Preserve early Noise ciphertext across reconnects

bitchat/Noise/NoiseSessionManager.swift

@@ -141,6 +141,16 @@ final class NoiseSessionManager {
         }
     }
 
+    /// Whether this peer has an inbound ordinary XX responder that still
+    /// needs message 3 before its receive keys can become authoritative.
+    func isAwaitingResponderHandshakeCompletion(for peerID: PeerID) -> Bool {
+        managerQueue.sync {
+            guard let session = sessions[peerID] else { return false }
+            return session.role == .responder
+                && session.getState() == .handshaking
+        }
+    }
+
     /// Transfers one bounded recovery generation to whatever ordinary XX
     /// handshake currently owns the peer, or starts the generation's single
     /// retry. The request token prevents stale transport callbacks from
@@ -1121,12 +1131,22 @@ final class NoiseSessionManager {
     /// the exact session object that authenticated these bytes.
     func decryptWithSessionGeneration(
         _ ciphertext: Data,
-        from peerID: PeerID
+        from peerID: PeerID,
+        establishedGenerationIsReady: (UUID) -> Bool = { _ in true },
+        authorizeDecrypt: () throws -> Void = {}
     ) throws -> (plaintext: Data, sessionGeneration: UUID) {
         try managerQueue.sync {
             if let session = sessions[peerID],
                session.isEstablished(),
                let generation = sessionGenerations[peerID] {
+                // Keep the generation lease across the transport-readiness
+                // check and decrypt. Promotion/restoration needs this queue's
+                // barrier, so no new receive nonce can be consumed before BLE
+                // installs state for the exact generation.
+                guard establishedGenerationIsReady(generation) else {
+                    throw NoiseEncryptionError.transportGenerationNotReady
+                }
+                try authorizeDecrypt()
                 return (try session.decrypt(ciphertext), generation)
             }
 
@@ -1138,6 +1158,7 @@ final class NoiseSessionManager {
                responder.role == .responder,
                responder.getState() == .handshaking,
                let quarantined = quarantinedTransports[peerID] {
+                try authorizeDecrypt()
                 return (
                     try quarantined.session.decrypt(ciphertext),
                     quarantined.generation

bitchat/Services/BLE/BLENoisePacketHandler.swift

@@ -1,5 +1,6 @@
 import BitFoundation
 import BitLogger
+import CryptoKit
 import Foundation
 
 struct BLENoiseHandshakeHandlingResult {
@@ -33,6 +34,8 @@ struct BLENoisePacketHandlerEnvironment {
             -> NoiseHandshakeProcessingResult
     /// Whether any Noise session (established or pending) exists for the peer (crypto).
     let hasNoiseSession: (PeerID) -> Bool
+    /// Whether an inbound ordinary XX responder is waiting for message 3.
+    let isAwaitingResponderHandshakeCompletion: (PeerID) -> Bool
     /// Initiates a fresh Noise handshake with the peer (crypto + send).
     let initiateHandshake: (PeerID) -> Void
     /// Broadcasts a packet on the mesh (caller is already on the message queue).
@@ -63,7 +66,28 @@ struct BLENoisePacketHandlerEnvironment {
 /// processing (with response), encrypted payload decryption and dispatch,
 /// and session recovery on decrypt failure.
 final class BLENoisePacketHandler {
+    private struct DeferredCiphertext {
+        let packet: BitchatPacket
+        let receivedAt: Date
+    }
+
+    /// Early post-handshake packets are normally tiny control messages or
+    /// queued DMs. Keep the recovery surface deliberately small so an
+    /// unauthenticated half-handshake cannot create an unbounded memory queue.
+    private static let maxDeferredPacketsPerPeer = 4
+    private static let maxDeferredPacketsGlobal = 32
+    /// One legacy sender can immediately follow message 3 with the largest
+    /// valid private-file ciphertext and has no application-level retry. Keep
+    /// room for that packet plus a small control-message budget.
+    private static let maxDeferredBytes =
+        NoiseSecurityConstants.maxPrivateFileCiphertextSize + 256 * 1024
+    private static let deferredLifetime =
+        NoiseSecurityConstants.ordinaryResponderHandshakeTimeout
+
     private let environment: BLENoisePacketHandlerEnvironment
+    private let deferredLock = NSLock()
+    private var deferredCiphertexts: [PeerID: [DeferredCiphertext]] = [:]
+    private var deferredCiphertextBytes = 0
 
     init(environment: BLENoisePacketHandlerEnvironment) {
         self.environment = environment
@@ -105,8 +129,8 @@ final class BLENoisePacketHandler {
                     env.broadcastPacket(responsePacket)
                 }
 
-                // Session establishment will trigger onPeerAuthenticated callback
+                // The serialized authentication callback installs transport
-                // which will send any pending messages at the right time
+                // state before it drains any bounded early ciphertext.
                 return BLENoiseHandshakeHandlingResult(
                     processed: true,
                     didEstablishAuthenticatedSession:
@@ -151,6 +175,20 @@ final class BLENoisePacketHandler {
     }
 
     func handleEncrypted(_ packet: BitchatPacket, from peerID: PeerID) {
+        handleEncrypted(packet, from: peerID, isDeferredRetry: false)
+    }
+
+    /// Called by the transport's serialized authentication callback after it
+    /// has installed state for the promoted or restored session generation.
+    func handleSessionAuthenticated(_ peerID: PeerID) {
+        drainDeferredCiphertextsIfReady(for: peerID)
+    }
+
+    private func handleEncrypted(
+        _ packet: BitchatPacket,
+        from peerID: PeerID,
+        isDeferredRetry: Bool
+    ) {
         let env = environment
         guard let recipientID = PeerID(hexData: packet.recipientID) else {
             SecureLogger.warning("⚠️ Encrypted message has no recipient ID", category: .session)
@@ -192,19 +230,205 @@ final class BLENoisePacketHandler {
 
