Pin announce signing keys to stop mesh identity spoofing (#1349)

TOFU-pins the Ed25519 signing key per noise key so a self-consistent announce that reuses a victim's peerID+noise key with the attacker's signing key/nickname is rejected instead of overwriting the registry and persisted identity. Complements #1432: that PR's signed-LEAVE verification reads the stored signing key this PR protects from announce-path poisoning.

Rebased onto main as a single commit; swift build --build-tests green, 40/40 targeted tests incl. the spoofing e2e cases, and #1432's suites 50/50 unaffected.

.gitignore

@@ -80,3 +80,4 @@ build.log
 
 # Local configs
 Local.xcconfig
+*.profraw

bitchat/Identity/IdentityModels.swift

@@ -161,24 +161,24 @@ struct VouchRecord: Codable, Equatable {
 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] = [:] 
-    
+    var lastInteractions: [String: Date] = [:]
+
     // Blocked Nostr pubkeys (lowercased hex) for geohash chats
     var blockedNostrPubkeys: Set<String> = []
 
     // Vouching (transitive verification). All three fields are Optional so
-    // caches persisted before this feature decode cleanly — the synthesized
-    // decoder uses decodeIfPresent for optionals, and a missing key must not
-    // trip the "unreadable cache" recovery path that discards everything.
+    // caches persisted before this feature decode cleanly — decodeIfPresent
+    // is used below, and a missing key must not trip the "unreadable cache"
+    // recovery path that discards everything.
 
     // Vouchee fingerprint -> accepted vouches (capped per vouchee)
     var vouchesByVouchee: [String: [VouchRecord]]? = nil
@@ -189,6 +189,36 @@ struct IdentityCache: Codable {
     // Fingerprint -> when we verified it (orders outgoing vouch batches;
     // entries verified before this field exists sort as oldest)
     var verifiedAt: [String: Date]? = nil
+
+    // Fingerprint -> Cryptographic identity (noise + pinned signing key).
+    // Persisting the signing-key pin is security-critical: it must survive
+    // app restarts so an attacker cannot replay a known peer's
+    // noiseKey/peerID with their own signing key and be treated as first
+    // contact (TOFU downgrade).
+    var cryptographicIdentities: [String: CryptographicIdentity] = [:]
+
+    // Schema version for future migrations
+    var version: Int = 1
+
+    init() {}
+
+    // Custom decoding so caches written by older builds (missing newer keys
+    // such as `cryptographicIdentities` or the vouching fields) still load
+    // instead of being discarded. Every field uses decodeIfPresent so a
+    // missing key falls back to its default rather than throwing.
+    init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+        socialIdentities = try container.decodeIfPresent([String: SocialIdentity].self, forKey: .socialIdentities) ?? [:]
+        nicknameIndex = try container.decodeIfPresent([String: Set<String>].self, forKey: .nicknameIndex) ?? [:]
+        verifiedFingerprints = try container.decodeIfPresent(Set<String>.self, forKey: .verifiedFingerprints) ?? []
+        lastInteractions = try container.decodeIfPresent([String: Date].self, forKey: .lastInteractions) ?? [:]
+        blockedNostrPubkeys = try container.decodeIfPresent(Set<String>.self, forKey: .blockedNostrPubkeys) ?? []
+        vouchesByVouchee = try container.decodeIfPresent([String: [VouchRecord]].self, forKey: .vouchesByVouchee)
+        vouchBatchSentAt = try container.decodeIfPresent([String: Date].self, forKey: .vouchBatchSentAt)
+        verifiedAt = try container.decodeIfPresent([String: Date].self, forKey: .verifiedAt)
+        cryptographicIdentities = try container.decodeIfPresent([String: CryptographicIdentity].self, forKey: .cryptographicIdentities) ?? [:]
+        version = try container.decodeIfPresent(Int.self, forKey: .version) ?? 1
+    }
 }
 
 //

bitchat/Identity/SecureIdentityStateManager.swift

@@ -152,18 +152,29 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
     
     // In-memory state
     private var ephemeralSessions: [PeerID: EphemeralIdentity] = [:]
-    private var cryptographicIdentities: [String: CryptographicIdentity] = [:]
+    // Cryptographic identities (including pinned signing keys) live inside
+    // `cache` so they persist across app restarts; see IdentityCache.
     private var cache: IdentityCache = IdentityCache()
     
     // Thread safety
     private let queue = DispatchQueue(label: "bitchat.identity.state", attributes: .concurrent)
     
     // Pending-save coalescing flag. Reads/writes are serialized on `queue`.
-    // Persistence is done with a fire-and-forget `queue.async(.barrier)` rather
-    // than a retained DispatchSourceTimer: a lingering, never-cancelled timer
-    // keeps the dispatch machinery alive and prevents the unit-test process from
-    // exiting. (The original code used Timer.scheduledTimer on a GCD queue with
-    // no run loop, so saves never actually fired.)
+    //
+    // Persistence is SYNCHRONOUS: every mutating API runs its mutate + encrypt
+    // + keychain write inside `queue.sync(flags: .barrier)`, so when the call
+    // returns the write is already complete and NOTHING is left scheduled on
+    // the queue. This is deliberate — a retained DispatchSourceTimer (the
+    // original design) kept the dispatch machinery alive and prevented the
+    // unit-test process from exiting, and fire-and-forget `queue.async(.barrier)`
+    // (a later design) left a backlog of instrumented barrier saves still
+    // draining when LLVM's `--enable-code-coverage` `atexit` handler dumped
+    // `.profraw`, deadlocking the process at teardown on the constrained CI
+    // runner. Synchronous persistence has zero outstanding dispatch at exit, so
+    // neither failure mode is possible. `pendingSave` is now effectively always
+    // false after any mutation (saveIdentityCache persists inline and clears
+    // it); it remains only as a belt-and-suspenders flag read by `forceSave`
+    // and `deinit`.
     private var pendingSave = false
 
     // Encryption key
@@ -223,7 +234,22 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
     }
     
     deinit {
-        forceSave()
+        // Do NOT dispatch onto `queue` here. `deinit` can run on any thread
+        // (including one draining `queue`), and the object is being
+        // deallocated: a `queue.sync` risks a re-entrant same-queue wait
+        // (deadlock) and a `queue.async` schedules work that resurrects `self`
+        // and may not drain before process exit.
+        //
+        // A flush here is redundant anyway: every mutating API already
+        // persists inline within its own barrier, so the keychain is already
+        // up to date. As a queue-free best-effort belt-and-suspenders, only
+        // flush if something is still pending. This is a direct read of
+        // in-hand state — safe because a deallocating object has no other
+        // live references, so nothing can be mutating `cache` concurrently.
+        if pendingSave {
+            pendingSave = false
+            persist(snapshot: cache)
+        }
     }
     
     // MARK: - Secure Loading/Saving
@@ -248,21 +274,27 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
         }
     }
     
-    /// Persists the cache. Always invoked on `queue` under a barrier (its callers
-    /// run inside `queue.async(.barrier)`), so it simply marks the cache dirty
-    /// and persists it on the same serialized context — no timer, nothing left
-    /// scheduled to keep the process alive.
+    /// Persists the cache. Always invoked on `queue` under a barrier (its
+    /// callers run inside `queue.sync(flags: .barrier)`), so `cache` is read
+    /// while serialized. The encode + keychain write are done here (already on
+    /// the exclusive barrier context), synchronously, so no separate hop is
+    /// scheduled and nothing is left to keep the process alive.
     private func saveIdentityCache() {
         pendingSave = true
-        performSave()
+        // On the barrier context already: snapshot is trivially consistent.
+        persist(snapshot: cache)
+        pendingSave = false
     }
 
