Merge pull request #244 from permissionlesstech/feat/bring-the-noise

Implement Noise Protocol Framework and peer ID rotation

BRING_THE_NOISE.md

@@ -0,0 +1,216 @@
+# Bringing the Noise: Secure Communication in BitChat
+
+## Overview
+
+BitChat implements the Noise Protocol Framework for end-to-end encryption, providing forward secrecy, identity hiding, and cryptographic authentication. This document details our Swift implementation and its integration with BitChat's decentralized mesh network.
+
+## The Noise Protocol Framework
+
+### Why Noise?
+
+The Noise Protocol Framework offers:
+- **Forward Secrecy**: Past messages remain secure even if keys are compromised
+- **Identity Hiding**: Peer identities are encrypted during handshake
+- **Simplicity**: Clean, auditable protocol with minimal complexity
+- **Performance**: Efficient for resource-constrained mobile devices
+- **Flexibility**: Supports various handshake patterns
+
+### The XX Pattern
+
+BitChat uses the Noise XX pattern:
+```
+XX:
+  -> e
+  <- e, ee, s, es
+  -> s, se
+```
+
+This three-message pattern provides:
+- Mutual authentication
+- Identity encryption (identities revealed only after initial key exchange)
+- Resistance to key-compromise impersonation
+
+## Implementation Architecture
+
+### Core Components
+
+#### NoiseEncryptionService
+The main service managing all Noise operations:
+```swift
+class NoiseEncryptionService {
+    private let staticIdentityKey: Curve25519.KeyAgreement.PrivateKey
+    private let sessionManager: NoiseSessionManager
+    private let channelEncryption = NoiseChannelEncryption()
+}
+```
+
+#### NoiseSession
+Individual session state for each peer:
+```swift
+class NoiseSession {
+    private var handshakeState: NoiseHandshakeState?
+    private var sendCipher: NoiseCipherState?
+    private var receiveCipher: NoiseCipherState?
+    private let remoteStaticKey: Curve25519.KeyAgreement.PublicKey?
+}
+```
+
+#### NoiseSessionManager
+Thread-safe session management:
+```swift
+class NoiseSessionManager {
+    private var sessions: [String: NoiseSession] = [:]
+    private let sessionsQueue = DispatchQueue(label: "noise.sessions", attributes: .concurrent)
+}
+```
+
+### Handshake Flow
+
+1. **Initiator sends ephemeral key**
+   ```swift
+   let ephemeralKey = Curve25519.KeyAgreement.PrivateKey()
+   let message = ephemeralKey.publicKey.rawRepresentation
+   ```
+
+2. **Responder sends ephemeral + encrypted static**
+   ```swift
+   // Generate ephemeral, perform DH, encrypt static key
+   let encryptedStatic = encrypt(staticKey, using: sharedSecret)
+   ```
+
+3. **Initiator sends encrypted static**
+   ```swift
+   // Complete handshake, derive session keys
+   let (sendKey, recvKey) = deriveSessionKeys(transcript)
+   ```
+
+### Session Management
+
+Sessions are managed with automatic cleanup and rekey support:
+
+```swift
+// Session lookup by peer ID
+func getSession(for peerID: String) -> NoiseSession?
+
+// Automatic session removal on disconnect
+func removeSession(for peerID: String)
+
+// Rekey detection
+func getSessionsNeedingRekey() -> [(String, Bool)]
+```
+
+## Integration with BitChat
+
+### Peer ID Rotation
+
+Noise sessions persist across peer ID rotations through fingerprint mapping:
+
+```swift
+// Identity announcement after handshake
+struct NoiseIdentityAnnouncement {
+    let peerID: String
+    let publicKey: Data
+    let nickname: String
+    let previousPeerID: String?
+    let signature: Data
+}
+```
+
+### Message Encryption
+
+All messages are encrypted using established Noise sessions:
+
+```swift
+// Encrypt message
+let encrypted = try noiseService.encrypt(messageData, for: peerID)
+
+// Decrypt message  
+let decrypted = try noiseService.decrypt(encryptedData, from: peerID)
+```
+
+### Channel Encryption
+
+Password-protected channels use Noise for key distribution:
+
+```swift
+// Share channel key securely
+let keyPacket = createChannelKeyPacket(password: password, channel: channel)
+let encrypted = try encrypt(keyPacket, for: peerID)
+```
+
+## Security Properties
+
+### Forward Secrecy
+- Ephemeral keys are generated for each handshake
+- Past sessions cannot be decrypted with current keys
+- Automatic rekey after 1 hour or 10,000 messages
+
+### Authentication
+- Static keys provide long-term identity
+- Handshake ensures mutual authentication
+- MAC tags prevent message tampering
+
+### Privacy
+- Peer identities encrypted during handshake
+- Metadata minimization through padding
+- No persistent session identifiers
+
+## Implementation Details
+
+### Key Derivation
+```swift
+// HKDF for key derivation
+func hkdf(salt: Data, ikm: Data, info: Data, length: Int) -> Data
+
+// Derive channel keys with PBKDF2
+func deriveChannelKey(password: String, salt: Data) -> SymmetricKey
+```
+
+### Cryptographic Primitives
+- **DH**: X25519 (Curve25519)
+- **Cipher**: ChaChaPoly (AEAD)
+- **Hash**: SHA-256
+- **KDF**: HKDF-SHA256
+
+### Error Handling
+```swift
+enum NoiseError: Error {
+    case handshakeFailed
+    case invalidMessage
+    case sessionNotEstablished
+    case decryptionFailed
+}
+```
+
+## Performance Optimizations
+
+### Connection Pooling
+- Reuse established sessions
+- Lazy handshake initiation
+- Session caching with TTL
+
+### Message Batching
+- Combine small messages
+- Reduce encryption overhead
+- Optimize for BLE MTU
+
+### Memory Management
+- Bounded session cache
+- Automatic cleanup of stale sessions
+- Efficient key rotation
+
+## Future Enhancements
+
+### Post-Quantum Readiness
+- Hybrid handshake patterns
+- Kyber integration plans
+- Graceful algorithm migration
+
+### Advanced Features
+- Multi-device support
+- Session backup/restore
+- Group messaging primitives
+
+## Conclusion
+
+BitChat's Noise implementation provides encryption while maintaining the simplicity and performance required for a peer-to-peer messaging application. The protocol's elegant design ensures that people's communications remain private, authenticated, and forward-secure without sacrificing usability.

WIFI_DIRECT_PLAN.md

@@ -1,202 +0,0 @@
-# WiFi Direct Integration Plan for BitChat
-
-## Overview
-
-WiFi Direct enables peer-to-peer WiFi connections without requiring an access point, offering significantly higher bandwidth and range compared to Bluetooth Low Energy.
-
-### Key Specifications
-- **Range**: 100-200 meters (vs BLE's 10-30m)
-- **Speed**: 250+ Mbps (vs BLE's 1-3 Mbps)
-- **Power**: Higher consumption than BLE
-- **Platform Support**: 
-  - iOS: MultipeerConnectivity framework
-  - Android: WiFi P2P API
-  - macOS: Network.framework with Bonjour
-
-## Alternative Transport Technologies
-
-### Ultrasonic Communication
-- **What**: Uses sound waves above human hearing (>20kHz) to transmit data
-- **Range**: 1-10 meters typically
-- **Speed**: ~1-10 kbps
-- **Pros**: Works through thin walls, no radio interference, very low power
-- **Cons**: Limited range, sensitive to noise, low bandwidth
-- **Use case**: Secret communication in meetings, data transfer when radio is jammed
-
-### LoRa (Long Range)
-- **What**: Low-power, wide-area network protocol using sub-GHz frequencies
-- **Range**: 2-15 km in rural areas, 2-5 km in urban
-- **Speed**: 0.3-50 kbps
-- **Pros**: Incredible range, very low power, penetrates buildings well
-- **Cons**: Very low bandwidth, requires special hardware, regulated frequencies
-- **Use case**: Disaster relief, rural communities, sensor networks
-
-## Architecture Design
-
-### Transport Protocol Interface
-
-```swift
-protocol TransportProtocol {
-    var transportType: TransportType { get }
-    var isAvailable: Bool { get }
-    var currentPeers: [PeerInfo] { get }
-    
-    func startDiscovery()
-    func stopDiscovery()
-    func send(_ packet: BitchatPacket, to peer: PeerID?) 
-    func setDelegate(_ delegate: TransportDelegate)
-}
-
-enum TransportType {
-    case bluetooth
-    case wifiDirect
-    case ultrasonic  // future
-    case lora        // future
-}
-
-// Transport Manager to coordinate multiple transports
-class TransportManager {
-    private var transports: [TransportProtocol] = []
-    private var routingTable: [PeerID: TransportType] = [:]
-    
-    func sendOptimal(_ packet: BitchatPacket, to peer: PeerID?) {
-        // Choose best transport based on:
-        // 1. Message size
-        // 2. Battery level
-        // 3. Available transports
-        // 4. Peer capabilities
-    }
-}
-```
-
-## Implementation Phases
-
-### Phase 1: Abstract Transport Layer
-1. Create `TransportProtocol` interface
-2. Refactor `BluetoothMeshService` to implement protocol
-3. Create `TransportManager` to coordinate transports
-4. Update `ChatViewModel` to use transport abstraction
-
-### Phase 2: WiFi Direct Transport
-1. Create `WiFiDirectTransport` class
-2. iOS: Use MultipeerConnectivity framework
-3. macOS: Use Network.framework with Bonjour
-4. Handle transport handoff (BLE → WiFi when available)
-
-### Phase 3: Intelligent Routing
-1. Implement bandwidth detection
-2. Create routing algorithm:
-   - Small messages (< 1KB): Use BLE (lower power)
-   - Large messages/files: Use WiFi Direct
-   - Emergency/broadcast: Use all transports
-3. Add transport negotiation protocol
-
-### Phase 4: Advanced Features
-1. File transfer with resumption
-2. Video/audio streaming support
-3. Hybrid mesh (some nodes BLE-only, some WiFi-capable)
-4. Transport bonding (use multiple simultaneously)
-
-## Key Considerations
-
-### Battery Impact
-- WiFi Direct uses significantly more power than BLE
-- Only activate when:
-  - Large file transfer needed
-  - User explicitly enables
-  - Device is charging
-  - Battery > 50%
-
-### Discovery Strategy
-- Use BLE for initial discovery (low power)
-- Exchange WiFi Direct capabilities
-- Establish WiFi Direct only when needed
-- Fall back to BLE if WiFi fails
-
-### Security
-- Use same encryption (X25519 + AES-256-GCM)
-- Pin WiFi Direct connections with BLE-exchanged keys
-- Prevent WiFi Direct spoofing attacks
-
-### User Experience
-- Automatic transport selection
-- Visual indicator showing active transport
-- Manual override option
-- Seamless handoff between transports
-
-## Proposed File Structure
-
-```
-bitchat/
-├── Transports/
-│   ├── TransportProtocol.swift
-│   ├── TransportManager.swift
-│   ├── BluetoothTransport.swift  (refactored from BluetoothMeshService)
-│   ├── WiFiDirectTransport.swift  (new)
-│   └── TransportDelegate.swift
-├── Services/
-│   └── RoutingService.swift       (intelligent message routing)
-```
-
-## Benefits
-
-1. **10-100x faster** file transfers
-2. **Longer range** for fixed installations  
-3. **Video chat** capability
-4. **Backwards compatible** (BLE-only devices still work)
-5. **Future-proof** (easy to add more transports)
-
-## Implementation Notes
-
-### iOS MultipeerConnectivity Example
-
-```swift
-import MultipeerConnectivity
-
-class WiFiDirectTransport: NSObject, TransportProtocol {
-    private let serviceType = "bitchat-wifi"
-    private var peerID: MCPeerID
-    private var session: MCSession
-    private var advertiser: MCNearbyServiceAdvertiser
-    private var browser: MCNearbyServiceBrowser
-    
-    func startDiscovery() {
-        advertiser.startAdvertisingPeer()
-        browser.startBrowsingForPeers()
-    }
-}
-```
-
-### Message Size Routing Logic
-
-```swift
-func selectTransport(for message: Data) -> TransportType {
-    let size = message.count
-    let batteryLevel = BatteryOptimizer.shared.batteryLevel
-    
-    if size > 10_000 && batteryLevel > 0.5 {
-        return .wifiDirect
-    } else if size < 1_000 || batteryLevel < 0.3 {
-        return .bluetooth
-    } else {
-        // Medium size, good battery - use faster if available
-        return wifiAvailable ? .wifiDirect : .bluetooth
-    }
-}
-```
-
-## Testing Strategy
-
-1. **Unit Tests**: Mock transport implementations
-2. **Integration Tests**: BLE + WiFi handoff scenarios
-3. **Performance Tests**: Throughput comparison
-4. **Battery Tests**: Power consumption analysis
-5. **Field Tests**: Real-world range and reliability
-
-## Future Considerations
-
-- **Transport Plugins**: Allow third-party transport implementations
-- **SDN Integration**: Software-defined networking for complex topologies
-- **QoS**: Quality of Service for different message types
-- **Compression**: Different algorithms per transport
-- **Multi-path**: Send redundant copies over multiple transports

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 		E65BBB6544FE0159F3C6C3A8 /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 95F16C3A4A5621C74461D8D3 /* LaunchScreen.storyboard */; };
 		F00B713D5053617FB5F3F1BE /* MessagePaddingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8DE9CDF66D4E52D268851048 /* MessagePaddingTests.swift */; };
 		F455F011B3B648ADA233F998 /* BinaryProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = A2136C3E22D02D4A8DBE7EAB /* BinaryProtocol.swift */; };
@@ -99,10 +145,33 @@
 /* Begin PBXFileReference section */
 		036A1A705AAF9EC21F4354BE /* PasswordProtectedChannelTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PasswordProtectedChannelTests.swift; sourceTree = "<group>"; };
 		03C57F452B55FD0FD8F51421 /* bitchatTests_macOS.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = bitchatTests_macOS.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
+		04891CA82E22971E0064A111 /* LRUCache.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LRUCache.swift; sourceTree = "<group>"; };
+		04B6BA3D2E2035220090FE39 /* NoiseProtocolTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseProtocolTests.swift; sourceTree = "<group>"; };
+		04B6BA402E2035530090FE39 /* NoiseChannelEncryption.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseChannelEncryption.swift; sourceTree = "<group>"; };
+		04B6BA412E2035530090FE39 /* NoiseProtocol.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseProtocol.swift; sourceTree = "<group>"; };
+		04B6BA422E2035530090FE39 /* NoiseSecurityConsiderations.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseSecurityConsiderations.swift; sourceTree = "<group>"; };
+		04B6BA432E2035530090FE39 /* NoiseSession.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseSession.swift; sourceTree = "<group>"; };
+		04B6BA4D2E2038A70090FE39 /* NoiseEncryptionService.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseEncryptionService.swift; sourceTree = "<group>"; };
+		04B6BA532E203D6C0090FE39 /* FingerprintView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FingerprintView.swift; sourceTree = "<group>"; };
+		04B6BA542E203D6C0090FE39 /* NoiseTestingView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseTestingView.swift; sourceTree = "<group>"; };
+		04B6BA592E215FDA0090FE39 /* NoiseChannelKeyRotation.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseChannelKeyRotation.swift; sourceTree = "<group>"; };
+		04B6BA5A2E2041220090FE39 /* NoiseIdentityPersistenceTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseIdentityPersistenceTests.swift; sourceTree = "<group>"; };
+		04B6BA5A2E215FDA0090FE39 /* NoisePostQuantum.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoisePostQuantum.swift; sourceTree = "<group>"; };
+		04B6BA5F2E21601B0090FE39 /* ChannelVerificationTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ChannelVerificationTests.swift; sourceTree = "<group>"; };
+		04B6BA602E21601B0090FE39 /* KeychainIntegrationTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = KeychainIntegrationTests.swift; sourceTree = "<group>"; };
+		04B6BA612E21601B0090FE39 /* NoiseChannelEncryptionTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseChannelEncryptionTests.swift; sourceTree = "<group>"; };
+		04B6BA622E21601B0090FE39 /* NoiseKeyRotationTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseKeyRotationTests.swift; sourceTree = "<group>"; };
+		04B6BA632E21601B0090FE39 /* NoiseRateLimiterTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseRateLimiterTests.swift; sourceTree = "<group>"; };
+		04B6BA642E21601B0090FE39 /* NoiseSecurityTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseSecurityTests.swift; sourceTree = "<group>"; };
+		04B6BA652E21601B0090FE39 /* NoiseSecurityValidatorTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseSecurityValidatorTests.swift; sourceTree = "<group>"; };
+		04B6BA662E21601B0090FE39 /* SecureNoiseSessionTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SecureNoiseSessionTests.swift; sourceTree = "<group>"; };
+		04B6BA772E2166A50090FE39 /* NoiseTestingHelper.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoiseTestingHelper.swift; sourceTree = "<group>"; };
+		04B6BA782E2166A50090FE39 /* SecurityLogger.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SecurityLogger.swift; sourceTree = "<group>"; };
 		12B9C3EDF3BC73D3BC106DA4 /* DeliveryTracker.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DeliveryTracker.swift; sourceTree = "<group>"; };
 		136696FC4436A02D98CE6A77 /* KeychainManager.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = KeychainManager.swift; sourceTree = "<group>"; };
 		1EB3A8FE16333ED12FCB8ACB /* BloomFilterTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BloomFilterTests.swift; sourceTree = "<group>"; };
 		229F17B68CFF7AB1BC91C847 /* BitchatProtocol.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BitchatProtocol.swift; sourceTree = "<group>"; };
+		2EE9D4FA625C4671ACD371D4 /* SecureIdentityStateManager.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SecureIdentityStateManager.swift; sourceTree = "<group>"; };
 		32F149C43D1915831B60FE09 /* CompressionUtil.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CompressionUtil.swift; sourceTree = "<group>"; };
 		3448F84BF86A42A3CC4A9379 /* NotificationService.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationService.swift; sourceTree = "<group>"; };
 		3668EEBB42FD4A24D5D83B7B /* bitchatShareExtension.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; path = bitchatShareExtension.entitlements; sourceTree = "<group>"; };
@@ -113,7 +182,7 @@
 		53D535D9CE0B875F47402290 /* BinaryProtocolTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BinaryProtocolTests.swift; sourceTree = "<group>"; };
 		61F92EBA29C47C0FCC482F1F /* bitchatShareExtension.appex */ = {isa = PBXFileReference; includeInIndex = 0; lastKnownFileType = "wrapper.extensionkit-extension"; path = bitchatShareExtension.appex; sourceTree = BUILT_PRODUCTS_DIR; };
 		67A85BFDDE65B4CD8BDF6DDB /* MessageRetentionService.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MessageRetentionService.swift; sourceTree = "<group>"; };
-		6DC1563390A15C042D059CF9 /* EncryptionService.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EncryptionService.swift; sourceTree = "<group>"; };
+		6E2446380E7A44E49A35B664 /* IdentityModels.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IdentityModels.swift; sourceTree = "<group>"; };
 		763E0DBA9492A654FC0CDCB9 /* AppInfoView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppInfoView.swift; sourceTree = "<group>"; };
 		8DE9CDF66D4E52D268851048 /* MessagePaddingTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MessagePaddingTests.swift; sourceTree = "<group>"; };
 		8F3A7C058C2C8E1A06C8CF8B /* bitchat_macOS.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; name = bitchat_macOS.app; path = bitchat.app; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -136,6 +205,19 @@
 /* End PBXFileReference section */
 
 /* Begin PBXGroup section */
+		04B6BA442E2035530090FE39 /* Noise */ = {
+			isa = PBXGroup;
+			children = (
+				04B6BA592E215FDA0090FE39 /* NoiseChannelKeyRotation.swift */,
+				04B6BA5A2E215FDA0090FE39 /* NoisePostQuantum.swift */,
+				04B6BA402E2035530090FE39 /* NoiseChannelEncryption.swift */,
+				04B6BA412E2035530090FE39 /* NoiseProtocol.swift */,
+				04B6BA422E2035530090FE39 /* NoiseSecurityConsiderations.swift */,
+				04B6BA432E2035530090FE39 /* NoiseSession.swift */,
+			);
+			path = Noise;
+			sourceTree = "<group>";
+		};
 		18198ED912AAF495D8AF7763 = {
 			isa = PBXGroup;
 			children = (
@@ -156,7 +238,9 @@
 				EA706D8E5097785414646A8E /* Info.plist */,
 				95F16C3A4A5621C74461D8D3 /* LaunchScreen.storyboard */,
 				ADD53BCDA233C02E53458926 /* Protocols */,
+				04B6BA442E2035530090FE39 /* Noise */,
 				D98A3186D7E4C72E35BDF7FE /* Services */,
+				6078981E5A3646BC84CC6DB4 /* Identity */,
 				9A78348821A7D3374607D4E3 /* Utils */,
 				45BB7D87CAE42A8C0447D909 /* ViewModels */,
 				A55126E93155456CAA8D6656 /* Views */,
@@ -172,9 +256,21 @@
 			path = ViewModels;
 			sourceTree = "<group>";
 		};
+		6078981E5A3646BC84CC6DB4 /* Identity */ = {
+			isa = PBXGroup;
+			children = (
+				6E2446380E7A44E49A35B664 /* IdentityModels.swift */,
+				2EE9D4FA625C4671ACD371D4 /* SecureIdentityStateManager.swift */,
+			);
+			path = Identity;
+			sourceTree = "<group>";
+		};
 		9A78348821A7D3374607D4E3 /* Utils */ = {
 			isa = PBXGroup;
 			children = (
+				04891CA82E22971E0064A111 /* LRUCache.swift */,
+				04B6BA772E2166A50090FE39 /* NoiseTestingHelper.swift */,
+				04B6BA782E2166A50090FE39 /* SecurityLogger.swift */,
 				ED176FF3B274E35C2D827894 /* BatteryOptimizer.swift */,
 				32F149C43D1915831B60FE09 /* CompressionUtil.swift */,
 				CB043CA5EEB9AC8B07D61E97 /* OptimizedBloomFilter.swift */,
@@ -207,6 +303,8 @@
 		A55126E93155456CAA8D6656 /* Views */ = {
 			isa = PBXGroup;
 			children = (
+				04B6BA532E203D6C0090FE39 /* FingerprintView.swift */,
+				04B6BA542E203D6C0090FE39 /* NoiseTestingView.swift */,
 				763E0DBA9492A654FC0CDCB9 /* AppInfoView.swift */,
 				A08E03AA0C63E97C91749AEC /* ContentView.swift */,
 				9AC141774F6671FCDC347DC7 /* LinkPreviewView.swift */,
@@ -226,6 +324,16 @@
 		C3D98EB3E1B455E321F519F4 /* bitchatTests */ = {
 			isa = PBXGroup;
 			children = (
+				04B6BA5F2E21601B0090FE39 /* ChannelVerificationTests.swift */,
+				04B6BA602E21601B0090FE39 /* KeychainIntegrationTests.swift */,
+				04B6BA612E21601B0090FE39 /* NoiseChannelEncryptionTests.swift */,
+				04B6BA622E21601B0090FE39 /* NoiseKeyRotationTests.swift */,
+				04B6BA632E21601B0090FE39 /* NoiseRateLimiterTests.swift */,
+				04B6BA642E21601B0090FE39 /* NoiseSecurityTests.swift */,
+				04B6BA652E21601B0090FE39 /* NoiseSecurityValidatorTests.swift */,
+				04B6BA662E21601B0090FE39 /* SecureNoiseSessionTests.swift */,
+				04B6BA3D2E2035220090FE39 /* NoiseProtocolTests.swift */,
+				04B6BA5A2E2041220090FE39 /* NoiseIdentityPersistenceTests.swift */,
 				53D535D9CE0B875F47402290 /* BinaryProtocolTests.swift */,
 				3FA8FF26ABDC1C642A8C7AE5 /* BitchatMessageTests.swift */,
 				1EB3A8FE16333ED12FCB8ACB /* BloomFilterTests.swift */,
@@ -239,9 +347,9 @@
 		D98A3186D7E4C72E35BDF7FE /* Services */ = {
 			isa = PBXGroup;
 			children = (
+				04B6BA4D2E2038A70090FE39 /* NoiseEncryptionService.swift */,
 				D5C3D880FF8AE1673B20E1E3 /* BluetoothMeshService.swift */,
 				12B9C3EDF3BC73D3BC106DA4 /* DeliveryTracker.swift */,
-				6DC1563390A15C042D059CF9 /* EncryptionService.swift */,
 				136696FC4436A02D98CE6A77 /* KeychainManager.swift */,
 				67A85BFDDE65B4CD8BDF6DDB /* MessageRetentionService.swift */,
 				AA4D7595A613F7ED3B386132 /* MessageRetryService.swift */,
@@ -434,15 +542,28 @@
 				C0A80BA73EC1A372B9338E3C /* BatteryOptimizer.swift in Sources */,
 				4B747085D07A1BCE0F5BA612 /* BinaryProtocol.swift in Sources */,
 				6E7761E21C99F28AE2F9BE5F /* BitchatApp.swift in Sources */,
+				04891CAA2E22971E0064A111 /* LRUCache.swift in Sources */,
+				04B6BA5B2E215FDA0090FE39 /* NoisePostQuantum.swift in Sources */,
+				04B6BA5C2E215FDA0090FE39 /* NoiseChannelKeyRotation.swift in Sources */,
 				923027D6F2F417AFA2488127 /* BitchatProtocol.swift in Sources */,
+				04B6BA452E2035530090FE39 /* NoiseSecurityConsiderations.swift in Sources */,
+				04B6BA462E2035530090FE39 /* NoiseSession.swift in Sources */,
+				04B6BA472E2035530090FE39 /* NoiseProtocol.swift in Sources */,
+				04B6BA482E2035530090FE39 /* NoiseChannelEncryption.swift in Sources */,
 				7A50E2F04A3515A7E90EEAE4 /* BluetoothMeshService.swift in Sources */,
 				D450CF41F207BDE1A1AAA56E /* ChatViewModel.swift in Sources */,
 				B0CA7796B2B2AC2B33F84548 /* CompressionUtil.swift in Sources */,
 				92D34E7A07C990C8A815B0CE /* ContentView.swift in Sources */,
+				04B6BA4F2E2038A70090FE39 /* NoiseEncryptionService.swift in Sources */,
 				8DCEEA289EF7C49E7CD38B08 /* DeliveryTracker.swift in Sources */,
-				739429DFDE5C5829CF70DA7D /* EncryptionService.swift in Sources */,
+				04B6BA792E2166A50090FE39 /* NoiseTestingHelper.swift in Sources */,
+				04B6BA7A2E2166A50090FE39 /* SecurityLogger.swift in Sources */,
 				FB8819B4C84FAFEF5C36B216 /* KeychainManager.swift in Sources */,
+				04AD0B4E2E25B9580002A40A /* IdentityModels.swift in Sources */,
+				04AD0B4F2E25B9580002A40A /* SecureIdentityStateManager.swift in Sources */,
 				31D147471B9F4E2815352DDA /* LinkPreviewView.swift in Sources */,
+				04B6BA572E203D6C0090FE39 /* FingerprintView.swift in Sources */,
+				04B6BA582E203D6C0090FE39 /* NoiseTestingView.swift in Sources */,
 				4E778E5A414571ACAC2A0F01 /* MessageRetentionService.swift in Sources */,
 				C99763A4761567F587D21688 /* MessageRetryService.swift in Sources */,
 				749D8CF8A362B6CD0786782D /* NotificationService.swift in Sources */,
@@ -458,15 +579,28 @@
 				5D95F2BFBE257A1225998389 /* BatteryOptimizer.swift in Sources */,
 				F455F011B3B648ADA233F998 /* BinaryProtocol.swift in Sources */,
 				10E68BB889356219189E38EC /* BitchatApp.swift in Sources */,
+				04891CA92E22971E0064A111 /* LRUCache.swift in Sources */,
+				04B6BA5D2E215FDA0090FE39 /* NoisePostQuantum.swift in Sources */,
+				04B6BA5E2E215FDA0090FE39 /* NoiseChannelKeyRotation.swift in Sources */,
 				6DE056E1EE9850E9FBF50157 /* BitchatProtocol.swift in Sources */,
+				04B6BA492E2035530090FE39 /* NoiseSecurityConsiderations.swift in Sources */,
+				04B6BA4A2E2035530090FE39 /* NoiseSession.swift in Sources */,
+				04B6BA4B2E2035530090FE39 /* NoiseProtocol.swift in Sources */,
+				04B6BA4C2E2035530090FE39 /* NoiseChannelEncryption.swift in Sources */,
 				D948085736ED8E736C1DE3B0 /* BluetoothMeshService.swift in Sources */,
 				7576A357B278E5733E9D9F33 /* ChatViewModel.swift in Sources */,
 				7DCA0DBCB8884E3B31C7BCE3 /* CompressionUtil.swift in Sources */,
 				1D9674FA5F998503831DC281 /* ContentView.swift in Sources */,
+				04B6BA4E2E2038A70090FE39 /* NoiseEncryptionService.swift in Sources */,
 				CD0AE423F03AC52BAFC16834 /* DeliveryTracker.swift in Sources */,
-				DDA1DFAB1FF7AADE52DC0F53 /* EncryptionService.swift in Sources */,
+				04B6BA7B2E2166A50090FE39 /* NoiseTestingHelper.swift in Sources */,
+				04B6BA7C2E2166A50090FE39 /* SecurityLogger.swift in Sources */,
 				8F737CE0435792CC2AD65FCB /* KeychainManager.swift in Sources */,
+				0FBC81FF78CF4711B78E092A /* IdentityModels.swift in Sources */,
+				1AF9F9036DEE42408D557A87 /* SecureIdentityStateManager.swift in Sources */,
 				7A5B1AB5642FEC168E917949 /* LinkPreviewView.swift in Sources */,
+				04B6BA552E203D6C0090FE39 /* FingerprintView.swift in Sources */,
+				04B6BA562E203D6C0090FE39 /* NoiseTestingView.swift in Sources */,
 				4274B6016F755946FBF2513E /* MessageRetentionService.swift in Sources */,
 				CEAE115C9C3EB3C4ED82F128 /* MessageRetryService.swift in Sources */,
 				61C81ED5F679D5E973EE0C07 /* NotificationService.swift in Sources */,
@@ -479,7 +613,17 @@
 			buildActionMask = 2147483647;
 			files = (
 				8F0BFC2D2B2A5E7B70C3B485 /* BinaryProtocolTests.swift in Sources */,
+				04B6BA6F2E21601B0090FE39 /* ChannelVerificationTests.swift in Sources */,
+				04B6BA702E21601B0090FE39 /* NoiseKeyRotationTests.swift in Sources */,
+				04B6BA712E21601B0090FE39 /* NoiseRateLimiterTests.swift in Sources */,
+				04B6BA722E21601B0090FE39 /* NoiseSecurityTests.swift in Sources */,
+				04B6BA732E21601B0090FE39 /* NoiseSecurityValidatorTests.swift in Sources */,
+				04B6BA742E21601B0090FE39 /* SecureNoiseSessionTests.swift in Sources */,
+				04B6BA752E21601B0090FE39 /* KeychainIntegrationTests.swift in Sources */,
+				04B6BA762E21601B0090FE39 /* NoiseChannelEncryptionTests.swift in Sources */,
 				2E71E320EA921498C57E023B /* BitchatMessageTests.swift in Sources */,
+				04B6BA3F2E2035220090FE39 /* NoiseProtocolTests.swift in Sources */,
+				04B6BA5C2E2041220090FE39 /* NoiseIdentityPersistenceTests.swift in Sources */,
 				C91FDE97070433E6CFE95C55 /* BloomFilterTests.swift in Sources */,
 				ADC66F95FBD513B10411ADB3 /* MessagePaddingTests.swift in Sources */,
 				24F17B1446E13F42652B7B08 /* PasswordProtectedChannelTests.swift in Sources */,
@@ -491,7 +635,17 @@
 			buildActionMask = 2147483647;
 			files = (
 				CDAD6629EB69916B95C80DAF /* BinaryProtocolTests.swift in Sources */,
+				04B6BA672E21601B0090FE39 /* ChannelVerificationTests.swift in Sources */,
+				04B6BA682E21601B0090FE39 /* NoiseKeyRotationTests.swift in Sources */,
+				04B6BA692E21601B0090FE39 /* NoiseRateLimiterTests.swift in Sources */,
+				04B6BA6A2E21601B0090FE39 /* NoiseSecurityTests.swift in Sources */,
+				04B6BA6B2E21601B0090FE39 /* NoiseSecurityValidatorTests.swift in Sources */,
+				04B6BA6C2E21601B0090FE39 /* SecureNoiseSessionTests.swift in Sources */,
+				04B6BA6D2E21601B0090FE39 /* KeychainIntegrationTests.swift in Sources */,
+				04B6BA6E2E21601B0090FE39 /* NoiseChannelEncryptionTests.swift in Sources */,
 				0DAFF1DDE9BA83FF648D5AB3 /* BitchatMessageTests.swift in Sources */,
+				04B6BA3E2E2035220090FE39 /* NoiseProtocolTests.swift in Sources */,
+				04B6BA5B2E2041220090FE39 /* NoiseIdentityPersistenceTests.swift in Sources */,
 				846E2B446E36639159704730 /* BloomFilterTests.swift in Sources */,
 				F00B713D5053617FB5F3F1BE /* MessagePaddingTests.swift in Sources */,
 				9269B4230187A9EA969BEDB7 /* PasswordProtectedChannelTests.swift in Sources */,

bitchat/BitchatApp.swift

@@ -14,6 +14,8 @@ struct BitchatApp: App {
     @StateObject private var chatViewModel = ChatViewModel()
     #if os(iOS)
     @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
+    #elseif os(macOS)
+    @NSApplicationDelegateAdaptor(MacAppDelegate.self) var appDelegate
     #endif
     
     init() {
@@ -28,6 +30,8 @@ struct BitchatApp: App {
                     NotificationDelegate.shared.chatViewModel = chatViewModel
                     #if os(iOS)
                     appDelegate.chatViewModel = chatViewModel
+                    #elseif os(macOS)
+                    appDelegate.chatViewModel = chatViewModel
                     #endif
                     // Check for shared content
                     checkForSharedContent()
@@ -58,24 +62,17 @@ struct BitchatApp: App {
     private func checkForSharedContent() {
         // Check app group for shared content from extension
         guard let userDefaults = UserDefaults(suiteName: "group.chat.bitchat") else {
-            print("DEBUG: Failed to access app group UserDefaults")
             return
         }
         
         guard let sharedContent = userDefaults.string(forKey: "sharedContent"),
               let sharedDate = userDefaults.object(forKey: "sharedContentDate") as? Date else {
-            print("DEBUG: No shared content found in UserDefaults")
             return
         }
         
-        print("DEBUG: Found shared content: \(sharedContent)")
-        print("DEBUG: Shared date: \(sharedDate)")
-        print("DEBUG: Time since shared: \(Date().timeIntervalSince(sharedDate)) seconds")
-        
         // Only process if shared within last 30 seconds
         if Date().timeIntervalSince(sharedDate) < 30 {
             let contentType = userDefaults.string(forKey: "sharedContentType") ?? "text"
-            print("DEBUG: Content type: \(contentType)")
             
             // Clear the shared content
             userDefaults.removeObject(forKey: "sharedContent")
@@ -98,7 +95,6 @@ struct BitchatApp: App {
             // Send the shared content after a short delay
             DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
                 if contentType == "url" {
-                    print("DEBUG: Processing URL content")
                     // Try to parse as JSON first
                     if let data = sharedContent.data(using: .utf8),
                        let urlData = try? JSONSerialization.jsonObject(with: data) as? [String: String],
@@ -106,20 +102,15 @@ struct BitchatApp: App {
                        let title = urlData["title"] {
                         // Send just emoji with hidden markdown link
                         let markdownLink = "👇 [\(title)](\(url))"
-                        print("DEBUG: Sending markdown link: \(markdownLink)")
                         self.chatViewModel.sendMessage(markdownLink)
                     } else {
                         // Fallback to simple URL
-                        print("DEBUG: Failed to parse JSON, sending as plain URL")
                         self.chatViewModel.sendMessage("Shared link: \(sharedContent)")
                     }
                 } else {
-                    print("DEBUG: Sending plain text: \(sharedContent)")
                     self.chatViewModel.sendMessage(sharedContent)
                 }
             }
-        } else {
-            print("DEBUG: Shared content is too old, ignoring")
         }
     }
 }
@@ -134,6 +125,22 @@ class AppDelegate: NSObject, UIApplicationDelegate {
 }
 #endif
 
+#if os(macOS)
+import AppKit
+
+class MacAppDelegate: NSObject, NSApplicationDelegate {
+    weak var chatViewModel: ChatViewModel?
+    
+    func applicationWillTerminate(_ notification: Notification) {
+        chatViewModel?.applicationWillTerminate()
+    }
+    
+    func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
+        return true
+    }
+}
+#endif
+
 class NotificationDelegate: NSObject, UNUserNotificationCenterDelegate {
     static let shared = NotificationDelegate()
     weak var chatViewModel: ChatViewModel?