             let ts = Date(timeIntervalSince1970: Double(packet.timestamp) / 1000)
             env.deliverNoisePayload(peerID, noisePayloadType, Data(payloadData), ts)
+        } catch NoiseEncryptionError.transportGenerationNotReady {
+            if isDeferredRetry {
+                SecureLogger.warning(
+                    "Dropping deferred Noise ciphertext from \(peerID.id.prefix(8))… because its authenticated transport generation changed again",
+                    category: .session
+                )
+                return
+            }
+            // The manager promoted or restored keys before BLE's serialized
+            // callback installed generation-bound transport state. The
+            // manager rejected this before decrypting, so replay is safe.
+            deferCiphertext(packet, from: peerID)
         } catch NoiseEncryptionError.sessionNotEstablished {
+            if isDeferredRetry {
+                SecureLogger.warning(
+                    "Dropping deferred Noise ciphertext from \(peerID.id.prefix(8))… because the authenticated session is unavailable",
+                    category: .session
+                )
+                return
+            }
             // We received an encrypted message before establishing a session with this peer.
-            // Trigger a handshake so future messages can be decrypted.
+            // An initiator may already have sent message 3 followed by this
+            // ciphertext, with BLE delivering the ciphertext first.
+            if env.isAwaitingResponderHandshakeCompletion(peerID) {
+                deferCiphertext(packet, from: peerID)
+                return
+            }
+            // Otherwise trigger a handshake so future messages can decrypt.
             SecureLogger.debug("🔑 Encrypted message from \(peerID.id.prefix(8))… without session; initiating handshake")
             if !env.hasNoiseSession(peerID) {
                 env.initiateHandshake(peerID)
             }
         } catch {
+            if isDeferredRetry {
+                // An early packet cannot tear down the authenticated session
+                // merely because its single bounded retry still fails.
+                SecureLogger.warning(
+                    "Dropping deferred Noise ciphertext from \(peerID.id.prefix(8))… after retry failed: \(error)",
+                    category: .session
+                )
+                return
+            }
+            // A responder may retain an older transport as receive-only
+            // rollback state while ordinary XX waits for message 3. New-key
+            // ciphertext can fail against those retained receive keys first.
+            if env.isAwaitingResponderHandshakeCompletion(peerID) {
+                if isDeferrableEarlyHandshakeFailure(error) {
+                    deferCiphertext(packet, from: peerID)
+                } else {
+                    SecureLogger.warning(
+                        "Dropping invalid Noise ciphertext from \(peerID.id.prefix(8))… while responder handshake is completing: \(error)",
+                        category: .session
+                    )
+                }
+                return
+            }
+            if isDropOnlyCiphertextFailure(error) {
+                // The packet is attacker-controlled and did not prove a
+                // transport-state failure. Never let malformed, replayed,
+                // forged, oversized, or rate-limited bytes evict working keys.
+                SecureLogger.warning(
+                    "Dropping rejected Noise ciphertext from \(peerID.id.prefix(8))… without clearing its session: \(error)",
+                    category: .security
+                )
+                return
+            }
             // Decryption failed - clear the corrupted session and re-initiate handshake
-            // This handles cases where session state got out of sync (nonce mismatch, etc.)
+            // Only local/session lifecycle failures reach this path.
             SecureLogger.error("❌ Failed to decrypt message from \(peerID.id.prefix(8))…: \(error) - clearing session and re-initiating handshake")
             env.clearSession(peerID)
             env.initiateHandshake(peerID)
         }
     }
+
+    private func isDeferrableEarlyHandshakeFailure(_ error: Error) -> Bool {
+        if let noiseError = error as? NoiseError {
+            switch noiseError {
+            case .authenticationFailure, .replayDetected:
+                return true
+            default:
+                return false
+            }
+        }
+        if let cryptoError = error as? CryptoKitError,
+           case .authenticationFailure = cryptoError {
+            return true
+        }
+        return false
+    }
+
+    private func isDropOnlyCiphertextFailure(_ error: Error) -> Bool {
+        if let securityError = error as? NoiseSecurityError {
+            switch securityError {
+            case .messageTooLarge, .rateLimitExceeded, .invalidPeerID:
+                return true
+            case .sessionExpired, .sessionExhausted:
+                return false
+            }
+        }
+        if let noiseError = error as? NoiseError {
+            switch noiseError {
+            case .invalidCiphertext, .authenticationFailure, .replayDetected:
+                return true
+            case .uninitializedCipher, .handshakeComplete,
+                    .handshakeNotComplete, .missingLocalStaticKey,
+                    .missingKeys, .invalidMessage, .invalidPublicKey,
+                    .nonceExceeded:
+                return false
+            }
+        }
+        return error is CryptoKitError
+    }
+
+    private func deferCiphertext(_ packet: BitchatPacket, from peerID: PeerID) {
+        guard NoiseSecurityValidator.validatePrivateFileCiphertextSize(
+            packet.payload
+        ) else {
+            SecureLogger.warning(
+                "Dropping oversized early Noise ciphertext from \(peerID.id.prefix(8))…",
+                category: .security
+            )
+            return
+        }
+
+        let now = environment.now()
+        deferredLock.lock()
+        defer { deferredLock.unlock() }
+        purgeExpiredCiphertextsLocked(now: now)
+
+        let peerCount = deferredCiphertexts[peerID]?.count ?? 0
+        let globalCount = deferredCiphertexts.values.reduce(0) {
+            $0 + $1.count
+        }
+        guard peerCount < Self.maxDeferredPacketsPerPeer,
+              globalCount < Self.maxDeferredPacketsGlobal,
+              deferredCiphertextBytes + packet.payload.count
+                <= Self.maxDeferredBytes else {
+            SecureLogger.warning(
+                "Dropping early Noise ciphertext from \(peerID.id.prefix(8))… because the handshake buffer is full",
+                category: .security
+            )
+            return
+        }
+
+        deferredCiphertexts[peerID, default: []].append(
+            DeferredCiphertext(packet: packet, receivedAt: now)
+        )
+        deferredCiphertextBytes += packet.payload.count
+        SecureLogger.debug(
+            "Deferring early Noise ciphertext from \(peerID.id.prefix(8))… until responder handshake completion",
+            category: .session
+        )
+    }
+
+    private func drainDeferredCiphertextsIfReady(for peerID: PeerID) {
+        let env = environment
+        guard !env.isAwaitingResponderHandshakeCompletion(peerID),
+              env.hasNoiseSession(peerID) else {
+            return
+        }
+
+        let now = env.now()
+        deferredLock.lock()
+        purgeExpiredCiphertextsLocked(now: now)
+        let deferred = deferredCiphertexts.removeValue(forKey: peerID) ?? []
+        deferredCiphertextBytes -= deferred.reduce(0) {
+            $0 + $1.packet.payload.count
+        }
+        deferredLock.unlock()
+
+        guard !deferred.isEmpty else { return }
+        SecureLogger.debug(
+            "Retrying \(deferred.count) early Noise ciphertext packet(s) from \(peerID.id.prefix(8))… after handshake completion",
+            category: .session
+        )
+        for item in deferred {
+            handleEncrypted(item.packet, from: peerID, isDeferredRetry: true)
+        }
+    }
+
+    private func purgeExpiredCiphertextsLocked(now: Date) {
+        for peerID in Array(deferredCiphertexts.keys) {
+            guard let items = deferredCiphertexts[peerID] else { continue }
+            let retained = items.filter {
+                now.timeIntervalSince($0.receivedAt) <= Self.deferredLifetime
+            }
+            guard retained.count != items.count else { continue }
+
+            deferredCiphertextBytes -= items.reduce(0) {
+                $0 + $1.packet.payload.count
+            }
+            deferredCiphertextBytes += retained.reduce(0) {
+                $0 + $1.packet.payload.count
+            }
+            if retained.isEmpty {
+                deferredCiphertexts.removeValue(forKey: peerID)
+            } else {
+                deferredCiphertexts[peerID] = retained
+            }
+        }
+    }
 }