-    /// Writes the cache to the keychain. Must run on `queue` with exclusive
-    /// (barrier) access.
-    private func performSave() {
-        guard pendingSave else { return }
-        pendingSave = false
-
+    /// Encodes, seals, and writes a *snapshot* of the cache to the keychain.
+    ///
+    /// Takes the cache by value so callers can capture a consistent snapshot
+    /// under `queue` and then encode without holding it. Reading `cache`
+    /// concurrently with a barrier writer would be a data race on the
+    /// dictionary storage, which — because `JSONEncoder` walks that storage —
+    /// can spin forever (observed as a CI test-suite hang), so the snapshot
+    /// must be taken on `queue`, never off it.
+    private func persist(snapshot: IdentityCache) {
         // Never persist under an ephemeral key — it would overwrite the real
         // cache with data the next launch cannot decrypt.
         guard !encryptionKeyIsEphemeral else {
@@ -271,7 +303,7 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
         }
 
         do {
-            let data = try JSONEncoder().encode(cache)
+            let data = try JSONEncoder().encode(snapshot)
             let sealedBox = try AES.GCM.seal(data, using: encryptionKey)
             let saved = keychain.saveIdentityKey(sealedBox.combined!, forKey: cacheKey)
             if saved {
@@ -282,14 +314,26 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
         }
     }
 
-    // Force immediate save (for app termination / lifecycle events). Mutations
-    // already persist synchronously via saveIdentityCache, so this is normally a
-    // no-op (performSave early-returns when nothing is pending). Runs directly on
-    // the caller's thread — deliberately NOT a `queue.sync(barrier)`, which is
-    // reachable from `deinit` and from async tests on the swift-concurrency
-    // cooperative pool where a blocking barrier-sync can starve/deadlock it.
+    // Force a flush (for app-termination / lifecycle events — NOT from
+    // `deinit`, which persists inline; see the deinit note). Every mutating
+    // API already persists inline inside its own barrier via
+    // `saveIdentityCache`, so by the time this is called the keychain is
+    // already up to date and this is normally a no-op; it exists as a
+    // belt-and-suspenders flush of any `pendingSave` left set.
+    //
+    // Runs synchronously inside a `queue.sync(flags: .barrier)`: the barrier
+    // makes the `cache` read race-free (a plain off-queue read races in-flight
+    // barrier writers — JSONEncoder walking a concurrently-mutated dictionary
+    // can spin forever, which surfaced as a CI hang), and being synchronous it
+    // leaves nothing scheduled to keep the process alive at teardown. Safe
+    // against re-entrant deadlock because this is never invoked from `deinit`
+    // (the only path that can run *on* `queue`).
     func forceSave() {
-        performSave()
+        queue.sync(flags: .barrier) {
+            guard pendingSave else { return }
+            pendingSave = false
+            persist(snapshot: cache)
+        }
     }
     
     // MARK: - Social Identity Management
@@ -303,15 +347,33 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
     // MARK: - Cryptographic Identities
 
     /// Insert or update a cryptographic identity and optionally persist its signing key and claimed nickname.
+    ///
+    /// TOFU signing-key pinning: once a signing key has been persisted for a
+    /// fingerprint, an update carrying a *different* signing key is refused in
+    /// full (including the claimed-nickname update) and security-logged. This
+    /// mirrors `BLEPeerRegistry.upsertVerifiedAnnounce` — without it, an
+    /// attacker replaying a victim's noiseKey/peerID with their own signing
+    /// key could overwrite the victim's persisted identity while the victim is
+    /// offline or after an app restart. The refusal is permanent: there is
+    /// currently no targeted in-app way to reset the pin (`setVerified` does
+    /// not touch it). Recovering from a legitimate signing re-key requires the
+    /// peer to establish a new noise identity (new peerID) or the local user
+    /// to wipe all identity data (`clearAllIdentityData`, e.g. panic wipe).
     /// - Parameters:
     ///   - fingerprint: SHA-256 hex of the Noise static public key
     ///   - noisePublicKey: Noise static public key data
     ///   - signingPublicKey: Optional Ed25519 signing public key for authenticating public messages
     ///   - claimedNickname: Optional latest claimed nickname to persist into social identity
     func upsertCryptographicIdentity(fingerprint: String, noisePublicKey: Data, signingPublicKey: Data?, claimedNickname: String? = nil) {
-        queue.async(flags: .barrier) {
+        queue.sync(flags: .barrier) {
             let now = Date()
-            if var existing = self.cryptographicIdentities[fingerprint] {
+            if var existing = self.cache.cryptographicIdentities[fingerprint] {
+                if let pinnedSigningKey = existing.signingPublicKey,
+                   let announcedSigningKey = signingPublicKey,
+                   pinnedSigningKey != announcedSigningKey {
+                    SecureLogger.warning("🚨 Refusing to replace pinned signing key for \(fingerprint.prefix(8))… (possible impersonation attempt)", category: .security)
+                    return
+                }
                 // Update keys if changed
                 if existing.publicKey != noisePublicKey {
                     existing = CryptographicIdentity(
@@ -320,11 +382,11 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
                         signingPublicKey: signingPublicKey ?? existing.signingPublicKey,
                         firstSeen: existing.firstSeen
                     )
-                    self.cryptographicIdentities[fingerprint] = existing
+                    self.cache.cryptographicIdentities[fingerprint] = existing
                 } else {
                     // Update signing key
                     existing.signingPublicKey = signingPublicKey ?? existing.signingPublicKey
-                    self.cryptographicIdentities[fingerprint] = existing
+                    self.cache.cryptographicIdentities[fingerprint] = existing
                 }
                 // Persist updated state (already assigned in branches above)
             } else {
@@ -335,7 +397,7 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
                     signingPublicKey: signingPublicKey,
                     firstSeen: now
                 )
-                self.cryptographicIdentities[fingerprint] = entry
+                self.cache.cryptographicIdentities[fingerprint] = entry
             }
 
             // Optionally persist claimed nickname into social identity
@@ -367,12 +429,12 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
         queue.sync {
             // Defensive: ensure hex and correct length
             guard peerID.isShort else { return [] }
-            return cryptographicIdentities.values.filter { $0.fingerprint.hasPrefix(peerID.id) }
+            return cache.cryptographicIdentities.values.filter { $0.fingerprint.hasPrefix(peerID.id) }
         }
     }
     
     func updateSocialIdentity(_ identity: SocialIdentity) {
-        queue.async(flags: .barrier) {
+        queue.sync(flags: .barrier) {
             let previousClaimedNickname = self.cache.socialIdentities[identity.fingerprint]?.claimedNickname
             self.cache.socialIdentities[identity.fingerprint] = identity
             
@@ -408,7 +470,7 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
     }
     
     func setFavorite(_ fingerprint: String, isFavorite: Bool) {
-        queue.async(flags: .barrier) {
+        queue.sync(flags: .barrier) {
             if var identity = self.cache.socialIdentities[fingerprint] {
                 identity.isFavorite = isFavorite
                 self.cache.socialIdentities[fingerprint] = identity
@@ -446,7 +508,7 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
     func setBlocked(_ fingerprint: String, isBlocked: Bool) {
         SecureLogger.info("User \(isBlocked ? "blocked" : "unblocked"): \(fingerprint)", category: .security)
         
-        queue.async(flags: .barrier) {
+        queue.sync(flags: .barrier) {
             if var identity = self.cache.socialIdentities[fingerprint] {
                 identity.isBlocked = isBlocked
                 if isBlocked {
@@ -480,7 +542,7 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
     
     func setNostrBlocked(_ pubkeyHexLowercased: String, isBlocked: Bool) {
         let key = pubkeyHexLowercased.lowercased()
-        queue.async(flags: .barrier) {
+        queue.sync(flags: .barrier) {
             if isBlocked {
                 self.cache.blockedNostrPubkeys.insert(key)
             } else {
@@ -503,7 +565,7 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
     }
     
     func updateHandshakeState(peerID: PeerID, state: HandshakeState) {
-        queue.async(flags: .barrier) {
+        queue.sync(flags: .barrier) {
             self.ephemeralSessions[peerID]?.handshakeState = state
             
             // If handshake completed, update last interaction
@@ -519,11 +581,10 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
     func clearAllIdentityData() {
         SecureLogger.warning("Clearing all identity data", category: .security)
         