bitchat/Identity/IdentityModels.swift

@@ -0,0 +1,140 @@
+//
+// IdentityModels.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+// MARK: - Three-Layer Identity Model
+
+// Layer 1: Ephemeral (per-session)
+struct EphemeralIdentity {
+    let peerID: String          // 8 random bytes
+    let sessionStart: Date
+    var handshakeState: HandshakeState
+}
+
+enum HandshakeState {
+    case none
+    case initiated
+    case inProgress
+    case completed(fingerprint: String)
+    case failed(reason: String)
+}
+
+// Layer 2: Cryptographic (persistent)
+struct CryptographicIdentity: Codable {
+    let fingerprint: String     // SHA256 of public key
+    let publicKey: Data         // Noise static public key
+    let firstSeen: Date
+    let lastHandshake: Date?
+}
+
+// Layer 3: Social (user-assigned)
+struct SocialIdentity: Codable {
+    let fingerprint: String
+    var localPetname: String?   // User's name for this peer
+    var claimedNickname: String // What peer calls themselves
+    var trustLevel: TrustLevel
+    var isFavorite: Bool
+    var isBlocked: Bool
+    var notes: String?
+}
+
+enum TrustLevel: String, Codable {
+    case unknown = "unknown"
+    case casual = "casual"
+    case trusted = "trusted"
+    case verified = "verified"
+}
+
+// MARK: - Identity Cache
+
+struct IdentityCache: Codable {
+    // Fingerprint -> Social mapping
+    var socialIdentities: [String: SocialIdentity] = [:]
+    
+    // Nickname -> [Fingerprints] reverse index
+    // Multiple fingerprints can claim same nickname
+    var nicknameIndex: [String: Set<String>] = [:]
+    
+    // Verified fingerprints (cryptographic proof)
+    var verifiedFingerprints: Set<String> = []
+    
+    // Last interaction timestamps (privacy: optional)
+    var lastInteractions: [String: Date] = [:] 
+    
+    // Schema version for future migrations
+    var version: Int = 1
+}
+
+// MARK: - Identity Resolution
+
+enum IdentityHint {
+    case unknown
+    case likelyKnown(fingerprint: String)
+    case ambiguous(candidates: Set<String>)
+    case verified(fingerprint: String)
+}
+
+// MARK: - Pending Actions
+
+struct PendingActions {
+    var toggleFavorite: Bool?
+    var setTrustLevel: TrustLevel?
+    var setPetname: String?
+}
+
+// MARK: - Privacy Settings
+
+struct PrivacySettings: Codable {
+    // Level 1: Maximum privacy (default)
+    var persistIdentityCache = false
+    var showLastSeen = false
+    
+    // Level 2: Convenience
+    var autoAcceptKnownFingerprints = false
+    var rememberNicknameHistory = false
+    
+    // Level 3: Social
+    var shareTrustNetworkHints = false  // "3 mutual contacts trust this person"
+}
+
+// MARK: - Conflict Resolution
+
+enum ConflictResolution {
+    case acceptNew(petname: String)      // "John (2)"
+    case rejectNew
+    case blockFingerprint(String)
+    case alertUser(message: String)
+}
+
+// MARK: - UI State
+
+struct PeerUIState {
+    let peerID: String
+    let nickname: String
+    var identityState: IdentityState
+    var connectionQuality: ConnectionQuality
+    
+    enum IdentityState {
+        case unknown                    // Gray - No identity info
+        case unverifiedKnown(String)   // Blue - Handshake done, matches cache
+        case verified(String)          // Green - Cryptographically verified
+        case conflict(String, String)  // Red - Nickname doesn't match fingerprint
+        case pending                   // Yellow - Handshake in progress
+    }
+}
+
+enum ConnectionQuality {
+    case excellent
+    case good
+    case poor
+    case disconnected
+}
+
+// MARK: - Migration Support
+// Removed LegacyFavorite - no longer needed

bitchat/Identity/SecureIdentityStateManager.swift

@@ -0,0 +1,328 @@
+//
+// SecureIdentityStateManager.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import CryptoKit
+
+class SecureIdentityStateManager {
+    static let shared = SecureIdentityStateManager()
+    
+    private let keychain = KeychainManager.shared
+    private let cacheKey = "bitchat.identityCache.v2"
+    private let encryptionKeyName = "identityCacheEncryptionKey"
+    
+    // In-memory state
+    private var ephemeralSessions: [String: EphemeralIdentity] = [:]
+    private var cryptographicIdentities: [String: CryptographicIdentity] = [:]
+    private var cache: IdentityCache = IdentityCache()
+    
+    // Pending actions before handshake
+    private var pendingActions: [String: PendingActions] = [:]
+    
+    // Thread safety
+    private let queue = DispatchQueue(label: "bitchat.identity.state", attributes: .concurrent)
+    
+    // Encryption key
+    private let encryptionKey: SymmetricKey
+    
+    private init() {
+        // Generate or retrieve encryption key from keychain
+        let loadedKey: SymmetricKey
+        
+        // Try to load from keychain
+        if let keyData = keychain.getIdentityKey(forKey: encryptionKeyName) {
+            loadedKey = SymmetricKey(data: keyData)
+        }
+        // Generate new key if needed
+        else {
+            loadedKey = SymmetricKey(size: .bits256)
+            let keyData = loadedKey.withUnsafeBytes { Data($0) }
+            // Save to keychain
+            _ = keychain.saveIdentityKey(keyData, forKey: encryptionKeyName)
+        }
+        
+        self.encryptionKey = loadedKey
+        
+        // Load identity cache on init
+        loadIdentityCache()
+    }
+    
+    // MARK: - Secure Loading/Saving
+    
+    func loadIdentityCache() {
+        guard let encryptedData = keychain.getIdentityKey(forKey: cacheKey) else {
+            // No existing cache, start fresh
+            return
+        }
+        
+        do {
+            let sealedBox = try AES.GCM.SealedBox(combined: encryptedData)
+            let decryptedData = try AES.GCM.open(sealedBox, using: encryptionKey)
+            cache = try JSONDecoder().decode(IdentityCache.self, from: decryptedData)
+        } catch {
+            // Log error but continue with empty cache
+            SecurityLogger.log("Failed to load identity cache", category: SecurityLogger.security, level: .error)
+        }
+    }
+    
+    func saveIdentityCache() {
+        do {
+            let data = try JSONEncoder().encode(cache)
+            let sealedBox = try AES.GCM.seal(data, using: encryptionKey)
+            _ = keychain.saveIdentityKey(sealedBox.combined!, forKey: cacheKey)
+        } catch {
+            SecurityLogger.log("Failed to save identity cache", category: SecurityLogger.security, level: .error)
+        }
+    }
+    
+    // MARK: - Identity Resolution
+    
+    func resolveIdentity(peerID: String, claimedNickname: String) -> IdentityHint {
+        queue.sync {
+            // Check if we have candidates based on nickname
+            if let fingerprints = cache.nicknameIndex[claimedNickname] {
+                if fingerprints.count == 1 {
+                    return .likelyKnown(fingerprint: fingerprints.first!)
+                } else {
+                    return .ambiguous(candidates: fingerprints)
+                }
+            }
+            return .unknown
+        }
+    }
+    
+    // MARK: - Social Identity Management
+    
+    func getSocialIdentity(for fingerprint: String) -> SocialIdentity? {
+        queue.sync {
+            return cache.socialIdentities[fingerprint]
+        }
+    }
+    
+    func getAllSocialIdentities() -> [SocialIdentity] {
+        queue.sync {
+            return Array(cache.socialIdentities.values)
+        }
+    }
+    
+    func updateSocialIdentity(_ identity: SocialIdentity) {
+        queue.async(flags: .barrier) {
+            self.cache.socialIdentities[identity.fingerprint] = identity
+            
+            // Update nickname index
+            if let existingIdentity = self.cache.socialIdentities[identity.fingerprint] {
+                // Remove old nickname from index if changed
+                if existingIdentity.claimedNickname != identity.claimedNickname {
+                    self.cache.nicknameIndex[existingIdentity.claimedNickname]?.remove(identity.fingerprint)
+                    if self.cache.nicknameIndex[existingIdentity.claimedNickname]?.isEmpty == true {
+                        self.cache.nicknameIndex.removeValue(forKey: existingIdentity.claimedNickname)
+                    }
+                }
+            }
+            
+            // Add new nickname to index
+            if self.cache.nicknameIndex[identity.claimedNickname] == nil {
+                self.cache.nicknameIndex[identity.claimedNickname] = Set<String>()
+            }
+            self.cache.nicknameIndex[identity.claimedNickname]?.insert(identity.fingerprint)
+            
+            // Save to keychain
+            self.saveIdentityCache()
+        }
+    }
+    
+    // MARK: - Favorites Management
+    
+    func getFavorites() -> Set<String> {
+        queue.sync {
+            let favorites = cache.socialIdentities.values
+                .filter { $0.isFavorite }
+                .map { $0.fingerprint }
+            return Set(favorites)
+        }
+    }
+    
+    func setFavorite(_ fingerprint: String, isFavorite: Bool) {
+        queue.async(flags: .barrier) {
+            if var identity = self.cache.socialIdentities[fingerprint] {
+                identity.isFavorite = isFavorite
+                self.cache.socialIdentities[fingerprint] = identity
+            } else {
+                // Create new social identity for this fingerprint
+                let newIdentity = SocialIdentity(
+                    fingerprint: fingerprint,
+                    localPetname: nil,
+                    claimedNickname: "Unknown",
+                    trustLevel: .unknown,
+                    isFavorite: isFavorite,
+                    isBlocked: false,
+                    notes: nil
+                )
+                self.cache.socialIdentities[fingerprint] = newIdentity
+            }
+            self.saveIdentityCache()
+        }
+    }
+    
+    func isFavorite(fingerprint: String) -> Bool {
+        queue.sync {
+            return cache.socialIdentities[fingerprint]?.isFavorite ?? false
+        }
+    }
+    
+    // MARK: - Blocked Users Management
+    
+    func isBlocked(fingerprint: String) -> Bool {
+        queue.sync {
+            return cache.socialIdentities[fingerprint]?.isBlocked ?? false
+        }
+    }
+    
+    func setBlocked(_ fingerprint: String, isBlocked: Bool) {
+        queue.async(flags: .barrier) {
+            if var identity = self.cache.socialIdentities[fingerprint] {
+                identity.isBlocked = isBlocked
+                if isBlocked {
+                    identity.isFavorite = false  // Can't be both favorite and blocked
+                }
+                self.cache.socialIdentities[fingerprint] = identity
+            } else {
+                // Create new social identity for this fingerprint
+                let newIdentity = SocialIdentity(
+                    fingerprint: fingerprint,
+                    localPetname: nil,
+                    claimedNickname: "Unknown",
+                    trustLevel: .unknown,
+                    isFavorite: false,
+                    isBlocked: isBlocked,
+                    notes: nil
+                )
+                self.cache.socialIdentities[fingerprint] = newIdentity
+            }
+            self.saveIdentityCache()
+        }
+    }
+    
+    // MARK: - Ephemeral Session Management
+    
+    func registerEphemeralSession(peerID: String, handshakeState: HandshakeState = .none) {
+        queue.async(flags: .barrier) {
+            self.ephemeralSessions[peerID] = EphemeralIdentity(
+                peerID: peerID,
+                sessionStart: Date(),
+                handshakeState: handshakeState
+            )
+        }
+    }
+    
+    func updateHandshakeState(peerID: String, state: HandshakeState) {
+        queue.async(flags: .barrier) {
+            self.ephemeralSessions[peerID]?.handshakeState = state
+            
+            // If handshake completed, update last interaction
+            if case .completed(let fingerprint) = state {
+                self.cache.lastInteractions[fingerprint] = Date()
+                self.saveIdentityCache()
+            }
+        }
+    }
+    
+    func getHandshakeState(peerID: String) -> HandshakeState? {
+        queue.sync {
+            return ephemeralSessions[peerID]?.handshakeState
+        }
+    }
+    
+    // MARK: - Pending Actions
+    
+    func setPendingAction(peerID: String, action: PendingActions) {
+        queue.async(flags: .barrier) {
+            self.pendingActions[peerID] = action
+        }
+    }
+    
+    func applyPendingActions(peerID: String, fingerprint: String) {
+        queue.async(flags: .barrier) {
+            guard let actions = self.pendingActions[peerID] else { return }
+            
+            // Get or create social identity
+            var identity = self.cache.socialIdentities[fingerprint] ?? SocialIdentity(
+                fingerprint: fingerprint,
+                localPetname: nil,
+                claimedNickname: "Unknown",
+                trustLevel: .unknown,
+                isFavorite: false,
+                isBlocked: false,
+                notes: nil
+            )
+            
+            // Apply pending actions
+            if let toggleFavorite = actions.toggleFavorite {
+                identity.isFavorite = toggleFavorite
+            }
+            if let trustLevel = actions.setTrustLevel {
+                identity.trustLevel = trustLevel
+            }
+            if let petname = actions.setPetname {
+                identity.localPetname = petname
+            }
+            
+            // Save updated identity
+            self.cache.socialIdentities[fingerprint] = identity
+            self.pendingActions.removeValue(forKey: peerID)
+            self.saveIdentityCache()
+        }
+    }
+    
+    // MARK: - Cleanup
+    
+    func clearAllIdentityData() {
+        queue.async(flags: .barrier) {
+            self.cache = IdentityCache()
+            self.ephemeralSessions.removeAll()
+            self.cryptographicIdentities.removeAll()
+            self.pendingActions.removeAll()
+            
+            // Delete from keychain
+            _ = self.keychain.deleteIdentityKey(forKey: self.cacheKey)
+        }
+    }
+    
+    func removeEphemeralSession(peerID: String) {
+        queue.async(flags: .barrier) {
+            self.ephemeralSessions.removeValue(forKey: peerID)
+            self.pendingActions.removeValue(forKey: peerID)
+        }
+    }
+    
+    // MARK: - Verification
+    
+    func setVerified(fingerprint: String, verified: Bool) {
+        queue.async(flags: .barrier) {
+            if verified {
+                self.cache.verifiedFingerprints.insert(fingerprint)
+            } else {
+                self.cache.verifiedFingerprints.remove(fingerprint)
+            }
+            
+            // Update trust level if social identity exists
+            if var identity = self.cache.socialIdentities[fingerprint] {
+                identity.trustLevel = verified ? .verified : .casual
+                self.cache.socialIdentities[fingerprint] = identity
+            }
+            
+            self.saveIdentityCache()
+        }
+    }
+    
+    func isVerified(fingerprint: String) -> Bool {
+        queue.sync {
+            return cache.verifiedFingerprints.contains(fingerprint)
+        }
+    }
+}

bitchat/Noise/NoiseChannelEncryption.swift

@@ -0,0 +1,273 @@
+//
+// NoiseChannelEncryption.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import CryptoKit
+import os.log
+
+// MARK: - Noise Channel Encryption
+
+class NoiseChannelEncryption {
+    // Channel keys derived from passwords
+    private var channelKeys: [String: SymmetricKey] = [:]
+    private let keyQueue = DispatchQueue(label: "chat.bitchat.noise.channels", attributes: .concurrent)
+    
+    // Key rotation support
+    private let keyRotation = NoiseChannelKeyRotation()
+    private var rotationEnabled: [String: Bool] = [:] // channel -> enabled
+    
+    // Replay protection
+    private var receivedNonces: Set<String> = []
+    private let nonceExpirationTime: TimeInterval = 600 // 10 minutes
+    private var nonceCleanupTimer: Timer?
+    
+    // MARK: - Channel Key Management
+    
+    /// Derive a channel key from password
+    func deriveChannelKey(from password: String, channel: String, creatorFingerprint: String? = nil) -> SymmetricKey {
+        // Use PBKDF2 with channel name + creator fingerprint as salt
+        // This prevents rainbow table attacks across different channel instances
+        var saltComponents = "bitchat-channel-\(channel)"
+        if let fingerprint = creatorFingerprint {
+            saltComponents += "-\(fingerprint)"
+        }
+        let salt = saltComponents.data(using: .utf8)!
+        
+        // Increased iterations for better security (OWASP recommends 210,000 for PBKDF2-SHA256)
+        let keyData = PBKDF2<SHA256>(
+            password: password.data(using: .utf8)!,
+            salt: salt,
+            iterations: 210_000,
+            keyByteCount: 32
+        ).makeIterator()
+        
+        return SymmetricKey(data: keyData)
+    }
+    
+    /// Set password for a channel
+    func setChannelPassword(_ password: String, for channel: String, creatorFingerprint: String? = nil) {
+        let key = deriveChannelKey(from: password, channel: channel, creatorFingerprint: creatorFingerprint)
+        
+        keyQueue.async(flags: .barrier) {
+            self.channelKeys[channel] = key
+        }
+        
+        // Store in keychain
+        _ = KeychainManager.shared.saveChannelPassword(password, for: channel)
+    }
+    
+    /// Get channel key
+    func getChannelKey(for channel: String) -> SymmetricKey? {
+        return keyQueue.sync {
+            return channelKeys[channel]
+        }
+    }
+    
+    /// Load channel password from keychain
+    func loadChannelPassword(for channel: String) -> Bool {
+        guard let password = KeychainManager.shared.getChannelPassword(for: channel) else {
+            return false
+        }
+        
+        setChannelPassword(password, for: channel)
+        return true
+    }
+    
+    /// Remove channel password
+    func removeChannelPassword(for channel: String) {
+        keyQueue.async(flags: .barrier) {
+            self.channelKeys.removeValue(forKey: channel)
+        }
+        
+        _ = KeychainManager.shared.deleteChannelPassword(for: channel)
+    }
+    
+    // MARK: - Replay Protection
+    
+    private func scheduleNonceCleanup() {
+        DispatchQueue.main.async { [weak self] in
+            self?.nonceCleanupTimer?.invalidate()
+            self?.nonceCleanupTimer = Timer.scheduledTimer(withTimeInterval: 300, repeats: true) { [weak self] _ in
+                self?.cleanupExpiredNonces()
+            }
+        }
+    }
+    
+    private func cleanupExpiredNonces() {
+        keyQueue.async(flags: .barrier) { [weak self] in
+            guard let self = self else { return }
+            
+            // In production, we'd need to store timestamps with nonces
+            // For now, we'll clear all nonces periodically
+            if self.receivedNonces.count > 1000 {
+                self.receivedNonces.removeAll()
+            }
+        }
+    }
+    
+    deinit {
+        nonceCleanupTimer?.invalidate()
+    }
+    
+    // MARK: - Channel Message Encryption
+    
+    /// Encrypt message for a channel
+    func encryptChannelMessage(_ message: String, for channel: String) throws -> Data {
+        guard let key = getChannelKey(for: channel) else {
+            throw NoiseChannelError.noChannelKey
+        }
+        
+        let messageData = message.data(using: .utf8)!
+        
+        // Generate random nonce
+        let nonce = ChaChaPoly.Nonce()
+        
+        // Encrypt with channel key
+        let sealedBox = try ChaChaPoly.seal(messageData, using: key, nonce: nonce)
+        
+        // Return nonce + ciphertext + tag
+        return nonce.withUnsafeBytes { Data($0) } + sealedBox.ciphertext + sealedBox.tag
+    }
+    
+    /// Decrypt channel message
+    func decryptChannelMessage(_ encryptedData: Data, for channel: String) throws -> String {
+        guard let key = getChannelKey(for: channel) else {
+            throw NoiseChannelError.noChannelKey
+        }
+        
+        guard encryptedData.count >= 12 + 16 else { // nonce + tag minimum
+            throw NoiseChannelError.invalidCiphertext
+        }
+        
+        // Extract components
+        let nonceData = encryptedData.prefix(12)
+        let ciphertext = encryptedData.dropFirst(12).dropLast(16)
+        let tag = encryptedData.suffix(16)
+        
+        // Create sealed box
+        let nonce = try ChaChaPoly.Nonce(data: nonceData)
+        let sealedBox = try ChaChaPoly.SealedBox(nonce: nonce, ciphertext: ciphertext, tag: tag)
+        
+        // Decrypt
+        let decryptedData = try ChaChaPoly.open(sealedBox, using: key)
+        
+        guard let message = String(data: decryptedData, encoding: .utf8) else {
+            throw NoiseChannelError.decryptionFailed
+        }
+        
+        return message
+    }
+    
+    // MARK: - Channel Key Sharing
+    
+    /// Create encrypted channel key packet for sharing via Noise session
+    func createChannelKeyPacket(password: String, channel: String) -> Data? {
+        // Generate a unique nonce for replay protection
+        var nonceData = Data(count: 16)
+        _ = nonceData.withUnsafeMutableBytes { bytes in
+            SecRandomCopyBytes(kSecRandomDefault, 16, bytes.baseAddress!)
+        }
+        let nonce = nonceData.base64EncodedString()
+        
+        let packet = ChannelKeyPacket(
+            channel: channel,
+            password: password,
+            timestamp: Date(),
+            nonce: nonce
+        )
+        
+        return try? JSONEncoder().encode(packet)
+    }
+    
+    /// Process received channel key packet
+    func processChannelKeyPacket(_ data: Data) -> (channel: String, password: String)? {
+        guard let packet = try? JSONDecoder().decode(ChannelKeyPacket.self, from: data) else {
+            return nil
+        }
+        
+        // Verify timestamp is recent (within 5 minutes)
+        let age = Date().timeIntervalSince(packet.timestamp)
+        guard age < 300 else { return nil }
+        
+        return keyQueue.sync(flags: .barrier) {
+            // Check for replay attack
+            if receivedNonces.contains(packet.nonce) {
+                SecurityLogger.logSecurityEvent(.replayAttackDetected(channel: packet.channel), level: .warning)
+                return nil // This nonce was already processed
+            }
+            
+            // Add nonce to received set
+            receivedNonces.insert(packet.nonce)
+            
+            // Schedule cleanup if not already scheduled
+            if nonceCleanupTimer == nil {
+                scheduleNonceCleanup()
+            }
+            
+            return (packet.channel, packet.password)
+        }
+    }
+}
+
+// MARK: - Supporting Types
+
+private struct ChannelKeyPacket: Codable {
+    let channel: String
+    let password: String
+    let timestamp: Date
+    let nonce: String
+}
+
+enum NoiseChannelError: Error {
+    case noChannelKey
+    case invalidCiphertext
+    case decryptionFailed
+}
+
+// MARK: - PBKDF2 Implementation
+
+private struct PBKDF2<H: HashFunction> {
+    let password: Data
+    let salt: Data
+    let iterations: Int
+    let keyByteCount: Int
+    
+    init(password: Data, salt: Data, iterations: Int, keyByteCount: Int) {
+        self.password = password
+        self.salt = salt
+        self.iterations = iterations
+        self.keyByteCount = keyByteCount
+    }
+    
+    func makeIterator() -> Data {
+        var derivedKey = Data()
+        var blockNum: UInt32 = 1
+        
+        while derivedKey.count < keyByteCount {
+            var block = salt
+            withUnsafeBytes(of: blockNum.bigEndian) { bytes in
+                block.append(contentsOf: bytes)
+            }
+            
+            var u = Data(HMAC<H>.authenticationCode(for: block, using: SymmetricKey(data: password)))
+            var xor = u
+            
+            for _ in 1..<iterations {
+                u = Data(HMAC<H>.authenticationCode(for: u, using: SymmetricKey(data: password)))
+                for i in 0..<xor.count {
+                    xor[i] ^= u[i]
+                }
+            }
+            
+            derivedKey.append(xor)
+            blockNum += 1
+        }
+        
+        return derivedKey.prefix(keyByteCount)
+    }
+}

bitchat/Noise/NoiseChannelKeyRotation.swift

@@ -0,0 +1,329 @@
+//
+// NoiseChannelKeyRotation.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import CryptoKit
+
+// MARK: - Channel Key Rotation for Forward Secrecy
+
+/// Implements key rotation for channels to provide forward secrecy
+/// This is a stepping stone toward full Double Ratchet implementation
+class NoiseChannelKeyRotation {
+    
+    // MARK: - Types
+    
+    struct KeyEpoch: Codable {
+        let epochNumber: UInt64
+        let startTime: Date
+        let endTime: Date
+        let keyCommitment: String
+        let previousEpochCommitment: String?
+    }
+    
+    struct RotatedChannelKey {
+        let epoch: KeyEpoch
+        let key: SymmetricKey
+        let isActive: Bool
+    }
+    
+    // MARK: - Constants
+    
+    private static let epochDuration: TimeInterval = 24 * 60 * 60 // 24 hours
+    private static let epochOverlap: TimeInterval = 60 * 60 // 1 hour overlap for late messages
+    private static let maxStoredEpochs = 7 // Keep 1 week of history
+    
+    // MARK: - Properties
+    
+    private var channelEpochs: [String: [KeyEpoch]] = [:] // channel -> epochs
+    private let keychainPrefix = "channel.epoch."
+    
+    // Thread safety
+    private let queue = DispatchQueue(label: "chat.bitchat.noise.keyrotation", attributes: .concurrent)
+    
+    // MARK: - Public Interface
+    
+    /// Get the current key for a channel with rotation
+    func getCurrentKey(for channel: String, basePassword: String, creatorFingerprint: String) -> RotatedChannelKey? {
+        let currentTime = Date()
+        
+        return queue.sync {
+            // Get or create current epoch
+            let epoch = getCurrentOrCreateEpoch(for: channel, at: currentTime)
+            
+            // Derive key for this epoch
+            let epochKey = deriveEpochKey(
+                basePassword: basePassword,
+                channel: channel,
+                creatorFingerprint: creatorFingerprint,
+                epochNumber: epoch.epochNumber
+            )
+            
+            return RotatedChannelKey(
+                epoch: epoch,
+                key: epochKey,
+                isActive: true
+            )
+        }
+    }
+    
+    /// Get valid keys for decryption (current + recent epochs)
+    func getValidKeysForDecryption(channel: String, basePassword: String, creatorFingerprint: String, messageTime: Date? = nil) -> [RotatedChannelKey] {
+        let checkTime = messageTime ?? Date()
+        
+        return queue.sync {
+            let epochs = getValidEpochs(for: channel, at: checkTime)
+            
+            return epochs.map { epoch in
+                let key = deriveEpochKey(
+                    basePassword: basePassword,
+                    channel: channel,
+                    creatorFingerprint: creatorFingerprint,
+                    epochNumber: epoch.epochNumber
+                )
+                
+                let isActive = checkTime >= epoch.startTime && checkTime < epoch.endTime
+                
+                return RotatedChannelKey(
+                    epoch: epoch,
+                    key: key,
+                    isActive: isActive
+                )
+            }
+        }
+    }
+    
+    /// Rotate key for a channel (channel owner only)
+    func rotateChannelKey(for channel: String, basePassword: String, creatorFingerprint: String) -> KeyEpoch {
+        return queue.sync(flags: .barrier) {
+            let currentTime = Date()
+            let epochs = channelEpochs[channel] ?? []
+            
+            // Get current epoch
+            let currentEpoch = epochs.last
+            let nextEpochNumber = (currentEpoch?.epochNumber ?? 0) + 1
+            
+            // Create new epoch
+            let newEpoch = KeyEpoch(
+                epochNumber: nextEpochNumber,
+                startTime: currentTime,
+                endTime: currentTime.addingTimeInterval(Self.epochDuration),
+                keyCommitment: computeEpochKeyCommitment(
+                    basePassword: basePassword,
+                    channel: channel,
+                    creatorFingerprint: creatorFingerprint,
+                    epochNumber: nextEpochNumber
+                ),
+                previousEpochCommitment: currentEpoch?.keyCommitment
+            )
+            
+            // Add to epochs
+            var updatedEpochs = epochs
+            updatedEpochs.append(newEpoch)
+            
+            // Trim old epochs
+            if updatedEpochs.count > Self.maxStoredEpochs {
+                updatedEpochs.removeFirst(updatedEpochs.count - Self.maxStoredEpochs)
+            }
+            
+            channelEpochs[channel] = updatedEpochs
+            
+            // Persist epochs
+            saveEpochs(updatedEpochs, for: channel)
+            
+            return newEpoch
+        }
+    }
+    
+    /// Check if a channel needs key rotation
+    func needsKeyRotation(for channel: String) -> Bool {
+        return queue.sync {
+            guard let epochs = channelEpochs[channel],
+                  let currentEpoch = epochs.last else {
+                return true // No epochs, needs initial key
+            }
+            
+            // Check if current epoch is near expiration (within 2 hours)
+            let timeUntilExpiration = currentEpoch.endTime.timeIntervalSinceNow
+            return timeUntilExpiration < 2 * 60 * 60
+        }
+    }
+    
+    // MARK: - Private Methods
+    
+    private func getCurrentOrCreateEpoch(for channel: String, at time: Date) -> KeyEpoch {
+        var epochs = channelEpochs[channel] ?? []
+        
+        // Find current epoch
+        if let currentEpoch = epochs.first(where: { epoch in
+            time >= epoch.startTime && time < epoch.endTime.addingTimeInterval(Self.epochOverlap)
+        }) {
+            return currentEpoch
+        }
+        
+        // No valid epoch, create initial one
+        let initialEpoch = KeyEpoch(
+            epochNumber: 1,
+            startTime: time,
+            endTime: time.addingTimeInterval(Self.epochDuration),
+            keyCommitment: "", // Will be computed when key is derived
+            previousEpochCommitment: nil
+        )
+        
+        epochs.append(initialEpoch)
+        channelEpochs[channel] = epochs
+        
+        return initialEpoch
+    }
+    
+    private func getValidEpochs(for channel: String, at time: Date) -> [KeyEpoch] {
+        let epochs = channelEpochs[channel] ?? []
+        
+        // Return epochs that are valid at the given time (including overlap period)
+        return epochs.filter { epoch in
+            time >= epoch.startTime.addingTimeInterval(-Self.epochOverlap) &&
+            time < epoch.endTime.addingTimeInterval(Self.epochOverlap)
+        }
+    }
+    
+    private func deriveEpochKey(basePassword: String, channel: String, creatorFingerprint: String, epochNumber: UInt64) -> SymmetricKey {
+        // Derive epoch-specific key using base password + epoch number
+        let epochSalt = "\(channel)-\(creatorFingerprint)-epoch-\(epochNumber)".data(using: .utf8)!
+        let keyData = pbkdf2(
+            password: basePassword,
+            salt: epochSalt,
+            iterations: 210_000, // Same as channel encryption
+            keyLength: 32
+        )
+        return SymmetricKey(data: keyData)
+    }
+    
+    private func computeEpochKeyCommitment(basePassword: String, channel: String, creatorFingerprint: String, epochNumber: UInt64) -> String {
+        let epochKey = deriveEpochKey(
+            basePassword: basePassword,
+            channel: channel,
+            creatorFingerprint: creatorFingerprint,
+            epochNumber: epochNumber
+        )
+        
+        let commitment = SHA256.hash(data: epochKey.withUnsafeBytes { Data($0) })
+        return commitment.map { String(format: "%02x", $0) }.joined()
+    }
+    
+    private func pbkdf2(password: String, salt: Data, iterations: Int, keyLength: Int) -> Data {
+        guard let passwordData = password.data(using: .utf8) else {
+            return Data()
+        }
+        
+        // Use CryptoKit's safer implementation instead of CommonCrypto
+        var derivedKey = Data()
+        var blockNum: UInt32 = 1
+        
+        while derivedKey.count < keyLength {
+            var block = salt
+            withUnsafeBytes(of: blockNum.bigEndian) { bytes in
+                block.append(contentsOf: bytes)
+            }
+            
+            var u = Data(HMAC<SHA256>.authenticationCode(for: block, using: SymmetricKey(data: passwordData)))
+            var xor = u
+            
+            for _ in 1..<iterations {
+                u = Data(HMAC<SHA256>.authenticationCode(for: u, using: SymmetricKey(data: passwordData)))
+                for i in 0..<xor.count {
+                    xor[i] ^= u[i]
+                }
+            }
+            
+            derivedKey.append(xor)
+            blockNum += 1
+        }
+        
+        return Data(derivedKey.prefix(keyLength))
+    }
+    
+    // MARK: - Persistence
+    
+    private func saveEpochs(_ epochs: [KeyEpoch], for channel: String) {
+        // Use channel password storage with special prefix for epoch data
+        let epochKey = "epoch::\(channel)"
+        
+        if let data = try? JSONEncoder().encode(epochs),
+           let epochString = String(data: data, encoding: .utf8) {
+            _ = KeychainManager.shared.saveChannelPassword(epochString, for: epochKey)
+        }
+    }
+    
+    private func loadEpochs(for channel: String) -> [KeyEpoch]? {
+        let epochKey = "epoch::\(channel)"
+        
+        guard let epochString = KeychainManager.shared.getChannelPassword(for: epochKey),
+              let data = epochString.data(using: .utf8),
+              let epochs = try? JSONDecoder().decode([KeyEpoch].self, from: data) else {
+            return nil
+        }
+        
+        return epochs
+    }
+    
+    /// Load all saved epochs on initialization
+    func loadSavedEpochs() {
+        queue.sync(flags: .barrier) {
+            // Get all channel passwords and filter for epoch data
+            let allPasswords = KeychainManager.shared.getAllChannelPasswords()
+            for (key, epochString) in allPasswords where key.hasPrefix("epoch::") {
+                let channel = String(key.dropFirst(7)) // Remove "epoch::" prefix
+                if let data = epochString.data(using: .utf8),
+                   let epochs = try? JSONDecoder().decode([KeyEpoch].self, from: data) {
+                    channelEpochs[channel] = epochs
+                }
+            }
+        }
+    }
+    
+    /// Clear all epochs for a channel
+    func clearEpochs(for channel: String) {
+        queue.sync(flags: .barrier) {
+            channelEpochs.removeValue(forKey: channel)
+            let epochKey = "epoch::\(channel)"
+            _ = KeychainManager.shared.deleteChannelPassword(for: epochKey)
+        }
+    }
+}
+
+// MARK: - Future Double Ratchet Support
+
+/// Placeholder for full Double Ratchet implementation
+/// This would handle per-message key derivation and ratcheting
+protocol DoubleRatchetProtocol {
+    /// Initialize a new ratchet session
+    func initializeRatchet(sharedSecret: Data, isInitiator: Bool) throws
+    
+    /// Ratchet forward and get next message key
+    func ratchetEncrypt(_ plaintext: Data) throws -> (ciphertext: Data, header: Data)
+    
+    /// Ratchet forward using received header and decrypt
+    func ratchetDecrypt(_ ciphertext: Data, header: Data) throws -> Data
+}
+
+/// Message header for Double Ratchet (future use)
+struct RatchetHeader: Codable {
+    let publicKey: Data       // Ephemeral public key
+    let previousChainLength: UInt32
+    let messageNumber: UInt32
+}
+
+/// Placeholder for full implementation
+class ChannelDoubleRatchet {
+    // This would implement the full Double Ratchet algorithm
+    // adapted for multi-party channels
+    // Challenges:
+    // - Sender keys for multi-party
+    // - Out-of-order delivery
+    // - State synchronization
+    // - Performance with many members
+}

bitchat/Noise/NoisePostQuantum.swift

@@ -0,0 +1,285 @@
+//
+// NoisePostQuantum.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import CryptoKit
+
+// MARK: - Post-Quantum Cryptography Framework
+
+/// Framework for integrating post-quantum algorithms with Noise Protocol
+/// Currently a placeholder until PQ libraries are available in Swift/iOS
+protocol PostQuantumKeyExchange {
+    associatedtype PublicKey
+    associatedtype PrivateKey
+    associatedtype SharedSecret
+    
+    /// Generate a new keypair
+    static func generateKeyPair() throws -> (publicKey: PublicKey, privateKey: PrivateKey)
+    
+    /// Derive shared secret (for initiator)
+    static func encapsulate(remotePublicKey: PublicKey) throws -> (sharedSecret: SharedSecret, ciphertext: Data)
+    
+    /// Derive shared secret (for responder)
+    static func decapsulate(ciphertext: Data, privateKey: PrivateKey) throws -> SharedSecret
+    
+    /// Get size requirements
+    static var publicKeySize: Int { get }
+    static var privateKeySize: Int { get }
+    static var ciphertextSize: Int { get }
+    static var sharedSecretSize: Int { get }
+}
+
+// MARK: - Hybrid Key Exchange
+
+/// Combines classical (Curve25519) with post-quantum algorithms
+class HybridNoiseKeyExchange {
+    
+    enum Algorithm {
+        case classicalOnly           // Current: Curve25519 only
+        case hybridKyber768         // Future: Curve25519 + Kyber768
+        case hybridKyber1024        // Future: Curve25519 + Kyber1024
+        
+        var name: String {
+            switch self {
+            case .classicalOnly:
+                return "25519"
+            case .hybridKyber768:
+                return "25519+Kyber768"
+            case .hybridKyber1024:
+                return "25519+Kyber1024"
+            }
+        }
+        
+        var isPostQuantum: Bool {
+            switch self {
+            case .classicalOnly:
+                return false
+            case .hybridKyber768, .hybridKyber1024:
+                return true
+            }
+        }
+    }
+    
+    struct HybridPublicKey {
+        let classical: Curve25519.KeyAgreement.PublicKey
+        let postQuantum: Data? // Future: actual PQ public key
+        
+        var serialized: Data {
+            var data = classical.rawRepresentation
+            if let pq = postQuantum {
+                data.append(pq)
+            }
+            return data
+        }
+    }
+    
+    struct HybridPrivateKey {
+        let classical: Curve25519.KeyAgreement.PrivateKey
+        let postQuantum: Data? // Future: actual PQ private key
+    }
+    
+    struct HybridSharedSecret {
+        let classical: SharedSecret
+        let postQuantum: Data? // Future: actual PQ shared secret
+        
+        /// Combine both secrets using KDF
+        func combinedSecret() -> SymmetricKey {
+            var combinedData = classical.withUnsafeBytes { Data($0) }
+            
+            if let pq = postQuantum {
+                combinedData.append(pq)
+            }
+            
+            // Use HKDF to combine secrets
+            let hash = SHA256.hash(data: combinedData)
+            return SymmetricKey(data: Data(hash))
+        }
+    }
+    
+    // MARK: - Key Generation
+    
+    static func generateKeyPair(algorithm: Algorithm) throws -> (publicKey: HybridPublicKey, privateKey: HybridPrivateKey) {
+        // Generate classical keypair
+        let classicalPrivate = Curve25519.KeyAgreement.PrivateKey()
+        let classicalPublic = classicalPrivate.publicKey
+        
+        // Generate PQ keypair when available
+        let pqPublic: Data? = nil
+        let pqPrivate: Data? = nil
+        
+        switch algorithm {
+        case .classicalOnly:
+            break // No PQ component
+            
+        case .hybridKyber768, .hybridKyber1024:
+            // Future: Generate Kyber keypair
+            // let (pqPub, pqPriv) = try KyberKeyExchange.generateKeyPair()
+            // pqPublic = pqPub.serialized
+            // pqPrivate = pqPriv.serialized
+            break
+        }
+        
+        return (
+            HybridPublicKey(classical: classicalPublic, postQuantum: pqPublic),
+            HybridPrivateKey(classical: classicalPrivate, postQuantum: pqPrivate)
+        )
+    }
+    
+    // MARK: - Key Agreement
+    
+    static func performKeyAgreement(
+        localPrivate: HybridPrivateKey,
+        remotePublic: HybridPublicKey,
+        algorithm: Algorithm
+    ) throws -> HybridSharedSecret {
+        // Perform classical ECDH
+        let classicalShared = try localPrivate.classical.sharedSecretFromKeyAgreement(
+            with: remotePublic.classical
+        )
+        
+        // Perform PQ key agreement when available
+        let pqShared: Data? = nil
+        
+        switch algorithm {
+        case .classicalOnly:
+            break // No PQ component
+            
+        case .hybridKyber768, .hybridKyber1024:
+            // Future: Perform Kyber decapsulation
+            // if let pqCiphertext = remotePublic.postQuantum,
+            //    let pqPrivateKey = localPrivate.postQuantum {
+            //     pqShared = try KyberKeyExchange.decapsulate(
+            //         ciphertext: pqCiphertext,
+            //         privateKey: pqPrivateKey
+            //     )
+            // }
+            break
+        }
+        
+        return HybridSharedSecret(classical: classicalShared, postQuantum: pqShared)
+    }
+}
+
+// MARK: - Modified Noise Pattern for PQ
+
+/// Extended Noise handshake pattern for post-quantum
+/// Based on Noise PQ patterns: https://github.com/noiseprotocol/noise_pq_spec
+struct NoisePQHandshakePattern {
+    // Pattern modifiers for PQ
+    enum Modifier {
+        case pq1    // First message includes PQ KEM
+        case pq2    // Second message includes PQ KEM
+        case pq3    // Third message includes PQ KEM
+    }
+    
+    // Example: XXpq1 pattern (XX with PQ in first message)
+    // -> e, epq
+    // <- e, ee, eepq, s, es
+    // -> s, se
+    
+    // This would modify the Noise XX pattern to include
+    // post-quantum key encapsulation material
+}
+
+// MARK: - Migration Support
+
+/// Helps transition from classical to post-quantum crypto
+class NoiseProtocolMigration {
+    
+    enum MigrationPhase {
+        case classicalOnly          // Current state
+        case hybridOptional         // Support both, prefer hybrid
+        case hybridRequired         // Require hybrid mode
+        case postQuantumOnly        // Future: PQ only
+    }
+    
+    struct MigrationConfig {
+        let currentPhase: MigrationPhase
+        let preferredAlgorithm: HybridNoiseKeyExchange.Algorithm
+        let acceptedAlgorithms: Set<HybridNoiseKeyExchange.Algorithm>
+        let migrationDeadline: Date?
+    }
+    
+    /// Check if a peer supports post-quantum
+    static func checkPQSupport(peerVersion: String) -> Bool {
+        // Future: Parse peer capabilities
+        // For now, assume no PQ support
+        return false
+    }
+    
+    /// Get migration configuration
+    static func getMigrationConfig() -> MigrationConfig {
+        // Current configuration: classical only
+        return MigrationConfig(
+            currentPhase: .classicalOnly,
+            preferredAlgorithm: .classicalOnly,
+            acceptedAlgorithms: [.classicalOnly],
+            migrationDeadline: nil
+        )
+    }
+}
+
+// MARK: - Future Implementation Notes
+
+/*
+ Post-Quantum Integration Plan:
+ 
+ 1. Wait for stable Swift PQ libraries (e.g., SwiftOQS)
+ 2. Implement Kyber768/1024 wrapper conforming to PostQuantumKeyExchange
+ 3. Update Noise handshake to support hybrid mode
+ 4. Add capability negotiation in protocol
+ 5. Implement gradual rollout with fallback
+ 
+ Challenges:
+ - Increased message sizes (Kyber768 public key ~1184 bytes)
+ - Performance impact on mobile devices
+ - Battery usage considerations
+ - Backward compatibility
+ - Library availability and maintenance
+ 
+ Timeline estimate:
+ - PQ libraries stable in Swift: 2025-2026
+ - Initial hybrid implementation: 2026
+ - Full deployment: 2027+
+ */
+
+// MARK: - Testing Support
+
+#if DEBUG
+/// Mock PQ implementation for testing
+class MockPostQuantumKeyExchange: PostQuantumKeyExchange {
+    typealias PublicKey = Data
+    typealias PrivateKey = Data
+    typealias SharedSecret = Data
+    
+    static func generateKeyPair() throws -> (publicKey: Data, privateKey: Data) {
+        // Generate mock keys for testing
+        let privateKey = Data((0..<32).map { _ in UInt8.random(in: 0...255) })
+        let publicKey = Data((0..<800).map { _ in UInt8.random(in: 0...255) }) // Simulate larger PQ key
+        return (publicKey, privateKey)
+    }
+    
+    static func encapsulate(remotePublicKey: Data) throws -> (sharedSecret: Data, ciphertext: Data) {
+        let sharedSecret = Data((0..<32).map { _ in UInt8.random(in: 0...255) })
+        let ciphertext = Data((0..<1088).map { _ in UInt8.random(in: 0...255) }) // Simulate Kyber ciphertext
+        return (sharedSecret, ciphertext)
+    }
+    
+    static func decapsulate(ciphertext: Data, privateKey: Data) throws -> Data {
+        // Return deterministic secret based on inputs for testing
+        let combined = ciphertext + privateKey
+        let hash = SHA256.hash(data: combined)
+        return Data(hash)
+    }
+    
+    static var publicKeySize: Int { 800 }
+    static var privateKeySize: Int { 1632 }
+    static var ciphertextSize: Int { 1088 }
+    static var sharedSecretSize: Int { 32 }
+}
+#endif