bitchat/Services/BLE/BLEService.swift

@@ -3556,6 +3556,28 @@ extension BLEService {
         }
     }
 
+    /// Replays the current generation's ready callback. Restore tests use
+    /// this to prove same-generation reconciliation is idempotent.
+    func _test_reconcileCurrentNoiseSession(for peerID: PeerID) {
+        let normalizedPeerID = peerID.toShort()
+        messageQueue.async(flags: .barrier) { [weak self] in
+            guard let self,
+                  let generation = self.noiseService.sessionGeneration(
+                    for: normalizedPeerID
+                  ),
+                  let fingerprint = self.noiseService.getPeerFingerprint(
+                    normalizedPeerID
+                  ) else {
+                return
+            }
+            self.handleNoisePeerAuthenticated(
+                peerID: normalizedPeerID,
+                fingerprint: fingerprint,
+                sessionGeneration: generation
+            )
+        }
+    }
+
     /// Builds an authenticated-session packet from an exact typed plaintext.
     /// Compatibility tests use this to model Android's deployed 0x20 file
     /// payload and the short-lived 0x09 prerelease payload without exposing a
@@ -4649,7 +4671,10 @@ extension BLEService {
     private func configureNoiseServiceCallbacks(for service: NoiseEncryptionService) {
         service.onPeerAuthenticatedWithGeneration = { [weak self] peerID, fingerprint, generation in
             SecureLogger.debug("🔐 Noise session authenticated with \(peerID.id.prefix(8))…, fingerprint: \(fingerprint.prefix(16))…")
-            self?.messageQueue.async { [weak self] in
+            // Authentication can be reported while an initiator is still
+            // returning XX message 3. Serialize generation-bound state and
+            // every post-handshake drain behind the handshake packet handler.
+            self?.messageQueue.async(flags: .barrier) { [weak self] in
                 self?.handleNoisePeerAuthenticated(
                     peerID: peerID,
                     fingerprint: fingerprint,
@@ -4724,7 +4749,9 @@ extension BLEService {
         }
         service.onSessionRestoredWithGeneration = { [weak self, weak service] peerID, generation in
             guard let self, let service else { return }
-            self.messageQueue.async { [weak self, weak service] in
+            // The manager makes restored keys visible atomically. Reconcile
+            // transport state and queued sends as the next serialized phase.
+            self.messageQueue.async(flags: .barrier) { [weak self, weak service] in
                 guard let self,
                       let service,
                       self.noiseService === service,
@@ -4792,7 +4819,16 @@ extension BLEService {
             }
         ) else { return }
 
-        guard let watchdog = transition.watchdog else { return }
+        guard let watchdog = transition.watchdog else {
+            // A quarantined transport restored the same cryptographic
+            // generation. Its capability proof and announce state never
+            // became stale; only work queued while outbound keys were paused
+            // needs one idempotent ready transition.
+            noisePacketHandler.handleSessionAuthenticated(normalizedPeerID)
+            sendPendingMessagesAfterHandshake(for: normalizedPeerID)
+            sendPendingNoisePayloadsAfterHandshake(for: normalizedPeerID)
+            return
+        }
 
         completePrivateMediaPolicyResolution(transition.rejected, with: .blockedDowngrade)
         schedulePrivateMediaProofTimeout(
@@ -4801,6 +4837,10 @@ extension BLEService {
             sessionGeneration: generation,
             nonce: watchdog.nonce
         )
+        // Cross-link delivery can put ciphertext sent immediately after
+        // message 3 ahead of message 3 itself. Retry the bounded queue only
+        // after this generation's transport state has been fully installed.
+        noisePacketHandler.handleSessionAuthenticated(normalizedPeerID)
 
         // `onPeerAuthenticated` can fire while the initiator is returning XX
         // message 3. This callback is queued behind the handshake handler, so
@@ -6415,7 +6455,12 @@ extension BLEService {
     // MARK: Packet Reception
     
     private func handleReceivedPacket(_ packet: BitchatPacket, from peerID: PeerID) {
-        // Call directly if already on messageQueue, otherwise dispatch
+        let isNoisePacket = packet.type == MessageType.noiseHandshake.rawValue
+            || packet.type == MessageType.noiseEncrypted.rawValue
+
+        // Capture the panic lifecycle at the first off-messageQueue handoff.
+        // Noise packets still enter through a barrier so handshake promotion,
+        // quarantine, and encrypted delivery share one ordered session.
         if DispatchQueue.getSpecific(key: messageQueueKey) == nil {
             guard let lifecycleGeneration =
                     capturePanicLifecycleGeneration() else {
@@ -6424,7 +6469,8 @@ extension BLEService {
             #if DEBUG
             _test_beforeReceivePacketHandoff?()
             #endif
-            messageQueue.async { [weak self] in
+            let flags: DispatchWorkItemFlags = isNoisePacket ? .barrier : []
+            messageQueue.async(flags: flags) { [weak self] in
                 guard let self,
                       self.isCurrentPanicLifecycleGeneration(
                           lifecycleGeneration
@@ -6434,11 +6480,34 @@ extension BLEService {
                 #if DEBUG
                 self._test_onReceivePacketHandoff?()
                 #endif
-                self.handleReceivedPacket(packet, from: peerID)
+                self.handleReceivedPacketOnQueue(packet, from: peerID)
             }
             return
         }
 
+        if isNoisePacket {
+            guard let lifecycleGeneration =
+                    capturePanicLifecycleGeneration() else {
+                return
+            }
+            messageQueue.async(flags: .barrier) { [weak self] in
+                guard let self,
+                      self.isCurrentPanicLifecycleGeneration(
+                          lifecycleGeneration
+                      ) else {
+                    return
+                }
+                self.handleReceivedPacketOnQueue(packet, from: peerID)
+            }
+        } else {
+            handleReceivedPacketOnQueue(packet, from: peerID)
+        }
+    }
+
+    private func handleReceivedPacketOnQueue(
+        _ packet: BitchatPacket,
+        from peerID: PeerID
+    ) {
         let context = BLEReceivePipeline.context(for: packet, localPeerID: myPeerID)
         let senderID = context.senderID
         let messageID = context.messageID
@@ -7214,16 +7283,16 @@ extension BLEService {
     }
 
     private func handleNoiseHandshake(_ packet: BitchatPacket, from peerID: PeerID) {
-        let wasEstablished = noiseService.hasEstablishedSession(with: peerID)
         let result = noisePacketHandler.handleHandshakeWithResult(
             packet,
             from: peerID
         )
-        let isEstablished = noiseService.hasEstablishedSession(with: peerID)
+        // An inbound message 1 quarantines the old transport receive-only.
-        if wasEstablished, result.processed,
+        // Keep its generation-bound BLE state intact: the manager's new
-           !isEstablished {
+        // handshaking generation already gates every outbound policy, while
-            noteNoiseSessionCleared(for: peerID)
+        // a rollback can become ready again without repeating capability
-        }
+        // proof or announce side effects. Only the exact handshake candidate's
+        // authenticated completion may promote the physical ingress link.
         if result.didEstablishAuthenticatedSession {
             markNoiseAuthenticatedIngressLink(for: packet, peerID: peerID)
         }
@@ -7261,6 +7330,11 @@ extension BLEService {
             hasNoiseSession: { [weak self] peerID in
                 self?.noiseService.hasSession(with: peerID) ?? false
             },
+            isAwaitingResponderHandshakeCompletion: { [weak self] peerID in
+                self?.noiseService.isAwaitingResponderHandshakeCompletion(
+                    with: peerID
+                ) ?? false
+            },
             initiateHandshake: { [weak self] peerID in
                 self?.initiateNoiseHandshake(with: peerID)
             },
@@ -7274,7 +7348,14 @@ extension BLEService {
                 guard let self = self else { throw NoiseEncryptionError.sessionNotEstablished }
                 let result = try self.noiseService.decryptWithSessionGeneration(
                     payload,
-                    from: peerID
+                    from: peerID,
+                    establishedGenerationIsReady: { generation in
+                        self.collectionsQueue.sync {
+                            self.privateMediaSessionGenerations[
+                                peerID.toShort()
+                            ] == generation
+                        }
+                    }
                 )
                 return BLENoiseDecryptionResult(
                     plaintext: result.plaintext,

bitchat/Services/NoiseEncryptionService.swift

@@ -853,6 +853,13 @@ final class NoiseEncryptionService {
     func hasSession(with peerID: PeerID) -> Bool {
         return sessionManager.getSession(for: peerID) != nil
     }
+
+    /// True while an inbound ordinary XX responder is waiting for message 3.
+    /// A small amount of immediately-following ciphertext may arrive first
+    /// over BLE and must be retried only after responder promotion.
+    func isAwaitingResponderHandshakeCompletion(with peerID: PeerID) -> Bool {
+        sessionManager.isAwaitingResponderHandshakeCompletion(for: peerID)
+    }
     