-        queue.async(flags: .barrier) {
+        queue.sync(flags: .barrier) {
             self.cache = IdentityCache()
             self.ephemeralSessions.removeAll()
-            self.cryptographicIdentities.removeAll()
-            
+
             // Delete from keychain
             let deleted = self.keychain.deleteIdentityKey(forKey: self.cacheKey)
             SecureLogger.logKeyOperation(.delete, keyType: "identity cache", success: deleted)
@@ -531,7 +592,7 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
     }
     
     func removeEphemeralSession(peerID: PeerID) {
-        queue.async(flags: .barrier) {
+        queue.sync(flags: .barrier) {
             self.ephemeralSessions.removeValue(forKey: peerID)
         }
     }
@@ -541,7 +602,7 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
     func setVerified(fingerprint: String, verified: Bool) {
         SecureLogger.info("Fingerprint \(verified ? "verified" : "unverified"): \(fingerprint)", category: .security)
         
-        queue.async(flags: .barrier) {
+        queue.sync(flags: .barrier) {
             if verified {
                 self.cache.verifiedFingerprints.insert(fingerprint)
                 var verifiedAt = self.cache.verifiedAt ?? [:]
@@ -709,7 +770,7 @@ final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
 
     /// The peer's announce-bound Ed25519 signing key, if seen this session.
     func signingPublicKey(forFingerprint fingerprint: String) -> Data? {
-        queue.sync { cryptographicIdentities[fingerprint]?.signingPublicKey }
+        queue.sync { cache.cryptographicIdentities[fingerprint]?.signingPublicKey }
     }
 
     /// Verified fingerprints ordered most recently verified first (entries

bitchat/Services/BLE/BLEAnnounceHandler.swift

@@ -14,8 +14,14 @@ struct BLEAnnounceHandlerEnvironment {
     let messageTTL: UInt8
     /// Current time source.
     let now: () -> Date
-    /// Noise public key already recorded for the peer, if any (registry read).
-    let existingNoisePublicKey: (PeerID) -> Data?
+    /// Noise and signing public keys already recorded for the peer, if any
+    /// (single registry read so both come from one consistent snapshot).
+    let existingPeerKeys: (PeerID) -> (noisePublicKey: Data?, signingPublicKey: Data?)
+    /// Signing key from the persisted cryptographic identity for the peer, if
+    /// any. Registry pins do not survive app restarts or offline-peer
+    /// eviction; this fallback keeps the TOFU signing-key pin effective for
+    /// returning peers.
+    let persistedSigningPublicKey: (PeerID) -> Data?
     /// Verifies the packet signature against the announced signing key.
     let verifySignature: (_ packet: BitchatPacket, _ signingPublicKey: Data) -> Bool
     /// Direct link state for the peer (BLE-queue read).
@@ -29,13 +35,15 @@ struct BLEAnnounceHandlerEnvironment {
     /// Runs the registry mutation phase under the collections barrier.
     let withRegistryBarrier: (() -> Void) -> Void
     /// Upserts the verified announce into the peer registry.
+    /// Returns `nil` when the registry refuses the announce because it carries
+    /// a signing key different from the one already pinned for this peer.
     /// Must only be called from inside `withRegistryBarrier`.
     let upsertVerifiedAnnounce: (
         _ peerID: PeerID,
         _ announcement: AnnouncementPacket,
         _ isConnected: Bool,
         _ now: Date
-    ) -> BLEPeerAnnounceUpdate
+    ) -> BLEPeerAnnounceUpdate?
     /// Debounced reconnect-log decision.
     /// Must only be called from inside `withRegistryBarrier`.
     let shouldEmitReconnectLog: (_ peerID: PeerID, _ now: Date) -> Bool
@@ -115,7 +123,16 @@ final class BLEAnnounceHandler {
         // Suppress announce logs to reduce noise
 
         // Precompute signature verification outside barrier to reduce contention
-        let existingNoisePublicKey = env.existingNoisePublicKey(peerID)
+        var existingPeerKeys = env.existingPeerKeys(peerID)
+        if existingPeerKeys.signingPublicKey == nil {
+            // The registry entry (and its signing-key pin) is dropped on app
+            // restart and offline-peer eviction, but the persisted
+            // cryptographic identity survives both. Fall back to it so a
+            // returning peer is not treated as first contact — otherwise an
+            // attacker could replay the peer's noiseKey/peerID with their own
+            // signing key and re-pin the identity (TOFU downgrade).
+            existingPeerKeys.signingPublicKey = env.persistedSigningPublicKey(peerID)
+        }
         let hasSignature = packet.signature != nil
         let signatureValid: Bool
         if hasSignature {
@@ -129,13 +146,18 @@ final class BLEAnnounceHandler {
         let trustDecision = BLEAnnounceTrustPolicy.evaluate(
             hasSignature: hasSignature,
             signatureValid: signatureValid,
-            existingNoisePublicKey: existingNoisePublicKey,
-            announcedNoisePublicKey: announcement.noisePublicKey
+            existingNoisePublicKey: existingPeerKeys.noisePublicKey,
+            announcedNoisePublicKey: announcement.noisePublicKey,
+            existingSigningPublicKey: existingPeerKeys.signingPublicKey,
+            announcedSigningPublicKey: announcement.signingPublicKey
         )
         if case .reject(.keyMismatch) = trustDecision {
             SecureLogger.warning("⚠️ Announce key mismatch for \(peerID.id.prefix(8))… — keeping unverified", category: .security)
         }
-        let verifiedAnnounce = trustDecision.isVerified
+        if case .reject(.signingKeyMismatch) = trustDecision {
+            SecureLogger.warning("🚨 Announce signing-key mismatch for \(peerID.id.prefix(8))… — refusing to replace pinned signing key (possible impersonation attempt)", category: .security)
+        }
+        var verifiedAnnounce = trustDecision.isVerified
 
         var isNewPeer = false
         var isReconnectedPeer = false
@@ -172,12 +194,22 @@ final class BLEAnnounceHandler {
                 return
             }
 
-            let update = env.upsertVerifiedAnnounce(
+            // The registry re-checks the signing-key pin inside the barrier.
+            // The pre-barrier trust check reads the registry outside the
+            // barrier, so this closes the race where two announces for the
+            // same peer are evaluated concurrently.
+            guard let update = env.upsertVerifiedAnnounce(
                 peerID,
                 announcement,
                 hasPeripheralConnection || hasCentralSubscription || (isDirectAnnounce && !linkBoundToOtherPeer),
                 now
-            )
+            ) else {
+                SecureLogger.warning("🚨 Registry refused announce for \(peerID.id.prefix(8))… — signing key differs from pinned key", category: .security)
+                verifiedAnnounce = false
+                isNewPeer = false
+                isReconnectedPeer = false
+                return
+            }
             isNewPeer = update.isNewPeer
             isReconnectedPeer = update.wasDisconnected
 

bitchat/Services/BLE/BLEAnnounceHandlingPolicy.swift

@@ -56,6 +56,7 @@ enum BLEAnnounceTrustRejection: Equatable {
     case missingSignature
     case invalidSignature
     case keyMismatch
+    case signingKeyMismatch
 }
 
 enum BLEAnnounceTrustDecision: Equatable {
@@ -72,12 +73,25 @@ enum BLEAnnounceTrustPolicy {
         hasSignature: Bool,
         signatureValid: Bool,
         existingNoisePublicKey: Data?,
-        announcedNoisePublicKey: Data
+        announcedNoisePublicKey: Data,
+        existingSigningPublicKey: Data?,
+        announcedSigningPublicKey: Data
     ) -> BLEAnnounceTrustDecision {
         if let existingNoisePublicKey, existingNoisePublicKey != announcedNoisePublicKey {
             return .reject(.keyMismatch)
         }
 
