 160 `print()` volání v produkčním kódu vypisovalo citlivý kryptografický materiál do systémových logů — root keys, chain keys, message keys, identity keys, shared secrets, DH výstupy, nonce hodnoty.
+
+**Riziko:** Na iOS jsou systémové logy čitelné přes USB (Console.app), diagnostické profily a potenciálně dalšími aplikacemi. Útočník s fyzickým přístupem k zařízení nebo se schopností číst logy mohl získat kompletní kryptografický stav relace.
+
+**Dotčené soubory:**
+
+- `Core/ChatClient.swift` — 118 výskytů (session data, OPK IDs, decryption debug)
+- `Crypto/DoubleRatchet.swift` — 11 výskytů (root keys, DH public keys, message keys, nonce)
+- `Crypto/X3DH.swift` — 9 výskytů (identity keys, ephemeral keys, DH outputs, shared secrets)
+- `ViewModels/AuthViewModel.swift` — 7 výskytů
+- `AppState.swift` — 7 výskytů
+- `Core/MessageCache.swift` — 3 výskyty
+- `ViewModels/ChatViewModel.swift` — 2 výskyty
+- `ViewModels/ConversationListVM.swift` — 3 výskyty
+
+**Náprava:** Všech 160 print statements zabaleno do `#if DEBUG` / `#endif` bloků. V release buildech nebude žádný kryptografický materiál logován.
+
+#### 3.1.2 Insecure TLS — bypass ověření certifikátu a volitelné TLS
+
+**Popis:** Parametr `tlsInsecure` umožňoval kompletní vypnutí TLS certificate verification. Navíc bylo TLS volitelné — uživatel mohl v UI vypnout šifrování transportní vrstvy přes toggle "Use TLS".
+
+**Riziko:** MitM útok — útočník na síti mohl odposlouchávat a modifikovat veškerou komunikaci, včetně challenge-response autentizace a metadat.
+
+**Dotčené soubory:**
+
+- `Network/ConnectionManager.swift`
+- `Core/ChatClient.swift`
+- `ViewModels/AuthViewModel.swift`
+- `Views/Auth/LoginView.swift`
+- `Views/Auth/PairingView.swift`
+- `Core/KeychainService.swift`
+
+**Náprava:** TLS je nyní povinné bez výjimek. Parametry `useTLS` a `tlsInsecure` kompletně odstraněny z celého codebase. Toggle "Use TLS" odstraněn z UI. `ConnectionManager.connect()` vždy navazuje TLS spojení. Credentials v Keychainu již neukládají `useTLS` flag.
+
+---
+
+### 3.2 VYSOKÉ — Opraveno
+
+#### 3.2.1 Heslo v paměti po úspěšném přihlášení
+
+**Popis:** `AuthViewModel` uchovával heslo jako `String` property i po úspěšném loginu. Swift String je immutable a garbage collector jej může držet v paměti neomezeně dlouho.
+
+**Riziko:** Memory dump útok — při fyzickém přístupu k zařízení nebo exploitu s přístupem do paměti procesu mohl útočník extrahovat heslo.
+
+**Dotčený soubor:** `ViewModels/AuthViewModel.swift`
+
+**Náprava:** Properties `password` a `confirmPassword` jsou vynulovány ihned po úspěšném přihlášení a uložení do Keychainu.
+
+**Poznámka:** Swift `String` neumožňuje bezpečné přepisování paměti (na rozdíl od `UnsafeMutableBufferPointer`). Kompletní mitigace by vyžadovala vlastní typ pro citlivé řetězce. Aktuální řešení minimalizuje dobu expozice.
+
+---
+
+### 3.3 STŘEDNÍ — Opraveno
+
+#### 3.3.1 Clipboard bez automatického vymazání
+
+**Popis:** Funkce kopírování zprávy zapisovala text do systémového clipboardu (`UIPasteboard.general`) bez časového omezení.
+
+**Riziko:** Jiné aplikace mohou číst obsah clipboardu (iOS 14+ zobrazuje notifikaci, ale nezabraňuje přístupu). Citlivý obsah zpráv mohl zůstat v clipboardu neomezeně.
+
+**Dotčený soubor:** `Views/Chat/MessageBubbleView.swift`
+
+**Náprava:** Přidán automatický clear clipboardu po 30 sekundách s kontrolou, že obsah nebyl mezitím uživatelem přepsán.
+
+#### 3.3.2 Komentované vývojové IP adresy
+
+**Popis:** `Constants.swift` obsahoval komentované dev server adresy (`192.168.88.65`, `85.71.71.188`), které odhalovaly interní síťovou infrastrukturu.