     // MARK: - Encryption/Decryption
     
@@ -920,20 +927,15 @@ final class NoiseEncryptionService {
 
     func decryptWithSessionGeneration(
         _ data: Data,
-        from peerID: PeerID
+        from peerID: PeerID,
+        establishedGenerationIsReady: (UUID) -> Bool = { _ in true }
     ) throws -> (plaintext: Data, sessionGeneration: UUID) {
         // Standard transport ciphertext has 20 bytes of nonce/tag overhead.
-        // A larger candidate is admitted only up to the framed-file ceiling;
+        // A larger ciphertext is admitted only up to the framed-file ceiling;
         // after authenticated decryption it must prove it is `.privateFile`.
         let isStandardCiphertext = NoiseSecurityValidator.validateCiphertextSize(data)
-        guard isStandardCiphertext || NoiseSecurityValidator.validatePrivateFileCiphertextSize(data) else {
+        let isAdmittedCiphertext = isStandardCiphertext
-            throw NoiseSecurityError.messageTooLarge
+            || NoiseSecurityValidator.validatePrivateFileCiphertextSize(data)
-        }
-        
-        // Check rate limit
-        guard rateLimiter.allowMessage(from: peerID) else {
-            throw NoiseSecurityError.rateLimitExceeded
-        }
         
         // A quarantined transport is deliberately unavailable for outbound
         // state, but remains receive-only until the responder proves identity
@@ -942,7 +944,20 @@ final class NoiseEncryptionService {
             throw NoiseEncryptionError.sessionNotEstablished
         }
         
-        let result = try sessionManager.decryptWithSessionGeneration(data, from: peerID)
+        let result = try sessionManager.decryptWithSessionGeneration(
+            data,
+            from: peerID,
+            establishedGenerationIsReady:
+                establishedGenerationIsReady,
+            authorizeDecrypt: { [rateLimiter] in
+                guard isAdmittedCiphertext else {
+                    throw NoiseSecurityError.messageTooLarge
+                }
+                guard rateLimiter.allowMessage(from: peerID) else {
+                    throw NoiseSecurityError.rateLimitExceeded
+                }
+            }
+        )
         if !isStandardCiphertext {
             guard NoisePayloadType.isPrivateFile(rawValue: result.plaintext.first),
                   NoiseSecurityValidator.validatePrivateFileMessageSize(result.plaintext) else {
@@ -1159,6 +1174,9 @@ struct NoiseMessage: Codable {
 enum NoiseEncryptionError: Error {
     case handshakeRequired
     case sessionNotEstablished
+    /// Manager keys are established or restored, but BLE has not installed
+    /// generation-bound transport state. No receive nonce was consumed.
+    case transportGenerationNotReady
     /// Envelope references a prekey ID we don't hold (never ours, already
     /// deleted after its grace window, or wiped in a panic).
     case unknownPrekey

bitchatTests/BLEServiceCoreTests.swift

@@ -639,7 +639,7 @@ struct BLEServiceCoreTests {
     }
 
     @Test
-    func failedInboundReconnectRestoresAndDrainsTypedPayloadQueue() async throws {
+    func failedInboundReconnectRestoresAndDrainsWaitingWorkOnce() async throws {
         let ble = makeService()
         let alice = NoiseEncryptionService(keychain: MockKeychain())
         let mallory = NoiseEncryptionService(keychain: MockKeychain())
@@ -722,21 +722,48 @@ struct BLEServiceCoreTests {
                 message: forgedMessage2
             )
         )
+        let forgedEarlyPayload = try #require(
+            BLENoisePayloadFactory.privateMessage(
+                content: "forged early message",
+                messageID: "forged-early"
+            )
+        )
+        try #require(
+            mallory.hasEstablishedSession(with: ble.myPeerID),
+            "forged initiator did not establish after producing message three"
+        )
+        let forgedEarlyCiphertext = try mallory.encrypt(
+            forgedEarlyPayload,
+            for: ble.myPeerID
+        )
+        let earlyPacket = BitchatPacket(
+            type: MessageType.noiseEncrypted.rawValue,
+            senderID: Data(hexString: alicePeerID.id) ?? Data(),
+            recipientID: Data(hexString: ble.myPeerID.id),
+            timestamp: UInt64(Date().timeIntervalSince1970 * 1_000) + 1,
+            payload: forgedEarlyCiphertext,
+            signature: nil,
+            ttl: 7
+        )
+        ble._test_handlePacket(earlyPacket, fromPeerID: alicePeerID)
+        await ble._test_drainNoiseMessagePipeline()
+
         let thirdPacket = BitchatPacket(
             type: MessageType.noiseHandshake.rawValue,
             senderID: Data(hexString: alicePeerID.id) ?? Data(),
             recipientID: Data(hexString: ble.myPeerID.id),
-            timestamp: UInt64(Date().timeIntervalSince1970 * 1_000) + 1,
+            timestamp: UInt64(Date().timeIntervalSince1970 * 1_000) + 2,
             payload: forgedMessage3,
             signature: nil,
             ttl: 7
         )
         ble._test_handlePacket(thirdPacket, fromPeerID: alicePeerID)
 
-        // Restore re-enters the generation-bound authentication transition:
+        // Rollback restores the same generation. It retries the bounded early
-        // authenticated state and both outbound queues drain exactly once.
+        // ciphertext and drains both outbound queues, but must not repeat a
+        // new-generation capability proof or forced announce.
         let drained = await TestHelpers.waitUntil(
-            { outbound.count(ofType: .noiseEncrypted) >= 3 },
+            { outbound.count(ofType: .noiseEncrypted) >= 2 },
             timeout: TestConstants.longTimeout
         )
         try #require(drained)
@@ -744,11 +771,11 @@ struct BLEServiceCoreTests {
         let plaintexts = try outbound.snapshot()
             .filter { $0.type == MessageType.noiseEncrypted.rawValue }
             .map { try alice.decrypt($0.payload, from: ble.myPeerID) }
-        #expect(plaintexts.count == 3)
+        #expect(plaintexts.count == 2)
         #expect(
             plaintexts.filter {
                 $0.first == NoisePayloadType.authenticatedPeerState.rawValue
-            }.count == 1
+            }.isEmpty
         )
         #expect(
             plaintexts.filter {
@@ -760,6 +787,13 @@ struct BLEServiceCoreTests {
                 $0.first == NoisePayloadType.groupInvite.rawValue
             }.count == 1
         )
+        #expect(outbound.count(ofType: .announce) == 0)
+
+        // A duplicate ready callback cannot replay either buffer.
+        ble._test_reconcileCurrentNoiseSession(for: alicePeerID)
+        await ble._test_drainNoiseMessagePipeline()
+        #expect(outbound.count(ofType: .noiseEncrypted) == 2)
+        #expect(outbound.count(ofType: .announce) == 0)
     }
 
     /// A legitimate rotation announce necessarily arrives on a link still
@@ -1255,6 +1289,7 @@ private final class PublicCaptureDelegate: BitchatDelegate {
         defer { lock.unlock() }
         return publicMessages
     }
+
 }
 