+        // TOFU signing-key pinning. The packet signature only proves the
+        // announce is self-consistent — it is verified against the Ed25519 key
+        // carried *inside the same announce*. Since peerIDs derive from the
+        // broadcast (public) noise key, an attacker can replay a victim's
+        // peerID+noiseKey with their own signing key and a valid
+        // self-signature. Once we have bound a signing key to this peer,
+        // refuse to silently replace it.
+        if let existingSigningPublicKey, existingSigningPublicKey != announcedSigningPublicKey {
+            return .reject(.signingKeyMismatch)
+        }
+
         guard hasSignature else {
             return .reject(.missingSignature)
         }

bitchat/Services/BLE/BLEPeerRegistry.swift

@@ -174,6 +174,14 @@ struct BLEPeerRegistry {
         peers[peerID] = peer
     }
 
+    /// Applies a verified announce to the registry.
+    ///
+    /// TOFU signing-key pinning: once a signing key has been bound to this
+    /// peer entry, an announce carrying a *different* signing key is refused
+    /// (returns `nil`) and the existing record is left untouched. PeerIDs are
+    /// derived from the (public) noise key, so without pinning an attacker
+    /// could replay a victim's noiseKey/peerID with their own signing key and
+    /// silently take over the victim's mesh identity and nickname.
     mutating func upsertVerifiedAnnounce(
         peerID: PeerID,
         nickname: String,
@@ -183,8 +191,15 @@ struct BLEPeerRegistry {
         now: Date,
         capabilities: PeerCapabilities = [],
         bridgeGeohash: String? = nil
-    ) -> BLEPeerAnnounceUpdate {
+    ) -> BLEPeerAnnounceUpdate? {
         let existing = peers[peerID]
+
+        if let pinnedSigningKey = existing?.signingPublicKey,
+           let announcedSigningKey = signingPublicKey,
+           pinnedSigningKey != announcedSigningKey {
+            return nil
+        }
+
         let update = BLEPeerAnnounceUpdate(
             isNewPeer: existing == nil,
             wasDisconnected: existing?.isConnected == false,
@@ -196,7 +211,8 @@ struct BLEPeerRegistry {
             nickname: nickname,
             isConnected: isConnected,
             noisePublicKey: noisePublicKey,
-            signingPublicKey: signingPublicKey,
+            // Never drop an already-pinned signing key.
+            signingPublicKey: signingPublicKey ?? existing?.signingPublicKey,
             isVerifiedNickname: true,
             lastSeen: now,
             capabilities: capabilities,

bitchat/Services/BLE/BLEService.swift

@@ -5469,9 +5469,21 @@ extension BLEService {
             },
             messageTTL: messageTTL,
             now: { Date() },
-            existingNoisePublicKey: { [weak self] peerID in
+            existingPeerKeys: { [weak self] peerID in
+                guard let self = self else { return (nil, nil) }
+                return self.collectionsQueue.sync {
+                    let info = self.peerRegistry.info(for: peerID)
+                    return (info?.noisePublicKey, info?.signingPublicKey)
+                }
+            },
+            persistedSigningPublicKey: { [weak self] peerID in
+                // Same synchronous identity-manager read pattern as
+                // signedSenderDisplayName(for:from:); the manager serializes
+                // access on its own internal queue.
                 guard let self = self else { return nil }
-                return self.collectionsQueue.sync { self.peerRegistry.info(for: peerID)?.noisePublicKey }
+                return self.identityManager.getCryptoIdentitiesByPeerIDPrefix(peerID)
+                    .compactMap { $0.signingPublicKey }
+                    .first
             },
             verifySignature: { [weak self] packet, signingPublicKey in
                 self?.noiseService.verifyPacketSignature(packet, publicKey: signingPublicKey) ?? false
@@ -5503,16 +5515,24 @@ extension BLEService {
             },
             upsertVerifiedAnnounce: { [weak self] peerID, announcement, isConnected, now in
                 // Called from inside withRegistryBarrier; access registry directly.
-                self?.peerRegistry.upsertVerifiedAnnounce(
+                guard let self = self else {
+                    return BLEPeerAnnounceUpdate(isNewPeer: false, wasDisconnected: false, previousNickname: nil)
+                }
+                return self.peerRegistry.upsertVerifiedAnnounce(
                     peerID: peerID,
                     nickname: announcement.nickname,
                     noisePublicKey: announcement.noisePublicKey,
                     signingPublicKey: announcement.signingPublicKey,
                     isConnected: isConnected,
+                    // Propagate `nil` (registry refused the announce because it
+                    // carries a signing key different from the pinned one) so
+                    // the handler's guard rejects it instead of overwriting the
+                    // pinned identity. Main's capabilities/bridgeGeohash are
+                    // preserved.
                     now: now,
                     capabilities: announcement.capabilities ?? [],
                     bridgeGeohash: announcement.bridgeGeohash
-                ) ?? BLEPeerAnnounceUpdate(isNewPeer: false, wasDisconnected: false, previousNickname: nil)
+                )
             },
             shouldEmitReconnectLog: { [weak self] peerID, now in
                 // Called from inside withRegistryBarrier; access debouncer directly.

bitchatTests/Services/BLEAnnounceHandlerTests.swift

@@ -6,10 +6,13 @@ import Testing
 struct BLEAnnounceHandlerTests {
     private final class Recorder {
         var existingNoisePublicKey: Data?
+        var existingSigningPublicKey: Data?
+        var persistedSigningPublicKey: Data?
+        var persistedSigningKeyQueries: [PeerID] = []
         var signatureValid = true
         var linkState: (hasPeripheral: Bool, hasCentral: Bool) = (false, false)
         var linkBoundToOtherPeer = false
-        var upsertResult = BLEPeerAnnounceUpdate(isNewPeer: false, wasDisconnected: false, previousNickname: nil)
+        var upsertResult: BLEPeerAnnounceUpdate? = BLEPeerAnnounceUpdate(isNewPeer: false, wasDisconnected: false, previousNickname: nil)
         var dedupSeenIDs: Set<String> = []
         var shouldEmitReconnectLogResult = true
 
@@ -36,7 +39,11 @@ struct BLEAnnounceHandlerTests {
             localPeerID: { localPeerID },
             messageTTL: TransportConfig.messageTTLDefault,
             now: { now },
-            existingNoisePublicKey: { _ in recorder.existingNoisePublicKey },
+            existingPeerKeys: { _ in (recorder.existingNoisePublicKey, recorder.existingSigningPublicKey) },
+            persistedSigningPublicKey: { peerID in
+                recorder.persistedSigningKeyQueries.append(peerID)
+                return recorder.persistedSigningPublicKey
+            },
             verifySignature: { packet, signingPublicKey in
                 recorder.verifySignatureCalls.append((packet, signingPublicKey))
                 return recorder.signatureValid
@@ -482,6 +489,168 @@ struct BLEAnnounceHandlerTests {
         #expect(recorder.topologyUpdates.first?.neighbors == neighbors)
     }
 