bitchat/Noise/NoiseProtocol.swift

@@ -0,0 +1,620 @@
+//
+// NoiseProtocol.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import CryptoKit
+import os.log
+
+// Core Noise Protocol implementation
+// Based on the Noise Protocol Framework specification
+
+// MARK: - Constants and Types
+
+enum NoisePattern {
+    case XX  // Most versatile, mutual authentication
+    case IK  // Initiator knows responder's static key
+    case NK  // Anonymous initiator
+}
+
+enum NoiseRole {
+    case initiator
+    case responder
+}
+
+enum NoiseMessagePattern {
+    case e     // Ephemeral key
+    case s     // Static key
+    case ee    // DH(ephemeral, ephemeral)
+    case es    // DH(ephemeral, static)
+    case se    // DH(static, ephemeral)
+    case ss    // DH(static, static)
+}
+
+// MARK: - Noise Protocol Configuration
+
+struct NoiseProtocolName {
+    let pattern: String
+    let dh: String = "25519"        // Curve25519
+    let cipher: String = "ChaChaPoly" // ChaCha20-Poly1305
+    let hash: String = "SHA256"      // SHA-256
+    
+    var fullName: String {
+        "Noise_\(pattern)_\(dh)_\(cipher)_\(hash)"
+    }
+}
+
+// MARK: - Cipher State
+
+class NoiseCipherState {
+    private var key: SymmetricKey?
+    private var nonce: UInt64 = 0
+    
+    init() {}
+    
+    init(key: SymmetricKey) {
+        self.key = key
+    }
+    
+    func initializeKey(_ key: SymmetricKey) {
+        self.key = key
+        self.nonce = 0
+    }
+    
+    func hasKey() -> Bool {
+        return key != nil
+    }
+    
+    func encrypt(plaintext: Data, associatedData: Data = Data()) throws -> Data {
+        guard let key = self.key else {
+            throw NoiseError.uninitializedCipher
+        }
+        
+        // Debug logging for nonce tracking
+        let currentNonce = nonce
+        
+        // Create nonce from counter
+        var nonceData = Data(count: 12)
+        withUnsafeBytes(of: nonce.littleEndian) { bytes in
+            nonceData.replaceSubrange(4..<12, with: bytes)
+        }
+        
+        let sealedBox = try ChaChaPoly.seal(plaintext, using: key, nonce: ChaChaPoly.Nonce(data: nonceData), authenticating: associatedData)
+        nonce += 1
+        
+        // Log high nonce values that might indicate issues
+        if currentNonce > 100 {
+        }
+        
+        return sealedBox.ciphertext + sealedBox.tag
+    }
+    
+    func decrypt(ciphertext: Data, associatedData: Data = Data()) throws -> Data {
+        guard let key = self.key else {
+            throw NoiseError.uninitializedCipher
+        }
+        
+        guard ciphertext.count >= 16 else {
+            throw NoiseError.invalidCiphertext
+        }
+        
+        // Debug logging for nonce tracking
+        let currentNonce = nonce
+        
+        // Split ciphertext and tag
+        let encryptedData = ciphertext.prefix(ciphertext.count - 16)
+        let tag = ciphertext.suffix(16)
+        
+        // Create nonce from counter
+        var nonceData = Data(count: 12)
+        withUnsafeBytes(of: nonce.littleEndian) { bytes in
+            nonceData.replaceSubrange(4..<12, with: bytes)
+        }
+        
+        let sealedBox = try ChaChaPoly.SealedBox(
+            nonce: ChaChaPoly.Nonce(data: nonceData),
+            ciphertext: encryptedData,
+            tag: tag
+        )
+        
+        // Log high nonce values that might indicate issues
+        if currentNonce > 100 {
+        }
+        
+        do {
+            let plaintext = try ChaChaPoly.open(sealedBox, using: key, authenticating: associatedData)
+            nonce += 1
+            return plaintext
+        } catch {
+            // Log authentication failures with nonce info
+            throw error
+        }
+    }
+}
+
+// MARK: - Symmetric State
+
+class NoiseSymmetricState {
+    private var cipherState: NoiseCipherState
+    private var chainingKey: Data
+    private var hash: Data
+    
+    init(protocolName: String) {
+        self.cipherState = NoiseCipherState()
+        
+        // Initialize with protocol name
+        let nameData = protocolName.data(using: .utf8)!
+        if nameData.count <= 32 {
+            self.hash = nameData + Data(repeating: 0, count: 32 - nameData.count)
+        } else {
+            self.hash = Data(SHA256.hash(data: nameData))
+        }
+        self.chainingKey = self.hash
+    }
+    
+    func mixKey(_ inputKeyMaterial: Data) {
+        let output = hkdf(chainingKey: chainingKey, inputKeyMaterial: inputKeyMaterial, numOutputs: 2)
+        chainingKey = output[0]
+        let tempKey = SymmetricKey(data: output[1])
+        cipherState.initializeKey(tempKey)
+    }
+    
+    func mixHash(_ data: Data) {
+        hash = Data(SHA256.hash(data: hash + data))
+    }
+    
+    func mixKeyAndHash(_ inputKeyMaterial: Data) {
+        let output = hkdf(chainingKey: chainingKey, inputKeyMaterial: inputKeyMaterial, numOutputs: 3)
+        chainingKey = output[0]
+        mixHash(output[1])
+        let tempKey = SymmetricKey(data: output[2])
+        cipherState.initializeKey(tempKey)
+    }
+    
+    func getHandshakeHash() -> Data {
+        return hash
+    }
+    
+    func hasCipherKey() -> Bool {
+        return cipherState.hasKey()
+    }
+    
+    func encryptAndHash(_ plaintext: Data) throws -> Data {
+        if cipherState.hasKey() {
+            let ciphertext = try cipherState.encrypt(plaintext: plaintext, associatedData: hash)
+            mixHash(ciphertext)
+            return ciphertext
+        } else {
+            mixHash(plaintext)
+            return plaintext
+        }
+    }
+    
+    func decryptAndHash(_ ciphertext: Data) throws -> Data {
+        if cipherState.hasKey() {
+            let plaintext = try cipherState.decrypt(ciphertext: ciphertext, associatedData: hash)
+            mixHash(ciphertext)
+            return plaintext
+        } else {
+            mixHash(ciphertext)
+            return ciphertext
+        }
+    }
+    
+    func split() -> (NoiseCipherState, NoiseCipherState) {
+        let output = hkdf(chainingKey: chainingKey, inputKeyMaterial: Data(), numOutputs: 2)
+        let tempKey1 = SymmetricKey(data: output[0])
+        let tempKey2 = SymmetricKey(data: output[1])
+        
+        let c1 = NoiseCipherState(key: tempKey1)
+        let c2 = NoiseCipherState(key: tempKey2)
+        
+        return (c1, c2)
+    }
+    
+    // HKDF implementation
+    private func hkdf(chainingKey: Data, inputKeyMaterial: Data, numOutputs: Int) -> [Data] {
+        let tempKey = HMAC<SHA256>.authenticationCode(for: inputKeyMaterial, using: SymmetricKey(data: chainingKey))
+        let tempKeyData = Data(tempKey)
+        
+        var outputs: [Data] = []
+        var currentOutput = Data()
+        
+        for i in 1...numOutputs {
+            currentOutput = Data(HMAC<SHA256>.authenticationCode(
+                for: currentOutput + Data([UInt8(i)]),
+                using: SymmetricKey(data: tempKeyData)
+            ))
+            outputs.append(currentOutput)
+        }
+        
+        return outputs
+    }
+}
+
+// MARK: - Handshake State
+
+class NoiseHandshakeState {
+    private let role: NoiseRole
+    private let pattern: NoisePattern
+    private var symmetricState: NoiseSymmetricState
+    
+    // Keys
+    private var localStaticPrivate: Curve25519.KeyAgreement.PrivateKey?
+    private var localStaticPublic: Curve25519.KeyAgreement.PublicKey?
+    private var localEphemeralPrivate: Curve25519.KeyAgreement.PrivateKey?
+    private var localEphemeralPublic: Curve25519.KeyAgreement.PublicKey?
+    
+    private var remoteStaticPublic: Curve25519.KeyAgreement.PublicKey?
+    private var remoteEphemeralPublic: Curve25519.KeyAgreement.PublicKey?
+    
+    // Message patterns
+    private var messagePatterns: [[NoiseMessagePattern]] = []
+    private var currentPattern = 0
+    
+    init(role: NoiseRole, pattern: NoisePattern, localStaticKey: Curve25519.KeyAgreement.PrivateKey? = nil, remoteStaticKey: Curve25519.KeyAgreement.PublicKey? = nil) {
+        self.role = role
+        self.pattern = pattern
+        
+        // Initialize static keys
+        if let localKey = localStaticKey {
+            self.localStaticPrivate = localKey
+            self.localStaticPublic = localKey.publicKey
+        }
+        self.remoteStaticPublic = remoteStaticKey
+        
+        // Initialize protocol name
+        let protocolName = NoiseProtocolName(pattern: pattern.patternName)
+        self.symmetricState = NoiseSymmetricState(protocolName: protocolName.fullName)
+        
+        // Initialize message patterns
+        self.messagePatterns = pattern.messagePatterns
+        
+        // Mix pre-message keys according to pattern
+        mixPreMessageKeys()
+    }
+    
+    private func mixPreMessageKeys() {
+        // For XX pattern, no pre-message keys
+        // For IK/NK patterns, we'd mix the responder's static key here
+        switch pattern {
+        case .XX:
+            break // No pre-message keys
+        case .IK, .NK:
+            if role == .initiator, let remoteStatic = remoteStaticPublic {
+                symmetricState.mixHash(remoteStatic.rawRepresentation)
+            }
+        }
+    }
+    
+    func writeMessage(payload: Data = Data()) throws -> Data {
+        guard currentPattern < messagePatterns.count else {
+            throw NoiseError.handshakeComplete
+        }
+        
+        
+        var messageBuffer = Data()
+        let patterns = messagePatterns[currentPattern]
+        
+        for pattern in patterns {
+            switch pattern {
+            case .e:
+                // Generate ephemeral key
+                localEphemeralPrivate = Curve25519.KeyAgreement.PrivateKey()
+                localEphemeralPublic = localEphemeralPrivate!.publicKey
+                messageBuffer.append(localEphemeralPublic!.rawRepresentation)
+                symmetricState.mixHash(localEphemeralPublic!.rawRepresentation)
+                
+            case .s:
+                // Send static key (encrypted if cipher is initialized)
+                guard let staticPublic = localStaticPublic else {
+                    throw NoiseError.missingLocalStaticKey
+                }
+                let encrypted = try symmetricState.encryptAndHash(staticPublic.rawRepresentation)
+                messageBuffer.append(encrypted)
+                
+            case .ee:
+                // DH(local ephemeral, remote ephemeral)
+                guard let localEphemeral = localEphemeralPrivate,
+                      let remoteEphemeral = remoteEphemeralPublic else {
+                    throw NoiseError.missingKeys
+                }
+                let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteEphemeral)
+                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                
+            case .es:
+                // DH(ephemeral, static) - direction depends on role
+                if role == .initiator {
+                    guard let localEphemeral = localEphemeralPrivate,
+                          let remoteStatic = remoteStaticPublic else {
+                        throw NoiseError.missingKeys
+                    }
+                    let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteStatic)
+                    symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                } else {
+                    guard let localStatic = localStaticPrivate,
+                          let remoteEphemeral = remoteEphemeralPublic else {
+                        throw NoiseError.missingKeys
+                    }
+                    let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteEphemeral)
+                    symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                }
+                
+            case .se:
+                // DH(static, ephemeral) - direction depends on role
+                if role == .initiator {
+                    guard let localStatic = localStaticPrivate,
+                          let remoteEphemeral = remoteEphemeralPublic else {
+                        throw NoiseError.missingKeys
+                    }
+                    let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteEphemeral)
+                    symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                } else {
+                    guard let localEphemeral = localEphemeralPrivate,
+                          let remoteStatic = remoteStaticPublic else {
+                        throw NoiseError.missingKeys
+                    }
+                    let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteStatic)
+                    symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                }
+                
+            case .ss:
+                // DH(static, static)
+                guard let localStatic = localStaticPrivate,
+                      let remoteStatic = remoteStaticPublic else {
+                    throw NoiseError.missingKeys
+                }
+                let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteStatic)
+                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+            }
+        }
+        
+        // Encrypt payload
+        let encryptedPayload = try symmetricState.encryptAndHash(payload)
+        messageBuffer.append(encryptedPayload)
+        
+        currentPattern += 1
+        return messageBuffer
+    }
+    
+    func readMessage(_ message: Data, expectedPayloadLength: Int = 0) throws -> Data {
+        
+        guard currentPattern < messagePatterns.count else {
+            throw NoiseError.handshakeComplete
+        }
+        
+        
+        var buffer = message
+        let patterns = messagePatterns[currentPattern]
+        
+        for pattern in patterns {
+            switch pattern {
+            case .e:
+                // Read ephemeral key
+                guard buffer.count >= 32 else {
+                    throw NoiseError.invalidMessage
+                }
+                let ephemeralData = buffer.prefix(32)
+                buffer = buffer.dropFirst(32)
+                
+                do {
+                    remoteEphemeralPublic = try NoiseHandshakeState.validatePublicKey(ephemeralData)
+                } catch {
+                    throw NoiseError.invalidMessage
+                }
+                symmetricState.mixHash(ephemeralData)
+                
+            case .s:
+                // Read static key (may be encrypted)
+                let keyLength = symmetricState.hasCipherKey() ? 48 : 32 // 32 + 16 byte tag if encrypted
+                guard buffer.count >= keyLength else {
+                    throw NoiseError.invalidMessage
+                }
+                let staticData = buffer.prefix(keyLength)
+                buffer = buffer.dropFirst(keyLength)
+                do {
+                    let decrypted = try symmetricState.decryptAndHash(staticData)
+                    remoteStaticPublic = try NoiseHandshakeState.validatePublicKey(decrypted)
+                } catch {
+                    throw NoiseError.authenticationFailure
+                }
+                
+            case .ee, .es, .se, .ss:
+                // Same DH operations as in writeMessage
+                try performDHOperation(pattern)
+            }
+        }
+        
+        // Decrypt payload
+        let payload = try symmetricState.decryptAndHash(buffer)
+        currentPattern += 1
+        
+        return payload
+    }
+    
+    private func performDHOperation(_ pattern: NoiseMessagePattern) throws {
+        switch pattern {
+        case .ee:
+            guard let localEphemeral = localEphemeralPrivate,
+                  let remoteEphemeral = remoteEphemeralPublic else {
+                throw NoiseError.missingKeys
+            }
+            let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteEphemeral)
+            symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+            
+        case .es:
+            if role == .initiator {
+                guard let localEphemeral = localEphemeralPrivate,
+                      let remoteStatic = remoteStaticPublic else {
+                    throw NoiseError.missingKeys
+                }
+                let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteStatic)
+                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+            } else {
+                guard let localStatic = localStaticPrivate,
+                      let remoteEphemeral = remoteEphemeralPublic else {
+                    throw NoiseError.missingKeys
+                }
+                let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteEphemeral)
+                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+            }
+            
+        case .se:
+            if role == .initiator {
+                guard let localStatic = localStaticPrivate,
+                      let remoteEphemeral = remoteEphemeralPublic else {
+                    throw NoiseError.missingKeys
+                }
+                let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteEphemeral)
+                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+            } else {
+                guard let localEphemeral = localEphemeralPrivate,
+                      let remoteStatic = remoteStaticPublic else {
+                    throw NoiseError.missingKeys
+                }
+                let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteStatic)
+                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+            }
+            
+        case .ss:
+            guard let localStatic = localStaticPrivate,
+                  let remoteStatic = remoteStaticPublic else {
+                throw NoiseError.missingKeys
+            }
+            let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteStatic)
+            symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+            
+        default:
+            break
+        }
+    }
+    
+    func isHandshakeComplete() -> Bool {
+        return currentPattern >= messagePatterns.count
+    }
+    
+    func getTransportCiphers() throws -> (send: NoiseCipherState, receive: NoiseCipherState) {
+        guard isHandshakeComplete() else {
+            throw NoiseError.handshakeNotComplete
+        }
+        
+        let (c1, c2) = symmetricState.split()
+        
+        // Initiator uses c1 for sending, c2 for receiving
+        // Responder uses c2 for sending, c1 for receiving
+        return role == .initiator ? (c1, c2) : (c2, c1)
+    }
+    
+    func getRemoteStaticPublicKey() -> Curve25519.KeyAgreement.PublicKey? {
+        return remoteStaticPublic
+    }
+    
+    func getHandshakeHash() -> Data {
+        return symmetricState.getHandshakeHash()
+    }
+}
+
+// MARK: - Pattern Extensions
+
+extension NoisePattern {
+    var patternName: String {
+        switch self {
+        case .XX: return "XX"
+        case .IK: return "IK"
+        case .NK: return "NK"
+        }
+    }
+    
+    var messagePatterns: [[NoiseMessagePattern]] {
+        switch self {
+        case .XX:
+            return [
+                [.e],           // -> e
+                [.e, .ee, .s, .es], // <- e, ee, s, es
+                [.s, .se]       // -> s, se
+            ]
+        case .IK:
+            return [
+                [.e, .es, .s, .ss], // -> e, es, s, ss
+                [.e, .ee, .se]      // <- e, ee, se
+            ]
+        case .NK:
+            return [
+                [.e, .es],      // -> e, es
+                [.e, .ee]       // <- e, ee
+            ]
+        }
+    }
+}
+
+// MARK: - Errors
+
+enum NoiseError: Error {
+    case uninitializedCipher
+    case invalidCiphertext
+    case handshakeComplete
+    case handshakeNotComplete
+    case missingLocalStaticKey
+    case missingKeys
+    case invalidMessage
+    case authenticationFailure
+    case invalidPublicKey
+}
+
+// MARK: - Key Validation
+
+extension NoiseHandshakeState {
+    /// Validate a Curve25519 public key
+    /// Checks for weak/invalid keys that could compromise security
+    static func validatePublicKey(_ keyData: Data) throws -> Curve25519.KeyAgreement.PublicKey {
+        // Check key length
+        guard keyData.count == 32 else {
+            throw NoiseError.invalidPublicKey
+        }
+        
+        // Check for all-zero key (point at infinity)
+        if keyData.allSatisfy({ $0 == 0 }) {
+            throw NoiseError.invalidPublicKey
+        }
+        
+        // Check for low-order points that could enable small subgroup attacks
+        // These are the known bad points for Curve25519
+        let lowOrderPoints: [Data] = [
+            Data(repeating: 0x00, count: 32), // Already checked above
+            Data([0x01] + Data(repeating: 0x00, count: 31)), // Point of order 1
+            Data([0x00] + Data(repeating: 0x00, count: 30) + [0x01]), // Another low-order point
+            Data([0xe0, 0xeb, 0x7a, 0x7c, 0x3b, 0x41, 0xb8, 0xae, 0x16, 0x56, 0xe3, 
+                  0xfa, 0xf1, 0x9f, 0xc4, 0x6a, 0xda, 0x09, 0x8d, 0xeb, 0x9c, 0x32,
+                  0xb1, 0xfd, 0x86, 0x62, 0x05, 0x16, 0x5f, 0x49, 0xb8, 0x00]), // Low order point
+            Data([0x5f, 0x9c, 0x95, 0xbc, 0xa3, 0x50, 0x8c, 0x24, 0xb1, 0xd0, 0xb1,
+                  0x55, 0x9c, 0x83, 0xef, 0x5b, 0x04, 0x44, 0x5c, 0xc4, 0x58, 0x1c,
+                  0x8e, 0x86, 0xd8, 0x22, 0x4e, 0xdd, 0xd0, 0x9f, 0x11, 0x57]), // Low order point
+            Data(repeating: 0xFF, count: 32), // All ones
+            Data([0xda, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+                  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+                  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]), // Another bad point
+            Data([0xdb, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+                  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+                  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff])  // Another bad point
+        ]
+        
+        // Check against known bad points
+        if lowOrderPoints.contains(keyData) {
+            SecurityLogger.logSecurityEvent(.invalidKey(reason: "Low-order point detected"), level: .warning)
+            throw NoiseError.invalidPublicKey
+        }
+        
+        // Try to create the key - CryptoKit will validate curve points internally
+        do {
+            let publicKey = try Curve25519.KeyAgreement.PublicKey(rawRepresentation: keyData)
+            return publicKey
+        } catch {
+            // If CryptoKit rejects it, it's invalid
+            throw NoiseError.invalidPublicKey
+        }
+    }
+}

bitchat/Noise/NoiseSecurityConsiderations.swift

@@ -0,0 +1,281 @@
+//
+// NoiseSecurityConsiderations.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import CryptoKit
+
+// MARK: - Security Constants
+
+enum NoiseSecurityConstants {
+    // Maximum message size to prevent memory exhaustion
+    static let maxMessageSize = 65535 // 64KB as per Noise spec
+    
+    // Maximum handshake message size
+    static let maxHandshakeMessageSize = 2048 // 2KB to accommodate XX pattern
+    
+    // Session timeout - sessions older than this should be renegotiated
+    static let sessionTimeout: TimeInterval = 86400 // 24 hours
+    
+    // Maximum number of messages before rekey (2^64 - 1 is the nonce limit)
+    static let maxMessagesPerSession: UInt64 = 1_000_000_000 // 1 billion messages
+    
+    // Handshake timeout - abandon incomplete handshakes
+    static let handshakeTimeout: TimeInterval = 60 // 1 minute
+    
+    // Maximum concurrent sessions per peer
+    static let maxSessionsPerPeer = 3
+    
+    // Rate limiting
+    static let maxHandshakesPerMinute = 10
+    static let maxMessagesPerSecond = 100
+    
+    // Global rate limiting (across all peers)
+    static let maxGlobalHandshakesPerMinute = 30
+    static let maxGlobalMessagesPerSecond = 500
+}
+
+// MARK: - Security Validations
+
+struct NoiseSecurityValidator {
+    
+    /// Validate message size
+    static func validateMessageSize(_ data: Data) -> Bool {
+        return data.count <= NoiseSecurityConstants.maxMessageSize
+    }
+    
+    /// Validate handshake message size
+    static func validateHandshakeMessageSize(_ data: Data) -> Bool {
+        return data.count <= NoiseSecurityConstants.maxHandshakeMessageSize
+    }
+    
+    /// Validate peer ID format
+    static func validatePeerID(_ peerID: String) -> Bool {
+        // Peer ID should be reasonable length and contain valid characters
+        let validCharset = CharacterSet.alphanumerics.union(CharacterSet(charactersIn: "-_"))
+        return peerID.count > 0 && 
+               peerID.count <= 64 && 
+               peerID.rangeOfCharacter(from: validCharset.inverted) == nil
+    }
+    
+    /// Validate channel name format
+    static func validateChannelName(_ channel: String) -> Bool {
+        // Channel should start with # and contain valid characters
+        let validCharset = CharacterSet.alphanumerics.union(CharacterSet(charactersIn: "-_"))
+        return channel.hasPrefix("#") && 
+               channel.count > 1 && 
+               channel.count <= 32 &&
+               channel.dropFirst().rangeOfCharacter(from: validCharset.inverted) == nil
+    }
+}
+
+// MARK: - Enhanced Noise Session with Security
+
+class SecureNoiseSession: NoiseSession {
+    private(set) var messageCount: UInt64 = 0
+    private let sessionStartTime = Date()
+    private(set) var lastActivityTime = Date()
+    
+    override func encrypt(_ plaintext: Data) throws -> Data {
+        // Check session age
+        if Date().timeIntervalSince(sessionStartTime) > NoiseSecurityConstants.sessionTimeout {
+            throw NoiseSecurityError.sessionExpired
+        }
+        
+        // Check message count
+        if messageCount >= NoiseSecurityConstants.maxMessagesPerSession {
+            throw NoiseSecurityError.sessionExhausted
+        }
+        
+        // Validate message size
+        guard NoiseSecurityValidator.validateMessageSize(plaintext) else {
+            throw NoiseSecurityError.messageTooLarge
+        }
+        
+        let encrypted = try super.encrypt(plaintext)
+        messageCount += 1
+        lastActivityTime = Date()
+        
+        return encrypted
+    }
+    
+    override func decrypt(_ ciphertext: Data) throws -> Data {
+        // Check session age
+        if Date().timeIntervalSince(sessionStartTime) > NoiseSecurityConstants.sessionTimeout {
+            throw NoiseSecurityError.sessionExpired
+        }
+        
+        // Validate message size
+        guard NoiseSecurityValidator.validateMessageSize(ciphertext) else {
+            throw NoiseSecurityError.messageTooLarge
+        }
+        
+        let decrypted = try super.decrypt(ciphertext)
+        lastActivityTime = Date()
+        
+        return decrypted
+    }
+    
+    func needsRenegotiation() -> Bool {
+        // Check if we've used more than 90% of message limit
+        let messageThreshold = UInt64(Double(NoiseSecurityConstants.maxMessagesPerSession) * 0.9)
+        if messageCount >= messageThreshold {
+            return true
+        }
+        
+        // Check if last activity was more than 30 minutes ago
+        if Date().timeIntervalSince(lastActivityTime) > NoiseSecurityConstants.sessionTimeout {
+            return true
+        }
+        
+        return false
+    }
+    
+    // MARK: - Testing Support
+    #if DEBUG
+    func setLastActivityTimeForTesting(_ date: Date) {
+        lastActivityTime = date
+    }
+    
+    func setMessageCountForTesting(_ count: UInt64) {
+        messageCount = count
+    }
+    #endif
+}
+
+// MARK: - Rate Limiter
+
+class NoiseRateLimiter {
+    private var handshakeTimestamps: [String: [Date]] = [:] // peerID -> timestamps
+    private var messageTimestamps: [String: [Date]] = [:] // peerID -> timestamps
+    
+    // Global rate limiting
+    private var globalHandshakeTimestamps: [Date] = []
+    private var globalMessageTimestamps: [Date] = []
+    
+    private let queue = DispatchQueue(label: "chat.bitchat.noise.ratelimit", attributes: .concurrent)
+    
+    func allowHandshake(from peerID: String) -> Bool {
+        return queue.sync(flags: .barrier) {
+            let now = Date()
+            let oneMinuteAgo = now.addingTimeInterval(-60)
+            
+            // Check global rate limit first
+            globalHandshakeTimestamps = globalHandshakeTimestamps.filter { $0 > oneMinuteAgo }
+            if globalHandshakeTimestamps.count >= NoiseSecurityConstants.maxGlobalHandshakesPerMinute {
+                return false
+            }
+            
+            // Check per-peer rate limit
+            var timestamps = handshakeTimestamps[peerID] ?? []
+            timestamps = timestamps.filter { $0 > oneMinuteAgo }
+            
+            if timestamps.count >= NoiseSecurityConstants.maxHandshakesPerMinute {
+                return false
+            }
+            
+            // Record new handshake
+            timestamps.append(now)
+            handshakeTimestamps[peerID] = timestamps
+            globalHandshakeTimestamps.append(now)
+            return true
+        }
+    }
+    
+    func allowMessage(from peerID: String) -> Bool {
+        return queue.sync(flags: .barrier) {
+            let now = Date()
+            let oneSecondAgo = now.addingTimeInterval(-1)
+            
+            // Check global rate limit first
+            globalMessageTimestamps = globalMessageTimestamps.filter { $0 > oneSecondAgo }
+            if globalMessageTimestamps.count >= NoiseSecurityConstants.maxGlobalMessagesPerSecond {
+                return false
+            }
+            
+            // Check per-peer rate limit
+            var timestamps = messageTimestamps[peerID] ?? []
+            timestamps = timestamps.filter { $0 > oneSecondAgo }
+            
+            if timestamps.count >= NoiseSecurityConstants.maxMessagesPerSecond {
+                return false
+            }
+            
+            // Record new message
+            timestamps.append(now)
+            messageTimestamps[peerID] = timestamps
+            globalMessageTimestamps.append(now)
+            return true
+        }
+    }
+    
+    func reset(for peerID: String) {
+        queue.async(flags: .barrier) {
+            self.handshakeTimestamps.removeValue(forKey: peerID)
+            self.messageTimestamps.removeValue(forKey: peerID)
+        }
+    }
+}
+
+// MARK: - Security Errors
+
+enum NoiseSecurityError: Error {
+    case sessionExpired
+    case sessionExhausted
+    case messageTooLarge
+    case invalidPeerID
+    case invalidChannelName
+    case rateLimitExceeded
+    case handshakeTimeout
+}
+
+// MARK: - Security Audit Checklist
+
+/*
+ SECURITY AUDIT CHECKLIST:
+ 
+ 1. KEY MANAGEMENT
+    ✓ Static keys stored in Keychain (most secure iOS storage)
+    ✓ Keys cleared on panic mode
+    ✓ Ephemeral keys generated per session
+    ✓ No key reuse across sessions
+ 
+ 2. PROTOCOL SECURITY
+    ✓ Using Noise XX pattern for mutual authentication
+    ✓ Forward secrecy via ephemeral keys
+    ✓ Replay protection via nonce counter
+    ✓ AEAD encryption (ChaCha20-Poly1305)
+    ✓ SHA-256 for hashing
+ 
+ 3. IMPLEMENTATION SECURITY
+    ✓ Message size limits to prevent DoS
+    ✓ Session timeout to limit exposure
+    ✓ Message count limits to prevent nonce reuse
+    ✓ Rate limiting for handshakes and messages
+    ✓ Input validation for all user data
+    ✓ Thread-safe operations
+ 
+ 4. NETWORK SECURITY
+    ✓ Messages padded to standard sizes for traffic analysis resistance
+    ✓ Cover traffic for anonymity
+    ✓ No metadata leakage in protocol
+    ✓ Fingerprint verification for identity
+ 
+ 5. EDGE CASES HANDLED
+    ✓ Incomplete handshakes timeout
+    ✓ Duplicate handshake messages ignored
+    ✓ Session renegotiation when needed
+    ✓ Graceful handling of decryption failures
+    ✓ Memory limits on message sizes
+ 
+ 6. FUTURE IMPROVEMENTS
+    - Implement post-quantum key exchange (when available)
+    - Add perfect forward secrecy for channel keys
+    - Implement key rotation for long-lived channels
+    - Add security event logging
+    - Implement secure key backup/restore
+ */

bitchat/Noise/NoiseSession.swift

@@ -0,0 +1,442 @@
+//
+// NoiseSession.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import CryptoKit
+import os.log
+
+// MARK: - Noise Session State
+
+enum NoiseSessionState: Equatable {
+    case uninitialized
+    case handshaking
+    case established
+    case failed(Error)
+    
+    static func == (lhs: NoiseSessionState, rhs: NoiseSessionState) -> Bool {
+        switch (lhs, rhs) {
+        case (.uninitialized, .uninitialized),
+             (.handshaking, .handshaking),
+             (.established, .established):
+            return true
+        case (.failed, .failed):
+            return true // We don't compare the errors
+        default:
+            return false
+        }
+    }
+}
+
+// MARK: - Noise Session
+
+class NoiseSession {
+    let peerID: String
+    let role: NoiseRole
+    private var state: NoiseSessionState = .uninitialized
+    private var handshakeState: NoiseHandshakeState?
+    private var sendCipher: NoiseCipherState?
+    private var receiveCipher: NoiseCipherState?
+    
+    // Keys
+    private let localStaticKey: Curve25519.KeyAgreement.PrivateKey
+    private var remoteStaticPublicKey: Curve25519.KeyAgreement.PublicKey?
+    
+    // Handshake messages for retransmission
+    private var sentHandshakeMessages: [Data] = []
+    private var handshakeHash: Data?
+    
+    // Thread safety
+    private let sessionQueue = DispatchQueue(label: "chat.bitchat.noise.session", attributes: .concurrent)
+    
+    init(peerID: String, role: NoiseRole, localStaticKey: Curve25519.KeyAgreement.PrivateKey, remoteStaticKey: Curve25519.KeyAgreement.PublicKey? = nil) {
+        self.peerID = peerID
+        self.role = role
+        self.localStaticKey = localStaticKey
+        self.remoteStaticPublicKey = remoteStaticKey
+    }
+    
+    // MARK: - Handshake
+    
+    func startHandshake() throws -> Data {
+        return try sessionQueue.sync(flags: .barrier) {
+            guard case .uninitialized = state else {
+                throw NoiseSessionError.invalidState
+            }
+            
+            // For XX pattern, we don't need remote static key upfront
+            handshakeState = NoiseHandshakeState(
+                role: role,
+                pattern: .XX,
+                localStaticKey: localStaticKey,
+                remoteStaticKey: nil
+            )
+            
+            state = .handshaking
+            
+            // Only initiator writes the first message
+            if role == .initiator {
+                let message = try handshakeState!.writeMessage()
+                sentHandshakeMessages.append(message)
+                return message
+            } else {
+                // Responder doesn't send first message in XX pattern
+                return Data()
+            }
+        }
+    }
+    
+    func processHandshakeMessage(_ message: Data) throws -> Data? {
+        return try sessionQueue.sync(flags: .barrier) {
+            
+            // Initialize handshake state if needed (for responders)
+            if state == .uninitialized && role == .responder {
+                handshakeState = NoiseHandshakeState(
+                    role: role,
+                    pattern: .XX,
+                    localStaticKey: localStaticKey,
+                    remoteStaticKey: nil
+                )
+                state = .handshaking
+            }
+            
+            guard case .handshaking = state, let handshake = handshakeState else {
+                throw NoiseSessionError.invalidState
+            }
+            
+            // Process incoming message
+            _ = try handshake.readMessage(message)
+            
+            // Check if handshake is complete
+            if handshake.isHandshakeComplete() {
+                // Get transport ciphers
+                let (send, receive) = try handshake.getTransportCiphers()
+                sendCipher = send
+                receiveCipher = receive
+                
+                // Store remote static key
+                remoteStaticPublicKey = handshake.getRemoteStaticPublicKey()
+                
+                // Store handshake hash for channel binding
+                handshakeHash = handshake.getHandshakeHash()
+                
+                state = .established
+                handshakeState = nil // Clear handshake state
+                
+                return nil
+            } else {
+                // Generate response
+                let response = try handshake.writeMessage()
+                sentHandshakeMessages.append(response)
+                
+                // Check if handshake is complete after writing
+                if handshake.isHandshakeComplete() {
+                    // Get transport ciphers
+                    let (send, receive) = try handshake.getTransportCiphers()
+                    sendCipher = send
+                    receiveCipher = receive
+                    
+                    // Store remote static key
+                    remoteStaticPublicKey = handshake.getRemoteStaticPublicKey()
+                    
+                    // Store handshake hash for channel binding
+                    handshakeHash = handshake.getHandshakeHash()
+                    
+                    state = .established
+                    handshakeState = nil // Clear handshake state
+                }
+                
+                return response
+            }
+        }
+    }
+    
+    // MARK: - Transport
+    
+    func encrypt(_ plaintext: Data) throws -> Data {
+        return try sessionQueue.sync {
+            guard case .established = state, let cipher = sendCipher else {
+                throw NoiseSessionError.notEstablished
+            }
+            
+            return try cipher.encrypt(plaintext: plaintext)
+        }
+    }
+    
+    func decrypt(_ ciphertext: Data) throws -> Data {
+        return try sessionQueue.sync {
+            guard case .established = state, let cipher = receiveCipher else {
+                throw NoiseSessionError.notEstablished
+            }
+            
+            return try cipher.decrypt(ciphertext: ciphertext)
+        }
+    }
+    
+    // MARK: - State Management
+    
+    func getState() -> NoiseSessionState {
+        return sessionQueue.sync {
+            return state
+        }
+    }
+    
+    func isEstablished() -> Bool {
+        return sessionQueue.sync {
+            if case .established = state {
+                return true
+            }
+            return false
+        }
+    }
+    
+    func getRemoteStaticPublicKey() -> Curve25519.KeyAgreement.PublicKey? {
+        return sessionQueue.sync {
+            return remoteStaticPublicKey
+        }
+    }
+    
+    func getHandshakeHash() -> Data? {
+        return sessionQueue.sync {
+            return handshakeHash
+        }
+    }
+    
+    func reset() {
+        sessionQueue.sync(flags: .barrier) {
+            state = .uninitialized
+            handshakeState = nil
+            sendCipher = nil
+            receiveCipher = nil
+            sentHandshakeMessages.removeAll()
+            handshakeHash = nil
+        }
+    }
+}
+
+// MARK: - Session Manager
+
+class NoiseSessionManager {
+    private var sessions: [String: NoiseSession] = [:]
+    private let localStaticKey: Curve25519.KeyAgreement.PrivateKey
+    private let managerQueue = DispatchQueue(label: "chat.bitchat.noise.manager", attributes: .concurrent)
+    
+    // Callbacks
+    var onSessionEstablished: ((String, Curve25519.KeyAgreement.PublicKey) -> Void)?
+    var onSessionFailed: ((String, Error) -> Void)?
+    
+    init(localStaticKey: Curve25519.KeyAgreement.PrivateKey) {
+        self.localStaticKey = localStaticKey
+    }
+    
+    // MARK: - Session Management
+    
+    func createSession(for peerID: String, role: NoiseRole) -> NoiseSession {
+        return managerQueue.sync(flags: .barrier) {
+            let session = SecureNoiseSession(
+                peerID: peerID,
+                role: role,
+                localStaticKey: localStaticKey
+            )
+            sessions[peerID] = session
+            return session
+        }
+    }
+    
+    func getSession(for peerID: String) -> NoiseSession? {
+        return managerQueue.sync {
+            return sessions[peerID]
+        }
+    }
+    
+    func removeSession(for peerID: String) {
+        _ = managerQueue.sync(flags: .barrier) {
+            sessions.removeValue(forKey: peerID)
+        }
+    }
+    
+    func getEstablishedSessions() -> [String: NoiseSession] {
+        return managerQueue.sync {
+            return sessions.filter { $0.value.isEstablished() }
+        }
+    }
+    
+    // MARK: - Handshake Helpers
+    
+    func initiateHandshake(with peerID: String) throws -> Data {
+        return try managerQueue.sync(flags: .barrier) {
+            // Check if we already have an established session
+            if let existingSession = sessions[peerID], existingSession.isEstablished() {
+                // Session already established, don't recreate
+                throw NoiseSessionError.alreadyEstablished
+            }
+            
+            // Remove any existing non-established session
+            if let existingSession = sessions[peerID], !existingSession.isEstablished() {
+                sessions.removeValue(forKey: peerID)
+            }
+            
+            // Create new initiator session
+            let session = SecureNoiseSession(
+                peerID: peerID,
+                role: .initiator,
+                localStaticKey: localStaticKey
+            )
+            sessions[peerID] = session
+            
+            do {
+                let handshakeData = try session.startHandshake()
+                return handshakeData
+            } catch {
+                // Clean up failed session
+                sessions.removeValue(forKey: peerID)
+                throw error
+            }
+        }
+    }
+    
+    func handleIncomingHandshake(from peerID: String, message: Data) throws -> Data? {
+        // Process everything within the synchronized block to prevent race conditions
+        return try managerQueue.sync(flags: .barrier) {
+            var shouldCreateNew = false
+            var existingSession: NoiseSession? = nil
+            
+            if let existing = sessions[peerID] {
+                // If we have an established session, we might need to help the other side complete theirs
+                if existing.isEstablished() {
+                    // If this is a handshake initiation (32 bytes), the other side doesn't have a session
+                    // We should complete the handshake to help them establish their session
+                    if message.count == 32 {
+                        // Remove existing session and create new one
+                        sessions.removeValue(forKey: peerID)
+                        shouldCreateNew = true
+                    } else {
+                        // For other handshake messages, ignore if already established
+                        throw NoiseSessionError.alreadyEstablished
+                    }
+                } else {
+                    // If we're in the middle of a handshake and receive a new initiation,
+                    // reset and start fresh (the other side may have restarted)
+                    if existing.getState() == .handshaking && message.count == 32 {
+                        sessions.removeValue(forKey: peerID)
+                        shouldCreateNew = true
+                    } else {
+                        existingSession = existing
+                    }
+                }
+            } else {
+                shouldCreateNew = true
+            }
+            
+            // Get or create session
+            let session: NoiseSession
+            if shouldCreateNew {
+                let newSession = SecureNoiseSession(
+                    peerID: peerID,
+                    role: .responder,
+                    localStaticKey: localStaticKey
+                )
+                sessions[peerID] = newSession
+                session = newSession
+            } else {
+                session = existingSession!
+            }
+            
+            // Process the handshake message within the synchronized block
+            do {
+                let response = try session.processHandshakeMessage(message)
+                
+                // Check if session is established after processing
+                if session.isEstablished() {
+                    if let remoteKey = session.getRemoteStaticPublicKey() {
+                        // Schedule callback outside the synchronized block to prevent deadlock
+                        DispatchQueue.global().async { [weak self] in
+                            self?.onSessionEstablished?(peerID, remoteKey)
+                        }
+                    }
+                }
+                
+                return response
+            } catch {
+                // Reset the session on handshake failure so next attempt can start fresh
+                sessions.removeValue(forKey: peerID)
+                
+                // Schedule callback outside the synchronized block to prevent deadlock
+                DispatchQueue.global().async { [weak self] in
+                    self?.onSessionFailed?(peerID, error)
+                }
+                
+                throw error
+            }
+        }
+    }
+    
+    // MARK: - Encryption/Decryption
+    
+    func encrypt(_ plaintext: Data, for peerID: String) throws -> Data {
+        guard let session = getSession(for: peerID) else {
+            throw NoiseSessionError.sessionNotFound
+        }
+        
+        return try session.encrypt(plaintext)
+    }
+    
+    func decrypt(_ ciphertext: Data, from peerID: String) throws -> Data {
+        guard let session = getSession(for: peerID) else {
+            throw NoiseSessionError.sessionNotFound
+        }
+        
+        return try session.decrypt(ciphertext)
+    }
+    
+    // MARK: - Key Management
+    
+    func getRemoteStaticKey(for peerID: String) -> Curve25519.KeyAgreement.PublicKey? {
+        return getSession(for: peerID)?.getRemoteStaticPublicKey()
+    }
+    
+    func getHandshakeHash(for peerID: String) -> Data? {
+        return getSession(for: peerID)?.getHandshakeHash()
+    }
+    
+    // MARK: - Session Rekeying
+    
+    func getSessionsNeedingRekey() -> [(peerID: String, needsRekey: Bool)] {
+        return managerQueue.sync {
+            var needingRekey: [(peerID: String, needsRekey: Bool)] = []
+            
+            for (peerID, session) in sessions {
+                if let secureSession = session as? SecureNoiseSession,
+                   secureSession.isEstablished(),
+                   secureSession.needsRenegotiation() {
+                    needingRekey.append((peerID: peerID, needsRekey: true))
+                }
+            }
+            
+            return needingRekey
+        }
+    }
+    
+    func initiateRekey(for peerID: String) throws {
+        // Remove old session
+        removeSession(for: peerID)
+        
+        // Initiate new handshake
+        _ = try initiateHandshake(with: peerID)
+        
+    }
+}
+
+// MARK: - Errors
+
+enum NoiseSessionError: Error {
+    case invalidState
+    case notEstablished
+    case sessionNotFound
+    case handshakeFailed(Error)
+    case alreadyEstablished
+}

bitchat/Protocols/BinaryProtocol.swift

@@ -49,17 +49,22 @@ struct BinaryProtocol {
     static func encode(_ packet: BitchatPacket) -> Data? {
         var data = Data()
         
+        
         // Try to compress payload if beneficial
         var payload = packet.payload
         var originalPayloadSize: UInt16? = nil
         var isCompressed = false
         
-        if CompressionUtil.shouldCompress(payload),
+        if CompressionUtil.shouldCompress(payload) {
-           let compressedPayload = CompressionUtil.compress(payload) {
+            if let compressedPayload = CompressionUtil.compress(payload) {
-            // Store original size for decompression (2 bytes after payload)
+                // Store original size for decompression (2 bytes after payload)
-            originalPayloadSize = UInt16(payload.count)
+                originalPayloadSize = UInt16(payload.count)
-            payload = compressedPayload
+                payload = compressedPayload
-            isCompressed = true
+                isCompressed = true
+                
+            } else {
+            }
+        } else {
         }
         
         // Header
@@ -88,6 +93,8 @@ struct BinaryProtocol {
         // Payload length (2 bytes, big-endian) - includes original size if compressed
         let payloadDataSize = payload.count + (isCompressed ? 2 : 0)
         let payloadLength = UInt16(payloadDataSize)
+        
+        
         data.append(UInt8((payloadLength >> 8) & 0xFF))
         data.append(UInt8(payloadLength & 0xFF))
         
@@ -120,37 +127,49 @@ struct BinaryProtocol {
             data.append(signature.prefix(signatureSize))
         }
         
-        return data
+        
+        // Apply padding to standard block sizes for traffic analysis resistance
+        let optimalSize = MessagePadding.optimalBlockSize(for: data.count)
+        let paddedData = MessagePadding.pad(data, toSize: optimalSize)
+        
+        
+        return paddedData
     }
     
     // Decode binary data to BitchatPacket
     static func decode(_ data: Data) -> BitchatPacket? {
-        guard data.count >= headerSize + senderIDSize else { return nil }
+        // Remove padding first
+        let unpaddedData = MessagePadding.unpad(data)
+        
+        
+        guard unpaddedData.count >= headerSize + senderIDSize else { 
+            return nil 
+        }
         
         var offset = 0
         
         // Header
-        let version = data[offset]; offset += 1
+        let version = unpaddedData[offset]; offset += 1
         // Only support version 1
         guard version == 1 else { return nil }
-        let type = data[offset]; offset += 1
+        let type = unpaddedData[offset]; offset += 1
-        let ttl = data[offset]; offset += 1
+        let ttl = unpaddedData[offset]; offset += 1
         
         // Timestamp
-        let timestampData = data[offset..<offset+8]
+        let timestampData = unpaddedData[offset..<offset+8]
         let timestamp = timestampData.reduce(0) { result, byte in
             (result << 8) | UInt64(byte)
         }
         offset += 8
         
         // Flags
-        let flags = data[offset]; offset += 1
+        let flags = unpaddedData[offset]; offset += 1
         let hasRecipient = (flags & Flags.hasRecipient) != 0
         let hasSignature = (flags & Flags.hasSignature) != 0
         let isCompressed = (flags & Flags.isCompressed) != 0
         
         // Payload length
-        let payloadLengthData = data[offset..<offset+2]
+        let payloadLengthData = unpaddedData[offset..<offset+2]
         let payloadLength = payloadLengthData.reduce(0) { result, byte in
             (result << 8) | UInt16(byte)
         }
@@ -165,16 +184,18 @@ struct BinaryProtocol {
             expectedSize += signatureSize
         }
         
-        guard data.count >= expectedSize else { return nil }
+        guard unpaddedData.count >= expectedSize else { 
+            return nil 
+        }
         
         // SenderID
-        let senderID = data[offset..<offset+senderIDSize]
+        let senderID = unpaddedData[offset..<offset+senderIDSize]
         offset += senderIDSize
         
         // RecipientID
         var recipientID: Data?
         if hasRecipient {
-            recipientID = data[offset..<offset+recipientIDSize]
+            recipientID = unpaddedData[offset..<offset+recipientIDSize]
             offset += recipientIDSize
         }
         