 @MainActor

bitchatTests/Services/BLENoisePacketHandlerTests.swift

@@ -1,4 +1,5 @@
 import BitFoundation
+import CryptoKit
 import Foundation
 import Testing
 @testable import bitchat
@@ -11,7 +12,11 @@ struct BLENoisePacketHandlerTests {
         var handshakeAuthenticated = false
         var hasSession = false
         let sessionGeneration = UUID()
+        var awaitingResponderHandshake = false
         var decryptResult: Result<Data, Error> = .success(Data())
+        var currentDate = Date(timeIntervalSince1970: 1_000)
+        var transportGenerationReady = false
+        var forcedServiceDecryptError: Error?
 
         var processedHandshakes: [(peerID: PeerID, message: Data)] = []
         var hasSessionQueries: [PeerID] = []
@@ -34,11 +39,12 @@ struct BLENoisePacketHandlerTests {
         recorder: Recorder,
         now: Date = Date(timeIntervalSince1970: 1_000)
     ) -> BLENoisePacketHandler {
+        recorder.currentDate = now
         let environment = BLENoisePacketHandlerEnvironment(
             localPeerID: { [localPeerID] in localPeerID },
             localPeerIDData: { [localPeerIDData] in localPeerIDData },
             messageTTL: TransportConfig.messageTTLDefault,
-            now: { now },
+            now: { recorder.currentDate },
             processHandshakeMessage: { peerID, message in
                 recorder.processedHandshakes.append((peerID, message))
                 return NoiseHandshakeProcessingResult(
@@ -51,6 +57,9 @@ struct BLENoisePacketHandlerTests {
                 recorder.hasSessionQueries.append(peerID)
                 return recorder.hasSession
             },
+            isAwaitingResponderHandshakeCompletion: { _ in
+                recorder.awaitingResponderHandshake
+            },
             initiateHandshake: { peerID in
                 recorder.initiatedHandshakes.append(peerID)
                 recorder.events.append("initiateHandshake")
@@ -82,6 +91,120 @@ struct BLENoisePacketHandlerTests {
         return BLENoisePacketHandler(environment: environment)
     }
 
+    private func makeServiceBackedHandler(
+        service: NoiseEncryptionService,
+        localPeerID: PeerID,
+        recorder: Recorder,
+        transportGenerationIsReady:
+            @escaping (UUID) -> Bool
+    ) -> BLENoisePacketHandler {
+        BLENoisePacketHandler(
+            environment: BLENoisePacketHandlerEnvironment(
+                localPeerID: { localPeerID },
+                localPeerIDData: {
+                    Data(hexString: localPeerID.id) ?? Data()
+                },
+                messageTTL: TransportConfig.messageTTLDefault,
+                now: { recorder.currentDate },
+                processHandshakeMessage: { peerID, message in
+                    try service.processHandshakeMessageWithResult(
+                        from: peerID,
+                        message: message
+                    )
+                },
+                hasNoiseSession: { peerID in
+                    service.hasSession(with: peerID)
+                },
+                isAwaitingResponderHandshakeCompletion: { peerID in
+                    service.isAwaitingResponderHandshakeCompletion(
+                        with: peerID
+                    )
+                },
+                initiateHandshake: { peerID in
+                    recorder.initiatedHandshakes.append(peerID)
+                },
+                broadcastPacket: { packet in
+                    recorder.broadcastPackets.append(packet)
+                },
+                updatePeerLastSeen: { peerID in
+                    recorder.lastSeenUpdates.append(peerID)
+                },
+                decrypt: { payload, peerID in
+                    recorder.decryptCalls.append((payload, peerID))
+                    if let error = recorder.forcedServiceDecryptError {
+                        throw error
+                    }
+                    let result =
+                        try service.decryptWithSessionGeneration(
+                            payload,
+                            from: peerID,
+                            establishedGenerationIsReady:
+                                transportGenerationIsReady
+                        )
+                    return BLENoiseDecryptionResult(
+                        plaintext: result.plaintext,
+                        sessionGeneration: result.sessionGeneration
+                    )
+                },
+                clearSession: { peerID in
+                    recorder.clearedSessions.append(peerID)
+                    service.clearSession(for: peerID)
+                },
+                handleAuthenticatedPeerState: {
+                    peerID, payload, generation in
+                    recorder.authenticatedPeerStates.append(
+                        (peerID, payload, generation)
+                    )
+                },
+                deliverNoisePayload: {
+                    peerID, type, payload, timestamp in
+                    recorder.deliveries.append(
+                        (peerID, type, payload, timestamp)
+                    )
+                }
+            )
+        )
+    }
+
+    private func establishedServices() throws -> (
+        sender: NoiseEncryptionService,
+        receiver: NoiseEncryptionService,
+        senderPeerID: PeerID,
+        receiverPeerID: PeerID
+    ) {
+        let sender = NoiseEncryptionService(keychain: MockKeychain())
+        let receiver = NoiseEncryptionService(keychain: MockKeychain())
+        let senderPeerID = PeerID(
+            publicKey: sender.getStaticPublicKeyData()
+        )
+        let receiverPeerID = PeerID(
+            publicKey: receiver.getStaticPublicKeyData()
+        )
+        let message1 = try sender.initiateHandshake(with: receiverPeerID)
+        let message2 = try #require(
+            try receiver.processHandshakeMessage(
+                from: senderPeerID,
+                message: message1
+            )
+        )
+        let message3 = try #require(
+            try sender.processHandshakeMessage(
+                from: receiverPeerID,
+                message: message2
+            )
+        )
+        _ = try receiver.processHandshakeMessage(
+            from: senderPeerID,
+            message: message3
+        )
+        return (
+            sender,
+            receiver,
+            senderPeerID,
+            receiverPeerID
+        )
+    }
+
     // MARK: Handshake
 
     @Test
@@ -364,6 +487,745 @@ struct BLENoisePacketHandlerTests {
         #expect(recorder.deliveries.isEmpty)
     }
 