+    @Test
+    func matchingPinnedSigningKeyIsAccepted() throws {
+        let now = Date(timeIntervalSince1970: 1_000)
+        let noiseKey = Data(repeating: 0x9A, count: 32)
+        let peerID = PeerID(publicKey: noiseKey)
+        let packet = try makeAnnouncePacket(
+            noisePublicKey: noiseKey,
+            peerID: peerID,
+            timestamp: timestamp(now),
+            signature: Data(repeating: 0xEE, count: 64)
+        )
+
+        let recorder = Recorder()
+        recorder.existingNoisePublicKey = noiseKey
+        // Matches the signing key encoded by makeAnnouncePacket.
+        recorder.existingSigningPublicKey = Data(repeating: 0x99, count: 32)
+        let handler = makeHandler(recorder: recorder, now: now)
+
+        handler.handle(packet, from: peerID)
+
+        #expect(recorder.upsertCalls.count == 1)
+        #expect(recorder.persistedIdentities.count == 1)
+    }
+
+    @Test
+    func signingKeyMismatchWithPinnedKeySkipsUpsertAndIdentityPersistence() throws {
+        let now = Date(timeIntervalSince1970: 1_000)
+        let noiseKey = Data(repeating: 0x9B, count: 32)
+        let peerID = PeerID(publicKey: noiseKey)
+        // Attacker announce: victim's noiseKey/peerID, attacker's signing key
+        // (0x99 from makeAnnouncePacket) with a "valid" self-signature.
+        let packet = try makeAnnouncePacket(
+            noisePublicKey: noiseKey,
+            peerID: peerID,
+            timestamp: timestamp(now),
+            signature: Data(repeating: 0xEE, count: 64)
+        )
+
+        let recorder = Recorder()
+        recorder.existingNoisePublicKey = noiseKey
+        recorder.existingSigningPublicKey = Data(repeating: 0x42, count: 32) // victim's pinned key
+        recorder.signatureValid = true
+        let handler = makeHandler(recorder: recorder, now: now)
+
+        handler.handle(packet, from: peerID)
+
+        #expect(recorder.upsertCalls.isEmpty)
+        #expect(recorder.persistedIdentities.isEmpty)
+        #expect(recorder.topologyUpdates.isEmpty)
+        #expect(recorder.uiEventDeliveries.count == 1)
+        #expect(recorder.uiEventDeliveries.first?.notifyPeerConnected == false)
+    }
+
+    @Test
+    func persistedSigningKeyMismatchWithoutRegistryEntryIsRejected() throws {
+        // Registry has no entry (app restart or offline-peer eviction), but
+        // the persisted cryptographic identity still pins the victim's
+        // signing key. An attacker replaying the victim's noiseKey/peerID
+        // with their own signing key must not be treated as first contact.
+        let now = Date(timeIntervalSince1970: 1_000)
+        let noiseKey = Data(repeating: 0x9D, count: 32)
+        let peerID = PeerID(publicKey: noiseKey)
+        let packet = try makeAnnouncePacket(
+            noisePublicKey: noiseKey,
+            peerID: peerID,
+            timestamp: timestamp(now),
+            signature: Data(repeating: 0xEE, count: 64)
+        )
+
+        let recorder = Recorder()
+        recorder.existingNoisePublicKey = nil
+        recorder.existingSigningPublicKey = nil
+        recorder.persistedSigningPublicKey = Data(repeating: 0x42, count: 32) // victim's persisted pin
+        let handler = makeHandler(recorder: recorder, now: now)
+
+        handler.handle(packet, from: peerID)
+
+        #expect(recorder.persistedSigningKeyQueries == [peerID])
+        #expect(recorder.upsertCalls.isEmpty)
+        #expect(recorder.persistedIdentities.isEmpty)
+        #expect(recorder.topologyUpdates.isEmpty)
+        #expect(recorder.uiEventDeliveries.count == 1)
+        #expect(recorder.uiEventDeliveries.first?.notifyPeerConnected == false)
+    }
+
+    @Test
+    func persistedSigningKeyMatchWithoutRegistryEntryIsAccepted() throws {
+        // Legitimate returning peer: registry entry evicted, persisted pin
+        // matches the announced signing key — accepted like a normal announce.
+        let now = Date(timeIntervalSince1970: 1_000)
+        let noiseKey = Data(repeating: 0x9E, count: 32)
+        let peerID = PeerID(publicKey: noiseKey)
+        let packet = try makeAnnouncePacket(
+            noisePublicKey: noiseKey,
+            peerID: peerID,
+            timestamp: timestamp(now),
+            signature: Data(repeating: 0xEE, count: 64)
+        )
+
+        let recorder = Recorder()
+        // Matches the signing key encoded by makeAnnouncePacket.
+        recorder.persistedSigningPublicKey = Data(repeating: 0x99, count: 32)
+        let handler = makeHandler(recorder: recorder, now: now)
+
+        handler.handle(packet, from: peerID)
+
+        #expect(recorder.upsertCalls.count == 1)
+        #expect(recorder.persistedIdentities.count == 1)
+    }
+
+    @Test
+    func registryPinnedSigningKeySkipsPersistedLookup() throws {
+        let now = Date(timeIntervalSince1970: 1_000)
+        let noiseKey = Data(repeating: 0x9F, count: 32)
+        let peerID = PeerID(publicKey: noiseKey)
+        let packet = try makeAnnouncePacket(
+            noisePublicKey: noiseKey,
+            peerID: peerID,
+            timestamp: timestamp(now),
+            signature: Data(repeating: 0xEE, count: 64)
+        )
+
+        let recorder = Recorder()
+        recorder.existingNoisePublicKey = noiseKey
+        recorder.existingSigningPublicKey = Data(repeating: 0x99, count: 32)
+        let handler = makeHandler(recorder: recorder, now: now)
+
+        handler.handle(packet, from: peerID)
+
+        #expect(recorder.persistedSigningKeyQueries.isEmpty)
+        #expect(recorder.upsertCalls.count == 1)
+    }
+
+    @Test
+    func registryPinRejectionSkipsTopologyAndIdentityPersistence() throws {
+        let now = Date(timeIntervalSince1970: 1_000)
+        let noiseKey = Data(repeating: 0x9C, count: 32)
+        let peerID = PeerID(publicKey: noiseKey)
+        let packet = try makeAnnouncePacket(
+            noisePublicKey: noiseKey,
+            peerID: peerID,
+            timestamp: timestamp(now),
+            signature: Data(repeating: 0xEE, count: 64),
+            directNeighbors: [Data(repeating: 0xAB, count: 8)]
+        )
+
+        // Pre-barrier trust check sees no pinned key (e.g. concurrent race),
+        // but the registry itself refuses to replace its pinned signing key.
+        let recorder = Recorder()
+        recorder.upsertResult = nil
+        let handler = makeHandler(recorder: recorder, now: now)
+
+        handler.handle(packet, from: peerID)
+
+        #expect(recorder.upsertCalls.count == 1)
+        #expect(recorder.persistedIdentities.isEmpty)
+        #expect(recorder.topologyUpdates.isEmpty)
+        #expect(recorder.uiEventDeliveries.count == 1)
+        #expect(recorder.uiEventDeliveries.first?.notifyPeerConnected == false)
+        #expect(recorder.afterglowDelays.isEmpty)
+    }
+
     @Test
     func keyMismatchWithExistingPeerKeepsAnnounceUnverified() throws {
         let now = Date(timeIntervalSince1970: 1_000)
@@ -506,6 +675,253 @@ struct BLEAnnounceHandlerTests {
         #expect(recorder.uiEventDeliveries.first?.notifyPeerConnected == false)
     }
 