@@ -183,14 +204,14 @@ struct BinaryProtocol {
         if isCompressed {
             // First 2 bytes are original size
             guard Int(payloadLength) >= 2 else { return nil }
-            let originalSizeData = data[offset..<offset+2]
+            let originalSizeData = unpaddedData[offset..<offset+2]
             let originalSize = Int(originalSizeData.reduce(0) { result, byte in
                 (result << 8) | UInt16(byte)
             })
             offset += 2
             
             // Compressed payload
-            let compressedPayload = data[offset..<offset+Int(payloadLength)-2]
+            let compressedPayload = unpaddedData[offset..<offset+Int(payloadLength)-2]
             offset += Int(payloadLength) - 2
             
             // Decompress
@@ -199,14 +220,14 @@ struct BinaryProtocol {
             }
             payload = decompressedPayload
         } else {
-            payload = data[offset..<offset+Int(payloadLength)]
+            payload = unpaddedData[offset..<offset+Int(payloadLength)]
             offset += Int(payloadLength)
         }
         
         // Signature
         var signature: Data?
         if hasSignature {
-            signature = data[offset..<offset+signatureSize]
+            signature = unpaddedData[offset..<offset+signatureSize]
         }
         
         return BitchatPacket(

bitchat/Protocols/BitchatProtocol.swift

@@ -41,9 +41,20 @@ struct MessagePadding {
         
         // Last byte tells us how much padding to remove
         let paddingLength = Int(data[data.count - 1])
-        guard paddingLength > 0 && paddingLength <= data.count else { return data }
+        guard paddingLength > 0 && paddingLength <= data.count else { 
+            // Debug logging for 243-byte packets
+            if data.count == 243 {
+            }
+            return data 
+        }
         
-        return data.prefix(data.count - paddingLength)
+        let result = data.prefix(data.count - paddingLength)
+        
+        // Debug logging for 243-byte packets
+        if data.count == 243 {
+        }
+        
+        return result
     }
     
     // Find optimal block size for data
@@ -66,7 +77,7 @@ struct MessagePadding {
 
 enum MessageType: UInt8 {
     case announce = 0x01
-    case keyExchange = 0x02
+    // 0x02 was legacy keyExchange - removed
     case leave = 0x03
     case message = 0x04  // All user messages (private and broadcast)
     case fragmentStart = 0x05
@@ -77,6 +88,40 @@ enum MessageType: UInt8 {
     case deliveryAck = 0x0A  // Acknowledge message received
     case deliveryStatusRequest = 0x0B  // Request delivery status update
     case readReceipt = 0x0C  // Message has been read/viewed
+    
+    // Noise Protocol messages
+    case noiseHandshakeInit = 0x10  // Noise handshake initiation
+    case noiseHandshakeResp = 0x11  // Noise handshake response
+    case noiseEncrypted = 0x12      // Noise encrypted transport message
+    case noiseIdentityAnnounce = 0x13  // Announce static public key for discovery
+    case channelKeyVerifyRequest = 0x14  // Request key verification for a channel
+    case channelKeyVerifyResponse = 0x15 // Response to key verification request
+    case channelPasswordUpdate = 0x16    // Distribute new password to channel members
+    case channelMetadata = 0x17         // Announce channel creator and metadata
+    
+    var description: String {
+        switch self {
+        case .announce: return "announce"
+        case .leave: return "leave"
+        case .message: return "message"
+        case .fragmentStart: return "fragmentStart"
+        case .fragmentContinue: return "fragmentContinue"
+        case .fragmentEnd: return "fragmentEnd"
+        case .channelAnnounce: return "channelAnnounce"
+        case .channelRetention: return "channelRetention"
+        case .deliveryAck: return "deliveryAck"
+        case .deliveryStatusRequest: return "deliveryStatusRequest"
+        case .readReceipt: return "readReceipt"
+        case .noiseHandshakeInit: return "noiseHandshakeInit"
+        case .noiseHandshakeResp: return "noiseHandshakeResp"
+        case .noiseEncrypted: return "noiseEncrypted"
+        case .noiseIdentityAnnounce: return "noiseIdentityAnnounce"
+        case .channelKeyVerifyRequest: return "channelKeyVerifyRequest"
+        case .channelKeyVerifyResponse: return "channelKeyVerifyResponse"
+        case .channelPasswordUpdate: return "channelPasswordUpdate"
+        case .channelMetadata: return "channelMetadata"
+        }
+    }
 }
 
 // Special recipient ID for broadcast messages
@@ -109,7 +154,17 @@ struct BitchatPacket: Codable {
     init(type: UInt8, ttl: UInt8, senderID: String, payload: Data) {
         self.version = 1
         self.type = type
-        self.senderID = senderID.data(using: .utf8)!
+        // Convert hex string peer ID to binary data (8 bytes)
+        var senderData = Data()
+        var tempID = senderID
+        while tempID.count >= 2 {
+            let hexByte = String(tempID.prefix(2))
+            if let byte = UInt8(hexByte, radix: 16) {
+                senderData.append(byte)
+            }
+            tempID = String(tempID.dropFirst(2))
+        }
+        self.senderID = senderData
         self.recipientID = nil
         self.timestamp = UInt64(Date().timeIntervalSince1970 * 1000) // milliseconds
         self.payload = payload
@@ -182,6 +237,151 @@ struct ReadReceipt: Codable {
     }
 }
 
+// Channel key verification request
+struct ChannelKeyVerifyRequest: Codable {
+    let channel: String
+    let requesterID: String
+    let keyCommitment: String  // SHA256 hash of the key they have
+    let timestamp: Date
+    
+    init(channel: String, requesterID: String, keyCommitment: String) {
+        self.channel = channel
+        self.requesterID = requesterID
+        self.keyCommitment = keyCommitment
+        self.timestamp = Date()
+    }
+    
+    func encode() -> Data? {
+        return try? JSONEncoder().encode(self)
+    }
+    
+    static func decode(from data: Data) -> ChannelKeyVerifyRequest? {
+        try? JSONDecoder().decode(ChannelKeyVerifyRequest.self, from: data)
+    }
+}
+
+// Channel key verification response
+struct ChannelKeyVerifyResponse: Codable {
+    let channel: String
+    let responderID: String
+    let verified: Bool  // Whether the key commitment matches
+    let timestamp: Date
+    
+    init(channel: String, responderID: String, verified: Bool) {
+        self.channel = channel
+        self.responderID = responderID
+        self.verified = verified
+        self.timestamp = Date()
+    }
+    
+    func encode() -> Data? {
+        return try? JSONEncoder().encode(self)
+    }
+    
+    static func decode(from data: Data) -> ChannelKeyVerifyResponse? {
+        try? JSONDecoder().decode(ChannelKeyVerifyResponse.self, from: data)
+    }
+}
+
+// Channel password update (sent by owner to members)
+struct ChannelPasswordUpdate: Codable {
+    let channel: String
+    let ownerID: String  // Deprecated, kept for backward compatibility
+    let ownerFingerprint: String  // Noise protocol fingerprint of owner
+    let encryptedPassword: Data  // New password encrypted with recipient's Noise session
+    let newKeyCommitment: String  // SHA256 of new key for verification
+    let timestamp: Date
+    
+    init(channel: String, ownerID: String, ownerFingerprint: String, encryptedPassword: Data, newKeyCommitment: String) {
+        self.channel = channel
+        self.ownerID = ownerID
+        self.ownerFingerprint = ownerFingerprint
+        self.encryptedPassword = encryptedPassword
+        self.newKeyCommitment = newKeyCommitment
+        self.timestamp = Date()
+    }
+    
+    func encode() -> Data? {
+        return try? JSONEncoder().encode(self)
+    }
+    
+    static func decode(from data: Data) -> ChannelPasswordUpdate? {
+        try? JSONDecoder().decode(ChannelPasswordUpdate.self, from: data)
+    }
+}
+
+// Channel metadata announcement
+struct ChannelMetadata: Codable {
+    let channel: String
+    let creatorID: String
+    let creatorFingerprint: String  // Noise protocol fingerprint
+    let createdAt: Date
+    let isPasswordProtected: Bool
+    let keyCommitment: String?  // SHA256 of channel key if password-protected
+    
+    init(channel: String, creatorID: String, creatorFingerprint: String, isPasswordProtected: Bool, keyCommitment: String?) {
+        self.channel = channel
+        self.creatorID = creatorID
+        self.creatorFingerprint = creatorFingerprint
+        self.createdAt = Date()
+        self.isPasswordProtected = isPasswordProtected
+        self.keyCommitment = keyCommitment
+    }
+    
+    func encode() -> Data? {
+        return try? JSONEncoder().encode(self)
+    }
+    
+    static func decode(from data: Data) -> ChannelMetadata? {
+        try? JSONDecoder().decode(ChannelMetadata.self, from: data)
+    }
+}
+
+// MARK: - Peer Identity Rotation
+
+// Enhanced identity announcement with rotation support
+struct NoiseIdentityAnnouncement: Codable {
+    let peerID: String               // Current ephemeral peer ID
+    let publicKey: Data              // Noise static public key
+    let nickname: String             // Current nickname
+    let timestamp: Date              // When this binding was created
+    let previousPeerID: String?      // Previous peer ID (for smooth transition)
+    let signature: Data              // Signature proving ownership
+    
+    init(peerID: String, publicKey: Data, nickname: String, previousPeerID: String? = nil, signature: Data) {
+        self.peerID = peerID
+        self.publicKey = publicKey
+        self.nickname = nickname
+        self.timestamp = Date()
+        self.previousPeerID = previousPeerID
+        self.signature = signature
+    }
+    
+    func encode() -> Data? {
+        return try? JSONEncoder().encode(self)
+    }
+    
+    static func decode(from data: Data) -> NoiseIdentityAnnouncement? {
+        try? JSONDecoder().decode(NoiseIdentityAnnouncement.self, from: data)
+    }
+}
+
+// Binding between ephemeral peer ID and cryptographic identity
+struct PeerIdentityBinding {
+    let currentPeerID: String        // Current ephemeral ID
+    let fingerprint: String          // Permanent cryptographic identity
+    let publicKey: Data              // Noise static public key
+    let nickname: String             // Last known nickname
+    let bindingTimestamp: Date       // When this binding was created
+    let signature: Data              // Cryptographic proof of binding
+    
+    // Verify the binding signature
+    func verify() -> Bool {
+        // TODO: Implement signature verification
+        return true
+    }
+}
+
 // Delivery status for messages
 enum DeliveryStatus: Codable, Equatable {
     case sending
@@ -260,6 +460,14 @@ protocol BitchatDelegate: AnyObject {
     func didReceiveDeliveryAck(_ ack: DeliveryAck)
     func didReceiveReadReceipt(_ receipt: ReadReceipt)
     func didUpdateMessageDeliveryStatus(_ messageID: String, status: DeliveryStatus)
+    
+    // Channel key verification methods
+    func didReceiveChannelKeyVerifyRequest(_ request: ChannelKeyVerifyRequest, from peerID: String)
+    func didReceiveChannelKeyVerifyResponse(_ response: ChannelKeyVerifyResponse, from peerID: String)
+    func didReceiveChannelPasswordUpdate(_ update: ChannelPasswordUpdate, from peerID: String)
+    
+    // Channel metadata methods
+    func didReceiveChannelMetadata(_ metadata: ChannelMetadata, from peerID: String)
 }
 
 // Provide default implementation to make it effectively optional
@@ -296,4 +504,20 @@ extension BitchatDelegate {
     func didUpdateMessageDeliveryStatus(_ messageID: String, status: DeliveryStatus) {
         // Default empty implementation
     }
+    
+    func didReceiveChannelKeyVerifyRequest(_ request: ChannelKeyVerifyRequest, from peerID: String) {
+        // Default empty implementation
+    }
+    
+    func didReceiveChannelKeyVerifyResponse(_ response: ChannelKeyVerifyResponse, from peerID: String) {
+        // Default empty implementation
+    }
+    
+    func didReceiveChannelPasswordUpdate(_ update: ChannelPasswordUpdate, from peerID: String) {
+        // Default empty implementation
+    }
+    
+    func didReceiveChannelMetadata(_ metadata: ChannelMetadata, from peerID: String) {
+        // Default empty implementation
+    }
 }

bitchat/Services/DeliveryTracker.swift

@@ -143,13 +143,19 @@ class DeliveryTracker {
     
     func generateAck(for message: BitchatMessage, myPeerID: String, myNickname: String, hopCount: UInt8) -> DeliveryAck? {
         // Don't ACK our own messages
-        guard message.senderPeerID != myPeerID else { return nil }
+        guard message.senderPeerID != myPeerID else { 
+            return nil 
+        }
         
         // Don't ACK broadcasts or system messages
-        guard message.isPrivate || message.channel != nil else { return nil }
+        guard message.isPrivate || message.channel != nil else { 
+            return nil 
+        }
         
         // Don't ACK if we've already sent an ACK for this message
-        guard !sentAckIDs.contains(message.id) else { return nil }
+        guard !sentAckIDs.contains(message.id) else { 
+            return nil 
+        }
         sentAckIDs.insert(message.id)
         
         

bitchat/Services/EncryptionService.swift

@@ -1,165 +0,0 @@
-//
-// EncryptionService.swift
-// bitchat
-//
-// This is free and unencumbered software released into the public domain.
-// For more information, see <https://unlicense.org>
-//
-
-import Foundation
-import CryptoKit
-
-class EncryptionService {
-    // Key agreement keys for encryption
-    private var privateKey: Curve25519.KeyAgreement.PrivateKey
-    public let publicKey: Curve25519.KeyAgreement.PublicKey
-    
-    // Signing keys for authentication
-    private var signingPrivateKey: Curve25519.Signing.PrivateKey
-    public let signingPublicKey: Curve25519.Signing.PublicKey
-    
-    // Storage for peer keys
-    private var peerPublicKeys: [String: Curve25519.KeyAgreement.PublicKey] = [:]
-    private var peerSigningKeys: [String: Curve25519.Signing.PublicKey] = [:]
-    private var peerIdentityKeys: [String: Curve25519.Signing.PublicKey] = [:]
-    private var sharedSecrets: [String: SymmetricKey] = [:]
-    
-    // Persistent identity for favorites (separate from ephemeral keys)
-    private let identityKey: Curve25519.Signing.PrivateKey
-    public let identityPublicKey: Curve25519.Signing.PublicKey
-    
-    // Thread safety
-    private let cryptoQueue = DispatchQueue(label: "chat.bitchat.crypto", attributes: .concurrent)
-    
-    init() {
-        // Generate ephemeral key pairs for this session
-        self.privateKey = Curve25519.KeyAgreement.PrivateKey()
-        self.publicKey = privateKey.publicKey
-        
-        self.signingPrivateKey = Curve25519.Signing.PrivateKey()
-        self.signingPublicKey = signingPrivateKey.publicKey
-        
-        // Load or create persistent identity key
-        if let identityData = UserDefaults.standard.data(forKey: "bitchat.identityKey"),
-           let loadedKey = try? Curve25519.Signing.PrivateKey(rawRepresentation: identityData) {
-            self.identityKey = loadedKey
-        } else {
-            // First run - create and save identity key
-            self.identityKey = Curve25519.Signing.PrivateKey()
-            UserDefaults.standard.set(identityKey.rawRepresentation, forKey: "bitchat.identityKey")
-        }
-        self.identityPublicKey = identityKey.publicKey
-    }
-    
-    // Create combined public key data for exchange
-    func getCombinedPublicKeyData() -> Data {
-        var data = Data()
-        data.append(publicKey.rawRepresentation)  // 32 bytes - ephemeral encryption key
-        data.append(signingPublicKey.rawRepresentation)  // 32 bytes - ephemeral signing key
-        data.append(identityPublicKey.rawRepresentation)  // 32 bytes - persistent identity key
-        return data  // Total: 96 bytes
-    }
-    
-    // Add peer's combined public keys
-    func addPeerPublicKey(_ peerID: String, publicKeyData: Data) throws {
-        try cryptoQueue.sync(flags: .barrier) {
-            // Convert to array for safe access
-            let keyBytes = [UInt8](publicKeyData)
-            
-            guard keyBytes.count == 96 else {
-                // print("[CRYPTO] Invalid public key data size: \(keyBytes.count), expected 96")
-                throw EncryptionError.invalidPublicKey
-            }
-            
-            // Extract all three keys: 32 for key agreement + 32 for signing + 32 for identity
-            let keyAgreementData = Data(keyBytes[0..<32])
-            let signingKeyData = Data(keyBytes[32..<64])
-            let identityKeyData = Data(keyBytes[64..<96])
-            
-            let publicKey = try Curve25519.KeyAgreement.PublicKey(rawRepresentation: keyAgreementData)
-            peerPublicKeys[peerID] = publicKey
-            
-            let signingKey = try Curve25519.Signing.PublicKey(rawRepresentation: signingKeyData)
-            peerSigningKeys[peerID] = signingKey
-            
-            let identityKey = try Curve25519.Signing.PublicKey(rawRepresentation: identityKeyData)
-            peerIdentityKeys[peerID] = identityKey
-            
-            // Stored all three keys for peer
-            
-            // Generate shared secret for encryption
-            if let publicKey = peerPublicKeys[peerID] {
-                let sharedSecret = try privateKey.sharedSecretFromKeyAgreement(with: publicKey)
-                let symmetricKey = sharedSecret.hkdfDerivedSymmetricKey(
-                    using: SHA256.self,
-                    salt: "bitchat-v1".data(using: .utf8)!,
-                    sharedInfo: Data(),
-                    outputByteCount: 32
-                )
-                sharedSecrets[peerID] = symmetricKey
-            }
-        }
-    }
-    
-    // Get peer's persistent identity key for favorites
-    func getPeerIdentityKey(_ peerID: String) -> Data? {
-        return cryptoQueue.sync {
-            return peerIdentityKeys[peerID]?.rawRepresentation
-        }
-    }
-    
-    // Clear persistent identity (for panic mode)
-    func clearPersistentIdentity() {
-        UserDefaults.standard.removeObject(forKey: "bitchat.identityKey")
-        // print("[CRYPTO] Cleared persistent identity key")
-    }
-    
-    func encrypt(_ data: Data, for peerID: String) throws -> Data {
-        let symmetricKey = try cryptoQueue.sync {
-            guard let key = sharedSecrets[peerID] else {
-                throw EncryptionError.noSharedSecret
-            }
-            return key
-        }
-        
-        let sealedBox = try AES.GCM.seal(data, using: symmetricKey)
-        return sealedBox.combined ?? Data()
-    }
-    
-    func decrypt(_ data: Data, from peerID: String) throws -> Data {
-        let symmetricKey = try cryptoQueue.sync {
-            guard let key = sharedSecrets[peerID] else {
-                throw EncryptionError.noSharedSecret
-            }
-            return key
-        }
-        
-        let sealedBox = try AES.GCM.SealedBox(combined: data)
-        return try AES.GCM.open(sealedBox, using: symmetricKey)
-    }
-    
-    func sign(_ data: Data) throws -> Data {
-        // Create a local copy of the key to avoid concurrent access
-        let key = signingPrivateKey
-        return try key.signature(for: data)
-    }
-    
-    func verify(_ signature: Data, for data: Data, from peerID: String) throws -> Bool {
-        let verifyingKey = try cryptoQueue.sync {
-            guard let key = peerSigningKeys[peerID] else {
-                throw EncryptionError.noSharedSecret
-            }
-            return key
-        }
-        
-        return verifyingKey.isValidSignature(signature, for: data)
-    }
-    
-}
-
-enum EncryptionError: Error {
-    case noSharedSecret
-    case invalidPublicKey
-    case encryptionFailed
-    case decryptionFailed
-}

bitchat/Services/KeychainManager.swift

@@ -8,14 +8,91 @@
 
 import Foundation
 import Security
+import os.log
 
 class KeychainManager {
     static let shared = KeychainManager()
     
-    private let service = "com.bitchat.passwords"
+    // Use consistent service name for all keychain items
-    private let accessGroup: String? = nil // Set this if using app groups
+    private let service = "chat.bitchat"
+    private let appGroup = "group.chat.bitchat"
     
-    private init() {}
+    private init() {
+        // Clean up legacy keychain items on first run
+        cleanupLegacyKeychainItems()
+    }
+    
+    private func cleanupLegacyKeychainItems() {
+        // Check if we've already done cleanup
+        let cleanupKey = "bitchat.keychain.cleanup.v2"
+        if UserDefaults.standard.bool(forKey: cleanupKey) {
+            return
+        }
+        
+        
+        // List of old service names to migrate from
+        let legacyServices = [
+            "com.bitchat.passwords",
+            "com.bitchat.deviceidentity",
+            "com.bitchat.noise.identity",
+            "chat.bitchat.passwords",
+            "bitchat.keychain"
+        ]
+        
+        var migratedItems = 0
+        
+        // Try to migrate identity keys
+        for oldService in legacyServices {
+            // Check for noise identity key
+            let query: [String: Any] = [
+                kSecClass as String: kSecClassGenericPassword,
+                kSecAttrService as String: oldService,
+                kSecAttrAccount as String: "identity_noiseStaticKey",
+                kSecReturnData as String: true
+            ]
+            
+            var result: AnyObject?
+            let status = SecItemCopyMatching(query as CFDictionary, &result)
+            
+            if status == errSecSuccess, let data = result as? Data {
+                // Save to new service
+                if saveIdentityKey(data, forKey: "noiseStaticKey") {
+                    migratedItems += 1
+                }
+                // Delete from old service
+                let deleteQuery: [String: Any] = [
+                    kSecClass as String: kSecClassGenericPassword,
+                    kSecAttrService as String: oldService,
+                    kSecAttrAccount as String: "identity_noiseStaticKey"
+                ]
+                SecItemDelete(deleteQuery as CFDictionary)
+            }
+        }
+        
+        // Clean up all other legacy items
+        for oldService in legacyServices {
+            let deleteQuery: [String: Any] = [
+                kSecClass as String: kSecClassGenericPassword,
+                kSecAttrService as String: oldService
+            ]
+            
+            SecItemDelete(deleteQuery as CFDictionary)
+        }
+        
+        
+        // Mark cleanup as done
+        UserDefaults.standard.set(true, forKey: cleanupKey)
+    }
+    
+    
+    private func isSandboxed() -> Bool {
+        #if os(macOS)
+        let environment = ProcessInfo.processInfo.environment
+        return environment["APP_SANDBOX_CONTAINER_ID"] != nil
+        #else
+        return false
+        #endif
+    }
     
     // MARK: - Channel Passwords
     
@@ -37,17 +114,17 @@ class KeychainManager {
     func getAllChannelPasswords() -> [String: String] {
         var passwords: [String: String] = [:]
         
-        // Query all items
+        // Build query without kSecReturnData to avoid error -50
         var query: [String: Any] = [
             kSecClass as String: kSecClassGenericPassword,
             kSecAttrService as String: service,
             kSecMatchLimit as String: kSecMatchLimitAll,
-            kSecReturnAttributes as String: true,
+            kSecReturnAttributes as String: true
-            kSecReturnData as String: true
         ]
         
-        if let accessGroup = accessGroup {
+        // For sandboxed apps, use the app group
-            query[kSecAttrAccessGroup as String] = accessGroup
+        if isSandboxed() {
+            query[kSecAttrAccessGroup as String] = appGroup
         }
         
         var result: AnyObject?
@@ -56,11 +133,12 @@ class KeychainManager {
         if status == errSecSuccess, let items = result as? [[String: Any]] {
             for item in items {
                 if let account = item[kSecAttrAccount as String] as? String,
-                   account.hasPrefix("channel_"),
+                   account.hasPrefix("channel_") {
-                   let data = item[kSecValueData as String] as? Data,
+                    // Now retrieve the actual password data for this specific item
-                   let password = String(data: data, encoding: .utf8) {
                     let channel = String(account.dropFirst(8)) // Remove "channel_" prefix
-                    passwords[channel] = password
+                    if let password = getChannelPassword(for: channel) {
+                        passwords[channel] = password
+                    }
                 }
             }
         }
@@ -71,11 +149,17 @@ class KeychainManager {
     // MARK: - Identity Keys
     
     func saveIdentityKey(_ keyData: Data, forKey key: String) -> Bool {
-        return saveData(keyData, forKey: "identity_\(key)")
+        let fullKey = "identity_\(key)"
+        return saveData(keyData, forKey: fullKey)
     }
     
     func getIdentityKey(forKey key: String) -> Data? {
-        return retrieveData(forKey: "identity_\(key)")
+        let fullKey = "identity_\(key)"
+        return retrieveData(forKey: fullKey)
+    }
+    
+    func deleteIdentityKey(forKey key: String) -> Bool {
+        return delete(forKey: "identity_\(key)")
     }
     
     // MARK: - Generic Operations
@@ -86,35 +170,43 @@ class KeychainManager {
     }
     
     private func saveData(_ data: Data, forKey key: String) -> Bool {
-        // First try to update existing
+        // Delete any existing item first to ensure clean state
-        let updateQuery: [String: Any] = [
+        _ = delete(forKey: key)
+        
+        // Build query with all necessary attributes for sandboxed apps
+        var query: [String: Any] = [
             kSecClass as String: kSecClassGenericPassword,
-            kSecAttrService as String: service,
+            kSecAttrAccount as String: key,
-            kSecAttrAccount as String: key
-        ]
-        
-        var mutableUpdateQuery = updateQuery
-        if let accessGroup = accessGroup {
-            mutableUpdateQuery[kSecAttrAccessGroup as String] = accessGroup
-        }
-        
-        let updateAttributes: [String: Any] = [
             kSecValueData as String: data,
-            kSecAttrAccessible as String: kSecAttrAccessibleWhenUnlockedThisDeviceOnly
+            kSecAttrService as String: service,
+            // Important for sandboxed apps: make it accessible when unlocked
+            kSecAttrAccessible as String: kSecAttrAccessibleWhenUnlocked
         ]
         
-        var status = SecItemUpdate(mutableUpdateQuery as CFDictionary, updateAttributes as CFDictionary)
+        // Add a label for easier debugging
+        query[kSecAttrLabel as String] = "bitchat-\(key)"
         
-        if status == errSecItemNotFound {
+        // For sandboxed apps, use the app group for sharing between app instances
-            // Item doesn't exist, create it
+        if isSandboxed() {
-            var createQuery = mutableUpdateQuery
+            query[kSecAttrAccessGroup as String] = appGroup
-            createQuery[kSecValueData as String] = data
-            createQuery[kSecAttrAccessible as String] = kSecAttrAccessibleWhenUnlockedThisDeviceOnly
-            
-            status = SecItemAdd(createQuery as CFDictionary, nil)
         }
         
-        return status == errSecSuccess
+        // For sandboxed macOS apps, we need to ensure the item is NOT synchronized
+        #if os(macOS)
+        query[kSecAttrSynchronizable as String] = false
+        #endif
+        
+        let status = SecItemAdd(query as CFDictionary, nil)
+        
+        if status == errSecSuccess {
+            return true
+        } else if status == -34018 {
+            SecurityLogger.logError(NSError(domain: "Keychain", code: -34018), context: "Missing keychain entitlement", category: SecurityLogger.keychain)
+        } else if status != errSecDuplicateItem {
+            SecurityLogger.logError(NSError(domain: "Keychain", code: Int(status)), context: "Error saving to keychain", category: SecurityLogger.keychain)
+        }
+        
+        return false
     }
     
     private func retrieve(forKey key: String) -> String? {
@@ -125,35 +217,40 @@ class KeychainManager {
     private func retrieveData(forKey key: String) -> Data? {
         var query: [String: Any] = [
             kSecClass as String: kSecClassGenericPassword,
-            kSecAttrService as String: service,
             kSecAttrAccount as String: key,
+            kSecAttrService as String: service,
             kSecReturnData as String: true,
             kSecMatchLimit as String: kSecMatchLimitOne
         ]
         
-        if let accessGroup = accessGroup {
+        // For sandboxed apps, use the app group
-            query[kSecAttrAccessGroup as String] = accessGroup
+        if isSandboxed() {
+            query[kSecAttrAccessGroup as String] = appGroup
         }
         
         var result: AnyObject?
         let status = SecItemCopyMatching(query as CFDictionary, &result)
         
-        if status == errSecSuccess, let data = result as? Data {
+        if status == errSecSuccess {
-            return data
+            return result as? Data
+        } else if status == -34018 {
+            SecurityLogger.logError(NSError(domain: "Keychain", code: -34018), context: "Missing keychain entitlement", category: SecurityLogger.keychain)
         }
         
         return nil
     }
     
     private func delete(forKey key: String) -> Bool {
+        // Build basic query
         var query: [String: Any] = [
             kSecClass as String: kSecClassGenericPassword,
-            kSecAttrService as String: service,
+            kSecAttrAccount as String: key,
-            kSecAttrAccount as String: key
+            kSecAttrService as String: service
         ]
         
-        if let accessGroup = accessGroup {
+        // For sandboxed apps, use the app group
-            query[kSecAttrAccessGroup as String] = accessGroup
+        if isSandboxed() {
+            query[kSecAttrAccessGroup as String] = appGroup
         }
         
         let status = SecItemDelete(query as CFDictionary)
@@ -164,15 +261,182 @@ class KeychainManager {
     
     func deleteAllPasswords() -> Bool {
         var query: [String: Any] = [
-            kSecClass as String: kSecClassGenericPassword,
+            kSecClass as String: kSecClassGenericPassword
-            kSecAttrService as String: service
         ]
         
-        if let accessGroup = accessGroup {
+        // Add service if not empty
-            query[kSecAttrAccessGroup as String] = accessGroup
+        if !service.isEmpty {
+            query[kSecAttrService as String] = service
         }
         
         let status = SecItemDelete(query as CFDictionary)
         return status == errSecSuccess || status == errSecItemNotFound
     }
+    
+    // Force cleanup to run again (for development/testing)
+    func resetCleanupFlag() {
+        UserDefaults.standard.removeObject(forKey: "bitchat.keychain.cleanup.v2")
+    }
+    
+    
+    // Delete ALL keychain data for panic mode
+    func deleteAllKeychainData() -> Bool {
+        
+        var totalDeleted = 0
+        
+        // Search without service restriction to catch all items
+        let searchQuery: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecMatchLimit as String: kSecMatchLimitAll,
+            kSecReturnAttributes as String: true
+        ]
+        
+        var result: AnyObject?
+        let searchStatus = SecItemCopyMatching(searchQuery as CFDictionary, &result)
+        
+        if searchStatus == errSecSuccess, let items = result as? [[String: Any]] {
+            for item in items {
+                var shouldDelete = false
+                let account = item[kSecAttrAccount as String] as? String ?? ""
+                let service = item[kSecAttrService as String] as? String ?? ""
+                
+                // ONLY delete if service name contains "bitchat"
+                // This is the safest approach - we only touch items we know are ours
+                if service.lowercased().contains("bitchat") {
+                    shouldDelete = true
+                }
+                
+                if shouldDelete {
+                    // Build delete query with all available attributes for precise deletion
+                    var deleteQuery: [String: Any] = [
+                        kSecClass as String: kSecClassGenericPassword
+                    ]
+                    
+                    if !account.isEmpty {
+                        deleteQuery[kSecAttrAccount as String] = account
+                    }
+                    if !service.isEmpty {
+                        deleteQuery[kSecAttrService as String] = service
+                    }
+                    
+                    // Add access group if present
+                    if let accessGroup = item[kSecAttrAccessGroup as String] as? String,
+                       !accessGroup.isEmpty && accessGroup != "test" {
+                        deleteQuery[kSecAttrAccessGroup as String] = accessGroup
+                    }
+                    
+                    let deleteStatus = SecItemDelete(deleteQuery as CFDictionary)
+                    if deleteStatus == errSecSuccess {
+                        totalDeleted += 1
+                    }
+                }
+            }
+        }
+        
+        // Also try to delete by known service names (in case we missed any)
+        let knownServices = [
+            "chat.bitchat",
+            "com.bitchat.passwords",
+            "com.bitchat.deviceidentity", 
+            "com.bitchat.noise.identity",
+            "chat.bitchat.passwords",
+            "bitchat.keychain",
+            "bitchat",
+            "com.bitchat"
+        ]
+        
+        for serviceName in knownServices {
+            let query: [String: Any] = [
+                kSecClass as String: kSecClassGenericPassword,
+                kSecAttrService as String: serviceName
+            ]
+            
+            let status = SecItemDelete(query as CFDictionary)
+            if status == errSecSuccess {
+                totalDeleted += 1
+            }
+        }
+        
+        
+        return totalDeleted > 0
+    }
+    
+    // MARK: - Debug
+    
+    func verifyIdentityKeyExists() -> Bool {
+        let key = "identity_noiseStaticKey"
+        return retrieveData(forKey: key) != nil
+    }
+    
+    // Aggressive cleanup for legacy items - can be called manually
+    func aggressiveCleanupLegacyItems() -> Int {
+        var deletedCount = 0
+        
+        // List of KNOWN bitchat service names from our development history
+        let knownBitchatServices = [
+            "com.bitchat.passwords",
+            "com.bitchat.deviceidentity",
+            "com.bitchat.noise.identity",
+            "chat.bitchat.passwords",
+            "bitchat.keychain",
+            "Bitchat",
+            "BitChat"
+        ]
+        
+        // First, delete all items from known legacy services
+        for legacyService in knownBitchatServices {
+            let deleteQuery: [String: Any] = [
+                kSecClass as String: kSecClassGenericPassword,
+                kSecAttrService as String: legacyService
+            ]
+            
+            let status = SecItemDelete(deleteQuery as CFDictionary)
+            if status == errSecSuccess {
+                deletedCount += 1
+            }
+        }
+        
+        // Now search for items that have our specific account patterns with bitchat service names
+        let searchQuery: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecMatchLimit as String: kSecMatchLimitAll,
+            kSecReturnAttributes as String: true
+        ]
+        
+        var result: AnyObject?
+        let status = SecItemCopyMatching(searchQuery as CFDictionary, &result)
+        
+        if status == errSecSuccess, let items = result as? [[String: Any]] {
+            for item in items {
+                let account = item[kSecAttrAccount as String] as? String ?? ""
+                let service = item[kSecAttrService as String] as? String ?? ""
+                
+                // ONLY delete if service name contains "bitchat" somewhere
+                // This ensures we never touch other apps' keychain items
+                var shouldDelete = false
+                
+                // Check if service contains "bitchat" (case insensitive) but NOT our current service
+                let serviceLower = service.lowercased()
+                if service != self.service && serviceLower.contains("bitchat") {
+                    shouldDelete = true
+                }
+                
+                if shouldDelete {
+                    // Build precise delete query
+                    let deleteQuery: [String: Any] = [
+                        kSecClass as String: kSecClassGenericPassword,
+                        kSecAttrService as String: service,
+                        kSecAttrAccount as String: account
+                    ]
+                    
+                    let deleteStatus = SecItemDelete(deleteQuery as CFDictionary)
+                    if deleteStatus == errSecSuccess {
+                        deletedCount += 1
+                    }
+                }
+            }
+        }
+        
+        return deletedCount
+    }
 }

bitchat/Services/MessageRetentionService.swift

@@ -30,24 +30,37 @@ class MessageRetentionService {
     private let encryptionKey: SymmetricKey
     
     private init() {
-        // Get documents directory
+        // Get documents directory with fallback to temp directory
-        guard let docsDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else {
+        if let docsDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first {
-            fatalError("Unable to access documents directory")
+            documentsDirectory = docsDir
+        } else {
+            // Fallback to temporary directory if documents directory is not accessible
+            documentsDirectory = FileManager.default.temporaryDirectory
+            SecurityLogger.log("Using temporary directory for message retention", 
+                             category: SecurityLogger.security, level: .warning)
         }
-        documentsDirectory = docsDir
         messagesDirectory = documentsDirectory.appendingPathComponent("Messages", isDirectory: true)
         
         // Create messages directory if it doesn't exist
         try? FileManager.default.createDirectory(at: messagesDirectory, withIntermediateDirectories: true)
         
         // Generate or retrieve encryption key from keychain
+        let loadedKey: SymmetricKey
+        
+        // Try to load from keychain
         if let keyData = KeychainManager.shared.getIdentityKey(forKey: "messageRetentionKey") {
-            encryptionKey = SymmetricKey(data: keyData)
+            loadedKey = SymmetricKey(data: keyData)
-        } else {
-            // Generate new key and store it
-            encryptionKey = SymmetricKey(size: .bits256)
-            _ = KeychainManager.shared.saveIdentityKey(encryptionKey.withUnsafeBytes { Data($0) }, forKey: "messageRetentionKey")
         }
+        // Generate new key if needed
+        else {
+            loadedKey = SymmetricKey(size: .bits256)
+            let keyData = loadedKey.withUnsafeBytes { Data($0) }
+            // Save to keychain
+            _ = KeychainManager.shared.saveIdentityKey(keyData, forKey: "messageRetentionKey")
+        }
+        
+        // Now assign the final value
+        self.encryptionKey = loadedKey
         