+    @Test
+    func earlyCiphertextIsRetriedAfterResponderHandshakeCompletes() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(
+            CryptoKitError.authenticationFailure
+        )
+        let handler = makeHandler(recorder: recorder)
+        let encrypted = makeEncryptedPacket(
+            recipientID: Data(hexString: localPeerID.id)
+        )
+
+        handler.handleEncrypted(encrypted, from: remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 1)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.privateMessage.rawValue, 0xCA, 0xFE])
+        )
+        handler.handleSessionAuthenticated(remotePeerID)
+        handler.handleSessionAuthenticated(remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 2)
+        #expect(recorder.deliveries.count == 1)
+        #expect(recorder.deliveries.first?.type == .privateMessage)
+        #expect(recorder.deliveries.first?.payload == Data([0xCA, 0xFE]))
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func ciphertextQueuedAheadOfEstablishmentCallbackDoesNotConsumeNonce()
+        throws {
+        let alice = NoiseEncryptionService(keychain: MockKeychain())
+        let bob = NoiseEncryptionService(keychain: MockKeychain())
+        let alicePeerID = PeerID(
+            publicKey: alice.getStaticPublicKeyData()
+        )
+        let bobPeerID = PeerID(publicKey: bob.getStaticPublicKeyData())
+
+        let message1 = try alice.initiateHandshake(with: bobPeerID)
+        let message2 = try #require(
+            try bob.processHandshakeMessage(
+                from: alicePeerID,
+                message: message1
+            )
+        )
+        let message3 = try #require(
+            try alice.processHandshakeMessage(
+                from: bobPeerID,
+                message: message2
+            )
+        )
+        let typedPayload = Data([
+            NoisePayloadType.privateMessage.rawValue,
+            0xCA, 0xFE
+        ])
+        let ciphertext = try alice.encrypt(
+            typedPayload,
+            for: bobPeerID
+        )
+
+        // Manager promotion has completed, but the serialized BLE callback is
+        // deliberately still behind this ciphertext.
+        _ = try bob.processHandshakeMessage(
+            from: alicePeerID,
+            message: message3
+        )
+        let recorder = Recorder()
+        recorder.transportGenerationReady = false
+        let handler = makeServiceBackedHandler(
+            service: bob,
+            localPeerID: bobPeerID,
+            recorder: recorder,
+            transportGenerationIsReady: { _ in
+                recorder.transportGenerationReady
+            }
+        )
+        let packet = makeEncryptedPacket(
+            recipientID: Data(hexString: bobPeerID.id),
+            payload: ciphertext
+        )
+
+        handler.handleEncrypted(packet, from: alicePeerID)
+        #expect(recorder.deliveries.isEmpty)
+        #expect(recorder.clearedSessions.isEmpty)
+
+        // The exact ciphertext must still authenticate, proving the readiness
+        // rejection happened before the receive nonce was consumed.
+        recorder.transportGenerationReady = true
+        handler.handleSessionAuthenticated(alicePeerID)
+
+        #expect(recorder.decryptCalls.count == 2)
+        #expect(recorder.deliveries.count == 1)
+        #expect(recorder.deliveries.first?.type == .privateMessage)
+        #expect(recorder.deliveries.first?.payload == Data([0xCA, 0xFE]))
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func ciphertextQueuedAheadOfRestoreCallbackDoesNotConsumeNonce()
+        throws {
+        let alice = NoiseEncryptionService(keychain: MockKeychain())
+        let bob = NoiseEncryptionService(keychain: MockKeychain())
+        let mallory = NoiseEncryptionService(keychain: MockKeychain())
+        let alicePeerID = PeerID(
+            publicKey: alice.getStaticPublicKeyData()
+        )
+        let bobPeerID = PeerID(publicKey: bob.getStaticPublicKeyData())
+
+        let initial1 = try alice.initiateHandshake(with: bobPeerID)
+        let initial2 = try #require(
+            try bob.processHandshakeMessage(
+                from: alicePeerID,
+                message: initial1
+            )
+        )
+        let initial3 = try #require(
+            try alice.processHandshakeMessage(
+                from: bobPeerID,
+                message: initial2
+            )
+        )
+        _ = try bob.processHandshakeMessage(
+            from: alicePeerID,
+            message: initial3
+        )
+        let typedPayload = Data([
+            NoisePayloadType.privateMessage.rawValue,
+            0xBE, 0xEF
+        ])
+        let delayedCiphertext = try alice.encrypt(
+            typedPayload,
+            for: bobPeerID
+        )
+
+        let forged1 = try mallory.initiateHandshake(with: bobPeerID)
+        let forged2 = try #require(
+            try bob.processHandshakeMessage(
+                from: alicePeerID,
+                message: forged1
+            )
+        )
+        let forged3 = try #require(
+            try mallory.processHandshakeMessage(
+                from: bobPeerID,
+                message: forged2
+            )
+        )
+        #expect(throws: NoiseSessionError.peerIdentityMismatch) {
+            try bob.processHandshakeMessage(
+                from: alicePeerID,
+                message: forged3
+            )
+        }
+        #expect(bob.hasEstablishedSession(with: alicePeerID))
+
+        let recorder = Recorder()
+        recorder.transportGenerationReady = false
+        let handler = makeServiceBackedHandler(
+            service: bob,
+            localPeerID: bobPeerID,
+            recorder: recorder,
+            transportGenerationIsReady: { _ in
+                recorder.transportGenerationReady
+            }
+        )
+        let packet = makeEncryptedPacket(
+            recipientID: Data(hexString: bobPeerID.id),
+            payload: delayedCiphertext
+        )
+
+        // Manager rollback is visible, while the BLE restore callback is
+        // deliberately still queued behind this ciphertext.
+        handler.handleEncrypted(packet, from: alicePeerID)
+        #expect(recorder.deliveries.isEmpty)
+        #expect(recorder.clearedSessions.isEmpty)
+
+        recorder.transportGenerationReady = true
+        handler.handleSessionAuthenticated(alicePeerID)
+
+        #expect(recorder.decryptCalls.count == 2)
+        #expect(recorder.deliveries.count == 1)
+        #expect(recorder.deliveries.first?.type == .privateMessage)
+        #expect(recorder.deliveries.first?.payload == Data([0xBE, 0xEF]))
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func oversizedCiphertextCannotEvictEstablishedTransport() throws {
+        let pair = try establishedServices()
+        let recorder = Recorder()
+        recorder.transportGenerationReady = true
+        let handler = makeServiceBackedHandler(
+            service: pair.receiver,
+            localPeerID: pair.receiverPeerID,
+            recorder: recorder,
+            transportGenerationIsReady: { _ in
+                recorder.transportGenerationReady
+            }
+        )
+
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: pair.receiverPeerID.id),
+                payload: Data(
+                    count:
+                        NoiseSecurityConstants
+                            .maxPrivateFileCiphertextSize + 1
+                )
+            ),
+            from: pair.senderPeerID
+        )
+        #expect(
+            pair.receiver.hasEstablishedSession(with: pair.senderPeerID)
+        )
+        #expect(recorder.clearedSessions.isEmpty)
+
+        let valid = try pair.sender.encrypt(
+            Data([NoisePayloadType.privateMessage.rawValue, 0x01]),
+            for: pair.receiverPeerID
+        )
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: pair.receiverPeerID.id),
+                payload: valid
+            ),
+            from: pair.senderPeerID
+        )
+
+        #expect(recorder.deliveries.count == 1)
+        #expect(recorder.deliveries.first?.payload == Data([0x01]))
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func forgedAuthenticationFailureCannotEvictEstablishedTransport()
+        throws {
+        let pair = try establishedServices()
+        let recorder = Recorder()
+        recorder.transportGenerationReady = true
+        let handler = makeServiceBackedHandler(
+            service: pair.receiver,
+            localPeerID: pair.receiverPeerID,
+            recorder: recorder,
+            transportGenerationIsReady: { _ in
+                recorder.transportGenerationReady
+            }
+        )
+        let valid = try pair.sender.encrypt(
+            Data([NoisePayloadType.privateMessage.rawValue, 0x02]),
+            for: pair.receiverPeerID
+        )
+        var forged = valid
+        forged[forged.index(before: forged.endIndex)] ^= 0xFF
+
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: pair.receiverPeerID.id),
+                payload: forged
+            ),
+            from: pair.senderPeerID
+        )
+        #expect(
+            pair.receiver.hasEstablishedSession(with: pair.senderPeerID)
+        )
+        #expect(recorder.clearedSessions.isEmpty)
+
+        // Authentication failure leaves nonce state untouched, so the exact
+        // original ciphertext remains valid.
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: pair.receiverPeerID.id),
+                payload: valid
+            ),
+            from: pair.senderPeerID
+        )
+
+        #expect(recorder.deliveries.count == 1)
+        #expect(recorder.deliveries.first?.payload == Data([0x02]))
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func replayCannotEvictEstablishedTransportOrBlockNextNonce() throws {
+        let pair = try establishedServices()
+        let recorder = Recorder()
+        recorder.transportGenerationReady = true
+        let handler = makeServiceBackedHandler(
+            service: pair.receiver,
+            localPeerID: pair.receiverPeerID,
+            recorder: recorder,
+            transportGenerationIsReady: { _ in
+                recorder.transportGenerationReady
+            }
+        )
+        let first = try pair.sender.encrypt(
+            Data([NoisePayloadType.privateMessage.rawValue, 0x03]),
+            for: pair.receiverPeerID
+        )
+        let firstPacket = makeEncryptedPacket(
+            recipientID: Data(hexString: pair.receiverPeerID.id),
+            payload: first
+        )
+
+        handler.handleEncrypted(firstPacket, from: pair.senderPeerID)
+        handler.handleEncrypted(firstPacket, from: pair.senderPeerID)
+        #expect(
+            pair.receiver.hasEstablishedSession(with: pair.senderPeerID)
+        )
+        #expect(recorder.clearedSessions.isEmpty)
+
+        let next = try pair.sender.encrypt(
+            Data([NoisePayloadType.privateMessage.rawValue, 0x04]),
+            for: pair.receiverPeerID
+        )
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: pair.receiverPeerID.id),
+                payload: next
+            ),
+            from: pair.senderPeerID
+        )
+
+        #expect(recorder.deliveries.count == 2)
+        #expect(recorder.deliveries.map { $0.payload } == [
+            Data([0x03]), Data([0x04])
+        ])
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func rateLimitFailureCannotEvictEstablishedTransportOrConsumeNonce()