+
+**Dotčený soubor:** `Utilities/Constants.swift`
+
+**Náprava:** Komentované IP adresy odstraněny.
+
+---
+
+### 3.4 STŘEDNÍ — Neřešeno (doporučení)
+
+#### 3.4.1 Chybějící certificate pinning
+
+**Popis:** Aplikace se spoléhá výhradně na systémovou validaci TLS certifikátů. Neimplementuje certificate pinning ani SPKI pinning.
+
+**Riziko:** Při kompromitaci certifikační autority, na enterprise-managed zařízeních s vlastním root CA, nebo při state-level útoku může útočník provést MitM. Dopady jsou omezené díky E2EE (obsah zpráv zůstává chráněn), ale metadata (kdo s kým komunikuje, timing) by byla vystavena.
+
+**Doporučení:** Implementovat SPKI pinning pro produkční server `chat.ai-tech.news` pomocí Network.framework `sec_protocol_options_set_verify_block` s vlastní validací veřejného klíče serveru.
+
+#### 3.4.2 Chybějící jailbreak detekce
+
+**Popis:** Aplikace nedetekuje jailbreaknutá zařízení a nevaruje uživatele.
+
+**Riziko:** Na jailbreaknutém zařízení jsou oslabeny iOS sandbox protekce — jiné aplikace mohou přistupovat k souborům aplikace, Keychain items mohou být extrahovány, a iOS file protection je částečně neúčinná.
+
+**Doporučení:** Implementovat detekci (existence `/Applications/Cydia.app`, zápis mimo sandbox, dynamické knihovny) a zobrazit varování uživateli. Neblokovat použití — pouze informovat o riziku.
+
+---
+
+## 4. Pozitivní bezpečnostní nálezy
+
+### 4.1 Keychain
+
+Implementace v `KeychainService.swift` je správná:
+
+- Přístupnost: `kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly`
+- Biometrická ochrana: `.biometryAny` (Face ID / Touch ID)
+- Credentials nejsou exportovatelné na jiná zařízení
+- Správné error handling pro biometrické selhání
+
+### 4.2 File protection
+
+Všechny soubory na disku používají `.completeFileProtection` — jsou šifrované iOS file protection a přístupné pouze když je zařízení odemčené.
+
+### 4.3 Šifrování lokálních dat
+
+Všechny persistentní soubory (sessions, sender keys, message cache, conversation cache, avatary, TOFU registry) jsou šifrované AES-256-GCM s klíčem derivovaným přes HKDF z identity private key.
+
+### 4.4 Žádné externí závislosti
+
+Aplikace nepoužívá žádné third-party knihovny (CocoaPods, SPM, Carthage). Veškerá kryptografie běží přes nativní Apple frameworky (CryptoKit, Security, CommonCrypto). To eliminuje supply chain rizika.
+
+### 4.5 Žádné WebView
+
+Celé UI je nativní SwiftUI/UIKit. Absence WebView eliminuje kategorii XSS a JavaScript injection zranitelností.
+
+### 4.6 Brute-force ochrana
+
+Login implementuje exponenciální backoff (2^n sekund, max 300s) při neúspěšných pokusech. Server může vyžadovat PoW challenge při registračních surge.
+
+### 4.7 Bezpečná registrace
+
+Registrační flow zahrnuje email verifikaci a volitelný SHA-256 Proof-of-Work challenge jako ochranu proti automatizovaným registracím.
+
+### 4.8 Actor isolation
+
+`ChatClient` je implementován jako Swift actor, což garantuje thread-safe přístup ke kryptografickému stavu bez možnosti race conditions.
+
+---
+
+## 5. Shrnutí změn
+
+| # | Závažnost | Nález | Stav |
+|---|---|---|---|
+| 3.1.1 | Kritická | Debug výpisy kryptografických klíčů (160×) | **Opraveno** |
+| 3.1.2 | Kritická | TLS insecure bypass + volitelné TLS | **Opraveno** |
+| 3.2.1 | Vysoká | Heslo zůstává v paměti po loginu | **Opraveno** |
+| 3.3.1 | Střední | Clipboard bez auto-clear | **Opraveno** |
+| 3.3.2 | Střední | Dev IP adresy v kódu | **Opraveno** |
+| 3.4.1 | Střední | Chybějící certificate pinning | Doporučení |
+| 3.4.2 | Střední | Chybějící jailbreak detekce | Doporučení |
+
+**Celkové hodnocení po opravách:** Aplikace splňuje vysoké bezpečnostní standardy pro E2EE messaging. Kryptografická architektura je solidní a odpovídá Signal Protocol specifikaci. Zbývající doporučení se týkají defense-in-depth opatření.