         // Clean up old messages on init
         cleanupOldMessages()

bitchat/Services/NoiseEncryptionService.swift

@@ -0,0 +1,417 @@
+//
+// NoiseEncryptionService.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import CryptoKit
+import os.log
+
+// MARK: - Noise Encryption Service
+
+class NoiseEncryptionService {
+    // Static identity key (persistent across sessions)
+    private let staticIdentityKey: Curve25519.KeyAgreement.PrivateKey
+    public let staticIdentityPublicKey: Curve25519.KeyAgreement.PublicKey
+    
+    // Session manager
+    private let sessionManager: NoiseSessionManager
+    
+    // Channel encryption
+    private let channelEncryption = NoiseChannelEncryption()
+    
+    // Peer fingerprints (SHA256 hash of static public key)
+    private var peerFingerprints: [String: String] = [:] // peerID -> fingerprint
+    private var fingerprintToPeerID: [String: String] = [:] // fingerprint -> peerID
+    
+    // Thread safety
+    private let serviceQueue = DispatchQueue(label: "chat.bitchat.noise.service", attributes: .concurrent)
+    
+    // Security components
+    private let rateLimiter = NoiseRateLimiter()
+    
+    // Session maintenance
+    private var rekeyTimer: Timer?
+    private let rekeyCheckInterval: TimeInterval = 60.0 // Check every minute
+    
+    // Callbacks
+    var onPeerAuthenticated: ((String, String) -> Void)? // peerID, fingerprint
+    var onHandshakeRequired: ((String) -> Void)? // peerID needs handshake
+    
+    init() {
+        // Load or create static identity key (ONLY from keychain)
+        let loadedKey: Curve25519.KeyAgreement.PrivateKey
+        
+        // Try to load from keychain
+        if let identityData = KeychainManager.shared.getIdentityKey(forKey: "noiseStaticKey"),
+           let key = try? Curve25519.KeyAgreement.PrivateKey(rawRepresentation: identityData) {
+            loadedKey = key
+        }
+        // If no identity exists, create new one
+        else {
+            loadedKey = Curve25519.KeyAgreement.PrivateKey()
+            let keyData = loadedKey.rawRepresentation
+            
+            // Save to keychain
+            _ = KeychainManager.shared.saveIdentityKey(keyData, forKey: "noiseStaticKey")
+        }
+        
+        // Now assign the final value
+        self.staticIdentityKey = loadedKey
+        self.staticIdentityPublicKey = staticIdentityKey.publicKey
+        
+        // Initialize session manager
+        self.sessionManager = NoiseSessionManager(localStaticKey: staticIdentityKey)
+        
+        // Set up session callbacks
+        sessionManager.onSessionEstablished = { [weak self] peerID, remoteStaticKey in
+            self?.handleSessionEstablished(peerID: peerID, remoteStaticKey: remoteStaticKey)
+        }
+        
+        // Start session maintenance timer
+        startRekeyTimer()
+    }
+    
+    // MARK: - Public Interface
+    
+    /// Get our static public key for sharing
+    func getStaticPublicKeyData() -> Data {
+        return staticIdentityPublicKey.rawRepresentation
+    }
+    
+    /// Get our identity fingerprint
+    func getIdentityFingerprint() -> String {
+        let hash = SHA256.hash(data: staticIdentityPublicKey.rawRepresentation)
+        return hash.map { String(format: "%02x", $0) }.joined()
+    }
+    
+    /// Get peer's public key data
+    func getPeerPublicKeyData(_ peerID: String) -> Data? {
+        return sessionManager.getRemoteStaticKey(for: peerID)?.rawRepresentation
+    }
+    
+    /// Clear persistent identity (for panic mode)
+    func clearPersistentIdentity() {
+        // Clear from keychain
+        _ = KeychainManager.shared.deleteIdentityKey(forKey: "noiseStaticKey")
+        // Stop rekey timer
+        stopRekeyTimer()
+    }
+    
+    /// Sign data with our static identity key
+    func signData(_ data: Data) -> Data? {
+        // For now, use HMAC with the private key as a simple signature
+        // This is not cryptographically ideal but works for identity binding
+        let key = SymmetricKey(data: staticIdentityKey.rawRepresentation)
+        let signature = HMAC<SHA256>.authenticationCode(for: data, using: key)
+        return Data(signature)
+    }
+    
+    /// Verify signature with a peer's public key
+    func verifySignature(_ signature: Data, for data: Data, publicKey: Data) -> Bool {
+        // For verification, we can't use the same HMAC approach since we don't have the private key
+        // For now, we'll skip signature verification but maintain the protocol structure
+        // In production, this should use proper Ed25519 signatures
+        return true  // Temporarily accept all signatures to fix the immediate issue
+    }
+    
+    // MARK: - Handshake Management
+    
+    /// Initiate a Noise handshake with a peer
+    func initiateHandshake(with peerID: String) throws -> Data {
+        
+        // Validate peer ID
+        guard NoiseSecurityValidator.validatePeerID(peerID) else {
+            throw NoiseSecurityError.invalidPeerID
+        }
+        
+        // Check rate limit
+        guard rateLimiter.allowHandshake(from: peerID) else {
+            throw NoiseSecurityError.rateLimitExceeded
+        }
+        
+        // Return raw handshake data without wrapper
+        // The Noise protocol handles its own message format
+        let handshakeData = try sessionManager.initiateHandshake(with: peerID)
+        return handshakeData
+    }
+    
+    /// Process an incoming handshake message
+    func processHandshakeMessage(from peerID: String, message: Data) throws -> Data? {
+        
+        // Validate peer ID
+        guard NoiseSecurityValidator.validatePeerID(peerID) else {
+            throw NoiseSecurityError.invalidPeerID
+        }
+        
+        // Validate message size
+        guard NoiseSecurityValidator.validateHandshakeMessageSize(message) else {
+            throw NoiseSecurityError.messageTooLarge
+        }
+        
+        // Check rate limit
+        guard rateLimiter.allowHandshake(from: peerID) else {
+            throw NoiseSecurityError.rateLimitExceeded
+        }
+        
+        // For handshakes, we process the raw data directly without NoiseMessage wrapper
+        // The Noise protocol handles its own message format
+        let responsePayload = try sessionManager.handleIncomingHandshake(from: peerID, message: message)
+        
+        
+        // Return raw response without wrapper
+        return responsePayload
+    }
+    
+    /// Check if we have an established session with a peer
+    func hasEstablishedSession(with peerID: String) -> Bool {
+        return sessionManager.getSession(for: peerID)?.isEstablished() ?? false
+    }
+    
+    // MARK: - Encryption/Decryption
+    
+    /// Encrypt data for a specific peer
+    func encrypt(_ data: Data, for peerID: String) throws -> Data {
+        // Validate message size
+        guard NoiseSecurityValidator.validateMessageSize(data) else {
+            throw NoiseSecurityError.messageTooLarge
+        }
+        
+        // Check rate limit
+        guard rateLimiter.allowMessage(from: peerID) else {
+            throw NoiseSecurityError.rateLimitExceeded
+        }
+        
+        // Check if we have an established session
+        guard hasEstablishedSession(with: peerID) else {
+            // Signal that handshake is needed
+            onHandshakeRequired?(peerID)
+            throw NoiseEncryptionError.handshakeRequired
+        }
+        
+        return try sessionManager.encrypt(data, for: peerID)
+    }
+    
+    /// Decrypt data from a specific peer
+    func decrypt(_ data: Data, from peerID: String) throws -> Data {
+        // Validate message size
+        guard NoiseSecurityValidator.validateMessageSize(data) else {
+            throw NoiseSecurityError.messageTooLarge
+        }
+        
+        // Check rate limit
+        guard rateLimiter.allowMessage(from: peerID) else {
+            throw NoiseSecurityError.rateLimitExceeded
+        }
+        
+        // Check if we have an established session
+        guard hasEstablishedSession(with: peerID) else {
+            throw NoiseEncryptionError.sessionNotEstablished
+        }
+        
+        return try sessionManager.decrypt(data, from: peerID)
+    }
+    
+    // MARK: - Peer Management
+    
+    /// Get fingerprint for a peer
+    func getPeerFingerprint(_ peerID: String) -> String? {
+        return serviceQueue.sync {
+            return peerFingerprints[peerID]
+        }
+    }
+    
+    /// Get peer ID for a fingerprint
+    func getPeerID(for fingerprint: String) -> String? {
+        return serviceQueue.sync {
+            return fingerprintToPeerID[fingerprint]
+        }
+    }
+    
+    /// Remove a peer session
+    func removePeer(_ peerID: String) {
+        sessionManager.removeSession(for: peerID)
+        
+        serviceQueue.sync(flags: .barrier) {
+            if let fingerprint = peerFingerprints[peerID] {
+                fingerprintToPeerID.removeValue(forKey: fingerprint)
+            }
+            peerFingerprints.removeValue(forKey: peerID)
+        }
+    }
+    
+    // MARK: - Private Helpers
+    
+    private func handleSessionEstablished(peerID: String, remoteStaticKey: Curve25519.KeyAgreement.PublicKey) {
+        // Calculate fingerprint
+        let fingerprint = calculateFingerprint(for: remoteStaticKey)
+        
+        // Store fingerprint mapping
+        serviceQueue.sync(flags: .barrier) {
+            peerFingerprints[peerID] = fingerprint
+            fingerprintToPeerID[fingerprint] = peerID
+        }
+        
+        // Log security event
+        SecurityLogger.logSecurityEvent(.handshakeCompleted(peerID: peerID))
+        
+        // Notify about authentication
+        onPeerAuthenticated?(peerID, fingerprint)
+    }
+    
+    private func calculateFingerprint(for publicKey: Curve25519.KeyAgreement.PublicKey) -> String {
+        let hash = SHA256.hash(data: publicKey.rawRepresentation)
+        return hash.map { String(format: "%02x", $0) }.joined()
+    }
+    
+    // MARK: - Channel Encryption
+    
+    /// Set password for a channel
+    func setChannelPassword(_ password: String, for channel: String) {
+        // Validate channel name
+        guard NoiseSecurityValidator.validateChannelName(channel) else {
+            return
+        }
+        
+        // Validate password is not empty
+        guard !password.isEmpty else {
+            return
+        }
+        
+        channelEncryption.setChannelPassword(password, for: channel)
+    }
+    
+    /// Load channel password from keychain
+    func loadChannelPassword(for channel: String) -> Bool {
+        return channelEncryption.loadChannelPassword(for: channel)
+    }
+    
+    /// Remove channel password
+    func removeChannelPassword(for channel: String) {
+        channelEncryption.removeChannelPassword(for: channel)
+    }
+    
+    /// Encrypt message for a channel
+    func encryptChannelMessage(_ message: String, for channel: String) throws -> Data {
+        return try channelEncryption.encryptChannelMessage(message, for: channel)
+    }
+    
+    /// Decrypt channel message
+    func decryptChannelMessage(_ encryptedData: Data, for channel: String) throws -> String {
+        return try channelEncryption.decryptChannelMessage(encryptedData, for: channel)
+    }
+    
+    /// Share channel password with a peer securely via Noise
+    func shareChannelPassword(_ password: String, channel: String, with peerID: String) throws -> Data? {
+        // Create channel key packet
+        guard let keyPacket = channelEncryption.createChannelKeyPacket(password: password, channel: channel) else {
+            return nil
+        }
+        
+        // Encrypt via Noise session
+        return try encrypt(keyPacket, for: peerID)
+    }
+    
+    /// Process received channel key via Noise
+    func processReceivedChannelKey(_ encryptedData: Data, from peerID: String) throws {
+        // Decrypt via Noise session
+        let decryptedData = try decrypt(encryptedData, from: peerID)
+        
+        // Process channel key packet
+        if let (channel, password) = channelEncryption.processChannelKeyPacket(decryptedData) {
+            setChannelPassword(password, for: channel)
+        }
+    }
+    
+    // MARK: - Session Maintenance
+    
+    private func startRekeyTimer() {
+        rekeyTimer = Timer.scheduledTimer(withTimeInterval: rekeyCheckInterval, repeats: true) { [weak self] _ in
+            self?.checkSessionsForRekey()
+        }
+    }
+    
+    private func stopRekeyTimer() {
+        rekeyTimer?.invalidate()
+        rekeyTimer = nil
+    }
+    
+    private func checkSessionsForRekey() {
+        let sessionsNeedingRekey = sessionManager.getSessionsNeedingRekey()
+        
+        for (peerID, needsRekey) in sessionsNeedingRekey where needsRekey {
+            
+            // Attempt to rekey the session
+            do {
+                try sessionManager.initiateRekey(for: peerID)
+                
+                // Signal that handshake is needed
+                onHandshakeRequired?(peerID)
+            } catch {
+                SecurityLogger.logError(error, context: "Failed to initiate rekey for peer", category: SecurityLogger.session)
+            }
+        }
+    }
+    
+    deinit {
+        stopRekeyTimer()
+    }
+}
+
+// MARK: - Protocol Message Types for Noise
+
+enum NoiseMessageType: UInt8 {
+    case handshakeInitiation = 0x10
+    case handshakeResponse = 0x11
+    case handshakeFinal = 0x12
+    case encryptedMessage = 0x13
+    case sessionRenegotiation = 0x14
+}
+
+// MARK: - Noise Message Wrapper
+
+struct NoiseMessage: Codable {
+    let type: UInt8
+    let sessionID: String  // Random ID for this handshake session
+    let payload: Data
+    
+    init(type: NoiseMessageType, sessionID: String, payload: Data) {
+        self.type = type.rawValue
+        self.sessionID = sessionID
+        self.payload = payload
+    }
+    
+    func encode() -> Data? {
+        do {
+            let encoded = try JSONEncoder().encode(self)
+            return encoded
+        } catch {
+            return nil
+        }
+    }
+    
+    static func decode(from data: Data) -> NoiseMessage? {
+        return try? JSONDecoder().decode(NoiseMessage.self, from: data)
+    }
+    
+    static func decodeWithError(from data: Data) -> NoiseMessage? {
+        do {
+            let decoded = try JSONDecoder().decode(NoiseMessage.self, from: data)
+            return decoded
+        } catch {
+            return nil
+        }
+    }
+}
+
+// MARK: - Errors
+
+enum NoiseEncryptionError: Error {
+    case handshakeRequired
+    case sessionNotEstablished
+    case invalidMessage
+    case handshakeFailed(Error)
+}

bitchat/Utils/LRUCache.swift

@@ -0,0 +1,171 @@
+//
+// LRUCache.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+/// Thread-safe LRU (Least Recently Used) cache implementation
+final class LRUCache<Key: Hashable, Value> {
+    private class Node {
+        var key: Key
+        var value: Value
+        var prev: Node?
+        var next: Node?
+        
+        init(key: Key, value: Value) {
+            self.key = key
+            self.value = value
+        }
+    }
+    
+    private let maxSize: Int
+    private var cache: [Key: Node] = [:]
+    private var head: Node?
+    private var tail: Node?
+    private let queue = DispatchQueue(label: "bitchat.lrucache", attributes: .concurrent)
+    
+    init(maxSize: Int) {
+        self.maxSize = maxSize
+    }
+    
+    func set(_ key: Key, value: Value) {
+        queue.sync(flags: .barrier) {
+            if let node = cache[key] {
+                // Update existing value and move to front
+                node.value = value
+                moveToFront(node)
+            } else {
+                // Add new node
+                let newNode = Node(key: key, value: value)
+                cache[key] = newNode
+                addToFront(newNode)
+                
+                // Remove oldest if over capacity
+                if cache.count > maxSize {
+                    if let tailNode = tail {
+                        removeNode(tailNode)
+                        cache.removeValue(forKey: tailNode.key)
+                    }
+                }
+            }
+        }
+    }
+    
+    func get(_ key: Key) -> Value? {
+        return queue.sync(flags: .barrier) {
+            guard let node = cache[key] else { return nil }
+            moveToFront(node)
+            return node.value
+        }
+    }
+    
+    func contains(_ key: Key) -> Bool {
+        return queue.sync {
+            return cache[key] != nil
+        }
+    }
+    
+    func remove(_ key: Key) {
+        queue.sync(flags: .barrier) {
+            if let node = cache[key] {
+                removeNode(node)
+                cache.removeValue(forKey: key)
+            }
+        }
+    }
+    
+    func removeAll() {
+        queue.sync(flags: .barrier) {
+            cache.removeAll()
+            head = nil
+            tail = nil
+        }
+    }
+    
+    var count: Int {
+        return queue.sync {
+            return cache.count
+        }
+    }
+    
+    var keys: [Key] {
+        return queue.sync {
+            return Array(cache.keys)
+        }
+    }
+    
+    // MARK: - Private Helpers
+    
+    private func addToFront(_ node: Node) {
+        node.next = head
+        node.prev = nil
+        
+        if let head = head {
+            head.prev = node
+        }
+        
+        head = node
+        
+        if tail == nil {
+            tail = node
+        }
+    }
+    
+    private func removeNode(_ node: Node) {
+        if let prev = node.prev {
+            prev.next = node.next
+        } else {
+            head = node.next
+        }
+        
+        if let next = node.next {
+            next.prev = node.prev
+        } else {
+            tail = node.prev
+        }
+        
+        node.prev = nil
+        node.next = nil
+    }
+    
+    private func moveToFront(_ node: Node) {
+        guard node !== head else { return }
+        removeNode(node)
+        addToFront(node)
+    }
+}
+
+// MARK: - Bounded Set
+
+/// Thread-safe set with maximum size using LRU eviction
+final class BoundedSet<Element: Hashable> {
+    private let cache: LRUCache<Element, Bool>
+    
+    init(maxSize: Int) {
+        self.cache = LRUCache(maxSize: maxSize)
+    }
+    
+    func insert(_ element: Element) {
+        cache.set(element, value: true)
+    }
+    
+    func contains(_ element: Element) -> Bool {
+        return cache.get(element) != nil
+    }
+    
+    func remove(_ element: Element) {
+        cache.remove(element)
+    }
+    
+    func removeAll() {
+        cache.removeAll()
+    }
+    
+    var count: Int {
+        return cache.count
+    }
+}

bitchat/Utils/NoiseTestingHelper.swift

@@ -0,0 +1,202 @@
+//
+// NoiseTestingHelper.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+// MARK: - Encryption Status Enum
+public enum EncryptionStatus {
+    case noiseVerified    // Noise + fingerprint verified
+    case noiseSecured     // Noise established
+    case noiseHandshaking // Noise in progress
+    case none             // No encryption
+    
+    var icon: String {
+        switch self {
+        case .noiseVerified:
+            return "checkmark.shield.fill"  // Verified secure
+        case .noiseSecured:
+            return "lock.fill"               // Secure
+        case .noiseHandshaking:
+            return "lock.rotation"           // In progress
+        // Legacy case removed
+        case .none:
+            return "lock.slash"              // Not secure
+        }
+    }
+    
+    var description: String {
+        switch self {
+        case .noiseVerified:
+            return "Verified Secure"
+        case .noiseSecured:
+            return "Secure (Noise)"
+        case .noiseHandshaking:
+            return "Securing..."
+        // Legacy case removed
+        case .none:
+            return "Not Encrypted"
+        }
+    }
+}
+
+// MARK: - Testing Helper for Noise Protocol Migration
+
+#if DEBUG
+class NoiseTestingHelper {
+    static let shared = NoiseTestingHelper()
+    
+    // Test Scenarios Checklist
+    struct TestScenario {
+        let name: String
+        let steps: [String]
+        var passed: Bool = false
+    }
+    
+    private var testScenarios: [TestScenario] = [
+        TestScenario(
+            name: "Basic Handshake",
+            steps: [
+                "1. Connect two devices via Bluetooth",
+                "2. Verify Noise handshake completes (check logs)",
+                "3. Confirm lock icon appears next to peer name",
+                "4. Send a message and verify delivery"
+            ]
+        ),
+        TestScenario(
+            name: "Legacy Fallback",
+            steps: [
+                "1. Connect old app version to new version",
+                "2. Verify legacy encryption still works",
+                "3. Check for warning icon (not fully secure)",
+                "4. Messages should still deliver"
+            ]
+        ),
+        TestScenario(
+            name: "Fingerprint Verification",
+            steps: [
+                "1. Long-press on peer name to see fingerprint",
+                "2. Compare fingerprints on both devices",
+                "3. Mark as verified",
+                "4. Check for verified checkmark"
+            ]
+        ),
+        TestScenario(
+            name: "Channel Encryption",
+            steps: [
+                "1. Create password-protected channel",
+                "2. Join from another device",
+                "3. Send messages to channel",
+                "4. Verify only members can decrypt"
+            ]
+        ),
+        TestScenario(
+            name: "Session Recovery",
+            steps: [
+                "1. Establish Noise session",
+                "2. Force quit app",
+                "3. Reopen and reconnect",
+                "4. Verify session re-establishes automatically"
+            ]
+        ),
+        TestScenario(
+            name: "Rate Limiting",
+            steps: [
+                "1. Send many messages rapidly",
+                "2. Verify rate limit kicks in after 100 msgs/sec",
+                "3. Wait and verify messaging resumes",
+                "4. Check no messages lost"
+            ]
+        ),
+        TestScenario(
+            name: "Panic Mode",
+            steps: [
+                "1. Establish sessions with peers",
+                "2. Trigger panic mode (shake device)",
+                "3. Verify all keys cleared",
+                "4. Check new identity generated on restart"
+            ]
+        )
+    ]
+    
+    // Debug logging for Noise events
+    func logNoiseEvent(_ event: String, details: Any? = nil) {
+        // Logging removed - keeping method signature for compatibility
+    }
+    
+    // Get encryption status for peer
+    func getEncryptionStatus(for peerID: String, noiseService: NoiseEncryptionService) -> EncryptionStatus {
+        if noiseService.hasEstablishedSession(with: peerID) {
+            // Check if fingerprint is verified
+            if let fingerprint = noiseService.getPeerFingerprint(peerID),
+               isFingerprinted(peerID: peerID, fingerprint: fingerprint) {
+                return .noiseVerified
+            }
+            return .noiseSecured
+        } else {
+            // Always use Noise - no legacy encryption
+            return .noiseHandshaking
+        }
+    }
+    
+    // Store verified fingerprints (in production, use Keychain)
+    private var verifiedFingerprints: [String: String] = [:]
+    
+    func verifyFingerprint(peerID: String, fingerprint: String) {
+        verifiedFingerprints[peerID] = fingerprint
+    }
+    
+    func isFingerprinted(peerID: String, fingerprint: String) -> Bool {
+        return verifiedFingerprints[peerID] == fingerprint
+    }
+    
+    // Format fingerprint for display
+    func formatFingerprint(_ fingerprint: String) -> String {
+        // Convert to uppercase and format into 2 lines (8 groups of 4 on each line)
+        let uppercased = fingerprint.uppercased()
+        var formatted = ""
+        
+        for (index, char) in uppercased.enumerated() {
+            // Add space every 4 characters (but not at the start)
+            if index > 0 && index % 4 == 0 {
+                // Add newline after 32 characters (8 groups of 4)
+                if index == 32 {
+                    formatted += "\n"
+                } else {
+                    formatted += " "
+                }
+            }
+            formatted += String(char)
+        }
+        
+        return formatted
+    }
+    
+    // Get test scenario checklist
+    func getTestChecklist() -> String {
+        var checklist = "NOISE PROTOCOL TEST CHECKLIST\n"
+        checklist += "=" .repeated(30) + "\n\n"
+        
+        for scenario in testScenarios {
+            checklist += "□ \(scenario.name)\n"
+            for step in scenario.steps {
+                checklist += "  \(step)\n"
+            }
+            checklist += "\n"
+        }
+        
+        return checklist
+    }
+}
+
+// String extension for repeating
+extension String {
+    func repeated(_ count: Int) -> String {
+        return String(repeating: self, count: count)
+    }
+}
+#endif

bitchat/Utils/SecurityLogger.swift

@@ -0,0 +1,196 @@
+//
+// SecurityLogger.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import os.log
+
+/// Centralized security-aware logging framework
+/// Provides safe logging that filters sensitive data and security events
+class SecurityLogger {
+    
+    // MARK: - Log Categories
+    
+    private static let subsystem = "chat.bitchat"
+    
+    static let noise = OSLog(subsystem: subsystem, category: "noise")
+    static let encryption = OSLog(subsystem: subsystem, category: "encryption")
+    static let keychain = OSLog(subsystem: subsystem, category: "keychain")
+    static let session = OSLog(subsystem: subsystem, category: "session")
+    static let security = OSLog(subsystem: subsystem, category: "security")
+    
+    // MARK: - Log Levels
+    
+    enum LogLevel {
+        case debug
+        case info
+        case warning
+        case error
+        case fault
+        
+        var osLogType: OSLogType {
+            switch self {
+            case .debug: return .debug
+            case .info: return .info
+            case .warning: return .default
+            case .error: return .error
+            case .fault: return .fault
+            }
+        }
+    }
+    
+    // MARK: - Security Event Types
+    
+    enum SecurityEvent {
+        case handshakeStarted(peerID: String)
+        case handshakeCompleted(peerID: String)
+        case handshakeFailed(peerID: String, error: String)
+        case sessionExpired(peerID: String)
+        case keyRotation(channel: String)
+        case invalidKey(reason: String)
+        case replayAttackDetected(channel: String)
+        case authenticationFailed(peerID: String)
+        
+        var message: String {
+            switch self {
+            case .handshakeStarted(let peerID):
+                return "Handshake started with peer: \(sanitize(peerID))"
+            case .handshakeCompleted(let peerID):
+                return "Handshake completed with peer: \(sanitize(peerID))"
+            case .handshakeFailed(let peerID, let error):
+                return "Handshake failed with peer: \(sanitize(peerID)), error: \(error)"
+            case .sessionExpired(let peerID):
+                return "Session expired for peer: \(sanitize(peerID))"
+            case .keyRotation(let channel):
+                return "Key rotation performed for channel: \(sanitize(channel))"
+            case .invalidKey(let reason):
+                return "Invalid key detected: \(reason)"
+            case .replayAttackDetected(let channel):
+                return "Replay attack detected on channel: \(sanitize(channel))"
+            case .authenticationFailed(let peerID):
+                return "Authentication failed for peer: \(sanitize(peerID))"
+            }
+        }
+    }
+    
+    // MARK: - Public Logging Methods
+    
+    /// Log a security event
+    static func logSecurityEvent(_ event: SecurityEvent, level: LogLevel = .info) {
+        #if DEBUG
+        os_log("%{public}@", log: security, type: level.osLogType, event.message)
+        #else
+        // In release, use private logging to prevent sensitive data exposure
+        os_log("%{private}@", log: security, type: level.osLogType, event.message)
+        #endif
+    }
+    
+    /// Log general messages with automatic sensitive data filtering
+    static func log(_ message: String, category: OSLog = noise, level: LogLevel = .debug) {
+        let sanitized = sanitize(message)
+        
+        #if DEBUG
+        os_log("%{public}@", log: category, type: level.osLogType, sanitized)
+        #else
+        // In release builds, only log non-debug messages
+        if level != .debug {
+            os_log("%{private}@", log: category, type: level.osLogType, sanitized)
+        }
+        #endif
+    }
+    
+    /// Log errors with context
+    static func logError(_ error: Error, context: String, category: OSLog = noise) {
+        let sanitized = sanitize(context)
+        let errorDesc = sanitize(error.localizedDescription)
+        
+        #if DEBUG
+        os_log("Error in %{public}@: %{public}@", log: category, type: .error, sanitized, errorDesc)
+        #else
+        os_log("Error in %{private}@: %{private}@", log: category, type: .error, sanitized, errorDesc)
+        #endif
+    }
+    
+    // MARK: - Private Helpers
+    
+    /// Sanitize strings to remove potentially sensitive data
+    private static func sanitize(_ input: String) -> String {
+        var sanitized = input
+        
+        // Remove full fingerprints (keep first 8 chars for debugging)
+        let fingerprintPattern = #/[a-fA-F0-9]{64}/#
+        sanitized = sanitized.replacing(fingerprintPattern) { match in
+            let fingerprint = String(match.output)
+            return String(fingerprint.prefix(8)) + "..."
+        }
+        
+        // Remove base64 encoded data that might be keys
+        let base64Pattern = #/[A-Za-z0-9+/]{40,}={0,2}/#
+        sanitized = sanitized.replacing(base64Pattern) { _ in
+            "<base64-data>"
+        }
+        
+        // Remove potential passwords (assuming they're in quotes or after "password:")
+        let passwordPattern = #/password["\s:=]+["']?[^"'\s]+["']?/#
+        sanitized = sanitized.replacing(passwordPattern) { _ in
+            "password: <redacted>"
+        }
+        
+        // Truncate peer IDs to first 8 characters
+        let peerIDPattern = #/peerID: ([a-zA-Z0-9]{8})[a-zA-Z0-9]+/#
+        sanitized = sanitized.replacing(peerIDPattern) { match in
+            "peerID: \(match.1)..."
+        }
+        
+        return sanitized
+    }
+    
+    /// Sanitize individual values
+    private static func sanitize<T>(_ value: T) -> String {
+        let stringValue = String(describing: value)
+        return sanitize(stringValue)
+    }
+}
+
+// MARK: - Convenience Extensions
+
+extension SecurityLogger {
+    
+    /// Log handshake events
+    static func logHandshake(_ phase: String, peerID: String, success: Bool = true) {
+        if success {
+            log("Handshake \(phase) with peer: \(peerID)", category: session, level: .info)
+        } else {
+            log("Handshake \(phase) failed with peer: \(peerID)", category: session, level: .warning)
+        }
+    }
+    
+    /// Log encryption operations
+    static func logEncryption(_ operation: String, success: Bool = true) {
+        let level: LogLevel = success ? .debug : .error
+        log("Encryption operation '\(operation)' \(success ? "succeeded" : "failed")", 
+            category: encryption, level: level)
+    }
+    
+    /// Log key management operations
+    static func logKeyOperation(_ operation: String, keyType: String, success: Bool = true) {
+        let level: LogLevel = success ? .info : .error
+        log("Key operation '\(operation)' for \(keyType) \(success ? "succeeded" : "failed")", 
+            category: keychain, level: level)
+    }
+}
+
+// MARK: - Migration Helper
+
+/// Helper to migrate from print statements to SecurityLogger
+/// Usage: Replace print(...) with secureLog(...)
+func secureLog(_ items: Any..., separator: String = " ", terminator: String = "\n") {
+    #if DEBUG
+    let message = items.map { String(describing: $0) }.joined(separator: separator)
+    SecurityLogger.log(message, level: .debug)
+    #endif
+}

bitchat/Views/AppInfoView.swift

@@ -22,7 +22,7 @@ struct AppInfoView: View {
             // Custom header for macOS
             HStack {
                 Spacer()
-                Button("Done") {
+                Button("DONE") {
                     dismiss()
                 }
                 .buttonStyle(.plain)
@@ -39,7 +39,7 @@ struct AppInfoView: View {
                             .font(.system(size: 32, weight: .bold, design: .monospaced))
                             .foregroundColor(textColor)
                         
-                        Text("secure mesh chat")
+                        Text("mesh sidegroupchat")
                             .font(.system(size: 16, design: .monospaced))
                             .foregroundColor(secondaryTextColor)
                     }
@@ -48,42 +48,42 @@ struct AppInfoView: View {
                     
                     // Features
                     VStack(alignment: .leading, spacing: 16) {
-                        SectionHeader("Features")
+                        SectionHeader("FEATURES")
                         
-                        FeatureRow(icon: "wifi.slash", title: "Offline Communication",
+                        FeatureRow(icon: "wifi.slash", title: "offline communication",
-                                  description: "Works without internet using Bluetooth mesh networking")
+                                  description: "works without internet using Bluetooth mesh networking")
                         
-                        FeatureRow(icon: "lock.shield", title: "End-to-End Encryption",
+                        FeatureRow(icon: "lock.shield", title: "end-to-end encryption",
-                                  description: "All messages encrypted with Curve25519 + AES-GCM")
+                                  description: "private messages encrypted with noise protocol")
                         
-                        FeatureRow(icon: "antenna.radiowaves.left.and.right", title: "Extended Range",
+                        FeatureRow(icon: "antenna.radiowaves.left.and.right", title: "extended range",
-                                  description: "Messages relay through peers, reaching 300m+")
+                                  description: "messages relay through peers, increasing the distance")
                         
-                        FeatureRow(icon: "star.fill", title: "Favorites System",
+                        FeatureRow(icon: "star.fill", title: "favorites",
-                                  description: "Store-and-forward messages for favorites indefinitely")
+                                  description: "store-and-forward messages for favorite people")
                         
-                        FeatureRow(icon: "at", title: "Mentions",
+                        FeatureRow(icon: "at", title: "mentions",
-                                  description: "Use @nickname to notify specific users")
+                                  description: "use @nickname to notify specific people")
                         
-                        FeatureRow(icon: "number", title: "Channels",
+                        FeatureRow(icon: "number", title: "channels",
-                                  description: "Create #channels for topic-based conversations")
+                                  description: "create #channels for topic-based conversations")
                         
-                        FeatureRow(icon: "lock.fill", title: "Password Channels",
+                        FeatureRow(icon: "lock.fill", title: "private channels",
-                                  description: "Secure channels with passwords and AES encryption")
+                                  description: "secure channels with passwords and noise encryption")
                     }
                     
                     // Privacy
                     VStack(alignment: .leading, spacing: 16) {
                         SectionHeader("Privacy")
                         
-                        FeatureRow(icon: "eye.slash", title: "No Tracking",
+                        FeatureRow(icon: "eye.slash", title: "no tracking",
-                                  description: "No servers, accounts, or data collection")
+                                  description: "no servers, accounts, or data collection")
                         
-                        FeatureRow(icon: "shuffle", title: "Ephemeral Identity",
+                        FeatureRow(icon: "shuffle", title: "ephemeral identity",
-                                  description: "New peer ID generated each session")
+                                  description: "new peer ID generated each session")
                         
-                        FeatureRow(icon: "hand.raised.fill", title: "Panic Mode",
+                        FeatureRow(icon: "hand.raised.fill", title: "panic mode",
-                                  description: "Triple-tap logo to instantly clear all data")
+                                  description: "triple-tap logo to instantly clear all data")
                     }
                     
                     // How to Use
@@ -91,12 +91,12 @@ struct AppInfoView: View {
                         SectionHeader("How to Use")
                         
                         VStack(alignment: .leading, spacing: 8) {
-                            Text("• Set your nickname in the header")
+                            Text("• set your nickname by tapping it")
-                            Text("• Swipe left or tap channel name for sidebar")
+                            Text("• swipe left for sidebar")
-                            Text("• Tap a peer to start a private chat")
+                            Text("• tap a peer to start a private chat")
-                            Text("• Use @nickname to mention someone")
+                            Text("• use @nickname to mention someone")
-                            Text("• Use #channelname to create/join channels")
+                            Text("• use #channelname to create/join channels")
-                            Text("• Triple-tap the logo for panic mode")
+                            Text("• triple-tap the logo for panic mode")
                         }
                         .font(.system(size: 14, design: .monospaced))
                         .foregroundColor(textColor)
@@ -127,14 +127,14 @@ struct AppInfoView: View {
                         SectionHeader("Technical Details")
                         
                         VStack(alignment: .leading, spacing: 8) {
-                            Text("Protocol: Custom binary over BLE")
+                            Text("protocol: custom binary over BLE")
-                            Text("Encryption: Curve25519 + AES-256-GCM")
+                            Text("encryption: noise protocol")
-                            Text("Range: ~100m direct, 300m+ with relay")
+                            Text("range: ~30m direct, 300m+ with relay")
-                            Text("Store & Forward: 12h for all, ∞ for favorites")
+                            Text("store & forward: 12h for all, ∞ for favorites")
-                            Text("Battery: Adaptive scanning based on level")
+                            Text("battery: Adaptive scanning based on level")
-                            Text("Platform: Universal (iOS, iPadOS, macOS)")
+                            Text("platform: Universal (iOS, iPadOS, macOS)")
-                            Text("Channels: Password-protected with key commitments")
+                            Text("channels: Password-protected with key commitments")
-                            Text("Storage: Keychain for passwords, encrypted retention")
+                            Text("storage: Keychain for passwords, encrypted retention")
                         }
                         .font(.system(size: 14, design: .monospaced))
                         .foregroundColor(textColor)
@@ -143,7 +143,7 @@ struct AppInfoView: View {
                     // Version
                     HStack {
                         Spacer()
-                        Text("Version 1.0.0")
+                        Text("VERSION 1.0.0")
                             .font(.system(size: 12, design: .monospaced))
                             .foregroundColor(secondaryTextColor)
                         Spacer()
@@ -165,7 +165,7 @@ struct AppInfoView: View {
                             .font(.system(size: 32, weight: .bold, design: .monospaced))
                             .foregroundColor(textColor)
                         
-                        Text("secure mesh chat")
+                        Text("mesh sidegroupchat")
                             .font(.system(size: 16, design: .monospaced))
                             .foregroundColor(secondaryTextColor)
                     }
@@ -176,40 +176,40 @@ struct AppInfoView: View {
                     VStack(alignment: .leading, spacing: 16) {
                         SectionHeader("Features")
                         
-                        FeatureRow(icon: "wifi.slash", title: "Offline Communication",
+                        FeatureRow(icon: "wifi.slash", title: "offline communication",
-                                  description: "Works without internet using Bluetooth mesh networking")
+                                  description: "works without internet using Bluetooth mesh networking")
                         
-                        FeatureRow(icon: "lock.shield", title: "End-to-End Encryption",
+                        FeatureRow(icon: "lock.shield", title: "end-to-end encryption",
-                                  description: "All messages encrypted with Curve25519 + AES-GCM")
+                                  description: "private messages and channels encrypted with noise protocol")
                         
                         FeatureRow(icon: "antenna.radiowaves.left.and.right", title: "Extended Range",
-                                  description: "Messages relay through peers, reaching 300m+")
+                                  description: "messages relay through peers, increasing the distance")
                         
-                        FeatureRow(icon: "star.fill", title: "Favorites System",
+                        FeatureRow(icon: "star.fill", title: "favorites",
-                                  description: "Store-and-forward messages for favorites indefinitely")
+                                  description: "store-and-forward messages for favorite people")
                         
-                        FeatureRow(icon: "at", title: "Mentions",
+                        FeatureRow(icon: "at", title: "mentions",
-                                  description: "Use @nickname to notify specific users")
+                                  description: "use @nickname to notify specific people")
                         
-                        FeatureRow(icon: "number", title: "Channels",
+                        FeatureRow(icon: "number", title: "channels",
-                                  description: "Create #channels for topic-based conversations")
+                                  description: "create #channels for topic-based conversations")
                         
-                        FeatureRow(icon: "lock.fill", title: "Password Channels",
+                        FeatureRow(icon: "lock.fill", title: "private channels",
-                                  description: "Secure channels with passwords and AES encryption")
+                                  description: "secure channels with passwords and noise encryption")
                     }
                     
                     // Privacy
                     VStack(alignment: .leading, spacing: 16) {
                         SectionHeader("Privacy")
                         
-                        FeatureRow(icon: "eye.slash", title: "No Tracking",
+                        FeatureRow(icon: "eye.slash", title: "no tracking",
-                                  description: "No servers, accounts, or data collection")
+                                  description: "no servers, accounts, or data collection")
                         
-                        FeatureRow(icon: "shuffle", title: "Ephemeral Identity",
+                        FeatureRow(icon: "shuffle", title: "ephemeral identity",
-                                  description: "New peer ID generated each session")
+                                  description: "new peer ID generated each session")
                         
-                        FeatureRow(icon: "hand.raised.fill", title: "Panic Mode",
+                        FeatureRow(icon: "hand.raised.fill", title: "panic mode",
-                                  description: "Triple-tap logo to instantly clear all data")
+                                  description: "triple-tap logo to instantly clear all data")
                     }
                     
                     // How to Use
@@ -217,12 +217,12 @@ struct AppInfoView: View {
                         SectionHeader("How to Use")
                         
                         VStack(alignment: .leading, spacing: 8) {
-                            Text("• Set your nickname in the header")
+                            Text("• set your nickname by tapping it")
-                            Text("• Swipe left or tap channel name for sidebar")
+                            Text("• swipe left for sidebar")
-                            Text("• Tap a peer to start a private chat")
+                            Text("• tap a peer to start a private chat")
-                            Text("• Use @nickname to mention someone")
+                            Text("• use @nickname to mention someone")
-                            Text("• Use #channelname to create/join channels")
+                            Text("• use #channelname to create/join channels")
-                            Text("• Triple-tap the logo for panic mode")
+                            Text("• triple-tap the logo for panic mode")
                         }
                         .font(.system(size: 14, design: .monospaced))
                         .foregroundColor(textColor)
@@ -253,14 +253,14 @@ struct AppInfoView: View {
                         SectionHeader("Technical Details")
                         
                         VStack(alignment: .leading, spacing: 8) {
-                            Text("Protocol: Custom binary over BLE")
+                            Text("protocol: custom binary over BLE")
-                            Text("Encryption: Curve25519 + AES-256-GCM")
+                            Text("encryption: noise protocol")
-                            Text("Range: ~100m direct, 300m+ with relay")
+                            Text("range: ~30m direct, 300m+ with relay")
-                            Text("Store & Forward: 12h for all, ∞ for favorites")
+                            Text("store & forward: 12h for all, ∞ for favorites")
-                            Text("Battery: Adaptive scanning based on level")
+                            Text("battery: adaptive scanning based on level")
-                            Text("Platform: Universal (iOS, iPadOS, macOS)")
+                            Text("platform: universal (iOS, iPadOS, macOS)")
-                            Text("Channels: Password-protected with key commitments")
+                            Text("channels: password-protected with key commitments")
-                            Text("Storage: Keychain for passwords, encrypted retention")
+                            Text("storage: keychain for passwords, encrypted retention")
                         }
                         .font(.system(size: 14, design: .monospaced))
                         .foregroundColor(textColor)
@@ -269,7 +269,7 @@ struct AppInfoView: View {
                     // Version
                     HStack {
                         Spacer()
-                        Text("Version 1.0.0")
+                        Text("VERSION 1.0.0")
                             .font(.system(size: 12, design: .monospaced))
                             .foregroundColor(secondaryTextColor)
                         Spacer()
@@ -282,7 +282,7 @@ struct AppInfoView: View {
             .navigationBarTitleDisplayMode(.inline)
             .toolbar {
                 ToolbarItem(placement: .navigationBarTrailing) {
-                    Button("Done") {
+                    Button("DONE") {
                         dismiss()
                     }
                     .foregroundColor(textColor)
@@ -352,4 +352,4 @@ struct FeatureRow: View {
 
 #Preview {
     AppInfoView()
-}
+}

bitchat/Views/ContentView.swift

@@ -120,6 +120,14 @@ struct ContentView: View {
         .sheet(isPresented: $showAppInfo) {
             AppInfoView()
         }
+        .sheet(isPresented: Binding(
+            get: { viewModel.showingFingerprintFor != nil },
+            set: { _ in viewModel.showingFingerprintFor = nil }
+        )) {
+            if let peerID = viewModel.showingFingerprintFor {
+                FingerprintView(viewModel: viewModel, peerID: peerID)
+            }
+        }
         .alert("Set Channel Password", isPresented: $showPasswordInput) {
             SecureField("Password", text: $passwordInput)
             Button("Cancel", role: .cancel) {
@@ -188,16 +196,27 @@ struct ContentView: View {
                 
                 Spacer()
                 
-                HStack(spacing: 6) {
+                Button(action: {
-                    Image(systemName: "lock.fill")
+                    viewModel.showFingerprint(for: privatePeerID)
-                        .font(.system(size: 14))
+                }) {
-                        .foregroundColor(Color.orange)
+                    HStack(spacing: 6) {
-                        .accessibilityLabel("Private chat with \(privatePeerNick)")
+                        // Dynamic encryption status icon
-                    Text("\(privatePeerNick)")
+                        let encryptionStatus = viewModel.getEncryptionStatus(for: privatePeerID)
-                        .font(.system(size: 16, weight: .medium, design: .monospaced))
+                        Image(systemName: encryptionStatus.icon)
-                        .foregroundColor(Color.orange)
+                            .font(.system(size: 14))
+                            .foregroundColor(encryptionStatus == .noiseVerified ? Color.green : 
+                                           encryptionStatus == .noiseSecured ? Color.orange :
+                                           Color.red)
+                            .accessibilityLabel("Encryption status: \(encryptionStatus == .noiseVerified ? "verified" : encryptionStatus == .noiseSecured ? "secured" : "not encrypted")")
+                        Text("\(privatePeerNick)")
+                            .font(.system(size: 16, weight: .medium, design: .monospaced))
+                            .foregroundColor(Color.orange)
+                    }
+                    .frame(maxWidth: .infinity)
+                    .accessibilityLabel("Private chat with \(privatePeerNick)")
+                    .accessibilityHint("Tap to view encryption fingerprint")
                 }
-                .frame(maxWidth: .infinity)
+                .buttonStyle(.plain)
                 
                 Spacer()
                 
@@ -236,16 +255,42 @@ struct ContentView: View {
                         sidebarDragOffset = 0
                     }
                 }) {
-                    HStack(spacing: 6) {
+                    HStack(spacing: 4) {
                         if viewModel.passwordProtectedChannels.contains(currentChannel) {
                             Image(systemName: "lock.fill")
                                 .font(.system(size: 14))
                                 .foregroundColor(Color.orange)
                                 .accessibilityLabel("Password protected channel")
                         }
-                        Text("channel: \(currentChannel)")
+                        
+                        Text(currentChannel)
                             .font(.system(size: 16, weight: .medium, design: .monospaced))
                             .foregroundColor(viewModel.passwordProtectedChannels.contains(currentChannel) ? Color.orange : Color.blue)
+                        
+                        // Verification status indicator after channel name
+                        if viewModel.passwordProtectedChannels.contains(currentChannel),
+                           let status = viewModel.channelVerificationStatus[currentChannel] {
+                            switch status {
+                            case .verifying:
+                                ProgressView()
+                                    .scaleEffect(0.5)
+                                    .frame(width: 12, height: 12)
+                            case .verified:
+                                Image(systemName: "checkmark.circle.fill")
+                                    .font(.system(size: 12))
+                                    .foregroundColor(Color.green)
+                            case .failed:
+                                Image(systemName: "xmark.circle.fill")
+                                    .font(.system(size: 12))
+                                    .foregroundColor(Color.red)
+                            case .unverified:
+                                Image(systemName: "questionmark.circle")
+                                    .font(.system(size: 12))
+                                    .foregroundColor(Color.gray)
+                                    .help("Password verification pending")
+                            }
+                        } else if viewModel.passwordProtectedChannels.contains(currentChannel) {
+                        }
                     }
                 }
                 .buttonStyle(.plain)
@@ -264,7 +309,7 @@ struct ContentView: View {
                     }
                     
                     // Save button - only for channel owner
-                    if viewModel.channelCreators[currentChannel] == viewModel.meshService.myPeerID {
+                    if viewModel.isChannelOwner(currentChannel) {
                         Button(action: {
                             viewModel.sendMessage("/save")
                         }) {
@@ -278,7 +323,7 @@ struct ContentView: View {
                     }
                     
                     // Password button for channel creator only
-                    if viewModel.channelCreators[currentChannel] == viewModel.meshService.myPeerID {
+                    if viewModel.isChannelOwner(currentChannel) {
                         Button(action: {
                             // Toggle password protection
                             if viewModel.passwordProtectedChannels.contains(currentChannel) {
@@ -301,9 +346,9 @@ struct ContentView: View {
                     Button(action: {
                         showLeaveChannelAlert = true
                     }) {
-                        Text("leave")
+                        Image(systemName: "xmark.circle")
-                            .font(.system(size: 12, design: .monospaced))
+                            .font(.system(size: 16))
-                            .foregroundColor(Color.red)
+                            .foregroundColor(Color.red.opacity(0.8))
                     }
                     .buttonStyle(.plain)
                     .alert("leave channel?", isPresented: $showLeaveChannelAlert) {
@@ -416,11 +461,10 @@ struct ContentView: View {
                     let messages: [BitchatMessage] = {
                         if let privatePeer = viewModel.selectedPrivateChatPeer {
                             let msgs = viewModel.getPrivateChatMessages(for: privatePeer)
-                            // Log what we're showing
-                            // Removed debug logging
                             return msgs
                         } else if let currentChannel = viewModel.currentChannel {
-                            return viewModel.getChannelMessages(currentChannel)
+                            let msgs = viewModel.getChannelMessages(currentChannel)
+                            return msgs
                         } else {
                             return viewModel.messages
                         }
@@ -466,7 +510,6 @@ struct ContentView: View {
                                     } else {
                                         // Check for plain URLs
                                         let urls = message.content.extractURLs()
-                                        let _ = urls.isEmpty ? nil : print("DEBUG: Found \(urls.count) plain URLs in message")
                                         ForEach(urls.prefix(3), id: \.url) { urlInfo in
                                             LinkPreviewView(url: urlInfo.url, title: nil)
                                                 .padding(.top, 4)
@@ -829,7 +872,7 @@ struct ContentView: View {
     private func channelControls(for channel: String) -> some View {
         HStack(spacing: 4) {
             // Password button for channel creator only
-            if viewModel.channelCreators[channel] == viewModel.meshService.myPeerID {
+            if viewModel.isChannelOwner(channel) {
                 Button(action: {
                     // Toggle password protection
                     if viewModel.passwordProtectedChannels.contains(channel) {
@@ -861,15 +904,9 @@ struct ContentView: View {
             Button(action: {
                 showLeaveChannelAlert = true
             }) {
-                Text("leave channel")
+                Image(systemName: "xmark.circle.fill")
-                    .font(.system(size: 10, design: .monospaced))
+                    .font(.system(size: 14))
-                    .foregroundColor(secondaryTextColor)
+                    .foregroundColor(Color.red.opacity(0.6))
-                    .padding(.horizontal, 8)
-                    .padding(.vertical, 2)
-                    .overlay(
-                        RoundedRectangle(cornerRadius: 4)
-                            .stroke(secondaryTextColor.opacity(0.5), lineWidth: 1)
-                    )
             }
             .buttonStyle(.plain)
             .alert("leave channel", isPresented: $showLeaveChannelAlert) {
@@ -982,13 +1019,13 @@ struct ContentView: View {
                                 return isFav1 // Favorites come first
                             }
                             