+        throws {
+        let pair = try establishedServices()
+        let recorder = Recorder()
+        recorder.transportGenerationReady = true
+        recorder.forcedServiceDecryptError =
+            NoiseSecurityError.rateLimitExceeded
+        let handler = makeServiceBackedHandler(
+            service: pair.receiver,
+            localPeerID: pair.receiverPeerID,
+            recorder: recorder,
+            transportGenerationIsReady: { _ in
+                recorder.transportGenerationReady
+            }
+        )
+        let valid = try pair.sender.encrypt(
+            Data([NoisePayloadType.privateMessage.rawValue, 0x05]),
+            for: pair.receiverPeerID
+        )
+
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: pair.receiverPeerID.id),
+                payload: Data(repeating: 0xA5, count: 20)
+            ),
+            from: pair.senderPeerID
+        )
+        #expect(
+            pair.receiver.hasEstablishedSession(with: pair.senderPeerID)
+        )
+        #expect(recorder.clearedSessions.isEmpty)
+
+        recorder.forcedServiceDecryptError = nil
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: pair.receiverPeerID.id),
+                payload: valid
+            ),
+            from: pair.senderPeerID
+        )
+
+        #expect(recorder.deliveries.count == 1)
+        #expect(recorder.deliveries.first?.payload == Data([0x05]))
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func maximumPrivateFileCiphertextIsEligibleForDeferredRetry() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(
+            CryptoKitError.authenticationFailure
+        )
+        let handler = makeHandler(recorder: recorder)
+        let encrypted = makeEncryptedPacket(
+            recipientID: Data(hexString: localPeerID.id),
+            payload: Data(
+                count: NoiseSecurityConstants.maxPrivateFileCiphertextSize
+            )
+        )
+
+        handler.handleEncrypted(encrypted, from: remotePeerID)
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.privateFile.rawValue, 0x01])
+        )
+        handler.handleSessionAuthenticated(remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 2)
+        #expect(recorder.deliveries.count == 1)
+        #expect(recorder.deliveries.first?.type == .privateFile)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func oversizedEarlyCiphertextIsNotDeferred() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(
+            CryptoKitError.authenticationFailure
+        )
+        let handler = makeHandler(recorder: recorder)
+        let encrypted = makeEncryptedPacket(
+            recipientID: Data(hexString: localPeerID.id),
+            payload: Data(
+                count:
+                    NoiseSecurityConstants.maxPrivateFileCiphertextSize + 1
+            )
+        )
+
+        handler.handleEncrypted(encrypted, from: remotePeerID)
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.delivered.rawValue, 0x01])
+        )
+        handler.handleSessionAuthenticated(remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 1)
+        #expect(recorder.deliveries.isEmpty)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func missingSessionCiphertextIsRetriedAfterResponderHandshakeCompletes() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(
+            NoiseEncryptionError.sessionNotEstablished
+        )
+        let handler = makeHandler(recorder: recorder)
+        let encrypted = makeEncryptedPacket(
+            recipientID: Data(hexString: localPeerID.id)
+        )
+
+        handler.handleEncrypted(encrypted, from: remotePeerID)
+        #expect(recorder.decryptCalls.count == 1)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.delivered.rawValue, 0x01])
+        )
+        handler.handleSessionAuthenticated(remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 2)
+        #expect(recorder.deliveries.count == 1)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func lowNonceCiphertextIsRetriedAfterResponderHandshakeCompletes() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(NoiseError.replayDetected)
+        let handler = makeHandler(recorder: recorder)
+        let encrypted = makeEncryptedPacket(
+            recipientID: Data(hexString: localPeerID.id)
+        )
+
+        handler.handleEncrypted(encrypted, from: remotePeerID)
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.readReceipt.rawValue, 0x02])
+        )
+        handler.handleSessionAuthenticated(remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 2)
+        #expect(recorder.deliveries.count == 1)
+        #expect(recorder.deliveries.first?.type == .readReceipt)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func invalidDeferredCiphertextDoesNotClearAuthenticatedSession() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(
+            CryptoKitError.authenticationFailure
+        )
+        let handler = makeHandler(recorder: recorder)
+        let encrypted = makeEncryptedPacket(
+            recipientID: Data(hexString: localPeerID.id)
+        )
+
+        handler.handleEncrypted(encrypted, from: remotePeerID)
+        recorder.awaitingResponderHandshake = false
+        handler.handleSessionAuthenticated(remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 2)
+        #expect(recorder.deliveries.isEmpty)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func nonCipherFailureDuringResponderHandshakeIsDroppedNotDeferred() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(TestError())
+        let handler = makeHandler(recorder: recorder)
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: localPeerID.id)
+            ),
+            from: remotePeerID
+        )
+
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.delivered.rawValue, 0x01])
+        )
+        handler.handleSessionAuthenticated(remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 1)
+        #expect(recorder.deliveries.isEmpty)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func earlyCiphertextBufferIsBoundedPerPeer() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(
+            CryptoKitError.authenticationFailure
+        )
+        let handler = makeHandler(recorder: recorder)
+
+        for index in 0..<5 {
+            handler.handleEncrypted(
+                makeEncryptedPacket(
+                    recipientID: Data(hexString: localPeerID.id),
+                    timestamp: UInt64(900_000 + index)
+                ),
+                from: remotePeerID
+            )
+        }
+        #expect(recorder.decryptCalls.count == 5)
+
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.delivered.rawValue, 0x01])
+        )
+        handler.handleSessionAuthenticated(remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 9)
+        #expect(recorder.deliveries.count == 4)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func earlyCiphertextBufferIsBoundedGlobally() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(
+            CryptoKitError.authenticationFailure
+        )
+        let handler = makeHandler(recorder: recorder)
+        let peers = (1...33).map {
+            PeerID(str: String(format: "%016llx", UInt64($0)))
+        }
+        let packet = makeEncryptedPacket(
+            recipientID: Data(hexString: localPeerID.id)
+        )
+
+        for peerID in peers {
+            handler.handleEncrypted(packet, from: peerID)
+        }
+        #expect(recorder.decryptCalls.count == 33)
+
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.delivered.rawValue, 0x01])
+        )
+        for peerID in peers {
+            handler.handleSessionAuthenticated(peerID)
+        }
+
+        #expect(recorder.decryptCalls.count == 65)
+        #expect(recorder.deliveries.count == 32)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func earlyCiphertextBufferKeepsPrivateFileRoomAndByteBound() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(
+            CryptoKitError.authenticationFailure
+        )
+        let handler = makeHandler(recorder: recorder)
+        let peers = [
+            PeerID(str: "0000000000000001"),
+            PeerID(str: "0000000000000002"),
+            PeerID(str: "0000000000000003")
+        ]
+
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: localPeerID.id),
+                payload: Data(
+                    count:
+                        NoiseSecurityConstants.maxPrivateFileCiphertextSize
+                )
+            ),
+            from: peers[0]
+        )
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: localPeerID.id),
+                payload: Data(count: 256 * 1024)
+            ),
+            from: peers[1]
+        )
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: localPeerID.id),
+                payload: Data([0x01])
+            ),
+            from: peers[2]
+        )
+
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.delivered.rawValue, 0x01])
+        )
+        for peerID in peers {
+            handler.handleSessionAuthenticated(peerID)
+        }
+
+        #expect(recorder.decryptCalls.count == 5)
+        #expect(recorder.deliveries.count == 2)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func expiredEarlyCiphertextIsNotRetried() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(
+            CryptoKitError.authenticationFailure
+        )
+        let handler = makeHandler(recorder: recorder)
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: localPeerID.id)
+            ),
+            from: remotePeerID
+        )
+
+        recorder.currentDate =
+            recorder.currentDate.addingTimeInterval(
+                NoiseSecurityConstants.ordinaryResponderHandshakeTimeout
+                    + 0.001
+            )
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.delivered.rawValue, 0x01])
+        )
+        handler.handleSessionAuthenticated(remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 1)
+        #expect(recorder.deliveries.isEmpty)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
+    @Test
+    func earlyCiphertextSurvivesResponderHandshakeWindow() {
+        let recorder = Recorder()
+        recorder.hasSession = true
+        recorder.awaitingResponderHandshake = true
+        recorder.decryptResult = .failure(
+            CryptoKitError.authenticationFailure
+        )
+        let handler = makeHandler(recorder: recorder)
+        handler.handleEncrypted(
+            makeEncryptedPacket(
+                recipientID: Data(hexString: localPeerID.id)
+            ),
+            from: remotePeerID
+        )
+
+        recorder.currentDate =
+            recorder.currentDate.addingTimeInterval(
+                NoiseSecurityConstants.ordinaryResponderHandshakeTimeout
+                    - 0.001
+            )
+        recorder.awaitingResponderHandshake = false
+        recorder.decryptResult = .success(
+            Data([NoisePayloadType.delivered.rawValue, 0x01])
+        )
+        handler.handleSessionAuthenticated(remotePeerID)
+
+        #expect(recorder.decryptCalls.count == 2)
+        #expect(recorder.deliveries.count == 1)
+        #expect(recorder.clearedSessions.isEmpty)
+        #expect(recorder.initiatedHandshakes.isEmpty)
+    }
+
     private func makeHandshakePacket(recipientID: Data?) -> BitchatPacket {
         BitchatPacket(
             type: MessageType.noiseHandshake.rawValue,
@@ -378,14 +1240,15 @@ struct BLENoisePacketHandlerTests {
 