+    @Test
+    func attackerReplayingVictimNoiseKeyWithOwnSigningKeyIsRejectedEndToEnd() throws {
+        // Real crypto: the attacker crafts a fully self-consistent announce
+        // (victim's noiseKey/peerID, attacker's signing key and nickname,
+        // valid packet signature made with the attacker's key). Without
+        // signing-key pinning this used to overwrite the victim's registry
+        // entry and persisted identity.
+        let victim = NoiseEncryptionService(keychain: MockKeychain())
+        let attacker = NoiseEncryptionService(keychain: MockKeychain())
+        let victimNoiseKey = victim.getStaticPublicKeyData()
+        let peerID = PeerID(publicKey: victimNoiseKey)
+        let now = Date()
+
+        final class RegistryBox {
+            var registry = BLEPeerRegistry()
+            var persistedIdentities: [AnnouncementPacket] = []
+        }
+        let box = RegistryBox()
+
+        let environment = BLEAnnounceHandlerEnvironment(
+            localPeerID: { PeerID(str: "0102030405060708") },
+            messageTTL: TransportConfig.messageTTLDefault,
+            now: { now },
+            existingPeerKeys: { peerID in
+                let info = box.registry.info(for: peerID)
+                return (info?.noisePublicKey, info?.signingPublicKey)
+            },
+            persistedSigningPublicKey: { _ in nil },
+            verifySignature: { packet, signingPublicKey in
+                victim.verifyPacketSignature(packet, publicKey: signingPublicKey)
+            },
+            linkState: { _ in (hasPeripheral: true, hasCentral: false) },
+            linkBoundToOtherPeer: { _, _ in false },
+            withRegistryBarrier: { body in body() },
+            upsertVerifiedAnnounce: { peerID, announcement, isConnected, now in
+                box.registry.upsertVerifiedAnnounce(
+                    peerID: peerID,
+                    nickname: announcement.nickname,
+                    noisePublicKey: announcement.noisePublicKey,
+                    signingPublicKey: announcement.signingPublicKey,
+                    isConnected: isConnected,
+                    now: now
+                )
+            },
+            shouldEmitReconnectLog: { _, _ in false },
+            updateTopology: { _, _ in },
+            persistIdentity: { announcement in
+                box.persistedIdentities.append(announcement)
+            },
+            dedupContains: { _ in true },
+            dedupMarkProcessed: { _ in },
+            deliverAnnounceUIEvents: { _, _, _ in },
+            trackPacketSeen: { _ in },
+            sendAnnounceBack: {},
+            scheduleAfterglow: { _ in }
+        )
+        let handler = BLEAnnounceHandler(environment: environment)
+
+        func makeSignedAnnounce(nickname: String, signer: NoiseEncryptionService) throws -> BitchatPacket {
+            let announcement = AnnouncementPacket(
+                nickname: nickname,
+                noisePublicKey: victimNoiseKey,
+                signingPublicKey: signer.getSigningPublicKeyData(),
+                directNeighbors: nil
+            )
+            let payload = try #require(announcement.encode())
+            let packet = BitchatPacket(
+                type: MessageType.announce.rawValue,
+                senderID: Data(hexString: peerID.id) ?? Data(),
+                recipientID: nil,
+                timestamp: UInt64(now.timeIntervalSince1970 * 1000),
+                payload: payload,
+                signature: nil,
+                ttl: TransportConfig.messageTTLDefault
+            )
+            return try #require(signer.signPacket(packet))
+        }
+
+        // Legitimate announce from the victim is accepted and pinned.
+        let victimAnnounce = try makeSignedAnnounce(nickname: "victim", signer: victim)
+        handler.handle(victimAnnounce, from: peerID)
+
+        #expect(box.registry.info(for: peerID)?.nickname == "victim")
+        #expect(box.registry.info(for: peerID)?.signingPublicKey == victim.getSigningPublicKeyData())
+        #expect(box.persistedIdentities.count == 1)
+
+        // Attacker announce with a valid self-signature must be rejected.
+        let attackerAnnounce = try makeSignedAnnounce(nickname: "attacker", signer: attacker)
+        handler.handle(attackerAnnounce, from: peerID)
+
+        #expect(box.registry.info(for: peerID)?.nickname == "victim")
+        #expect(box.registry.info(for: peerID)?.signingPublicKey == victim.getSigningPublicKeyData())
+        #expect(box.persistedIdentities.count == 1)
+
+        // The victim's subsequent announces (same pinned key) still work.
+        let victimRename = try makeSignedAnnounce(nickname: "victim-renamed", signer: victim)
+        handler.handle(victimRename, from: peerID)
+
+        #expect(box.registry.info(for: peerID)?.nickname == "victim-renamed")
+        #expect(box.persistedIdentities.count == 2)
+    }
+
+    @Test
+    func signingKeyPinSurvivesRegistryEvictionAndRestartEndToEnd() throws {
+        // Real crypto + real persistence: the victim announces and gets
+        // pinned, then the registry entry disappears (offline-peer eviction
+        // via reconcileConnectivity, or app restart which starts with an
+        // empty registry). The attacker replays the victim's
+        // noiseKey/peerID with their own signing key and a valid
+        // self-signature — the persisted identity must still block the
+        // takeover, and must not be overwritten. The victim (same signing
+        // key) must be re-accepted.
+        let victim = NoiseEncryptionService(keychain: MockKeychain())
+        let attacker = NoiseEncryptionService(keychain: MockKeychain())
+        let victimNoiseKey = victim.getStaticPublicKeyData()
+        let peerID = PeerID(publicKey: victimNoiseKey)
+        let now = Date()
+
+        let identityKeychain = MockKeychain()
+        let identityManager = SecureIdentityStateManager(identityKeychain)
+
+        final class RegistryBox {
+            var registry = BLEPeerRegistry()
+        }
+        let box = RegistryBox()
+
+        func makeEnvironment(identityManager: SecureIdentityStateManager) -> BLEAnnounceHandlerEnvironment {
+            BLEAnnounceHandlerEnvironment(
+                localPeerID: { PeerID(str: "0102030405060708") },
+                messageTTL: TransportConfig.messageTTLDefault,
+                now: { now },
+                existingPeerKeys: { peerID in
+                    let info = box.registry.info(for: peerID)
+                    return (info?.noisePublicKey, info?.signingPublicKey)
+                },
+                // Mirrors the BLEService wiring: fall back to the persisted
+                // cryptographic identity.
+                persistedSigningPublicKey: { peerID in
+                    identityManager.getCryptoIdentitiesByPeerIDPrefix(peerID)
+                        .compactMap { $0.signingPublicKey }
+                        .first
+                },
+                verifySignature: { packet, signingPublicKey in
+                    victim.verifyPacketSignature(packet, publicKey: signingPublicKey)
+                },
+                linkState: { _ in (hasPeripheral: true, hasCentral: false) },
+                linkBoundToOtherPeer: { _, _ in false },
+                withRegistryBarrier: { body in body() },
+                upsertVerifiedAnnounce: { peerID, announcement, isConnected, now in
+                    box.registry.upsertVerifiedAnnounce(
+                        peerID: peerID,
+                        nickname: announcement.nickname,
+                        noisePublicKey: announcement.noisePublicKey,
+                        signingPublicKey: announcement.signingPublicKey,
+                        isConnected: isConnected,
+                        now: now
+                    )
+                },
+                shouldEmitReconnectLog: { _, _ in false },
+                updateTopology: { _, _ in },
+                persistIdentity: { announcement in
+                    identityManager.upsertCryptographicIdentity(
+                        fingerprint: announcement.noisePublicKey.sha256Fingerprint(),
+                        noisePublicKey: announcement.noisePublicKey,
+                        signingPublicKey: announcement.signingPublicKey,
+                        claimedNickname: announcement.nickname
+                    )
+                },
+                dedupContains: { _ in true },
+                dedupMarkProcessed: { _ in },
+                deliverAnnounceUIEvents: { _, _, _ in },
+                trackPacketSeen: { _ in },
+                sendAnnounceBack: {},
+                scheduleAfterglow: { _ in }
+            )
+        }
+        let handler = BLEAnnounceHandler(environment: makeEnvironment(identityManager: identityManager))
+
+        func makeSignedAnnounce(nickname: String, signer: NoiseEncryptionService) throws -> BitchatPacket {
+            let announcement = AnnouncementPacket(
+                nickname: nickname,
+                noisePublicKey: victimNoiseKey,
+                signingPublicKey: signer.getSigningPublicKeyData(),
+                directNeighbors: nil
+            )
+            let payload = try #require(announcement.encode())
+            let packet = BitchatPacket(
+                type: MessageType.announce.rawValue,
+                senderID: Data(hexString: peerID.id) ?? Data(),
+                recipientID: nil,
+                timestamp: UInt64(now.timeIntervalSince1970 * 1000),
+                payload: payload,
+                signature: nil,
+                ttl: TransportConfig.messageTTLDefault
+            )
+            return try #require(signer.signPacket(packet))
+        }
+
+        func persistedIdentity() -> CryptographicIdentity? {
+            // queue.sync read; fences the manager's pending barrier writes.
+            identityManager.getCryptoIdentitiesByPeerIDPrefix(peerID).first
+        }
+
+        // 1. Victim announces: pinned in the registry and persisted.
+        handler.handle(try makeSignedAnnounce(nickname: "victim", signer: victim), from: peerID)
+        #expect(box.registry.info(for: peerID)?.signingPublicKey == victim.getSigningPublicKeyData())
+        #expect(persistedIdentity()?.signingPublicKey == victim.getSigningPublicKeyData())
+
+        // 2. Registry entry disappears (eviction / restart).
+        _ = box.registry.remove(peerID)
+        #expect(box.registry.info(for: peerID) == nil)
+
+        // 3. Attacker replay with own signing key: rejected via the persisted
+        //    pin, and neither the registry nor the persisted identity change.
+        handler.handle(try makeSignedAnnounce(nickname: "attacker", signer: attacker), from: peerID)
+        #expect(box.registry.info(for: peerID) == nil)
+        #expect(persistedIdentity()?.signingPublicKey == victim.getSigningPublicKeyData())
+        #expect(identityManager.getSocialIdentity(for: victimNoiseKey.sha256Fingerprint())?.claimedNickname == "victim")
+
+        // 4. Victim re-announces with the same signing key: accepted again.
+        handler.handle(try makeSignedAnnounce(nickname: "victim", signer: victim), from: peerID)
+        #expect(box.registry.info(for: peerID)?.nickname == "victim")
+        #expect(box.registry.info(for: peerID)?.signingPublicKey == victim.getSigningPublicKeyData())
+
+        // 5. Simulated app restart: a fresh identity manager reloads the pin
+        //    from the (mock) keychain, and a fresh registry starts empty. The
+        //    attacker replay is still rejected.
+        identityManager.forceSave()
+        let reloadedManager = SecureIdentityStateManager(identityKeychain)
+        #expect(
+            reloadedManager.getCryptoIdentitiesByPeerIDPrefix(peerID).first?.signingPublicKey
+                == victim.getSigningPublicKeyData()
+        )
+        box.registry = BLEPeerRegistry()
+        let restartedHandler = BLEAnnounceHandler(environment: makeEnvironment(identityManager: reloadedManager))
+        restartedHandler.handle(try makeSignedAnnounce(nickname: "attacker", signer: attacker), from: peerID)
+        #expect(box.registry.info(for: peerID) == nil)
+        #expect(
+            reloadedManager.getCryptoIdentitiesByPeerIDPrefix(peerID).first?.signingPublicKey
+                == victim.getSigningPublicKeyData()
+        )
+
+        // ...while the victim is accepted after the restart.
+        restartedHandler.handle(try makeSignedAnnounce(nickname: "victim", signer: victim), from: peerID)
+        #expect(box.registry.info(for: peerID)?.signingPublicKey == victim.getSigningPublicKeyData())
+    }
+
     private func expectNoSideEffects(_ recorder: Recorder) {
         #expect(recorder.barrierCount == 0)
         #expect(recorder.upsertCalls.isEmpty)