-                            let name1 = peerNicknames[peer1] ?? "person-\(peer1.prefix(4))"
+                            let name1 = peerNicknames[peer1] ?? "anon\(peer1.prefix(4))"
-                            let name2 = peerNicknames[peer2] ?? "person-\(peer2.prefix(4))"
+                            let name2 = peerNicknames[peer2] ?? "anon\(peer2.prefix(4))"
                             return name1 < name2
                         }
                         
                         ForEach(sortedPeers, id: \.self) { peerID in
-                            let displayName = peerID == myPeerID ? viewModel.nickname : (peerNicknames[peerID] ?? "person-\(peerID.prefix(4))")
+                            let displayName = peerID == myPeerID ? viewModel.nickname : (peerNicknames[peerID] ?? "anon\(peerID.prefix(4))")
                             let rssi = peerRSSI[peerID]?.intValue ?? -100
                             let isFavorite = viewModel.isFavorite(peerID: peerID)
                             let isMe = peerID == myPeerID
@@ -1012,17 +1049,16 @@ struct ContentView: View {
                                         .accessibilityLabel("Signal strength: \(rssi > -60 ? "excellent" : rssi > -70 ? "good" : rssi > -80 ? "fair" : "poor")")
                                 }
                                 
-                                // Favorite star (not for self)
+                                // Encryption status icon (between connection dot and name)
                                 if !isMe {
-                                    Button(action: {
+                                    let encryptionStatus = viewModel.getEncryptionStatus(for: peerID)
-                                        viewModel.toggleFavorite(peerID: peerID)
+                                    Image(systemName: encryptionStatus.icon)
-                                    }) {
+                                        .font(.system(size: 10))
-                                        Image(systemName: isFavorite ? "star.fill" : "star")
+                                        .foregroundColor(encryptionStatus == .noiseVerified ? Color.green : 
-                                            .font(.system(size: 12))
+                                                       encryptionStatus == .noiseSecured ? textColor :
-                                            .foregroundColor(isFavorite ? Color.yellow : secondaryTextColor)
+                                                       encryptionStatus == .noiseHandshaking ? Color.orange :
-                                    }
+                                                       Color.red)
-                                    .buttonStyle(.plain)
+                                        .accessibilityLabel("Encryption: \(encryptionStatus == .noiseVerified ? "verified" : encryptionStatus == .noiseSecured ? "secured" : encryptionStatus == .noiseHandshaking ? "establishing" : "none")")
-                                    .accessibilityLabel(isFavorite ? "Remove \(displayName) from favorites" : "Add \(displayName) to favorites")
                                 }
                                 
                                 // Peer name
@@ -1044,16 +1080,29 @@ struct ContentView: View {
                                             }
                                         }
                                     }) {
-                                        HStack {
+                                        Text(displayName)
-                                            Text(displayName)
+                                            .font(.system(size: 14, design: .monospaced))
-                                                .font(.system(size: 14, design: .monospaced))
+                                            .foregroundColor(peerNicknames[peerID] != nil ? textColor : secondaryTextColor)
-                                                .foregroundColor(peerNicknames[peerID] != nil ? textColor : secondaryTextColor)
-                                            
-                                            Spacer()
-                                        }
                                     }
                                     .buttonStyle(.plain)
                                     .disabled(peerNicknames[peerID] == nil)
+                                    .onTapGesture(count: 2) {
+                                        // Show fingerprint on double tap
+                                        viewModel.showFingerprint(for: peerID)
+                                    }
+                                    
+                                    Spacer()
+                                    
+                                    // Favorite star
+                                    Button(action: {
+                                        viewModel.toggleFavorite(peerID: peerID)
+                                    }) {
+                                        Image(systemName: isFavorite ? "star.fill" : "star")
+                                            .font(.system(size: 12))
+                                            .foregroundColor(isFavorite ? Color.yellow : secondaryTextColor)
+                                    }
+                                    .buttonStyle(.plain)
+                                    .accessibilityLabel(isFavorite ? "Remove \(displayName) from favorites" : "Add \(displayName) to favorites")
                                 }
                             }
                             .padding(.horizontal)

bitchat/Views/FingerprintView.swift

@@ -0,0 +1,204 @@
+//
+// FingerprintView.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import SwiftUI
+
+struct FingerprintView: View {
+    @ObservedObject var viewModel: ChatViewModel
+    let peerID: String
+    @Environment(\.dismiss) var dismiss
+    @Environment(\.colorScheme) var colorScheme
+    
+    private var textColor: Color {
+        colorScheme == .dark ? Color.green : Color(red: 0, green: 0.5, blue: 0)
+    }
+    
+    private var backgroundColor: Color {
+        colorScheme == .dark ? Color.black : Color.white
+    }
+    
+    var body: some View {
+        VStack(spacing: 20) {
+            // Header
+            HStack {
+                Text("SECURITY VERIFICATION")
+                    .font(.system(size: 16, weight: .bold, design: .monospaced))
+                    .foregroundColor(textColor)
+                
+                Spacer()
+                
+                Button("DONE") {
+                    dismiss()
+                }
+                .foregroundColor(textColor)
+            }
+            .padding()
+            
+            VStack(alignment: .leading, spacing: 16) {
+                // Peer info
+                let peerNickname = viewModel.meshService.getPeerNicknames()[peerID] ?? "Unknown"
+                let encryptionStatus = viewModel.getEncryptionStatus(for: peerID)
+                
+                HStack {
+                    Image(systemName: encryptionStatus.icon)
+                        .font(.system(size: 20))
+                        .foregroundColor(encryptionStatus == .noiseVerified ? Color.green : textColor)
+                    
+                    VStack(alignment: .leading, spacing: 4) {
+                        Text(peerNickname)
+                            .font(.system(size: 18, weight: .semibold, design: .monospaced))
+                            .foregroundColor(textColor)
+                        
+                        Text(encryptionStatus.description)
+                            .font(.system(size: 12, design: .monospaced))
+                            .foregroundColor(textColor.opacity(0.7))
+                    }
+                    
+                    Spacer()
+                }
+                .padding()
+                .background(Color.gray.opacity(0.1))
+                .cornerRadius(8)
+                
+                // Their fingerprint
+                VStack(alignment: .leading, spacing: 8) {
+                    Text("THEIR FINGERPRINT:")
+                        .font(.system(size: 12, weight: .bold, design: .monospaced))
+                        .foregroundColor(textColor.opacity(0.7))
+                    
+                    if let fingerprint = viewModel.getFingerprint(for: peerID) {
+                        Text(formatFingerprint(fingerprint))
+                            .font(.system(size: 14, design: .monospaced))
+                            .foregroundColor(textColor)
+                            .multilineTextAlignment(.leading)
+                            .lineLimit(nil)
+                            .fixedSize(horizontal: false, vertical: true)
+                            .padding()
+                            .frame(maxWidth: .infinity)
+                            .background(Color.gray.opacity(0.1))
+                            .cornerRadius(8)
+                            .contextMenu {
+                                Button("Copy") {
+                                    #if os(iOS)
+                                    UIPasteboard.general.string = fingerprint
+                                    #else
+                                    NSPasteboard.general.clearContents()
+                                    NSPasteboard.general.setString(fingerprint, forType: .string)
+                                    #endif
+                                }
+                            }
+                    } else {
+                        Text("not available - handshake in progress")
+                            .font(.system(size: 14, design: .monospaced))
+                            .foregroundColor(Color.orange)
+                            .padding()
+                    }
+                }
+                
+                // My fingerprint
+                VStack(alignment: .leading, spacing: 8) {
+                    Text("YOUR FINGERPRINT:")
+                        .font(.system(size: 12, weight: .bold, design: .monospaced))
+                        .foregroundColor(textColor.opacity(0.7))
+                    
+                    let myFingerprint = viewModel.getMyFingerprint()
+                    Text(formatFingerprint(myFingerprint))
+                        .font(.system(size: 14, design: .monospaced))
+                        .foregroundColor(textColor)
+                        .multilineTextAlignment(.leading)
+                        .lineLimit(nil)
+                        .fixedSize(horizontal: false, vertical: true)
+                        .padding()
+                        .frame(maxWidth: .infinity)
+                        .background(Color.gray.opacity(0.1))
+                        .cornerRadius(8)
+                        .contextMenu {
+                            Button("Copy") {
+                                #if os(iOS)
+                                UIPasteboard.general.string = myFingerprint
+                                #else
+                                NSPasteboard.general.clearContents()
+                                NSPasteboard.general.setString(myFingerprint, forType: .string)
+                                #endif
+                            }
+                        }
+                }
+                
+                // Verification status
+                if encryptionStatus == .noiseSecured || encryptionStatus == .noiseVerified {
+                    let isVerified = encryptionStatus == .noiseVerified
+                    
+                    VStack(spacing: 12) {
+                        Text(isVerified ? "✓ VERIFIED" : "⚠️ NOT VERIFIED")
+                            .font(.system(size: 14, weight: .bold, design: .monospaced))
+                            .foregroundColor(isVerified ? Color.green : Color.orange)
+                            .frame(maxWidth: .infinity)
+                        
+                        Text(isVerified ? 
+                             "you have verified this person's identity." :
+                             "compare these fingerprints with \(peerNickname) using a secure channel.")
+                            .font(.system(size: 12, design: .monospaced))
+                            .foregroundColor(textColor.opacity(0.7))
+                            .multilineTextAlignment(.center)
+                            .lineLimit(nil)
+                            .fixedSize(horizontal: false, vertical: true)
+                            .frame(maxWidth: .infinity)
+                        
+                        if !isVerified {
+                            Button(action: {
+                                viewModel.verifyFingerprint(for: peerID)
+                                dismiss()
+                            }) {
+                                Text("MARK AS VERIFIED")
+                                    .font(.system(size: 14, weight: .bold, design: .monospaced))
+                                    .foregroundColor(.white)
+                                    .padding(.horizontal, 20)
+                                    .padding(.vertical, 10)
+                                    .background(Color.green)
+                                    .cornerRadius(8)
+                            }
+                            .buttonStyle(PlainButtonStyle())
+                        }
+                    }
+                    .padding(.top)
+                    .frame(maxWidth: .infinity)
+                }
+            }
+            .padding()
+            .frame(maxWidth: 500) // Constrain max width for better readability
+            
+            Spacer()
+        }
+        .padding()
+        .frame(maxWidth: .infinity, maxHeight: .infinity)
+        .background(backgroundColor)
+        .presentationDetents([.large])
+        .presentationDragIndicator(.visible)
+    }
+    
+    private func formatFingerprint(_ fingerprint: String) -> String {
+        // Convert to uppercase and format into 4 lines (4 groups of 4 on each line)
+        let uppercased = fingerprint.uppercased()
+        var formatted = ""
+        
+        for (index, char) in uppercased.enumerated() {
+            // Add space every 4 characters (but not at the start)
+            if index > 0 && index % 4 == 0 {
+                // Add newline after every 16 characters (4 groups of 4)
+                if index % 16 == 0 {
+                    formatted += "\n"
+                } else {
+                    formatted += " "
+                }
+            }
+            formatted += String(char)
+        }
+        
+        return formatted
+    }
+}

bitchat/Views/NoiseTestingView.swift

@@ -0,0 +1,129 @@
+//
+// NoiseTestingView.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import SwiftUI
+
+#if DEBUG
+struct NoiseTestingView: View {
+    @ObservedObject var viewModel: ChatViewModel
+    @Environment(\.colorScheme) var colorScheme
+    @State private var testChecklist = NoiseTestingHelper.shared.getTestChecklist()
+    
+    private var textColor: Color {
+        colorScheme == .dark ? Color.green : Color(red: 0, green: 0.5, blue: 0)
+    }
+    
+    private var backgroundColor: Color {
+        colorScheme == .dark ? Color.black : Color.white
+    }
+    
+    var body: some View {
+        VStack(alignment: .leading, spacing: 16) {
+            // Header
+            Text("NOISE PROTOCOL TEST HELPER")
+                .font(.system(size: 16, weight: .bold, design: .monospaced))
+                .foregroundColor(textColor)
+                .padding(.bottom)
+            
+            // Status Overview
+            VStack(alignment: .leading, spacing: 8) {
+                Text("CURRENT STATUS:")
+                    .font(.system(size: 12, weight: .bold, design: .monospaced))
+                    .foregroundColor(textColor.opacity(0.7))
+                
+                ForEach(viewModel.connectedPeers, id: \.self) { peerID in
+                    let nickname = viewModel.meshService.getPeerNicknames()[peerID] ?? "Unknown"
+                    let status = viewModel.getEncryptionStatus(for: peerID)
+                    
+                    HStack {
+                        Image(systemName: status.icon)
+                            .font(.system(size: 12))
+                            .foregroundColor(status == .noiseVerified ? Color.green : 
+                                           status == .noiseSecured ? textColor :
+                                           Color.red)
+                        
+                        Text("\(nickname): \(status.description)")
+                            .font(.system(size: 12, design: .monospaced))
+                            .foregroundColor(textColor)
+                        
+                        Spacer()
+                    }
+                }
+                
+                if viewModel.connectedPeers.isEmpty {
+                    Text("No peers connected")
+                        .font(.system(size: 12, design: .monospaced))
+                        .foregroundColor(Color.gray)
+                }
+            }
+            .padding()
+            .background(Color.gray.opacity(0.1))
+            .cornerRadius(8)
+            
+            // Test Checklist
+            ScrollView {
+                Text(testChecklist)
+                    .font(.system(size: 11, design: .monospaced))
+                    .foregroundColor(textColor)
+                    .textSelection(.enabled)
+            }
+            .padding()
+            .background(Color.gray.opacity(0.1))
+            .cornerRadius(8)
+            
+            // Debug Actions
+            HStack(spacing: 16) {
+                Button("Force Handshake") {
+                    // Trigger handshake with all peers by sending a broadcast announce
+                    // This will cause all peers to re-exchange keys
+                    viewModel.meshService.sendBroadcastAnnounce()
+                }
+                .foregroundColor(textColor)
+                
+                Button("Clear Sessions") {
+                    // Clear all Noise sessions for testing
+                    let noiseService = viewModel.meshService.getNoiseService()
+                    for peerID in viewModel.connectedPeers {
+                        noiseService.removePeer(peerID)
+                    }
+                    viewModel.peerEncryptionStatus.removeAll()
+                }
+                .foregroundColor(Color.orange)
+                
+                Button("Copy Logs") {
+                    // Copy test results to clipboard
+                    var logs = "NOISE PROTOCOL TEST RESULTS\n"
+                    logs += "===========================\n\n"
+                    logs += "Timestamp: \(Date())\n"
+                    logs += "Connected Peers: \(viewModel.connectedPeers.count)\n\n"
+                    
+                    for peerID in viewModel.connectedPeers {
+                        let nickname = viewModel.meshService.getPeerNicknames()[peerID] ?? "Unknown"
+                        let status = viewModel.getEncryptionStatus(for: peerID)
+                        logs += "\(nickname) (\(peerID)): \(status.description)\n"
+                    }
+                    
+                    #if os(iOS)
+                    UIPasteboard.general.string = logs
+                    #else
+                    NSPasteboard.general.clearContents()
+                    NSPasteboard.general.setString(logs, forType: .string)
+                    #endif
+                }
+                .foregroundColor(textColor)
+                
+                
+                Spacer()
+            }
+        }
+        .padding()
+        .frame(width: 500, height: 600)
+        .background(backgroundColor)
+    }
+}
+#endif

bitchatShareExtension/ShareViewController.swift

@@ -40,11 +40,9 @@ class ShareViewController: SLComposeServiceViewController {
             return
         }
         
-        print("ShareExtension: Processing share with \(extensionItem.attachments?.count ?? 0) attachments")
         
         // Get the page title from the compose view or extension item
         let pageTitle = self.contentText ?? extensionItem.attributedContentText?.string ?? extensionItem.attributedTitle?.string
-        print("ShareExtension: Page title: \(pageTitle ?? "none")")
         
         var foundURL: URL? = nil
         let group = DispatchGroup()
@@ -52,20 +50,17 @@ class ShareViewController: SLComposeServiceViewController {
         // IMPORTANT: Check if the NSExtensionItem itself has a URL
         // Safari often provides the URL as an attributedString with a link
         if let attributedText = extensionItem.attributedContentText {
-            print("ShareExtension: Checking attributed text for URLs")
             let text = attributedText.string
             let detector = try? NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
             let matches = detector?.matches(in: text, options: [], range: NSRange(location: 0, length: text.utf16.count))
             if let firstMatch = matches?.first, let url = firstMatch.url {
-                print("ShareExtension: Found URL in attributed text: \(url.absoluteString)")
                 foundURL = url
             }
         }
         
         // Only check attachments if we haven't found a URL yet
         if foundURL == nil {
-            for (index, itemProvider) in (extensionItem.attachments ?? []).enumerated() {
+            for (_, itemProvider) in (extensionItem.attachments ?? []).enumerated() {
-                print("ShareExtension: Attachment \(index) types: \(itemProvider.registeredTypeIdentifiers)")
                 
                 // Try multiple URL type identifiers that Safari might use
                 let urlTypes = [
@@ -81,16 +76,13 @@ class ShareViewController: SLComposeServiceViewController {
                             defer { group.leave() }
                             
                             if let url = item as? URL {
-                                print("ShareExtension: Found URL: \(url.absoluteString)")
                                 foundURL = url
                         } else if let data = item as? Data,
                                   let urlString = String(data: data, encoding: .utf8),
                                   let url = URL(string: urlString) {
-                            print("ShareExtension: Found URL from data: \(url.absoluteString)")
                             foundURL = url
                         } else if let string = item as? String,
                                   let url = URL(string: string) {
-                            print("ShareExtension: Found URL from string: \(url.absoluteString)")
                             foundURL = url
                         }
                     }
@@ -108,7 +100,6 @@ class ShareViewController: SLComposeServiceViewController {
                         // Check if the text is actually a URL
                         if let url = URL(string: text),
                            (url.scheme == "http" || url.scheme == "https") {
-                            print("ShareExtension: Found URL in plain text: \(url.absoluteString)")
                             foundURL = url
                         }
                     }
@@ -126,7 +117,6 @@ class ShareViewController: SLComposeServiceViewController {
                     "title": pageTitle ?? url.host ?? "Shared Link"
                 ]
                 
-                print("ShareExtension: Saving URL share - url: \(url.absoluteString), title: \(urlData["title"] ?? "")")
                 
                 if let jsonData = try? JSONSerialization.data(withJSONObject: urlData),
                    let jsonString = String(data: jsonData, encoding: .utf8) {
@@ -134,7 +124,6 @@ class ShareViewController: SLComposeServiceViewController {
                 }
             } else if let title = pageTitle, !title.isEmpty {
                 // No URL found, just share the text
-                print("ShareExtension: No URL found, sharing as text: \(title)")
                 self?.saveToSharedDefaults(content: title, type: "text")
             }
             
@@ -190,7 +179,6 @@ class ShareViewController: SLComposeServiceViewController {
     private func saveToSharedDefaults(content: String, type: String) {
         // Use app groups to share data between extension and main app
         guard let userDefaults = UserDefaults(suiteName: "group.chat.bitchat") else {
-            print("ShareExtension: Failed to access app group UserDefaults")
             return
         }
         
@@ -199,8 +187,6 @@ class ShareViewController: SLComposeServiceViewController {
         userDefaults.set(Date(), forKey: "sharedContentDate")
         userDefaults.synchronize()
         
-        print("ShareExtension: Saved content of type \(type) to shared defaults")
-        print("ShareExtension: Content: \(content)")
         
         // Force open the main app
         self.openMainApp()

bitchatTests/BitchatMessageTests.swift

@@ -198,4 +198,45 @@ class BitchatMessageTests: XCTestCase {
         
         XCTAssertEqual(decoded.content, longContent)
     }
+    
+    func testPrivateMessageWithAllFieldsForNoise() {
+        // Test that private messages with ID field (used by Noise) are encoded/decoded correctly
+        let messageID = UUID().uuidString
+        let privateMessage = BitchatMessage(
+            id: messageID,
+            sender: "alice",
+            content: "Hello Bob, this is a private message via Noise",
+            timestamp: Date(),
+            isRelay: false,
+            originalSender: nil,
+            isPrivate: true,
+            recipientNickname: "bob",
+            senderPeerID: "alice-peer-id-123",
+            mentions: nil,
+            channel: nil
+        )
+        
+        // Encode to binary payload (as used by Noise encryption)
+        guard let encoded = privateMessage.toBinaryPayload() else {
+            XCTFail("Failed to encode private message with ID to binary payload")
+            return
+        }
+        
+        // Decode from binary payload (as received from Noise decryption)
+        guard let decoded = BitchatMessage.fromBinaryPayload(encoded) else {
+            XCTFail("Failed to decode private message with ID from binary payload")
+            return
+        }
+        
+        // Verify all fields match
+        XCTAssertEqual(decoded.id, messageID)
+        XCTAssertEqual(decoded.sender, "alice")
+        XCTAssertEqual(decoded.content, "Hello Bob, this is a private message via Noise")
+        XCTAssertEqual(decoded.isPrivate, true)
+        XCTAssertEqual(decoded.recipientNickname, "bob")
+        XCTAssertEqual(decoded.senderPeerID, "alice-peer-id-123")
+        XCTAssertNil(decoded.channel)
+        XCTAssertFalse(decoded.isRelay)
+        XCTAssertNil(decoded.originalSender)
+    }
 }

bitchatTests/ChannelVerificationTests.swift

@@ -0,0 +1,203 @@
+//
+// ChannelVerificationTests.swift
+// bitchatTests
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import XCTest
+import CryptoKit
+@testable import bitchat
+
+class ChannelVerificationTests: XCTestCase {
+    
+    var viewModel: ChatViewModel!
+    var mockMeshService: MockBluetoothMeshService!
+    
+    override func setUp() {
+        super.setUp()
+        viewModel = ChatViewModel()
+        mockMeshService = MockBluetoothMeshService()
+        viewModel.meshService = mockMeshService
+    }
+    
+    override func tearDown() {
+        viewModel = nil
+        mockMeshService = nil
+        super.tearDown()
+    }
+    
+    // MARK: - Key Derivation Tests
+    
+    func testChannelKeyDerivation() {
+        let password = "testPassword123"
+        let channel = "#testchannel"
+        
+        // Derive key twice with same inputs
+        let key1 = viewModel.deriveChannelKey(from: password, channelName: channel)
+        let key2 = viewModel.deriveChannelKey(from: password, channelName: channel)
+        
+        // Keys should be identical for same password/channel
+        XCTAssertEqual(key1.withUnsafeBytes { Data($0) }, 
+                      key2.withUnsafeBytes { Data($0) })
+    }
+    
+    func testDifferentPasswordsProduceDifferentKeys() {
+        let channel = "#testchannel"
+        let password1 = "password123"
+        let password2 = "password456"
+        
+        let key1 = viewModel.deriveChannelKey(from: password1, channelName: channel)
+        let key2 = viewModel.deriveChannelKey(from: password2, channelName: channel)
+        
+        // Different passwords should produce different keys
+        XCTAssertNotEqual(key1.withUnsafeBytes { Data($0) }, 
+                         key2.withUnsafeBytes { Data($0) })
+    }
+    
+    func testKeyCommitmentComputation() {
+        let password = "testPassword"
+        let channel = "#test"
+        
+        let key = viewModel.deriveChannelKey(from: password, channelName: channel)
+        let commitment1 = viewModel.computeKeyCommitment(for: key)
+        let commitment2 = viewModel.computeKeyCommitment(for: key)
+        
+        // Same key should produce same commitment
+        XCTAssertEqual(commitment1, commitment2)
+        
+        // Commitment should be 64 characters (SHA256 hex)
+        XCTAssertEqual(commitment1.count, 64)
+    }
+    
+    // MARK: - Verification Request/Response Tests
+    
+    func testChannelKeyVerifyRequestHandling() {
+        // Setup
+        let channel = "#test"
+        let password = "secret123"
+        let peerID = "peer123"
+        
+        // Join channel with password
+        _ = viewModel.joinChannel(channel, password: password)
+        
+        // Create verification request with matching key
+        let key = viewModel.deriveChannelKey(from: password, channelName: channel)
+        let commitment = viewModel.computeKeyCommitment(for: key)
+        
+        let request = ChannelKeyVerifyRequest(
+            channel: channel,
+            requesterID: peerID,
+            keyCommitment: commitment
+        )
+        
+        // Handle request
+        viewModel.didReceiveChannelKeyVerifyRequest(request, from: peerID)
+        
+        // Should have sent a positive response
+        XCTAssertTrue(mockMeshService.sentVerifyResponse)
+        XCTAssertTrue(mockMeshService.lastVerifyResponse?.verified ?? false)
+    }
+    
+    func testChannelKeyVerifyResponseHandling() {
+        // Setup
+        let channel = "#test"
+        let peerID = "peer123"
+        
+        // Set initial verification status
+        viewModel.channelVerificationStatus[channel] = .verifying
+        viewModel.joinedChannels.insert(channel)
+        
+        // Create positive response
+        let response = ChannelKeyVerifyResponse(
+            channel: channel,
+            responderID: peerID,
+            verified: true
+        )
+        
+        // Handle response
+        viewModel.didReceiveChannelKeyVerifyResponse(response, from: peerID)
+        
+        // Status should be verified
+        XCTAssertEqual(viewModel.channelVerificationStatus[channel], .verified)
+    }
+    
+    func testFailedVerificationResponse() {
+        // Setup
+        let channel = "#test"
+        let peerID = "peer123"
+        
+        viewModel.channelVerificationStatus[channel] = .verifying
+        viewModel.joinedChannels.insert(channel)
+        
+        // Create negative response
+        let response = ChannelKeyVerifyResponse(
+            channel: channel,
+            responderID: peerID,
+            verified: false
+        )
+        
+        // Handle response
+        viewModel.didReceiveChannelKeyVerifyResponse(response, from: peerID)
+        
+        // Status should be failed
+        XCTAssertEqual(viewModel.channelVerificationStatus[channel], .failed)
+    }
+    
+    // MARK: - Password Update Tests
+    
+    func testChannelPasswordUpdateHandling() {
+        // Setup
+        let channel = "#test"
+        let ownerID = "owner123"
+        let newPassword = "newSecret456"
+        
+        // Join channel first
+        viewModel.joinedChannels.insert(channel)
+        viewModel.channelCreators[channel] = ownerID
+        
+        // Simulate having a Noise session
+        mockMeshService.mockNoiseSessionEstablished = true
+        
+        // Create password update
+        let newKey = viewModel.deriveChannelKey(from: newPassword, channelName: channel)
+        let newCommitment = viewModel.computeKeyCommitment(for: newKey)
+        
+        let update = ChannelPasswordUpdate(
+            channel: channel,
+            ownerID: ownerID,
+            encryptedPassword: Data(), // Would be encrypted in real scenario
+            newKeyCommitment: newCommitment
+        )
+        
+        // Mock decryption to return new password
+        mockMeshService.mockDecryptedPassword = newPassword
+        
+        // Handle update
+        viewModel.didReceiveChannelPasswordUpdate(update, from: ownerID)
+        
+        // Should have updated local key
+        XCTAssertNotNil(viewModel.channelKeys[channel])
+        XCTAssertEqual(viewModel.channelKeyCommitments[channel], newCommitment)
+    }
+}
+
+// MARK: - Mock Mesh Service
+
+class MockBluetoothMeshService: BluetoothMeshService {
+    var sentVerifyResponse = false
+    var lastVerifyResponse: ChannelKeyVerifyResponse?
+    var mockNoiseSessionEstablished = false
+    var mockDecryptedPassword: String?
+    
+    override func sendChannelKeyVerifyResponse(_ response: ChannelKeyVerifyResponse, to peerID: String) {
+        sentVerifyResponse = true
+        lastVerifyResponse = response
+    }
+    
+    override func getNoiseService() -> NoiseEncryptionService {
+        // Return actual noise service - tests should use real crypto
+        return super.getNoiseService()
+    }
+}

bitchatTests/KeychainIntegrationTests.swift

@@ -0,0 +1,185 @@
+//
+// KeychainIntegrationTests.swift
+// bitchatTests
+//
+// Integration tests for keychain functionality
+//
+
+import XCTest
+@testable import bitchat
+
+class KeychainIntegrationTests: XCTestCase {
+    
+    override func setUp() {
+        super.setUp()
+        // Start with clean state
+        _ = KeychainManager.shared.deleteAllKeychainData()
+    }
+    
+    override func tearDown() {
+        // Clean up test data
+        _ = KeychainManager.shared.deleteAllKeychainData()
+        super.tearDown()
+    }
+    
+    // MARK: - App Lifecycle Simulation Tests
+    
+    func testCompleteAppLifecycle() {
+        print("\n🧪 Testing Complete App Lifecycle")
+        
+        // 1. First app launch - create identity
+        print("1️⃣ First launch...")
+        let service1 = NoiseEncryptionService()
+        let fingerprint1 = service1.getIdentityFingerprint()
+        print("   Initial fingerprint: \(fingerprint1)")
+        
+        // Verify stored in keychain
+        let keychainData1 = KeychainManager.shared.getIdentityKey(forKey: "noiseStaticKey")
+        XCTAssertNotNil(keychainData1, "Identity should be in keychain after first launch")
+        
+        // 2. App goes to background and comes back
+        print("2️⃣ Background/foreground cycle...")
+        let service2 = NoiseEncryptionService()
+        let fingerprint2 = service2.getIdentityFingerprint()
+        XCTAssertEqual(fingerprint1, fingerprint2, "Identity should persist through background")
+        
+        // 3. App terminates and relaunches
+        print("3️⃣ Terminate and relaunch...")
+        // In real app this would be a new process
+        let service3 = NoiseEncryptionService()
+        let fingerprint3 = service3.getIdentityFingerprint()
+        XCTAssertEqual(fingerprint1, fingerprint3, "Identity should persist through termination")
+        
+        // 4. User triggers panic mode
+        print("4️⃣ Panic mode triggered...")
+        service3.clearPersistentIdentity()
+        
+        // 5. App creates new identity
+        print("5️⃣ New identity after panic...")
+        let service4 = NoiseEncryptionService()
+        let fingerprint4 = service4.getIdentityFingerprint()
+        XCTAssertNotEqual(fingerprint1, fingerprint4, "New identity should be created after panic")
+        print("   New fingerprint: \(fingerprint4)")
+        
+        print("✅ Lifecycle test complete\n")
+    }
+    
+    // MARK: - Channel Password Tests
+    
+    func testChannelPasswordPersistence() {
+        let channel1 = "#testchannel1"
+        let channel2 = "#testchannel2"
+        let password1 = "password123"
+        let password2 = "differentpass456"
+        
+        // Save passwords
+        XCTAssertTrue(KeychainManager.shared.saveChannelPassword(password1, for: channel1))
+        XCTAssertTrue(KeychainManager.shared.saveChannelPassword(password2, for: channel2))
+        
+        // Retrieve passwords
+        XCTAssertEqual(KeychainManager.shared.getChannelPassword(for: channel1), password1)
+        XCTAssertEqual(KeychainManager.shared.getChannelPassword(for: channel2), password2)
+        
+        // Test getAllChannelPasswords
+        let allPasswords = KeychainManager.shared.getAllChannelPasswords()
+        XCTAssertEqual(allPasswords.count, 2)
+        XCTAssertEqual(allPasswords[channel1], password1)
+        XCTAssertEqual(allPasswords[channel2], password2)
+        
+        // Delete one password
+        XCTAssertTrue(KeychainManager.shared.deleteChannelPassword(for: channel1))
+        XCTAssertNil(KeychainManager.shared.getChannelPassword(for: channel1))
+        XCTAssertEqual(KeychainManager.shared.getChannelPassword(for: channel2), password2)
+    }
+    
+    // MARK: - Security Tests
+    
+    func testNoPlaintextInUserDefaults() {
+        // Create services to generate keys
+        _ = NoiseEncryptionService()
+        _ = MessageRetentionService.shared
+        
+        // Check UserDefaults for any sensitive data
+        let keysToCheck = [
+            "bitchat.noiseIdentityKey",
+            "bitchat.messageRetentionKey",
+            "bitchat.channelPasswords",
+            "bitchat.identityKey",
+            "bitchat.staticKey"
+        ]
+        
+        for key in keysToCheck {
+            let data = UserDefaults.standard.object(forKey: key)
+            XCTAssertNil(data, "UserDefaults should not contain: \(key)")
+        }
+    }
+    
+    // MARK: - Error Handling Tests
+    
+    func testKeychainErrorRecovery() {
+        // Test that the app can recover from keychain errors
+        // This is difficult to test without mocking, but we can verify
+        // that multiple save attempts don't crash
+        
+        let testData = "test".data(using: .utf8)!
+        
+        // Rapid saves
+        for i in 0..<10 {
+            let saved = KeychainManager.shared.saveIdentityKey(testData, forKey: "rapidTest\(i)")
+            XCTAssertTrue(saved, "Save \(i) should succeed")
+        }
+        
+        // Rapid deletes
+        for i in 0..<10 {
+            _ = KeychainManager.shared.deleteIdentityKey(forKey: "rapidTest\(i)")
+        }
+    }
+    
+    // MARK: - Cleanup Tests
+    
+    func testAggressiveCleanupOnlyDeletesBitchatItems() {
+        // This test verifies we don't delete other apps' keychain items
+        
+        // Add a non-bitchat item (simulating another app)
+        let otherAppQuery: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: "com.otherapp.service",
+            kSecAttrAccount as String: "other_app_account",
+            kSecValueData as String: "other app data".data(using: .utf8)!
+        ]
+        
+        // Clean first
+        SecItemDelete(otherAppQuery as CFDictionary)
+        
+        // Add the item
+        let addStatus = SecItemAdd(otherAppQuery as CFDictionary, nil)
+        XCTAssertEqual(addStatus, errSecSuccess, "Should add other app item")
+        
+        // Add a bitchat legacy item
+        let bitchatQuery: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: "com.bitchat.legacy",
+            kSecAttrAccount as String: "test_account",
+            kSecValueData as String: "bitchat data".data(using: .utf8)!
+        ]
+        SecItemDelete(bitchatQuery as CFDictionary)
+        let bitchatStatus = SecItemAdd(bitchatQuery as CFDictionary, nil)
+        XCTAssertEqual(bitchatStatus, errSecSuccess, "Should add bitchat item")
+        
+        // Run aggressive cleanup
+        _ = KeychainManager.shared.aggressiveCleanupLegacyItems()
+        
+        // Verify other app item still exists
+        var result: AnyObject?
+        let checkStatus = SecItemCopyMatching(otherAppQuery as CFDictionary, &result)
+        XCTAssertEqual(checkStatus, errSecSuccess, "Other app item should still exist")
+        
+        // Verify bitchat item was deleted
+        var bitchatResult: AnyObject?
+        let bitchatCheck = SecItemCopyMatching(bitchatQuery as CFDictionary, &bitchatResult)
+        XCTAssertEqual(bitchatCheck, errSecItemNotFound, "Bitchat legacy item should be deleted")
+        
+        // Clean up
+        SecItemDelete(otherAppQuery as CFDictionary)
+    }
+}

bitchatTests/MessagePaddingTests.swift

@@ -104,4 +104,144 @@ class MessagePaddingTests: XCTestCase {
         XCTAssertEqual(MessagePadding.unpad(padded1), data)
         XCTAssertEqual(MessagePadding.unpad(padded2), data)
     }
+    
+    // MARK: - Edge Case Tests
+    
+    func testExactBlockSizeData() {
+        // Test data that exactly matches block sizes
+        for blockSize in MessagePadding.blockSizes {
+            // Account for 16 bytes encryption overhead
+            let dataSize = blockSize - 16
+            let data = Data(repeating: 0x42, count: dataSize)
+            
+            let optimalSize = MessagePadding.optimalBlockSize(for: data.count)
+            XCTAssertEqual(optimalSize, blockSize)
+            
+            // Should fit exactly, no padding needed
+            let padded = MessagePadding.pad(data, toSize: blockSize)
+            XCTAssertEqual(padded.count, blockSize)
+        }
+    }
+    
+    func testOneByteOverBlockSize() {
+        // Test data that's one byte over block size threshold
+        let blockSizes = [256, 512, 1024]
+        
+        for blockSize in blockSizes {
+            // Create data that's 1 byte too large for current block
+            let dataSize = blockSize - 16 + 1
+            let data = Data(repeating: 0x42, count: dataSize)
+            
+            let optimalSize = MessagePadding.optimalBlockSize(for: data.count)
+            
+            // Should jump to next block size
+            if blockSize < 2048 {
+                XCTAssertGreaterThan(optimalSize, blockSize)
+            }
+        }
+    }
+    
+    func testVerySmallData() {
+        // Test tiny messages
+        let tinyMessages = [
+            Data([0x01]),
+            Data([0x01, 0x02]),
+            Data("a".utf8),
+            Data()
+        ]
+        
+        for data in tinyMessages {
+            let blockSize = MessagePadding.optimalBlockSize(for: data.count)
+            XCTAssertEqual(blockSize, 256) // Should use minimum block size
+            
+            if !data.isEmpty {
+                let padded = MessagePadding.pad(data, toSize: blockSize)
+                XCTAssertEqual(padded.count, blockSize)
+                
+                let unpadded = MessagePadding.unpad(padded)
+                XCTAssertEqual(unpadded, data)
+            }
+        }
+    }
+    
+    func testPaddingBoundaryConditions() {
+        // Test PKCS#7 padding limit (255 bytes)
+        let testCases = [
+            (dataSize: 1, targetSize: 256),    // Need 255 bytes padding - exactly at limit
+            (dataSize: 2, targetSize: 256),    // Need 254 bytes padding - just under limit
+            (dataSize: 256, targetSize: 512),  // Need 256 bytes padding - just over limit
+        ]
+        
+        for testCase in testCases {
+            let data = Data(repeating: 0x42, count: testCase.dataSize)
+            let padded = MessagePadding.pad(data, toSize: testCase.targetSize)
+            
+            let paddingNeeded = testCase.targetSize - testCase.dataSize
+            if paddingNeeded <= 255 {
+                // Padding should be applied
+                XCTAssertEqual(padded.count, testCase.targetSize)
+                
+                // Verify correct padding byte value
+                let paddingByte = padded[padded.count - 1]
+                XCTAssertEqual(Int(paddingByte), paddingNeeded)
+                
+                // Should unpad correctly
+                let unpadded = MessagePadding.unpad(padded)
+                XCTAssertEqual(unpadded, data)
+            } else {
+                // No padding applied
+                XCTAssertEqual(padded, data)
+            }
+        }
+    }
+    
+    func testCorruptedPadding() {
+        let data = Data("Test message".utf8)
+        let padded = MessagePadding.pad(data, toSize: 256)
+        
+        // Corrupt the padding length byte
+        var corrupted = padded
+        corrupted[corrupted.count - 1] = 0
+        
+        let result = MessagePadding.unpad(corrupted)
+        XCTAssertEqual(result, corrupted) // Should return original when padding is invalid
+        
+        // Test with padding length > data size
+        var corruptedTooLarge = padded
+        corruptedTooLarge[corruptedTooLarge.count - 1] = 255
+        
+        let result2 = MessagePadding.unpad(corruptedTooLarge)
+        XCTAssertEqual(result2, corruptedTooLarge)
+    }
+    
+    func testDataAlreadyLargerThanTarget() {
+        let data = Data(repeating: 0x42, count: 1000)
+        let tooSmallTarget = 256
+        
+        // Should return original data when it's already larger than target
+        let result = MessagePadding.pad(data, toSize: tooSmallTarget)
+        XCTAssertEqual(result, data)
+        XCTAssertEqual(result.count, data.count)
+    }
+    
+    func testOptimalBlockSizeForLargeData() {
+        // Test data larger than largest block size
+        let hugeData = Data(repeating: 0x42, count: 5000)
+        let blockSize = MessagePadding.optimalBlockSize(for: hugeData.count)
+        
+        // Should return data size when larger than all blocks
+        XCTAssertEqual(blockSize, hugeData.count)
+    }
+    
+    func testPaddingPerformance() {
+        let data = Data(repeating: 0x42, count: 1000)
+        
+        measure {
+            for _ in 0..<1000 {
+                let blockSize = MessagePadding.optimalBlockSize(for: data.count)
+                let padded = MessagePadding.pad(data, toSize: blockSize)
+                _ = MessagePadding.unpad(padded)
+            }
+        }
+    }
 }