     private func makeEncryptedPacket(
         recipientID: Data?,
-        timestamp: UInt64 = 900_000
+        timestamp: UInt64 = 900_000,
+        payload: Data = Data([0xC0, 0xFF, 0xEE])
     ) -> BitchatPacket {
         BitchatPacket(
             type: MessageType.noiseEncrypted.rawValue,
             senderID: Data(hexString: remotePeerID.id) ?? Data(),
             recipientID: recipientID,
             timestamp: timestamp,
-            payload: Data([0xC0, 0xFF, 0xEE]),
+            payload: payload,
             signature: nil,
             ttl: TransportConfig.messageTTLDefault
         )

bitchatTests/Services/NoiseEncryptionServiceTests.swift

@@ -1351,6 +1351,89 @@ struct NoiseEncryptionServiceTests {
         }
     }
 
+    @Test("Responder completion state spans ordinary XX message three")
+    func responderCompletionStateTracksOrdinaryHandshake() throws {
+        let alice = NoiseEncryptionService(keychain: MockKeychain())
+        let bob = NoiseEncryptionService(keychain: MockKeychain())
+        let alicePeerID = PeerID(
+            publicKey: alice.getStaticPublicKeyData()
+        )
+        let bobPeerID = PeerID(publicKey: bob.getStaticPublicKeyData())
+
+        let message1 = try alice.initiateHandshake(with: bobPeerID)
+        #expect(
+            !bob.isAwaitingResponderHandshakeCompletion(with: alicePeerID)
+        )
+
+        let message2 = try #require(
+            try bob.processHandshakeMessage(
+                from: alicePeerID,
+                message: message1
+            )
+        )
+        #expect(
+            bob.isAwaitingResponderHandshakeCompletion(with: alicePeerID)
+        )
+
+        let message3 = try #require(
+            try alice.processHandshakeMessage(
+                from: bobPeerID,
+                message: message2
+            )
+        )
+        #expect(
+            bob.isAwaitingResponderHandshakeCompletion(with: alicePeerID)
+        )
+
+        _ = try bob.processHandshakeMessage(
+            from: alicePeerID,
+            message: message3
+        )
+        #expect(
+            !bob.isAwaitingResponderHandshakeCompletion(with: alicePeerID)
+        )
+    }
+
+    @Test("Transport readiness rejection spends no message budget")
+    func transportReadinessRejectionSpendsNoMessageBudget() throws {
+        let alice = NoiseEncryptionService(keychain: MockKeychain())
+        let bob = NoiseEncryptionService(keychain: MockKeychain())
+        let alicePeerID = PeerID(
+            publicKey: alice.getStaticPublicKeyData()
+        )
+        let bobPeerID = PeerID(publicKey: bob.getStaticPublicKeyData())
+        try establishSessions(alice: alice, bob: bob)
+        let plaintext = Data([
+            NoisePayloadType.privateMessage.rawValue,
+            0xAB, 0xCD
+        ])
+        let ciphertext = try alice.encrypt(plaintext, for: bobPeerID)
+
+        for _ in 0...NoiseSecurityConstants.maxMessagesPerSecond {
+            do {
+                _ = try bob.decryptWithSessionGeneration(
+                    ciphertext,
+                    from: alicePeerID,
+                    establishedGenerationIsReady: { _ in false }
+                )
+                Issue.record(
+                    "Expected transport generation readiness rejection"
+                )
+            } catch NoiseEncryptionError.transportGenerationNotReady {
+                // Expected: authorization and nonce mutation are both later.
+            } catch {
+                Issue.record("Unexpected readiness error: \(error)")
+            }
+        }
+
+        let decrypted = try bob.decryptWithSessionGeneration(
+            ciphertext,
+            from: alicePeerID,
+            establishedGenerationIsReady: { _ in true }
+        )
+        #expect(decrypted.plaintext == plaintext)
+    }
+
     @Test("NoiseMessage JSON and binary encoding round-trip")
     func noiseMessageRoundTrips() throws {
         let message = NoiseMessage(