bitchatTests/Services/BLEAnnounceHandlingPolicyTests.swift

@@ -123,7 +123,9 @@ struct BLEAnnounceHandlingPolicyTests {
             hasSignature: false,
             signatureValid: false,
             existingNoisePublicKey: nil,
-            announcedNoisePublicKey: Data(repeating: 0x11, count: 32)
+            announcedNoisePublicKey: Data(repeating: 0x11, count: 32),
+            existingSigningPublicKey: nil,
+            announcedSigningPublicKey: Data(repeating: 0x99, count: 32)
         )
 
         #expect(decision == .reject(.missingSignature))
@@ -136,7 +138,9 @@ struct BLEAnnounceHandlingPolicyTests {
             hasSignature: true,
             signatureValid: false,
             existingNoisePublicKey: nil,
-            announcedNoisePublicKey: Data(repeating: 0x11, count: 32)
+            announcedNoisePublicKey: Data(repeating: 0x11, count: 32),
+            existingSigningPublicKey: nil,
+            announcedSigningPublicKey: Data(repeating: 0x99, count: 32)
         )
 
         #expect(decision == .reject(.invalidSignature))
@@ -148,7 +152,9 @@ struct BLEAnnounceHandlingPolicyTests {
             hasSignature: true,
             signatureValid: true,
             existingNoisePublicKey: Data(repeating: 0xAA, count: 32),
-            announcedNoisePublicKey: Data(repeating: 0xBB, count: 32)
+            announcedNoisePublicKey: Data(repeating: 0xBB, count: 32),
+            existingSigningPublicKey: nil,
+            announcedSigningPublicKey: Data(repeating: 0x99, count: 32)
         )
 
         #expect(decision == .reject(.keyMismatch))
@@ -162,13 +168,51 @@ struct BLEAnnounceHandlingPolicyTests {
             hasSignature: true,
             signatureValid: true,
             existingNoisePublicKey: noiseKey,
-            announcedNoisePublicKey: noiseKey
+            announcedNoisePublicKey: noiseKey,
+            existingSigningPublicKey: nil,
+            announcedSigningPublicKey: Data(repeating: 0x99, count: 32)
         )
 
         #expect(decision == .verified)
         #expect(decision.isVerified)
     }
 
+    @Test
+    func trustPolicyRejectsPinnedSigningKeyMismatchEvenWithValidSignature() {
+        let noiseKey = Data(repeating: 0xCC, count: 32)
+
+        // Attacker replays the victim's noiseKey/peerID with their own signing
+        // key and a valid self-signature; the pinned key must win.
+        let decision = BLEAnnounceTrustPolicy.evaluate(
+            hasSignature: true,
+            signatureValid: true,
+            existingNoisePublicKey: noiseKey,
+            announcedNoisePublicKey: noiseKey,
+            existingSigningPublicKey: Data(repeating: 0x99, count: 32),
+            announcedSigningPublicKey: Data(repeating: 0x66, count: 32)
+        )
+
+        #expect(decision == .reject(.signingKeyMismatch))
+        #expect(!decision.isVerified)
+    }
+
+    @Test
+    func trustPolicyAcceptsMatchingPinnedSigningKey() {
+        let noiseKey = Data(repeating: 0xCC, count: 32)
+        let signingKey = Data(repeating: 0x99, count: 32)
+
+        let decision = BLEAnnounceTrustPolicy.evaluate(
+            hasSignature: true,
+            signatureValid: true,
+            existingNoisePublicKey: noiseKey,
+            announcedNoisePublicKey: noiseKey,
+            existingSigningPublicKey: signingKey,
+            announcedSigningPublicKey: signingKey
+        )
+
+        #expect(decision == .verified)
+    }
+
     @Test
     func responsePolicyConnectsOnlyForDirectNewOrReconnectedPeers() {
         let directNew = BLEAnnounceResponsePolicy.plan(

bitchatTests/Services/BLEPeerRegistryTests.swift

@@ -6,12 +6,12 @@ import Testing
 @Suite("BLE peer registry tests")
 struct BLEPeerRegistryTests {
     @Test("upserted announces track new, reconnect, and rename transitions")
-    func upsertVerifiedAnnounceTracksTransitions() {
+    func upsertVerifiedAnnounceTracksTransitions() throws {
         var registry = BLEPeerRegistry()
         let peerID = PeerID(str: "1122334455667788")
         let firstSeen = Date(timeIntervalSince1970: 100)
 
-        let first = registry.upsertVerifiedAnnounce(
+        let firstResult = registry.upsertVerifiedAnnounce(
             peerID: peerID,
             nickname: "alice",
             noisePublicKey: Data([1, 2, 3]),
@@ -19,6 +19,7 @@ struct BLEPeerRegistryTests {
             isConnected: true,
             now: firstSeen
         )
+        let first = try #require(firstResult)
 
         #expect(first.isNewPeer)
         #expect(!first.wasDisconnected)
@@ -27,7 +28,7 @@ struct BLEPeerRegistryTests {
         #expect(registry.nickname(for: peerID, connectedOnly: true) == "alice")
 
         registry.markDisconnected(peerID)
-        let reconnect = registry.upsertVerifiedAnnounce(
+        let reconnectResult = registry.upsertVerifiedAnnounce(
             peerID: peerID,
             nickname: "alice-renamed",
             noisePublicKey: Data([1, 2, 3]),
@@ -35,6 +36,7 @@ struct BLEPeerRegistryTests {
             isConnected: true,
             now: firstSeen.addingTimeInterval(1)
         )
+        let reconnect = try #require(reconnectResult)
 
         #expect(!reconnect.isNewPeer)
         #expect(reconnect.wasDisconnected)
@@ -42,6 +44,85 @@ struct BLEPeerRegistryTests {
         #expect(registry.info(for: peerID)?.nickname == "alice-renamed")
     }
 