bitchatTests/NoiseChannelEncryptionTests.swift

@@ -0,0 +1,222 @@
+//
+// NoiseChannelEncryptionTests.swift
+// bitchatTests
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import XCTest
+import CryptoKit
+@testable import bitchat
+
+class NoiseChannelEncryptionTests: XCTestCase {
+    
+    // MARK: - Channel Key Derivation with Fingerprint Tests
+    
+    func testChannelEncryptionWithFingerprint() {
+        let encryption = NoiseChannelEncryption()
+        let password = "test-password-123"
+        let channel = "#secure-channel"
+        let fingerprint = "e36f7993abc123def456789012345678901234567890abcdef1234567890abcd"
+        
+        // Set channel password with fingerprint
+        encryption.setChannelPasswordForCreator(password, channel: channel, creatorFingerprint: fingerprint)
+        
+        // Test encryption
+        let message = "This is a secret message"
+        do {
+            let encrypted = try encryption.encryptChannelMessage(message, for: channel)
+            
+            // Ensure it's actually encrypted
+            XCTAssertNotEqual(encrypted, Data(message.utf8))
+            XCTAssertGreaterThan(encrypted.count, message.count) // Should have IV + tag
+            
+            // Test decryption
+            let decrypted = try encryption.decryptChannelMessage(encrypted, for: channel)
+            XCTAssertEqual(decrypted, message)
+            
+        } catch {
+            XCTFail("Encryption/decryption failed: \(error)")
+        }
+    }
+    
+    func testBackwardsCompatibilityWithoutFingerprint() {
+        let encryption = NoiseChannelEncryption()
+        let password = "test-password-123"
+        let channel = "#legacy-channel"
+        
+        // Set password without fingerprint (legacy mode)
+        encryption.setChannelPassword(password, for: channel)
+        
+        // Encrypt message
+        let message = "Legacy message"
+        do {
+            let encrypted = try encryption.encryptChannelMessage(message, for: channel)
+            
+            // Should still work
+            let decrypted = try encryption.decryptChannelMessage(encrypted, for: channel)
+            XCTAssertEqual(decrypted, message)
+            
+        } catch {
+            XCTFail("Legacy encryption failed: \(error)")
+        }
+    }
+    
+    func testDifferentFingerprintsProduceDifferentEncryption() throws {
+        let encryption1 = NoiseChannelEncryption()
+        let encryption2 = NoiseChannelEncryption()
+        
+        let password = "same-password"
+        let channel = "#test-channel"
+        let message = "Test message"
+        
+        let fingerprint1 = "1111111111111111111111111111111111111111111111111111111111111111"
+        let fingerprint2 = "2222222222222222222222222222222222222222222222222222222222222222"
+        
+        // Set same password with different fingerprints
+        encryption1.setChannelPasswordForCreator(password, channel: channel, creatorFingerprint: fingerprint1)
+        encryption2.setChannelPasswordForCreator(password, channel: channel, creatorFingerprint: fingerprint2)
+        
+        // Encrypt same message
+        let encrypted1 = try encryption1.encryptChannelMessage(message, for: channel)
+        let encrypted2 = try encryption2.encryptChannelMessage(message, for: channel)
+        
+        // Encrypted data should be different (different keys due to different salts)
+        // Note: We can't directly compare ciphertexts due to random IVs, but we can verify they don't decrypt with wrong key
+        
+        // Try to decrypt with wrong fingerprint - should fail
+        encryption1.removeChannelPassword(for: channel)
+        encryption1.setChannelPasswordForCreator(password, channel: channel, creatorFingerprint: fingerprint2)
+        
+        XCTAssertThrowsError(try encryption1.decryptChannelMessage(encrypted1, for: channel)) { error in
+            // Should fail to decrypt because key is different
+        }
+    }
+    
+    // MARK: - Key Management Tests
+    
+    func testChannelKeyPersistence() {
+        let encryption = NoiseChannelEncryption()
+        let password = "persistent-password"
+        let channel = "#persistent-channel"
+        
+        // Set and save password
+        encryption.setChannelPassword(password, for: channel)
+        
+        // Verify it's saved in keychain
+        XCTAssertTrue(encryption.loadChannelPassword(for: channel))
+        
+        // Create new instance and load
+        let encryption2 = NoiseChannelEncryption()
+        XCTAssertTrue(encryption2.loadChannelPassword(for: channel))
+        
+        // Should be able to decrypt messages from first instance
+        do {
+            let message = "Cross-instance message"
+            let encrypted = try encryption.encryptChannelMessage(message, for: channel)
+            let decrypted = try encryption2.decryptChannelMessage(encrypted, for: channel)
+            XCTAssertEqual(decrypted, message)
+        } catch {
+            XCTFail("Cross-instance encryption failed: \(error)")
+        }
+        
+        // Clean up
+        encryption.removeChannelPassword(for: channel)
+    }
+    
+    func testChannelKeyPacketCreation() {
+        let encryption = NoiseChannelEncryption()
+        let password = "shared-password"
+        let channel = "#shared-channel"
+        
+        // Create key packet
+        guard let packet = encryption.createChannelKeyPacket(password: password, channel: channel) else {
+            XCTFail("Failed to create key packet")
+            return
+        }
+        
+        // Verify packet structure
+        XCTAssertGreaterThan(packet.count, 32) // Should have channel name + password + metadata
+        
+        // Process packet in another instance
+        let encryption2 = NoiseChannelEncryption()
+        guard let (extractedChannel, extractedPassword) = encryption2.processChannelKeyPacket(packet) else {
+            XCTFail("Failed to process key packet")
+            return
+        }
+        
+        XCTAssertEqual(extractedChannel, channel)
+        XCTAssertEqual(extractedPassword, password)
+    }
+    
+    // MARK: - Error Handling Tests
+    
+    func testDecryptionWithWrongPassword() {
+        let encryption = NoiseChannelEncryption()
+        let channel = "#error-test"
+        
+        // Encrypt with one password
+        encryption.setChannelPassword("correct-password", for: channel)
+        let message = "Secret message"
+        
+        do {
+            let encrypted = try encryption.encryptChannelMessage(message, for: channel)
+            
+            // Change to wrong password
+            encryption.setChannelPassword("wrong-password", for: channel)
+            
+            // Should fail to decrypt
+            XCTAssertThrowsError(try encryption.decryptChannelMessage(encrypted, for: channel))
+            
+        } catch {
+            XCTFail("Encryption failed: \(error)")
+        }
+    }
+    
+    func testEncryptionWithoutPassword() {
+        let encryption = NoiseChannelEncryption()
+        let channel = "#no-password"
+        
+        // Try to encrypt without setting password
+        XCTAssertThrowsError(try encryption.encryptChannelMessage("Test", for: channel)) { error in
+            // Should throw channelKeyMissing error
+            if let encryptionError = error as? NoiseChannelEncryptionError {
+                XCTAssertEqual(encryptionError, NoiseChannelEncryptionError.channelKeyMissing)
+            } else {
+                XCTFail("Wrong error type")
+            }
+        }
+    }
+    
+    func testInvalidChannelName() {
+        let encryption = NoiseChannelEncryption()
+        
+        // Empty channel
+        XCTAssertThrowsError(try encryption.encryptChannelMessage("Test", for: ""))
+        
+        // Channel without # prefix
+        XCTAssertThrowsError(try encryption.encryptChannelMessage("Test", for: "invalid"))
+    }
+    
+    // MARK: - Performance Tests
+    
+    func testEncryptionPerformance() {
+        let encryption = NoiseChannelEncryption()
+        let channel = "#perf-test"
+        let fingerprint = "e36f7993abc123def456789012345678901234567890abcdef1234567890abcd"
+        
+        encryption.setChannelPasswordForCreator("test-password", channel: channel, creatorFingerprint: fingerprint)
+        
+        let message = String(repeating: "Hello World! ", count: 100) // ~1.3KB message
+        
+        measure {
+            do {
+                let encrypted = try encryption.encryptChannelMessage(message, for: channel)
+                _ = try encryption.decryptChannelMessage(encrypted, for: channel)
+            } catch {
+                XCTFail("Performance test failed: \(error)")
+            }
+        }
+    }
+}

bitchatTests/NoiseIdentityPersistenceTests.swift

@@ -0,0 +1,226 @@
+//
+// NoiseIdentityPersistenceTests.swift
+// bitchatTests
+//
+// Tests for Noise Protocol identity key persistence
+//
+
+import XCTest
+@testable import bitchat
+
+class NoiseIdentityPersistenceTests: XCTestCase {
+    
+    override func setUp() {
+        super.setUp()
+        // Clean up any existing test data
+        cleanupTestData()
+    }
+    
+    override func tearDown() {
+        // Clean up after tests
+        cleanupTestData()
+        super.tearDown()
+    }
+    
+    private func cleanupTestData() {
+        // Clear any existing identity keys
+        _ = KeychainManager.shared.deleteIdentityKey(forKey: "noiseStaticKey")
+        _ = KeychainManager.shared.deleteIdentityKey(forKey: "messageRetentionKey")
+        
+        // Clear any UserDefaults that might interfere
+        UserDefaults.standard.removeObject(forKey: "bitchat.noiseIdentityKey")
+        UserDefaults.standard.removeObject(forKey: "bitchat.messageRetentionKey")
+        UserDefaults.standard.synchronize()
+    }
+    
+    // MARK: - Identity Persistence Tests
+    
+    func testIdentityPersistsAcrossInstances() {
+        // Create first instance
+        let service1 = NoiseEncryptionService()
+        let fingerprint1 = service1.getIdentityFingerprint()
+        let publicKey1 = service1.getStaticPublicKeyData()
+        
+        XCTAssertFalse(fingerprint1.isEmpty, "Fingerprint should not be empty")
+        XCTAssertEqual(publicKey1.count, 32, "Public key should be 32 bytes")
+        
+        // Create second instance
+        let service2 = NoiseEncryptionService()
+        let fingerprint2 = service2.getIdentityFingerprint()
+        let publicKey2 = service2.getStaticPublicKeyData()
+        
+        // Verify same identity
+        XCTAssertEqual(fingerprint1, fingerprint2, "Fingerprint should persist across instances")
+        XCTAssertEqual(publicKey1, publicKey2, "Public key should persist across instances")
+    }
+    
+    func testIdentityNotStoredInUserDefaults() {
+        // Create service to generate identity
+        _ = NoiseEncryptionService()
+        
+        // Verify identity is NOT in UserDefaults
+        let userDefaultsData = UserDefaults.standard.data(forKey: "bitchat.noiseIdentityKey")
+        XCTAssertNil(userDefaultsData, "Identity key should NOT be stored in UserDefaults")
+    }
+    
+    func testIdentityStoredInKeychain() {
+        // Create service to generate identity
+        _ = NoiseEncryptionService()
+        
+        // Verify identity IS in Keychain
+        let keychainData = KeychainManager.shared.getIdentityKey(forKey: "noiseStaticKey")
+        XCTAssertNotNil(keychainData, "Identity key should be stored in Keychain")
+        XCTAssertEqual(keychainData?.count, 32, "Identity key should be 32 bytes")
+    }
+    
+    func testPanicModeClearsIdentity() {
+        // Create service and get initial fingerprint
+        let service1 = NoiseEncryptionService()
+        let fingerprint1 = service1.getIdentityFingerprint()
+        
+        // Clear identity (panic mode)
+        service1.clearPersistentIdentity()
+        
+        // Create new service and verify new identity
+        let service2 = NoiseEncryptionService()
+        let fingerprint2 = service2.getIdentityFingerprint()
+        
+        XCTAssertNotEqual(fingerprint1, fingerprint2, "New identity should be created after panic mode")
+    }
+    
+    func testMultipleRapidInstantiations() {
+        // Create multiple services rapidly
+        var fingerprints: [String] = []
+        
+        for _ in 0..<10 {
+            let service = NoiseEncryptionService()
+            fingerprints.append(service.getIdentityFingerprint())
+        }
+        
+        // Verify all fingerprints are the same
+        let firstFingerprint = fingerprints[0]
+        for fingerprint in fingerprints {
+            XCTAssertEqual(fingerprint, firstFingerprint, "All instances should have same identity")
+        }
+    }
+    
+    func testKeychainAccessFailureHandling() {
+        // This test would require mocking KeychainManager, but we can at least
+        // verify the service initializes even if keychain is problematic
+        let service = NoiseEncryptionService()
+        XCTAssertFalse(service.getIdentityFingerprint().isEmpty, "Service should initialize with valid identity")
+    }
+    
+    // MARK: - Message Retention Key Tests
+    
+    func testMessageRetentionKeyPersistence() {
+        // Create first instance
+        _ = MessageRetentionService.shared
+        
+        // Get key from keychain
+        let keyData1 = KeychainManager.shared.getIdentityKey(forKey: "messageRetentionKey")
+        XCTAssertNotNil(keyData1, "Message retention key should be stored")
+        
+        // Simulate app restart by clearing the singleton
+        // (In real app, this would be a new process)
+        
+        // Get key again
+        let keyData2 = KeychainManager.shared.getIdentityKey(forKey: "messageRetentionKey")
+        XCTAssertEqual(keyData1, keyData2, "Message retention key should persist")
+    }
+    
+    func testMessageRetentionKeyNotInUserDefaults() {
+        // Ensure service is initialized
+        _ = MessageRetentionService.shared
+        
+        // Verify key is NOT in UserDefaults
+        let userDefaultsData = UserDefaults.standard.data(forKey: "bitchat.messageRetentionKey")
+        XCTAssertNil(userDefaultsData, "Message retention key should NOT be in UserDefaults")
+    }
+    
+    // MARK: - Keychain Service Name Tests
+    
+    func testKeychainServiceName() {
+        // Verify we're using the correct service name
+        let expectedService = "chat.bitchat"
+        
+        // Save a test item
+        let testKey = "test_service_verification"
+        let testData = "test".data(using: .utf8)!
+        _ = KeychainManager.shared.saveIdentityKey(testData, forKey: testKey)
+        
+        // Query directly to verify service name
+        let query: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: expectedService,
+            kSecAttrAccount as String: "identity_\(testKey)",
+            kSecMatchLimit as String: kSecMatchLimitOne,
+            kSecReturnData as String: true
+        ]
+        
+        var result: AnyObject?
+        let status = SecItemCopyMatching(query as CFDictionary, &result)
+        
+        XCTAssertEqual(status, errSecSuccess, "Should find item with expected service name")
+        XCTAssertNotNil(result as? Data, "Should retrieve data")
+        
+        // Clean up
+        _ = KeychainManager.shared.deleteIdentityKey(forKey: testKey)
+    }
+    
+    // MARK: - Legacy Cleanup Tests
+    
+    func testLegacyKeychainCleanup() {
+        // Create some legacy items with old service names
+        let legacyServices = [
+            "com.bitchat.passwords",
+            "com.bitchat.noise.identity",
+            "bitchat.keychain"
+        ]
+        
+        // Add test items with legacy service names
+        for service in legacyServices {
+            let addQuery: [String: Any] = [
+                kSecClass as String: kSecClassGenericPassword,
+                kSecAttrService as String: service,
+                kSecAttrAccount as String: "test_legacy_item",
+                kSecValueData as String: "test".data(using: .utf8)!
+            ]
+            
+            // Add item (ignore if already exists)
+            _ = SecItemAdd(addQuery as CFDictionary, nil)
+        }
+        
+        // Run aggressive cleanup
+        let deletedCount = KeychainManager.shared.aggressiveCleanupLegacyItems()
+        
+        // Verify items were deleted
+        XCTAssertGreaterThan(deletedCount, 0, "Should delete at least some legacy items")
+        
+        // Verify legacy items are gone
+        for service in legacyServices {
+            let query: [String: Any] = [
+                kSecClass as String: kSecClassGenericPassword,
+                kSecAttrService as String: service,
+                kSecMatchLimit as String: kSecMatchLimitOne
+            ]
+            
+            var result: AnyObject?
+            let status = SecItemCopyMatching(query as CFDictionary, &result)
+            
+            XCTAssertEqual(status, errSecItemNotFound, "Legacy service '\(service)' should be deleted")
+        }
+    }
+    
+    // MARK: - Performance Tests
+    
+    func testIdentityLoadPerformance() {
+        // Ensure identity exists
+        _ = NoiseEncryptionService()
+        
+        measure {
+            // Measure how long it takes to load identity
+            _ = NoiseEncryptionService()
+        }
+    }
+}

bitchatTests/NoiseKeyRotationTests.swift

@@ -0,0 +1,386 @@
+//
+// NoiseKeyRotationTests.swift
+// bitchatTests
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import XCTest
+import CryptoKit
+@testable import bitchat
+
+class NoiseKeyRotationTests: XCTestCase {
+    
+    var keyRotation: NoiseChannelKeyRotation!
+    
+    override func setUp() {
+        super.setUp()
+        keyRotation = NoiseChannelKeyRotation()
+    }
+    
+    override func tearDown() {
+        // Clean up test data
+        keyRotation.clearEpochs(for: "#test-channel")
+        super.tearDown()
+    }
+    
+    // MARK: - Basic Key Rotation Tests
+    
+    func testInitialKeyGeneration() {
+        let channel = "#test-channel"
+        let password = "test-password"
+        let fingerprint = "abc123def456"
+        
+        // Get initial key
+        guard let rotatedKey = keyRotation.getCurrentKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        ) else {
+            XCTFail("Failed to get initial key")
+            return
+        }
+        
+        XCTAssertEqual(rotatedKey.epoch.epochNumber, 1)
+        XCTAssertTrue(rotatedKey.isActive)
+        XCTAssertNotNil(rotatedKey.key)
+    }
+    
+    func testKeyRotation() {
+        let channel = "#test-channel"
+        let password = "test-password"
+        let fingerprint = "abc123def456"
+        
+        // Get initial key
+        let initialKey = keyRotation.getCurrentKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        // Rotate key
+        let newEpoch = keyRotation.rotateChannelKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        XCTAssertEqual(newEpoch.epochNumber, 2)
+        XCTAssertNotNil(newEpoch.previousEpochCommitment)
+        
+        // Get new current key
+        let rotatedKey = keyRotation.getCurrentKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        XCTAssertEqual(rotatedKey?.epoch.epochNumber, 2)
+        
+        // Keys should be different
+        if let initial = initialKey, let rotated = rotatedKey {
+            XCTAssertNotEqual(
+                initial.key.withUnsafeBytes { Data($0) },
+                rotated.key.withUnsafeBytes { Data($0) }
+            )
+        }
+    }
+    
+    func testKeyRotationNeeded() {
+        let channel = "#test-channel"
+        let password = "test-password"
+        let fingerprint = "abc123def456"
+        
+        // Initially needs rotation (no epochs)
+        XCTAssertTrue(keyRotation.needsKeyRotation(for: channel))
+        
+        // After getting initial key, shouldn't need rotation
+        _ = keyRotation.getCurrentKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        XCTAssertFalse(keyRotation.needsKeyRotation(for: channel))
+        
+        // Note: We can't easily test time-based rotation need without
+        // modifying internal state or waiting 22+ hours
+    }
+    
+    // MARK: - Multiple Epoch Tests
+    
+    func testMultipleEpochsForDecryption() {
+        let channel = "#test-channel"
+        let password = "test-password"
+        let fingerprint = "abc123def456"
+        
+        // Create initial epoch
+        _ = keyRotation.getCurrentKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        // Rotate multiple times
+        for _ in 0..<3 {
+            _ = keyRotation.rotateChannelKey(
+                for: channel,
+                basePassword: password,
+                creatorFingerprint: fingerprint
+            )
+        }
+        
+        // Get valid keys for decryption
+        let validKeys = keyRotation.getValidKeysForDecryption(
+            channel: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        // Should have at least the current epoch
+        XCTAssertGreaterThanOrEqual(validKeys.count, 1)
+        
+        // Check that we have the latest epoch
+        XCTAssertTrue(validKeys.contains { $0.epoch.epochNumber == 4 })
+    }
+    
+    func testEpochKeyDerivationConsistency() {
+        let channel = "#test-channel"
+        let password = "test-password"
+        let fingerprint = "abc123def456"
+        
+        // Get key for epoch 1
+        let key1a = keyRotation.getCurrentKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        // Get the same key again
+        let key1b = keyRotation.getCurrentKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        // Keys should be identical for same epoch
+        if let a = key1a, let b = key1b {
+            XCTAssertEqual(
+                a.key.withUnsafeBytes { Data($0) },
+                b.key.withUnsafeBytes { Data($0) }
+            )
+            XCTAssertEqual(a.epoch.epochNumber, b.epoch.epochNumber)
+        }
+    }
+    
+    // MARK: - Edge Cases
+    
+    func testMaxEpochLimit() {
+        let channel = "#test-channel"
+        let password = "test-password"
+        let fingerprint = "abc123def456"
+        
+        // Create initial epoch
+        _ = keyRotation.getCurrentKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        // Rotate many times (more than max stored epochs)
+        for _ in 0..<10 {
+            _ = keyRotation.rotateChannelKey(
+                for: channel,
+                basePassword: password,
+                creatorFingerprint: fingerprint
+            )
+        }
+        
+        // Get all valid epochs
+        let validKeys = keyRotation.getValidKeysForDecryption(
+            channel: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        // Should not exceed reasonable limit
+        XCTAssertLessThanOrEqual(validKeys.count, 7) // maxStoredEpochs
+    }
+    
+    func testDifferentChannelsDifferentEpochs() {
+        let password = "test-password"
+        let fingerprint = "abc123def456"
+        
+        let channel1 = "#channel-1"
+        let channel2 = "#channel-2"
+        
+        // Get keys for both channels
+        let key1 = keyRotation.getCurrentKey(
+            for: channel1,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        let key2 = keyRotation.getCurrentKey(
+            for: channel2,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        // Keys should be different even with same password
+        if let k1 = key1, let k2 = key2 {
+            XCTAssertNotEqual(
+                k1.key.withUnsafeBytes { Data($0) },
+                k2.key.withUnsafeBytes { Data($0) }
+            )
+        }
+    }
+    
+    // MARK: - Integration Tests
+    
+    func testKeyRotationWithEncryption() throws {
+        let channel = "#test-channel"
+        let password = "test-password"
+        let fingerprint = "abc123def456"
+        
+        // Get initial key
+        guard let initialRotatedKey = keyRotation.getCurrentKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        ) else {
+            XCTFail("Failed to get initial key")
+            return
+        }
+        
+        // Encrypt a message with initial key
+        let message = "Test message before rotation"
+        let nonce = ChaChaPoly.Nonce()
+        let sealed1 = try ChaChaPoly.seal(
+            Data(message.utf8),
+            using: initialRotatedKey.key,
+            nonce: nonce
+        )
+        
+        // Rotate key
+        _ = keyRotation.rotateChannelKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        // Get new key
+        guard let newRotatedKey = keyRotation.getCurrentKey(
+            for: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        ) else {
+            XCTFail("Failed to get rotated key")
+            return
+        }
+        
+        // New key should not decrypt old message
+        XCTAssertThrowsError(
+            try ChaChaPoly.open(sealed1, using: newRotatedKey.key)
+        )
+        
+        // But we should still be able to decrypt with old epoch key
+        let validKeys = keyRotation.getValidKeysForDecryption(
+            channel: channel,
+            basePassword: password,
+            creatorFingerprint: fingerprint
+        )
+        
+        // Try each valid key until one works
+        var decrypted = false
+        for rotatedKey in validKeys {
+            do {
+                let plaintext = try ChaChaPoly.open(sealed1, using: rotatedKey.key)
+                XCTAssertEqual(String(data: plaintext, encoding: .utf8), message)
+                decrypted = true
+                break
+            } catch {
+                continue
+            }
+        }
+        
+        XCTAssertTrue(decrypted, "Failed to decrypt with any valid key")
+    }
+}
+
+// MARK: - Post-Quantum Framework Tests
+
+class NoisePostQuantumTests: XCTestCase {
+    
+    func testHybridKeyGeneration() throws {
+        let (publicKey, privateKey) = try HybridNoiseKeyExchange.generateKeyPair(algorithm: .classicalOnly)
+        
+        XCTAssertNotNil(publicKey.classical)
+        XCTAssertNil(publicKey.postQuantum) // No PQ component yet
+        XCTAssertEqual(publicKey.serialized.count, 32) // Just Curve25519
+        
+        XCTAssertNotNil(privateKey.classical)
+        XCTAssertNil(privateKey.postQuantum)
+    }
+    
+    func testHybridKeyAgreement() throws {
+        // Generate two keypairs
+        let (alicePub, alicePriv) = try HybridNoiseKeyExchange.generateKeyPair(algorithm: .classicalOnly)
+        let (bobPub, bobPriv) = try HybridNoiseKeyExchange.generateKeyPair(algorithm: .classicalOnly)
+        
+        // Perform key agreement
+        let aliceShared = try HybridNoiseKeyExchange.performKeyAgreement(
+            localPrivate: alicePriv,
+            remotePublic: bobPub,
+            algorithm: .classicalOnly
+        )
+        
+        let bobShared = try HybridNoiseKeyExchange.performKeyAgreement(
+            localPrivate: bobPriv,
+            remotePublic: alicePub,
+            algorithm: .classicalOnly
+        )
+        
+        // Shared secrets should match
+        XCTAssertEqual(
+            aliceShared.combinedSecret().withUnsafeBytes { Data($0) },
+            bobShared.combinedSecret().withUnsafeBytes { Data($0) }
+        )
+    }
+    
+    func testMigrationConfig() {
+        let config = NoiseProtocolMigration.getMigrationConfig()
+        
+        XCTAssertEqual(config.currentPhase, .classicalOnly)
+        XCTAssertEqual(config.preferredAlgorithm, .classicalOnly)
+        XCTAssertTrue(config.acceptedAlgorithms.contains(.classicalOnly))
+        XCTAssertNil(config.migrationDeadline)
+    }
+    
+    #if DEBUG
+    func testMockPostQuantum() throws {
+        // Test mock PQ implementation
+        let (publicKey, privateKey) = try MockPostQuantumKeyExchange.generateKeyPair()
+        
+        XCTAssertEqual(publicKey.count, MockPostQuantumKeyExchange.publicKeySize)
+        XCTAssertEqual(privateKey.count, 32) // Mock uses smaller private key
+        
+        let (sharedSecret, ciphertext) = try MockPostQuantumKeyExchange.encapsulate(
+            remotePublicKey: publicKey
+        )
+        
+        XCTAssertEqual(ciphertext.count, MockPostQuantumKeyExchange.ciphertextSize)
+        XCTAssertEqual(sharedSecret.count, MockPostQuantumKeyExchange.sharedSecretSize)
+        
+        let decapsulatedSecret = try MockPostQuantumKeyExchange.decapsulate(
+            ciphertext: ciphertext,
+            privateKey: privateKey
+        )
+        
+        // In real implementation, these would match
+        // Mock just returns deterministic values
+        XCTAssertEqual(decapsulatedSecret.count, 32)
+    }
+    #endif
+}

bitchatTests/NoiseProtocolTests.swift

@@ -0,0 +1,369 @@
+//
+// NoiseProtocolTests.swift
+// bitchatTests
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import XCTest
+import CryptoKit
+@testable import bitchat
+
+class NoiseProtocolTests: XCTestCase {
+    
+    // MARK: - Cipher State Tests
+    
+    func testCipherStateEncryptDecrypt() throws {
+        let key = SymmetricKey(size: .bits256)
+        let cipher = NoiseCipherState(key: key)
+        
+        let plaintext = "Hello, Noise Protocol!".data(using: .utf8)!
+        let associatedData = "metadata".data(using: .utf8)!
+        
+        // Encrypt
+        let ciphertext = try cipher.encrypt(plaintext: plaintext, associatedData: associatedData)
+        
+        // Create new cipher with same key for decryption
+        let decryptCipher = NoiseCipherState(key: key)
+        let decrypted = try decryptCipher.decrypt(ciphertext: ciphertext, associatedData: associatedData)
+        
+        XCTAssertEqual(plaintext, decrypted)
+    }
+    
+    func testCipherStateNonceIncrement() throws {
+        let key = SymmetricKey(size: .bits256)
+        let cipher = NoiseCipherState(key: key)
+        
+        let plaintext = "Test".data(using: .utf8)!
+        
+        // Encrypt multiple messages
+        let ct1 = try cipher.encrypt(plaintext: plaintext)
+        let ct2 = try cipher.encrypt(plaintext: plaintext)
+        let ct3 = try cipher.encrypt(plaintext: plaintext)
+        
+        // All ciphertexts should be different due to nonce increment
+        XCTAssertNotEqual(ct1, ct2)
+        XCTAssertNotEqual(ct2, ct3)
+        XCTAssertNotEqual(ct1, ct3)
+    }
+    
+    // MARK: - Symmetric State Tests
+    
+    func testSymmetricStateInitialization() {
+        let protocolName = "Noise_XX_25519_ChaChaPoly_SHA256"
+        let state = NoiseSymmetricState(protocolName: protocolName)
+        
+        // Hash should be initialized with protocol name
+        let hash = state.getHandshakeHash()
+        XCTAssertEqual(hash.count, 32) // SHA256 output
+    }
+    
+    func testSymmetricStateMixKey() throws {
+        let state = NoiseSymmetricState(protocolName: "Noise_XX_25519_ChaChaPoly_SHA256")
+        
+        let keyMaterial = Data(repeating: 0x42, count: 32)
+        state.mixKey(keyMaterial)
+        
+        // After mixKey, cipher should be initialized
+        let plaintext = "Test".data(using: .utf8)!
+        let encrypted = try state.encryptAndHash(plaintext)
+        
+        XCTAssertNotEqual(plaintext, encrypted)
+        XCTAssertEqual(encrypted.count, plaintext.count + 16) // ChaCha20Poly1305 adds 16-byte tag
+    }
+    
+    // MARK: - Handshake State Tests
+    
+    func testNoiseXXHandshakeComplete() throws {
+        // Create initiator and responder
+        let initiatorStatic = Curve25519.KeyAgreement.PrivateKey()
+        let responderStatic = Curve25519.KeyAgreement.PrivateKey()
+        
+        var initiator = NoiseHandshakeState(role: .initiator, pattern: .XX, localStaticKey: initiatorStatic)
+        var responder = NoiseHandshakeState(role: .responder, pattern: .XX, localStaticKey: responderStatic)
+        
+        // Message 1: initiator -> responder (e)
+        let msg1 = try initiator.writeMessage()
+        _ = try responder.readMessage(msg1)
+        
+        // Message 2: responder -> initiator (e, ee, s, es)
+        let msg2 = try responder.writeMessage()
+        _ = try initiator.readMessage(msg2)
+        
+        // Message 3: initiator -> responder (s, se)
+        let msg3 = try initiator.writeMessage()
+        _ = try responder.readMessage(msg3)
+        
+        // Both should have completed handshake
+        XCTAssertTrue(initiator.isHandshakeComplete())
+        XCTAssertTrue(responder.isHandshakeComplete())
+        
+        // Get transport ciphers
+        let (initSend, initRecv) = try initiator.getTransportCiphers()
+        let (respSend, respRecv) = try responder.getTransportCiphers()
+        
+        // Test transport encryption
+        let testMessage = "Secret message".data(using: .utf8)!
+        let encrypted = try initSend.encrypt(plaintext: testMessage)
+        let decrypted = try respRecv.decrypt(ciphertext: encrypted)
+        
+        XCTAssertEqual(testMessage, decrypted)
+        
+        // Test reverse direction
+        let encrypted2 = try respSend.encrypt(plaintext: testMessage)
+        let decrypted2 = try initRecv.decrypt(ciphertext: encrypted2)
+        
+        XCTAssertEqual(testMessage, decrypted2)
+    }
+    
+    func testNoiseXXWithPayloads() throws {
+        let initiatorStatic = Curve25519.KeyAgreement.PrivateKey()
+        let responderStatic = Curve25519.KeyAgreement.PrivateKey()
+        
+        var initiator = NoiseHandshakeState(role: .initiator, pattern: .XX, localStaticKey: initiatorStatic)
+        var responder = NoiseHandshakeState(role: .responder, pattern: .XX, localStaticKey: responderStatic)
+        
+        // Message 1 with payload
+        let payload1 = "Hello from initiator".data(using: .utf8)!
+        let msg1 = try initiator.writeMessage(payload: payload1)
+        let received1 = try responder.readMessage(msg1)
+        XCTAssertEqual(payload1, received1)
+        
+        // Message 2 with payload
+        let payload2 = "Hello from responder".data(using: .utf8)!
+        let msg2 = try responder.writeMessage(payload: payload2)
+        let received2 = try initiator.readMessage(msg2)
+        XCTAssertEqual(payload2, received2)
+        
+        // Message 3 with payload
+        let payload3 = "Final message".data(using: .utf8)!
+        let msg3 = try initiator.writeMessage(payload: payload3)
+        let received3 = try responder.readMessage(msg3)
+        XCTAssertEqual(payload3, received3)
+    }
+    
+    // MARK: - Session Tests
+    
+    func testNoiseSessionLifecycle() throws {
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        
+        let aliceSession = NoiseSession(peerID: "bob", role: .initiator, localStaticKey: aliceKey)
+        let bobSession = NoiseSession(peerID: "alice", role: .responder, localStaticKey: bobKey)
+        
+        // Start handshake - only initiator calls startHandshake
+        let msg1 = try aliceSession.startHandshake()
+        XCTAssertFalse(msg1.isEmpty, "Initiator should send first message")
+        
+        // Process messages - responder will auto-initialize on first message
+        let msg2 = try bobSession.processHandshakeMessage(msg1)!
+        XCTAssertFalse(msg2.isEmpty, "Responder should send second message")
+        
+        let msg3 = try aliceSession.processHandshakeMessage(msg2)!
+        XCTAssertFalse(msg3.isEmpty, "Initiator should send third message")
+        
+        let finalMsg = try bobSession.processHandshakeMessage(msg3)
+        XCTAssertNil(finalMsg, "No more messages after handshake complete")
+        
+        // Both sessions should be established
+        XCTAssertTrue(aliceSession.isEstablished(), "Alice session should be established")
+        XCTAssertTrue(bobSession.isEstablished(), "Bob session should be established")
+        
+        // Test encryption
+        let plaintext = "Test message".data(using: .utf8)!
+        let encrypted = try aliceSession.encrypt(plaintext)
+        let decrypted = try bobSession.decrypt(encrypted)
+        
+        XCTAssertEqual(plaintext, decrypted)
+    }
+    
+    // MARK: - Integration Tests
+    
+    func testNoiseEncryptionServiceIntegration() throws {
+        // Clean up any existing keys
+        _ = KeychainManager.shared.deleteIdentityKey(forKey: "noiseStaticKey")
+        
+        let service1 = NoiseEncryptionService()
+        let service2 = NoiseEncryptionService()
+        
+        let peer1ID = "peer1"
+        let peer2ID = "peer2"
+        
+        // Initiate handshake from peer1 to peer2
+        let handshake1 = try service1.initiateHandshake(with: peer2ID)
+        
+        // Process on peer2 and get response
+        let handshake2 = try service2.processHandshakeMessage(from: peer1ID, message: handshake1)!
+        
+        // Process response on peer1
+        let handshake3 = try service1.processHandshakeMessage(from: peer2ID, message: handshake2)!
+        
+        // Final message on peer2
+        let final = try service2.processHandshakeMessage(from: peer1ID, message: handshake3)
+        XCTAssertNil(final)
+        
+        // Both should have established sessions
+        XCTAssertTrue(service1.hasEstablishedSession(with: peer2ID))
+        XCTAssertTrue(service2.hasEstablishedSession(with: peer1ID))
+        
+        // Test message encryption
+        let message = "Secret message".data(using: .utf8)!
+        let encrypted = try service1.encrypt(message, for: peer2ID)
+        let decrypted = try service2.decrypt(encrypted, from: peer1ID)
+        
+        XCTAssertEqual(message, decrypted)
+    }
+    
+    func testBidirectionalNoiseSession() throws {
+        // This test verifies that messages can be sent in both directions after handshake
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        
+        // Create session managers
+        let aliceManager = NoiseSessionManager(localStaticKey: aliceKey)
+        let bobManager = NoiseSessionManager(localStaticKey: bobKey)
+        
+        // Alice initiates handshake (msg1: -> e)
+        let msg1 = try aliceManager.initiateHandshake(with: "bob")
+        XCTAssertFalse(msg1.isEmpty)
+        
+        // Bob processes and responds (msg2: <- e, ee, s, es)
+        let msg2 = try bobManager.handleIncomingHandshake(from: "alice", message: msg1)
+        XCTAssertNotNil(msg2)
+        XCTAssertFalse(msg2!.isEmpty)
+        
+        // Alice processes and sends final message (msg3: -> s, se)
+        let msg3 = try aliceManager.handleIncomingHandshake(from: "bob", message: msg2!)
+        XCTAssertNotNil(msg3)
+        XCTAssertFalse(msg3!.isEmpty)
+        
+        // Bob processes final message
+        let msg4 = try bobManager.handleIncomingHandshake(from: "alice", message: msg3!)
+        XCTAssertNil(msg4) // Now handshake is complete
+        
+        // Verify both sessions are established
+        XCTAssertTrue(aliceManager.getSession(for: "bob")?.isEstablished() ?? false)
+        XCTAssertTrue(bobManager.getSession(for: "alice")?.isEstablished() ?? false)
+        
+        // Test Alice -> Bob
+        let aliceMessage = "Hello Bob!".data(using: .utf8)!
+        let encrypted1 = try aliceManager.encrypt(aliceMessage, for: "bob")
+        let decrypted1 = try bobManager.decrypt(encrypted1, from: "alice")
+        XCTAssertEqual(decrypted1, aliceMessage)
+        
+        // Test Bob -> Alice
+        let bobMessage = "Hello Alice!".data(using: .utf8)!
+        let encrypted2 = try bobManager.encrypt(bobMessage, for: "alice")
+        let decrypted2 = try aliceManager.decrypt(encrypted2, from: "bob")
+        XCTAssertEqual(decrypted2, bobMessage)
+        
+        // Test multiple messages in both directions
+        for i in 1...5 {
+            // Alice -> Bob
+            let msg = "Message \(i) from Alice".data(using: .utf8)!
+            let enc = try aliceManager.encrypt(msg, for: "bob")
+            let dec = try bobManager.decrypt(enc, from: "alice")
+            XCTAssertEqual(dec, msg)
+            
+            // Bob -> Alice
+            let msg2 = "Message \(i) from Bob".data(using: .utf8)!
+            let enc2 = try bobManager.encrypt(msg2, for: "alice")
+            let dec2 = try aliceManager.decrypt(enc2, from: "bob")
+            XCTAssertEqual(dec2, msg2)
+        }
+    }
+    
+    // MARK: - Channel Encryption Tests
+    
+    func testChannelEncryption() throws {
+        let channelEnc = NoiseChannelEncryption()
+        let channel = "#test-channel"
+        let password = "super-secret-password"
+        
+        // Set channel password
+        channelEnc.setChannelPassword(password, for: channel)
+        
+        // Encrypt message
+        let message = "Hello channel!"
+        let encrypted = try channelEnc.encryptChannelMessage(message, for: channel)
+        
+        // Decrypt message
+        let decrypted = try channelEnc.decryptChannelMessage(encrypted, for: channel)
+        
+        XCTAssertEqual(message, decrypted)
+    }
+    
+    func testChannelKeyDerivation() {
+        let channelEnc = NoiseChannelEncryption()
+        let password = "test-password"
+        
+        // Same password and channel should produce same key
+        let key1 = channelEnc.deriveChannelKey(from: password, channel: "#channel1")
+        let key2 = channelEnc.deriveChannelKey(from: password, channel: "#channel1")
+        
+        // Different channels should produce different keys
+        let key3 = channelEnc.deriveChannelKey(from: password, channel: "#channel2")
+        
+        // Can't directly compare SymmetricKey, but we can test encryption
+        let testData = "test".data(using: .utf8)!
+        let nonce = ChaChaPoly.Nonce()
+        
+        let sealed1 = try! ChaChaPoly.seal(testData, using: key1, nonce: nonce)
+        let sealed2 = try! ChaChaPoly.seal(testData, using: key2, nonce: nonce)
+        
+        XCTAssertEqual(sealed1.ciphertext, sealed2.ciphertext)
+        
+        // Different key should produce different ciphertext
+        let sealed3 = try! ChaChaPoly.seal(testData, using: key3, nonce: nonce)
+        XCTAssertNotEqual(sealed1.ciphertext, sealed3.ciphertext)
+    }
+    
+    // MARK: - Security Tests
+    
+    func testHandshakeAuthentication() throws {
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        let eveKey = Curve25519.KeyAgreement.PrivateKey() // Attacker
+        
+        var alice = NoiseHandshakeState(role: .initiator, pattern: .XX, localStaticKey: aliceKey)
+        var eve = NoiseHandshakeState(role: .responder, pattern: .XX, localStaticKey: eveKey)
+        
+        // Alice initiates handshake thinking she's talking to Bob
+        let msg1 = try alice.writeMessage()
+        _ = try eve.readMessage(msg1)
+        
+        // Eve responds with her keys
+        let msg2 = try eve.writeMessage()
+        _ = try alice.readMessage(msg2)
+        
+        // Alice completes handshake
+        let msg3 = try alice.writeMessage()
+        _ = try eve.readMessage(msg3)
+        
+        // Both complete handshake, but Alice has Eve's public key, not Bob's
+        let aliceRemoteKey = alice.getRemoteStaticPublicKey()
+        XCTAssertEqual(aliceRemoteKey?.rawRepresentation, eveKey.publicKey.rawRepresentation)
+        XCTAssertNotEqual(aliceRemoteKey?.rawRepresentation, bobKey.publicKey.rawRepresentation)
+        
+        // This demonstrates that authentication requires out-of-band verification
+        // or pre-shared knowledge of public keys
+    }
+    
+    func testReplayProtection() throws {
+        let key = SymmetricKey(size: .bits256)
+        let cipher1 = NoiseCipherState(key: key)
+        let cipher2 = NoiseCipherState(key: key)
+        
+        let plaintext = "Test".data(using: .utf8)!
+        
+        // Encrypt a message
+        let ciphertext = try cipher1.encrypt(plaintext: plaintext)
+        
+        // Decrypt normally works
+        _ = try cipher2.decrypt(ciphertext: ciphertext)
+        
+        // Replaying the same ciphertext should fail due to nonce mismatch
+        XCTAssertThrowsError(try cipher2.decrypt(ciphertext: ciphertext))
+    }
+}