+    @Test("pinned signing key cannot be silently replaced by a later announce")
+    func upsertVerifiedAnnounceRefusesToReplacePinnedSigningKey() throws {
+        var registry = BLEPeerRegistry()
+        let peerID = PeerID(str: "1122334455667788")
+        let noiseKey = Data(repeating: 0x11, count: 32)
+        let victimSigningKey = Data(repeating: 0x42, count: 32)
+        let attackerSigningKey = Data(repeating: 0x66, count: 32)
+        let firstSeen = Date(timeIntervalSince1970: 100)
+
+        let pinResult = registry.upsertVerifiedAnnounce(
+            peerID: peerID,
+            nickname: "victim",
+            noisePublicKey: noiseKey,
+            signingPublicKey: victimSigningKey,
+            isConnected: true,
+            now: firstSeen
+        )
+        #expect(pinResult != nil)
+
+        // Attacker replays the victim's noiseKey/peerID with their own
+        // signing key and nickname; the upsert must be refused wholesale.
+        let attack = registry.upsertVerifiedAnnounce(
+            peerID: peerID,
+            nickname: "attacker",
+            noisePublicKey: noiseKey,
+            signingPublicKey: attackerSigningKey,
+            isConnected: true,
+            now: firstSeen.addingTimeInterval(1)
+        )
+
+        #expect(attack == nil)
+        let info = try #require(registry.info(for: peerID))
+        #expect(info.nickname == "victim")
+        #expect(info.signingPublicKey == victimSigningKey)
+
+        // A legitimate re-announce with the pinned key is still accepted.
+        let legit = registry.upsertVerifiedAnnounce(
+            peerID: peerID,
+            nickname: "victim-renamed",
+            noisePublicKey: noiseKey,
+            signingPublicKey: victimSigningKey,
+            isConnected: true,
+            now: firstSeen.addingTimeInterval(2)
+        )
+        #expect(legit != nil)
+        #expect(registry.info(for: peerID)?.nickname == "victim-renamed")
+    }
+
+    @Test("announce without a signing key keeps the pinned key")
+    func upsertVerifiedAnnounceKeepsPinnedSigningKeyWhenAnnounceOmitsIt() throws {
+        var registry = BLEPeerRegistry()
+        let peerID = PeerID(str: "1122334455667788")
+        let noiseKey = Data(repeating: 0x11, count: 32)
+        let signingKey = Data(repeating: 0x42, count: 32)
+        let firstSeen = Date(timeIntervalSince1970: 100)
+
+        let initialResult = registry.upsertVerifiedAnnounce(
+            peerID: peerID,
+            nickname: "alice",
+            noisePublicKey: noiseKey,
+            signingPublicKey: signingKey,
+            isConnected: true,
+            now: firstSeen
+        )
+        #expect(initialResult != nil)
+
+        let update = registry.upsertVerifiedAnnounce(
+            peerID: peerID,
+            nickname: "alice",
+            noisePublicKey: noiseKey,
+            signingPublicKey: nil,
+            isConnected: true,
+            now: firstSeen.addingTimeInterval(1)
+        )
+
+        #expect(update != nil)
+        #expect(registry.info(for: peerID)?.signingPublicKey == signingKey)
+    }
+
     @Test("reachability keeps recent verified offline peers only when mesh is attached")
     func reachabilityRequiresMeshAttachmentForOfflinePeers() {
         let offlinePeer = PeerID(str: "1122334455667788")

bitchatTests/Services/SecureIdentityStateManagerTests.swift

@@ -79,6 +79,100 @@ final class SecureIdentityStateManagerTests: XCTestCase {
         XCTAssertEqual(matches.first?.signingPublicKey, signingPublicKey)
     }
 
+    func test_upsertCryptographicIdentity_refusesToReplacePinnedSigningKey() async {
+        let manager = SecureIdentityStateManager(MockKeychain())
+        let noisePublicKey = Data(repeating: 0x11, count: 32)
+        let fingerprint = noisePublicKey.sha256Fingerprint()
+        let peerID = PeerID(publicKey: noisePublicKey)
+        let victimSigningKey = Data(repeating: 0x22, count: 32)
+        let attackerSigningKey = Data(repeating: 0x66, count: 32)
+
+        manager.upsertCryptographicIdentity(
+            fingerprint: fingerprint,
+            noisePublicKey: noisePublicKey,
+            signingPublicKey: victimSigningKey,
+            claimedNickname: "victim"
+        )
+        let pinned = await waitUntil {
+            manager.getCryptoIdentitiesByPeerIDPrefix(peerID).first?.signingPublicKey == victimSigningKey
+        }
+        XCTAssertTrue(pinned)
+
+        // Attacker upsert with a different signing key must be refused in
+        // full — signing key AND claimed nickname stay the victim's.
+        manager.upsertCryptographicIdentity(
+            fingerprint: fingerprint,
+            noisePublicKey: noisePublicKey,
+            signingPublicKey: attackerSigningKey,
+            claimedNickname: "attacker"
+        )
+
+        // Synchronous reads fence the manager's pending barrier writes.
+        XCTAssertEqual(
+            manager.getCryptoIdentitiesByPeerIDPrefix(peerID).first?.signingPublicKey,
+            victimSigningKey
+        )
+        XCTAssertEqual(manager.getSocialIdentity(for: fingerprint)?.claimedNickname, "victim")
+
+        // The legitimate peer (same signing key) can still update.
+        manager.upsertCryptographicIdentity(
+            fingerprint: fingerprint,
+            noisePublicKey: noisePublicKey,
+            signingPublicKey: victimSigningKey,
+            claimedNickname: "victim-renamed"
+        )
+        let renamed = await waitUntil {
+            manager.getSocialIdentity(for: fingerprint)?.claimedNickname == "victim-renamed"
+        }
+        XCTAssertTrue(renamed)
+        XCTAssertEqual(
+            manager.getCryptoIdentitiesByPeerIDPrefix(peerID).first?.signingPublicKey,
+            victimSigningKey
+        )
+    }
+
+    func test_cryptographicIdentity_persistsAcrossReinitAndKeepsSigningKeyPin() async {
+        let keychain = MockKeychain()
+        let manager = SecureIdentityStateManager(keychain)
+        let noisePublicKey = Data(repeating: 0x13, count: 32)
+        let fingerprint = noisePublicKey.sha256Fingerprint()
+        let peerID = PeerID(publicKey: noisePublicKey)
+        let victimSigningKey = Data(repeating: 0x24, count: 32)
+        let attackerSigningKey = Data(repeating: 0x77, count: 32)
+
+        manager.upsertCryptographicIdentity(
+            fingerprint: fingerprint,
+            noisePublicKey: noisePublicKey,
+            signingPublicKey: victimSigningKey,
+            claimedNickname: "victim"
+        )
+        let pinned = await waitUntil {
+            manager.getCryptoIdentitiesByPeerIDPrefix(peerID).first?.signingPublicKey == victimSigningKey
+        }
+        XCTAssertTrue(pinned)
+        manager.forceSave()
+
+        // Simulated app restart: the pin must survive and still refuse a
+        // different signing key.
+        let reloaded = SecureIdentityStateManager(keychain)
+        XCTAssertEqual(
+            reloaded.getCryptoIdentitiesByPeerIDPrefix(peerID).first?.signingPublicKey,
+            victimSigningKey
+        )
+
+        reloaded.upsertCryptographicIdentity(
+            fingerprint: fingerprint,
+            noisePublicKey: noisePublicKey,
+            signingPublicKey: attackerSigningKey,
+            claimedNickname: "attacker"
+        )
+        XCTAssertEqual(
+            reloaded.getCryptoIdentitiesByPeerIDPrefix(peerID).first?.signingPublicKey,
+            victimSigningKey
+        )
+        XCTAssertEqual(reloaded.getSocialIdentity(for: fingerprint)?.claimedNickname, "victim")
+    }
+
     func test_setBlocked_clearsFavoriteState() async {
         let manager = SecureIdentityStateManager(MockKeychain())
         let fingerprint = String(repeating: "ab", count: 32)