bitchatTests/NoiseRateLimiterTests.swift

@@ -0,0 +1,206 @@
+//
+// NoiseRateLimiterTests.swift
+// bitchatTests
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import XCTest
+@testable import bitchat
+
+class NoiseRateLimiterTests: XCTestCase {
+    
+    // MARK: - Basic Rate Limiting Tests
+    
+    func testHandshakeRateLimiting() {
+        let rateLimiter = NoiseRateLimiter()
+        let peerID = "test-peer"
+        
+        // First few handshakes should be allowed
+        XCTAssertTrue(rateLimiter.allowHandshake(from: peerID))
+        XCTAssertTrue(rateLimiter.allowHandshake(from: peerID))
+        XCTAssertTrue(rateLimiter.allowHandshake(from: peerID))
+        
+        // After hitting limit, should be rate limited
+        // Default is 3 handshakes per minute
+        XCTAssertFalse(rateLimiter.allowHandshake(from: peerID))
+        XCTAssertFalse(rateLimiter.allowHandshake(from: peerID))
+    }
+    
+    func testMessageRateLimiting() {
+        let rateLimiter = NoiseRateLimiter()
+        let peerID = "test-peer"
+        
+        // Messages have higher limit (100 per minute default)
+        for _ in 0..<100 {
+            XCTAssertTrue(rateLimiter.allowMessage(from: peerID))
+        }
+        
+        // 101st message should be rate limited
+        XCTAssertFalse(rateLimiter.allowMessage(from: peerID))
+    }
+    
+    func testPerPeerRateLimiting() {
+        let rateLimiter = NoiseRateLimiter()
+        let peer1 = "alice"
+        let peer2 = "bob"
+        
+        // Rate limit peer1
+        XCTAssertTrue(rateLimiter.allowHandshake(from: peer1))
+        XCTAssertTrue(rateLimiter.allowHandshake(from: peer1))
+        XCTAssertTrue(rateLimiter.allowHandshake(from: peer1))
+        XCTAssertFalse(rateLimiter.allowHandshake(from: peer1))
+        
+        // Peer2 should still be allowed
+        XCTAssertTrue(rateLimiter.allowHandshake(from: peer2))
+        XCTAssertTrue(rateLimiter.allowHandshake(from: peer2))
+    }
+    
+    // MARK: - Time Window Tests
+    
+    func testRateLimitResetsAfterWindow() {
+        let rateLimiter = NoiseRateLimiter()
+        let peerID = "test-peer"
+        
+        // Use up the limit
+        for _ in 0..<3 {
+            XCTAssertTrue(rateLimiter.allowHandshake(from: peerID))
+        }
+        XCTAssertFalse(rateLimiter.allowHandshake(from: peerID))
+        
+        // Simulate time passing by clearing the window
+        rateLimiter.clearExpiredEntries()
+        
+        // Should be allowed again after window expires
+        // Note: In real implementation, this would require actual time to pass
+        // For testing, we might need to inject a clock or expose internal state
+    }
+    
+    // MARK: - Global Rate Limiting Tests
+    
+    func testGlobalHandshakeLimit() {
+        let rateLimiter = NoiseRateLimiter()
+        
+        // Global limit prevents too many handshakes across all peers
+        var allowedCount = 0
+        
+        // Try many handshakes from different peers
+        for i in 0..<50 {
+            let peerID = "peer-\(i)"
+            if rateLimiter.allowHandshake(from: peerID) {
+                allowedCount += 1
+            }
+        }
+        
+        // Should hit global limit before allowing all 50
+        XCTAssertLessThan(allowedCount, 50)
+        XCTAssertGreaterThan(allowedCount, 10) // But should allow reasonable amount
+    }
+    
+    // MARK: - Attack Mitigation Tests
+    
+    func testRapidHandshakeAttackMitigation() {
+        let rateLimiter = NoiseRateLimiter()
+        let attackerID = "attacker"
+        
+        var blockedCount = 0
+        
+        // Simulate rapid handshake attempts
+        for _ in 0..<20 {
+            if !rateLimiter.allowHandshake(from: attackerID) {
+                blockedCount += 1
+            }
+        }
+        
+        // Most attempts should be blocked
+        XCTAssertGreaterThan(blockedCount, 15)
+    }
+    
+    func testDistributedAttackMitigation() {
+        let rateLimiter = NoiseRateLimiter()
+        
+        var blockedCount = 0
+        
+        // Simulate distributed attack from many IPs
+        for i in 0..<100 {
+            let attackerID = "192.168.1.\(i)"
+            // Each attacker tries multiple times
+            for _ in 0..<5 {
+                if !rateLimiter.allowHandshake(from: attackerID) {
+                    blockedCount += 1
+                }
+            }
+        }
+        
+        // Global rate limiting should kick in
+        XCTAssertGreaterThan(blockedCount, 0)
+    }
+    
+    // MARK: - Memory Management Tests
+    
+    func testMemoryBoundedTracking() {
+        let rateLimiter = NoiseRateLimiter()
+        
+        // Add many different peers
+        for i in 0..<10000 {
+            let peerID = "peer-\(i)"
+            _ = rateLimiter.allowMessage(from: peerID)
+        }
+        
+        // Rate limiter should have bounds on memory usage
+        // Implementation should clean up old entries
+        rateLimiter.clearExpiredEntries()
+        
+        // Verify it still functions correctly
+        XCTAssertTrue(rateLimiter.allowMessage(from: "new-peer"))
+    }
+    
+    // MARK: - Configuration Tests
+    
+    func testCustomRateLimits() {
+        // Test with custom configuration
+        let config = NoiseRateLimiter.Configuration(
+            handshakesPerMinute: 5,
+            messagesPerMinute: 200,
+            globalHandshakesPerMinute: 30
+        )
+        
+        let rateLimiter = NoiseRateLimiter(configuration: config)
+        let peerID = "test-peer"
+        
+        // Should allow up to 5 handshakes
+        for i in 0..<5 {
+            XCTAssertTrue(rateLimiter.allowHandshake(from: peerID), "Handshake \(i+1) should be allowed")
+        }
+        
+        // 6th should be blocked
+        XCTAssertFalse(rateLimiter.allowHandshake(from: peerID))
+    }
+    
+    // MARK: - Thread Safety Tests
+    
+    func testConcurrentAccess() {
+        let rateLimiter = NoiseRateLimiter()
+        let expectation = self.expectation(description: "Concurrent access")
+        expectation.expectedFulfillmentCount = 10
+        
+        // Multiple threads accessing rate limiter
+        for i in 0..<10 {
+            DispatchQueue.global().async {
+                let peerID = "peer-\(i)"
+                for _ in 0..<100 {
+                    _ = rateLimiter.allowMessage(from: peerID)
+                }
+                expectation.fulfill()
+            }
+        }
+        
+        waitForExpectations(timeout: 5) { error in
+            XCTAssertNil(error)
+        }
+        
+        // Verify rate limiter still works
+        XCTAssertTrue(rateLimiter.allowMessage(from: "final-test"))
+    }
+}

bitchatTests/NoiseSecurityTests.swift

@@ -0,0 +1,507 @@
+//
+// NoiseSecurityTests.swift
+// bitchatTests
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import XCTest
+import CryptoKit
+@testable import bitchat
+
+class NoiseSecurityTests: XCTestCase {
+    
+    // MARK: - Channel Password Salt Tests
+    
+    func testChannelPasswordSaltIncludesFingerprint() {
+        let encryption = NoiseChannelEncryption()
+        let password = "test-password-123"
+        let channel = "#secure-channel"
+        
+        // Derive key without fingerprint
+        let key1 = encryption.deriveChannelKey(from: password, channel: channel, creatorFingerprint: nil)
+        
+        // Derive key with fingerprint
+        let fingerprint = "e36f7993abc123def456789012345678901234567890abcdef1234567890abcd"
+        let key2 = encryption.deriveChannelKey(from: password, channel: channel, creatorFingerprint: fingerprint)
+        
+        // Keys should be different due to different salts
+        XCTAssertNotEqual(key1.withUnsafeBytes { Data($0) }, key2.withUnsafeBytes { Data($0) })
+    }
+    
+    func testChannelPasswordDerivationPerformance() {
+        let encryption = NoiseChannelEncryption()
+        let password = "test-password-123"
+        let channel = "#performance-test"
+        let fingerprint = "e36f7993abc123def456789012345678901234567890abcdef1234567890abcd"
+        
+        // Measure time for PBKDF2 with 210,000 iterations
+        measure {
+            _ = encryption.deriveChannelKey(from: password, channel: channel, creatorFingerprint: fingerprint)
+        }
+        
+        // Should complete within reasonable time (< 1 second on modern hardware)
+    }
+    
+    func testDifferentChannelsProduceDifferentKeys() {
+        let encryption = NoiseChannelEncryption()
+        let password = "same-password"
+        let fingerprint = "e36f7993abc123def456789012345678901234567890abcdef1234567890abcd"
+        
+        let key1 = encryption.deriveChannelKey(from: password, channel: "#channel1", creatorFingerprint: fingerprint)
+        let key2 = encryption.deriveChannelKey(from: password, channel: "#channel2", creatorFingerprint: fingerprint)
+        
+        // Same password but different channels should produce different keys
+        XCTAssertNotEqual(key1.withUnsafeBytes { Data($0) }, key2.withUnsafeBytes { Data($0) })
+    }
+    
+    // MARK: - Message Padding Tests
+    
+    func testMessagePaddingAppliedToAllPackets() throws {
+        // Create a small packet
+        let packet = BitchatPacket(
+            type: MessageType.message.rawValue,
+            senderID: Data("testuser".utf8),
+            recipientID: nil,
+            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
+            payload: Data("Hello".utf8),
+            signature: nil,
+            ttl: 3
+        )
+        
+        // Encode packet
+        guard let encodedData = packet.toBinaryData() else {
+            XCTFail("Failed to encode packet")
+            return
+        }
+        
+        // Check that size matches one of the standard block sizes
+        let blockSizes = [256, 512, 1024, 2048]
+        XCTAssertTrue(blockSizes.contains(encodedData.count) || encodedData.count > 2048,
+                      "Encoded data size \(encodedData.count) doesn't match expected block sizes")
+        
+        // Decode should work correctly
+        guard let decodedPacket = BitchatPacket.from(encodedData) else {
+            XCTFail("Failed to decode packet")
+            return
+        }
+        
+        // Verify decoded content matches original
+        XCTAssertEqual(decodedPacket.type, packet.type)
+        XCTAssertEqual(String(data: decodedPacket.payload, encoding: .utf8),
+                       String(data: packet.payload, encoding: .utf8))
+    }
+    
+    func testPaddingConsistentAcrossMessages() {
+        // Create multiple packets with same size payload
+        let packets: [BitchatPacket] = (0..<5).map { i in
+            BitchatPacket(
+                type: MessageType.message.rawValue,
+                senderID: Data("user\(i)".utf8),
+                recipientID: nil,
+                timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
+                payload: Data("Same size message content here".utf8),
+                signature: nil,
+                ttl: 3
+            )
+        }
+        
+        // Encode all packets
+        let encodedSizes = packets.compactMap { $0.toBinaryData()?.count }
+        
+        // All should have same padded size
+        XCTAssertEqual(encodedSizes.count, packets.count)
+        let firstSize = encodedSizes[0]
+        XCTAssertTrue(encodedSizes.allSatisfy { $0 == firstSize },
+                      "All packets with similar content should pad to same size")
+    }
+    
+    // MARK: - Public Key Validation Tests
+    
+    func testValidPublicKeyAccepted() throws {
+        // Generate a valid key
+        let validKey = Curve25519.KeyAgreement.PrivateKey()
+        let publicKeyData = validKey.publicKey.rawRepresentation
+        
+        // Should validate successfully
+        let validated = try NoiseHandshakeState.validatePublicKey(publicKeyData)
+        XCTAssertEqual(validated.rawRepresentation, publicKeyData)
+    }
+    
+    func testAllZeroKeyRejected() {
+        let zeroKey = Data(repeating: 0x00, count: 32)
+        
+        XCTAssertThrowsError(try NoiseHandshakeState.validatePublicKey(zeroKey)) { error in
+            XCTAssertEqual(error as? NoiseError, NoiseError.invalidPublicKey)
+        }
+    }
+    
+    func testAllOneKeyRejected() {
+        let oneKey = Data(repeating: 0xFF, count: 32)
+        
+        XCTAssertThrowsError(try NoiseHandshakeState.validatePublicKey(oneKey)) { error in
+            XCTAssertEqual(error as? NoiseError, NoiseError.invalidPublicKey)
+        }
+    }
+    
+    func testInvalidKeySizeRejected() {
+        // Too short
+        let shortKey = Data(repeating: 0x42, count: 16)
+        XCTAssertThrowsError(try NoiseHandshakeState.validatePublicKey(shortKey)) { error in
+            XCTAssertEqual(error as? NoiseError, NoiseError.invalidPublicKey)
+        }
+        
+        // Too long
+        let longKey = Data(repeating: 0x42, count: 64)
+        XCTAssertThrowsError(try NoiseHandshakeState.validatePublicKey(longKey)) { error in
+            XCTAssertEqual(error as? NoiseError, NoiseError.invalidPublicKey)
+        }
+    }
+    
+    func testWeakKeyRejected() {
+        // Known weak Curve25519 key patterns
+        // Low order points that would result in weak DH
+        let weakKeys = [
+            Data([0x01] + Array(repeating: 0x00, count: 31)), // Near zero
+            Data(Array(repeating: 0x00, count: 31) + [0x01]), // Different pattern
+        ]
+        
+        for weakKey in weakKeys {
+            // CryptoKit should reject these during DH operation
+            if (try? NoiseHandshakeState.validatePublicKey(weakKey)) != nil {
+                // If key creation succeeds, DH should fail in validation
+                print("Note: Weak key pattern was not rejected by CryptoKit directly")
+            }
+        }
+    }
+    
+    // MARK: - Integration Tests
+    
+    func testSecureHandshakeWithValidation() throws {
+        // Create two parties
+        let aliceStatic = Curve25519.KeyAgreement.PrivateKey()
+        let bobStatic = Curve25519.KeyAgreement.PrivateKey()
+        
+        var alice = NoiseHandshakeState(role: .initiator, pattern: .XX, localStaticKey: aliceStatic)
+        var bob = NoiseHandshakeState(role: .responder, pattern: .XX, localStaticKey: bobStatic)
+        
+        // Perform handshake - validation happens automatically
+        let msg1 = try alice.writeMessage()
+        _ = try bob.readMessage(msg1)
+        
+        let msg2 = try bob.writeMessage()
+        _ = try alice.readMessage(msg2)
+        
+        let msg3 = try alice.writeMessage()
+        _ = try bob.readMessage(msg3)
+        
+        // Both should complete successfully
+        XCTAssertTrue(alice.isHandshakeComplete())
+        XCTAssertTrue(bob.isHandshakeComplete())
+    }
+    
+    func testPaddedMessageTransmission() throws {
+        // Create a packet and encode it
+        let originalMessage = "Test message for padding"
+        let packet = BitchatPacket(
+            type: MessageType.message.rawValue,
+            senderID: Data("sender123".utf8),
+            recipientID: Data("recipient".utf8),
+            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
+            payload: Data(originalMessage.utf8),
+            signature: nil,
+            ttl: 5
+        )
+        
+        // Encode (with padding)
+        guard let encoded = packet.toBinaryData() else {
+            XCTFail("Failed to encode")
+            return
+        }
+        
+        // Verify padded size
+        XCTAssertTrue(encoded.count >= originalMessage.count + 21) // Header + sender + payload
+        
+        // Decode (removes padding)
+        guard let decoded = BitchatPacket.from(encoded) else {
+            XCTFail("Failed to decode")
+            return
+        }
+        
+        // Verify message integrity
+        XCTAssertEqual(String(data: decoded.payload, encoding: .utf8), originalMessage)
+    }
+    
+    // MARK: - Session Rekeying Tests
+    
+    func testSessionRekeyingTriggered() {
+        // Create session manager
+        let localKey = Curve25519.KeyAgreement.PrivateKey()
+        let sessionManager = NoiseSessionManager(localStaticKey: localKey)
+        
+        // Create a session
+        let session = sessionManager.createSession(for: "testPeer", role: .initiator)
+        
+        // Complete handshake
+        let remoteKey = Curve25519.KeyAgreement.PrivateKey()
+        var remoteHandshake = NoiseHandshakeState(role: .responder, pattern: .XX, localStaticKey: remoteKey)
+        
+        do {
+            let msg1 = try session.startHandshake()
+            _ = try remoteHandshake.readMessage(msg1)
+            
+            let msg2 = try remoteHandshake.writeMessage()
+            _ = try session.processHandshakeMessage(msg2)
+            
+            let msg3 = try session.writeMessage()
+            _ = try remoteHandshake.readMessage(msg3)
+            
+            XCTAssertTrue(session.isEstablished())
+            
+            // Get sessions needing rekey (should be empty)
+            var needsRekey = sessionManager.getSessionsNeedingRekey()
+            XCTAssertTrue(needsRekey.isEmpty)
+            
+            // Force the session to need rekeying by manipulating its state
+            if let secureSession = session as? SecureNoiseSession {
+                // Set old activity time
+                let oldTime = Date().addingTimeInterval(-35 * 60)
+                secureSession.setLastActivityTimeForTesting(oldTime)
+                
+                // Now check again
+                needsRekey = sessionManager.getSessionsNeedingRekey()
+                XCTAssertFalse(needsRekey.isEmpty)
+                XCTAssertTrue(needsRekey.contains(where: { $0.peerID == "testPeer" && $0.needsRekey }))
+            }
+            
+        } catch {
+            XCTFail("Test failed: \(error)")
+        }
+    }
+    
+    func testRekeyInitiation() {
+        // Create session manager
+        let localKey = Curve25519.KeyAgreement.PrivateKey()
+        let sessionManager = NoiseSessionManager(localStaticKey: localKey)
+        
+        // Create and establish a session
+        let session = sessionManager.createSession(for: "testPeer", role: .initiator)
+        
+        // Complete handshake
+        let remoteKey = Curve25519.KeyAgreement.PrivateKey()
+        var remoteHandshake = NoiseHandshakeState(role: .responder, pattern: .XX, localStaticKey: remoteKey)
+        
+        do {
+            let msg1 = try session.startHandshake()
+            _ = try remoteHandshake.readMessage(msg1)
+            
+            let msg2 = try remoteHandshake.writeMessage()
+            _ = try session.processHandshakeMessage(msg2)
+            
+            let msg3 = try session.writeMessage()
+            _ = try remoteHandshake.readMessage(msg3)
+            
+            XCTAssertTrue(session.isEstablished())
+            
+            // Store the old session's remote key
+            let oldRemoteKey = session.getRemoteStaticPublicKey()
+            XCTAssertNotNil(oldRemoteKey)
+            
+            // Initiate rekey
+            try sessionManager.initiateRekey(for: "testPeer")
+            
+            // The old session should be removed
+            let currentSession = sessionManager.getSession(for: "testPeer")
+            XCTAssertNil(currentSession) // Session removed, waiting for new handshake
+            
+        } catch {
+            XCTFail("Test failed: \(error)")
+        }
+    }
+    
+    // MARK: - Integration Tests
+    
+    func testFullRekeyHandshake() {
+        // Create encryption service
+        let alice = NoiseEncryptionService()
+        let bob = NoiseEncryptionService()
+        
+        let aliceID = "alice"
+        let bobID = "bob"
+        
+        do {
+            // Initial handshake
+            let msg1 = try alice.initiateHandshake(with: bobID)
+            let msg2 = try bob.processHandshakeMessage(from: aliceID, message: msg1)!
+            _ = try alice.processHandshakeMessage(from: bobID, message: msg2)
+            
+            // Verify sessions established
+            XCTAssertTrue(alice.hasEstablishedSession(with: bobID))
+            XCTAssertTrue(bob.hasEstablishedSession(with: aliceID))
+            
+            // Exchange some messages
+            let plaintext1 = "Hello Bob"
+            let encrypted1 = try alice.encrypt(Data(plaintext1.utf8), for: bobID)
+            let decrypted1 = try bob.decrypt(encrypted1, from: aliceID)
+            XCTAssertEqual(String(data: decrypted1, encoding: .utf8), plaintext1)
+            
+            // Force session to expire by manipulating internal state
+            // (In real scenario, this would happen after 30 minutes or 1M messages)
+            
+            // Trigger rekey from Alice's side
+            var rekeyHandshakeCompleted = false
+            alice.onHandshakeRequired = { peerID in
+                XCTAssertEqual(peerID, bobID)
+                rekeyHandshakeCompleted = true
+            }
+            
+            // After rekey, should be able to continue messaging
+            // Note: In real implementation, the rekey would be triggered automatically
+            
+        } catch {
+            XCTFail("Integration test failed: \(error)")
+        }
+    }
+    
+    func testErrorHandlingDuringHandshake() {
+        let service = NoiseEncryptionService()
+        
+        // Test invalid peer ID
+        XCTAssertThrowsError(try service.initiateHandshake(with: "")) { error in
+            if let securityError = error as? NoiseSecurityError {
+                XCTAssertEqual(securityError, NoiseSecurityError.invalidPeerID)
+            }
+        }
+        
+        // Test invalid handshake message
+        XCTAssertThrowsError(try service.processHandshakeMessage(from: "peer", message: Data())) { error in
+            // Should fail to parse empty data as handshake
+        }
+        
+        // Test oversized handshake message
+        let oversizedMessage = Data(repeating: 0x42, count: 100_000)
+        XCTAssertThrowsError(try service.processHandshakeMessage(from: "peer", message: oversizedMessage)) { error in
+            if let securityError = error as? NoiseSecurityError {
+                XCTAssertEqual(securityError, NoiseSecurityError.messageTooLarge)
+            }
+        }
+    }
+    
+    func testRateLimitingIntegration() {
+        let service = NoiseEncryptionService()
+        let peerID = "rate-limited-peer"
+        
+        var handshakeAttempts = 0
+        var rateLimitHit = false
+        
+        // Try many rapid handshakes
+        for _ in 0..<10 {
+            do {
+                _ = try service.initiateHandshake(with: peerID)
+                handshakeAttempts += 1
+            } catch {
+                if let securityError = error as? NoiseSecurityError,
+                   securityError == NoiseSecurityError.rateLimitExceeded {
+                    rateLimitHit = true
+                    break
+                }
+            }
+        }
+        
+        // Should hit rate limit before all 10 attempts
+        XCTAssertTrue(rateLimitHit)
+        XCTAssertLessThan(handshakeAttempts, 10)
+    }
+    
+    func testChannelEncryptionIntegration() {
+        let service = NoiseEncryptionService()
+        let channel = "#integration-test"
+        let password = "test-password"
+        let fingerprint = service.getIdentityFingerprint()
+        
+        // Set channel password
+        service.setChannelPassword(password, for: channel)
+        
+        // Encrypt channel message
+        do {
+            let message = "Channel message test"
+            let encrypted = try service.encryptChannelMessage(message, for: channel)
+            
+            // Verify it's encrypted
+            XCTAssertNotEqual(encrypted, Data(message.utf8))
+            
+            // Decrypt
+            let decrypted = try service.decryptChannelMessage(encrypted, for: channel)
+            XCTAssertEqual(decrypted, message)
+            
+            // Clean up
+            service.removeChannelPassword(for: channel)
+            
+        } catch {
+            XCTFail("Channel encryption failed: \(error)")
+        }
+    }
+    
+    func testSecureSessionConcurrency() {
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        
+        let alice = SecureNoiseSession(peerID: "bob", role: .initiator, localStaticKey: aliceKey)
+        let bob = SecureNoiseSession(peerID: "alice", role: .responder, localStaticKey: bobKey)
+        
+        // Complete handshake
+        do {
+            let msg1 = try alice.startHandshake()
+            _ = try bob.processHandshakeMessage(msg1)
+            
+            let msg2 = try bob.writeMessage()
+            _ = try alice.processHandshakeMessage(msg2)
+            
+            let msg3 = try alice.writeMessage()
+            _ = try bob.processHandshakeMessage(msg3)
+            
+            XCTAssertTrue(alice.isEstablished())
+            XCTAssertTrue(bob.isEstablished())
+            
+            // Concurrent encryption/decryption
+            let expectation = self.expectation(description: "Concurrent operations")
+            expectation.expectedFulfillmentCount = 20
+            
+            let queue = DispatchQueue(label: "test.concurrent", attributes: .concurrent)
+            
+            for i in 0..<10 {
+                // Encrypt from Alice
+                queue.async {
+                    do {
+                        let message = "Message \(i) from Alice"
+                        let encrypted = try alice.encrypt(Data(message.utf8))
+                        let decrypted = try bob.decrypt(encrypted)
+                        XCTAssertEqual(String(data: decrypted, encoding: .utf8), message)
+                        expectation.fulfill()
+                    } catch {
+                        XCTFail("Concurrent encrypt failed: \(error)")
+                    }
+                }
+                
+                // Encrypt from Bob
+                queue.async {
+                    do {
+                        let message = "Message \(i) from Bob"
+                        let encrypted = try bob.encrypt(Data(message.utf8))
+                        let decrypted = try alice.decrypt(encrypted)
+                        XCTAssertEqual(String(data: decrypted, encoding: .utf8), message)
+                        expectation.fulfill()
+                    } catch {
+                        XCTFail("Concurrent decrypt failed: \(error)")
+                    }
+                }
+            }
+            
+            waitForExpectations(timeout: 5)
+            
+        } catch {
+            XCTFail("Handshake failed: \(error)")
+        }
+    }
+}

bitchatTests/NoiseSecurityValidatorTests.swift

@@ -0,0 +1,191 @@
+//
+// NoiseSecurityValidatorTests.swift
+// bitchatTests
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import XCTest
+@testable import bitchat
+
+class NoiseSecurityValidatorTests: XCTestCase {
+    
+    // MARK: - Peer ID Validation Tests
+    
+    func testValidPeerIDAccepted() {
+        // Valid peer IDs
+        XCTAssertTrue(NoiseSecurityValidator.validatePeerID("user123"))
+        XCTAssertTrue(NoiseSecurityValidator.validatePeerID("alice"))
+        XCTAssertTrue(NoiseSecurityValidator.validatePeerID("bob_2024"))
+        XCTAssertTrue(NoiseSecurityValidator.validatePeerID("test-user"))
+        XCTAssertTrue(NoiseSecurityValidator.validatePeerID("192.168.1.1:8080")) // IP:port format
+    }
+    
+    func testInvalidPeerIDRejected() {
+        // Empty
+        XCTAssertFalse(NoiseSecurityValidator.validatePeerID(""))
+        
+        // Too long (over 255 chars)
+        let longID = String(repeating: "a", count: 256)
+        XCTAssertFalse(NoiseSecurityValidator.validatePeerID(longID))
+        
+        // Control characters
+        XCTAssertFalse(NoiseSecurityValidator.validatePeerID("user\0null"))
+        XCTAssertFalse(NoiseSecurityValidator.validatePeerID("user\nline"))
+        XCTAssertFalse(NoiseSecurityValidator.validatePeerID("user\ttab"))
+        
+        // Path traversal attempts
+        XCTAssertFalse(NoiseSecurityValidator.validatePeerID("../../../etc/passwd"))
+        XCTAssertFalse(NoiseSecurityValidator.validatePeerID("user/../admin"))
+    }
+    
+    // MARK: - Message Size Validation Tests
+    
+    func testValidMessageSizeAccepted() {
+        // Small message
+        let smallData = Data(repeating: 0x42, count: 100)
+        XCTAssertTrue(NoiseSecurityValidator.validateMessageSize(smallData))
+        
+        // Medium message (1MB)
+        let mediumData = Data(repeating: 0x42, count: 1024 * 1024)
+        XCTAssertTrue(NoiseSecurityValidator.validateMessageSize(mediumData))
+        
+        // Just under limit (10MB - 1 byte)
+        let nearLimitData = Data(repeating: 0x42, count: 10 * 1024 * 1024 - 1)
+        XCTAssertTrue(NoiseSecurityValidator.validateMessageSize(nearLimitData))
+    }
+    
+    func testOversizedMessageRejected() {
+        // Exactly at limit (10MB)
+        let limitData = Data(repeating: 0x42, count: 10 * 1024 * 1024)
+        XCTAssertFalse(NoiseSecurityValidator.validateMessageSize(limitData))
+        
+        // Over limit
+        let overData = Data(repeating: 0x42, count: 11 * 1024 * 1024)
+        XCTAssertFalse(NoiseSecurityValidator.validateMessageSize(overData))
+    }
+    
+    func testHandshakeMessageSizeValidation() {
+        // Valid handshake size
+        let validHandshake = Data(repeating: 0x42, count: 500)
+        XCTAssertTrue(NoiseSecurityValidator.validateHandshakeMessageSize(validHandshake))
+        
+        // Too large for handshake (over 64KB)
+        let largeHandshake = Data(repeating: 0x42, count: 65 * 1024)
+        XCTAssertFalse(NoiseSecurityValidator.validateHandshakeMessageSize(largeHandshake))
+    }
+    
+    // MARK: - Channel Name Validation Tests
+    
+    func testValidChannelNameAccepted() {
+        XCTAssertTrue(NoiseSecurityValidator.validateChannelName("#general"))
+        XCTAssertTrue(NoiseSecurityValidator.validateChannelName("#test-channel"))
+        XCTAssertTrue(NoiseSecurityValidator.validateChannelName("#channel_123"))
+        XCTAssertTrue(NoiseSecurityValidator.validateChannelName("#🎉party"))
+        XCTAssertTrue(NoiseSecurityValidator.validateChannelName("#2024"))
+    }
+    
+    func testInvalidChannelNameRejected() {
+        // Missing # prefix
+        XCTAssertFalse(NoiseSecurityValidator.validateChannelName("general"))
+        
+        // Empty or just #
+        XCTAssertFalse(NoiseSecurityValidator.validateChannelName(""))
+        XCTAssertFalse(NoiseSecurityValidator.validateChannelName("#"))
+        
+        // Too long (over 50 chars)
+        let longName = "#" + String(repeating: "a", count: 51)
+        XCTAssertFalse(NoiseSecurityValidator.validateChannelName(longName))
+        
+        // Invalid characters
+        XCTAssertFalse(NoiseSecurityValidator.validateChannelName("#channel\nwith\nnewlines"))
+        XCTAssertFalse(NoiseSecurityValidator.validateChannelName("#../../etc"))
+        XCTAssertFalse(NoiseSecurityValidator.validateChannelName("#channel<script>"))
+    }
+    
+    // MARK: - Encryption Parameters Validation
+    
+    func testValidateEncryptionNonce() {
+        // Valid 12-byte nonce for ChaCha20
+        let validNonce = Data(repeating: 0x42, count: 12)
+        XCTAssertTrue(NoiseSecurityValidator.validateNonce(validNonce))
+        
+        // Invalid sizes
+        let shortNonce = Data(repeating: 0x42, count: 8)
+        XCTAssertFalse(NoiseSecurityValidator.validateNonce(shortNonce))
+        
+        let longNonce = Data(repeating: 0x42, count: 16)
+        XCTAssertFalse(NoiseSecurityValidator.validateNonce(longNonce))
+        
+        // Empty
+        XCTAssertFalse(NoiseSecurityValidator.validateNonce(Data()))
+    }
+    
+    func testValidateKeyMaterial() {
+        // Valid 32-byte key
+        let validKey = Data(repeating: 0x42, count: 32)
+        XCTAssertTrue(NoiseSecurityValidator.validateKeyMaterial(validKey))
+        
+        // Invalid sizes
+        XCTAssertFalse(NoiseSecurityValidator.validateKeyMaterial(Data(repeating: 0x42, count: 16)))
+        XCTAssertFalse(NoiseSecurityValidator.validateKeyMaterial(Data(repeating: 0x42, count: 64)))
+        XCTAssertFalse(NoiseSecurityValidator.validateKeyMaterial(Data()))
+    }
+    
+    // MARK: - Input Sanitization Tests
+    
+    func testSanitizePeerID() {
+        // Normal case
+        XCTAssertEqual(NoiseSecurityValidator.sanitizePeerID("alice123"), "alice123")
+        
+        // Remove control characters
+        XCTAssertEqual(NoiseSecurityValidator.sanitizePeerID("alice\0bob"), "alicebob")
+        XCTAssertEqual(NoiseSecurityValidator.sanitizePeerID("user\n\r\t"), "user")
+        
+        // Truncate long IDs
+        let longID = String(repeating: "a", count: 300)
+        let sanitized = NoiseSecurityValidator.sanitizePeerID(longID)
+        XCTAssertEqual(sanitized.count, 255)
+        
+        // Empty becomes placeholder
+        XCTAssertEqual(NoiseSecurityValidator.sanitizePeerID(""), "unknown")
+    }
+    
+    func testSanitizeChannelName() {
+        // Normal case
+        XCTAssertEqual(NoiseSecurityValidator.sanitizeChannelName("#general"), "#general")
+        
+        // Add # prefix if missing
+        XCTAssertEqual(NoiseSecurityValidator.sanitizeChannelName("general"), "#general")
+        
+        // Remove invalid characters
+        XCTAssertEqual(NoiseSecurityValidator.sanitizeChannelName("#test\nchannel"), "#testchannel")
+        
+        // Truncate long names
+        let longName = String(repeating: "a", count: 100)
+        let sanitized = NoiseSecurityValidator.sanitizeChannelName(longName)
+        XCTAssertTrue(sanitized.hasPrefix("#"))
+        XCTAssertLessThanOrEqual(sanitized.count, 50)
+    }
+    
+    // MARK: - Security Pattern Detection Tests
+    
+    func testDetectSuspiciousPatterns() {
+        // Path traversal
+        XCTAssertTrue(NoiseSecurityValidator.containsSuspiciousPattern("../../../etc/passwd"))
+        XCTAssertTrue(NoiseSecurityValidator.containsSuspiciousPattern("..\\..\\windows\\system32"))
+        
+        // Script injection
+        XCTAssertTrue(NoiseSecurityValidator.containsSuspiciousPattern("<script>alert('xss')</script>"))
+        XCTAssertTrue(NoiseSecurityValidator.containsSuspiciousPattern("javascript:void(0)"))
+        
+        // SQL injection patterns
+        XCTAssertTrue(NoiseSecurityValidator.containsSuspiciousPattern("'; DROP TABLE users; --"))
+        XCTAssertTrue(NoiseSecurityValidator.containsSuspiciousPattern("1' OR '1'='1"))
+        
+        // Normal text should pass
+        XCTAssertFalse(NoiseSecurityValidator.containsSuspiciousPattern("Hello, this is a normal message!"))
+        XCTAssertFalse(NoiseSecurityValidator.containsSuspiciousPattern("Meeting at 3:00 PM"))
+    }
+}

bitchatTests/SecureNoiseSessionTests.swift

@@ -0,0 +1,287 @@
+//
+// SecureNoiseSessionTests.swift
+// bitchatTests
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import XCTest
+import CryptoKit
+@testable import bitchat
+
+class SecureNoiseSessionTests: XCTestCase {
+    
+    // MARK: - Session Timeout Tests
+    
+    func testSessionTimesOutAfter30Minutes() {
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let session = SecureNoiseSession(peerID: "bob", role: .initiator, localStaticKey: aliceKey)
+        
+        // Complete handshake
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        var bob = NoiseHandshakeState(role: .responder, pattern: .XX, localStaticKey: bobKey)
+        
+        // Perform handshake
+        do {
+            let msg1 = try session.startHandshake()
+            _ = try bob.readMessage(msg1)
+            
+            let msg2 = try bob.writeMessage()
+            _ = try session.processHandshakeMessage(msg2)
+            
+            let msg3 = try session.writeMessage()
+            _ = try bob.readMessage(msg3)
+            
+            XCTAssertTrue(session.isEstablished())
+            
+            // Check initial state
+            XCTAssertFalse(session.needsRenegotiation())
+            
+            // Fast-forward time by setting lastActivity to 31 minutes ago
+            let thirtyOneMinutesAgo = Date().addingTimeInterval(-31 * 60)
+            session.setLastActivityTimeForTesting(thirtyOneMinutesAgo)
+            
+            // Should now need renegotiation
+            XCTAssertTrue(session.needsRenegotiation())
+            
+        } catch {
+            XCTFail("Handshake failed: \(error)")
+        }
+    }
+    
+    func testSessionRemainsValidUnder30Minutes() {
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let session = SecureNoiseSession(peerID: "bob", role: .initiator, localStaticKey: aliceKey)
+        
+        // Complete handshake
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        var bob = NoiseHandshakeState(role: .responder, pattern: .XX, localStaticKey: bobKey)
+        
+        do {
+            let msg1 = try session.startHandshake()
+            _ = try bob.readMessage(msg1)
+            
+            let msg2 = try bob.writeMessage()
+            _ = try session.processHandshakeMessage(msg2)
+            
+            let msg3 = try session.writeMessage()
+            _ = try bob.readMessage(msg3)
+            
+            XCTAssertTrue(session.isEstablished())
+            
+            // Set lastActivity to 29 minutes ago
+            let twentyNineMinutesAgo = Date().addingTimeInterval(-29 * 60)
+            session.setLastActivityTimeForTesting(twentyNineMinutesAgo)
+            
+            // Should NOT need renegotiation
+            XCTAssertFalse(session.needsRenegotiation())
+            
+        } catch {
+            XCTFail("Handshake failed: \(error)")
+        }
+    }
+    
+    // MARK: - Message Count Limit Tests
+    
+    func testSessionNeedsRekeyAfterMessageLimit() {
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        
+        let alice = SecureNoiseSession(peerID: "bob", role: .initiator, localStaticKey: aliceKey)
+        let bob = SecureNoiseSession(peerID: "alice", role: .responder, localStaticKey: bobKey)
+        
+        // Complete handshake
+        do {
+            let msg1 = try alice.startHandshake()
+            _ = try bob.processHandshakeMessage(msg1)
+            
+            let msg2 = try bob.writeMessage()
+            _ = try alice.processHandshakeMessage(msg2)
+            
+            let msg3 = try alice.writeMessage()
+            _ = try bob.processHandshakeMessage(msg3)
+            
+            XCTAssertTrue(alice.isEstablished())
+            XCTAssertTrue(bob.isEstablished())
+            
+            // Check initial state
+            XCTAssertFalse(alice.needsRenegotiation())
+            
+            // Set message count to just under 90% threshold (900,000)
+            alice.setMessageCountForTesting(899_999)
+            XCTAssertFalse(alice.needsRenegotiation())
+            
+            // Set message count to 90% threshold
+            alice.setMessageCountForTesting(900_000)
+            XCTAssertTrue(alice.needsRenegotiation())
+            
+        } catch {
+            XCTFail("Handshake failed: \(error)")
+        }
+    }
+    
+    // MARK: - Activity Tracking Tests
+    
+    func testActivityUpdatesOnEncryption() {
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        
+        let alice = SecureNoiseSession(peerID: "bob", role: .initiator, localStaticKey: aliceKey)
+        let bob = SecureNoiseSession(peerID: "alice", role: .responder, localStaticKey: bobKey)
+        
+        // Complete handshake
+        do {
+            let msg1 = try alice.startHandshake()
+            _ = try bob.processHandshakeMessage(msg1)
+            
+            let msg2 = try bob.writeMessage()
+            _ = try alice.processHandshakeMessage(msg2)
+            
+            let msg3 = try alice.writeMessage()
+            _ = try bob.processHandshakeMessage(msg3)
+            
+            // Set lastActivity to 5 minutes ago
+            let fiveMinutesAgo = Date().addingTimeInterval(-5 * 60)
+            alice.setLastActivityTimeForTesting(fiveMinutesAgo)
+            
+            // Encrypt a message
+            let plaintext = Data("Hello Bob".utf8)
+            _ = try alice.encrypt(plaintext)
+            
+            // Activity should be updated to now
+            let timeSinceUpdate = Date().timeIntervalSince(alice.lastActivityTime)
+            XCTAssertLessThan(timeSinceUpdate, 1.0) // Should be within 1 second
+            
+        } catch {
+            XCTFail("Test failed: \(error)")
+        }
+    }
+    
+    func testActivityUpdatesOnDecryption() {
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        
+        let alice = SecureNoiseSession(peerID: "bob", role: .initiator, localStaticKey: aliceKey)
+        let bob = SecureNoiseSession(peerID: "alice", role: .responder, localStaticKey: bobKey)
+        
+        // Complete handshake
+        do {
+            let msg1 = try alice.startHandshake()
+            _ = try bob.processHandshakeMessage(msg1)
+            
+            let msg2 = try bob.writeMessage()
+            _ = try alice.processHandshakeMessage(msg2)
+            
+            let msg3 = try alice.writeMessage()
+            _ = try bob.processHandshakeMessage(msg3)
+            
+            // Encrypt a message from Alice
+            let plaintext = Data("Hello Bob".utf8)
+            let ciphertext = try alice.encrypt(plaintext)
+            
+            // Set Bob's lastActivity to 5 minutes ago
+            let fiveMinutesAgo = Date().addingTimeInterval(-5 * 60)
+            bob.setLastActivityTimeForTesting(fiveMinutesAgo)
+            
+            // Decrypt the message
+            _ = try bob.decrypt(ciphertext)
+            
+            // Activity should be updated to now
+            let timeSinceUpdate = Date().timeIntervalSince(bob.lastActivityTime)
+            XCTAssertLessThan(timeSinceUpdate, 1.0) // Should be within 1 second
+            
+        } catch {
+            XCTFail("Test failed: \(error)")
+        }
+    }
+    
+    // MARK: - Message Count Tracking Tests
+    
+    func testMessageCountIncrements() {
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        
+        let alice = SecureNoiseSession(peerID: "bob", role: .initiator, localStaticKey: aliceKey)
+        let bob = SecureNoiseSession(peerID: "alice", role: .responder, localStaticKey: bobKey)
+        
+        // Complete handshake
+        do {
+            let msg1 = try alice.startHandshake()
+            _ = try bob.processHandshakeMessage(msg1)
+            
+            let msg2 = try bob.writeMessage()
+            _ = try alice.processHandshakeMessage(msg2)
+            
+            let msg3 = try alice.writeMessage()
+            _ = try bob.processHandshakeMessage(msg3)
+            
+            // Check initial message count
+            XCTAssertEqual(alice.messageCount, 0)
+            
+            // Send multiple messages
+            for i in 1...5 {
+                let plaintext = Data("Message \(i)".utf8)
+                let ciphertext = try alice.encrypt(plaintext)
+                _ = try bob.decrypt(ciphertext)
+            }
+            
+            // Check message count incremented
+            XCTAssertEqual(alice.messageCount, 5) // Alice sent 5 messages
+            XCTAssertEqual(bob.messageCount, 0)   // Bob received but didn't send
+            
+        } catch {
+            XCTFail("Test failed: \(error)")
+        }
+    }
+    
+    // MARK: - Integration Tests
+    
+    func testFullSessionLifecycle() {
+        let aliceKey = Curve25519.KeyAgreement.PrivateKey()
+        let bobKey = Curve25519.KeyAgreement.PrivateKey()
+        
+        let alice = SecureNoiseSession(peerID: "bob", role: .initiator, localStaticKey: aliceKey)
+        let bob = SecureNoiseSession(peerID: "alice", role: .responder, localStaticKey: bobKey)
+        
+        do {
+            // 1. Perform handshake
+            let msg1 = try alice.startHandshake()
+            _ = try bob.processHandshakeMessage(msg1)
+            
+            let msg2 = try bob.writeMessage()
+            _ = try alice.processHandshakeMessage(msg2)
+            
+            let msg3 = try alice.writeMessage()
+            _ = try bob.processHandshakeMessage(msg3)
+            
+            XCTAssertTrue(alice.isEstablished())
+            XCTAssertTrue(bob.isEstablished())
+            
+            // 2. Exchange messages
+            let message1 = "Hello from Alice"
+            let ciphertext1 = try alice.encrypt(Data(message1.utf8))
+            let decrypted1 = try bob.decrypt(ciphertext1)
+            XCTAssertEqual(String(data: decrypted1, encoding: .utf8), message1)
+            
+            let message2 = "Hello from Bob"
+            let ciphertext2 = try bob.encrypt(Data(message2.utf8))
+            let decrypted2 = try alice.decrypt(ciphertext2)
+            XCTAssertEqual(String(data: decrypted2, encoding: .utf8), message2)
+            
+            // 3. Check session health
+            XCTAssertFalse(alice.needsRenegotiation())
+            XCTAssertFalse(bob.needsRenegotiation())
+            
+            // 4. Simulate time passing
+            let oldTime = Date().addingTimeInterval(-35 * 60)
+            alice.setLastActivityTimeForTesting(oldTime)
+            
+            // 5. Check renegotiation needed
+            XCTAssertTrue(alice.needsRenegotiation())
+            
+        } catch {
+            XCTFail("Test failed: \(error)")
+        }
+    }
+}