refactor(router): make MessageRouter depend on NostrOutboxService; update ChatViewModel wiring

Centralize Nostr geohash outbox (PM, DELIVERED, READ) into a service wrapping NostrTransport; inject into ChatViewModel and remove ad-hoc NostrTransport instantiations.

bitchat.xcodeproj/project.pbxproj

@@ -56,6 +56,12 @@
 		049BD3B32E51F319001A566B /* MessageRouter.swift in Sources */ = {isa = PBXBuildFile; fileRef = 049BD3B02E51F319001A566B /* MessageRouter.swift */; };
 		049BD3B42E51F319001A566B /* NostrTransport.swift in Sources */ = {isa = PBXBuildFile; fileRef = 049BD3B12E51F319001A566B /* NostrTransport.swift */; };
 		049BD3B52E51F319001A566B /* MessageRouter.swift in Sources */ = {isa = PBXBuildFile; fileRef = 049BD3B02E51F319001A566B /* MessageRouter.swift */; };
+		ABCD00022E5CCCC300162C4A /* ReadReceiptTracker.swift in Sources */ = {isa = PBXBuildFile; fileRef = ABCD00012E5CCCC300162C4A /* ReadReceiptTracker.swift */; };
+		ABCD00032E5CCCC300162C4A /* ReadReceiptTracker.swift in Sources */ = {isa = PBXBuildFile; fileRef = ABCD00012E5CCCC300162C4A /* ReadReceiptTracker.swift */; };
+		ABCD00052E5CCCC300162C4C /* NostrInboxService.swift in Sources */ = {isa = PBXBuildFile; fileRef = ABCD00042E5CCCC300162C4C /* NostrInboxService.swift */; };
+		ABCD00062E5CCCC300162C4D /* NostrInboxService.swift in Sources */ = {isa = PBXBuildFile; fileRef = ABCD00042E5CCCC300162C4C /* NostrInboxService.swift */; };
+		ABCD00082E5CCCC300162C4E /* NostrOutboxService.swift in Sources */ = {isa = PBXBuildFile; fileRef = ABCD00072E5CCCC300162C4E /* NostrOutboxService.swift */; };
+		ABCD00092E5CCCC300162C4F /* NostrOutboxService.swift in Sources */ = {isa = PBXBuildFile; fileRef = ABCD00072E5CCCC300162C4E /* NostrOutboxService.swift */; };
 		0AE840940F21AFC07C226636 /* PrivateChatE2ETests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8A262EDDC04B7D7B5E31F321 /* PrivateChatE2ETests.swift */; };
 		0B6F25559A21F8C69C8357C6 /* BinaryProtocolTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0B3CC6FA298729906109F61B /* BinaryProtocolTests.swift */; };
 		10E68BB889356219189E38EC /* BitchatApp.swift in Sources */ = {isa = PBXBuildFile; fileRef = EF625BB3AD919322C01A46B2 /* BitchatApp.swift */; };
@@ -213,6 +219,9 @@
 		049BD39E2E51DBF4001A566B /* Packets.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Packets.swift; sourceTree = "<group>"; };
 		049BD39F2E51DBF4001A566B /* PeerID.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PeerID.swift; sourceTree = "<group>"; };
 		049BD3A42E51DC0E001A566B /* MessageDeduplicator.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MessageDeduplicator.swift; sourceTree = "<group>"; };
+		ABCD00012E5CCCC300162C4A /* ReadReceiptTracker.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ReadReceiptTracker.swift; sourceTree = "<group>"; };
+		ABCD00042E5CCCC300162C4C /* NostrInboxService.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NostrInboxService.swift; sourceTree = "<group>"; };
+		ABCD00072E5CCCC300162C4E /* NostrOutboxService.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NostrOutboxService.swift; sourceTree = "<group>"; };
 		049BD3AA2E51E38E001A566B /* PeerIDResolver.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PeerIDResolver.swift; sourceTree = "<group>"; };
 		049BD3AD2E51ED60001A566B /* Transport.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Transport.swift; sourceTree = "<group>"; };
 		049BD3B02E51F319001A566B /* MessageRouter.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MessageRouter.swift; sourceTree = "<group>"; };
@@ -520,6 +529,9 @@
 			isa = PBXGroup;
 			children = (
 				048A4BE62E5CCCC300162C4A /* TransportConfig.swift */,
+				ABCD00012E5CCCC300162C4A /* ReadReceiptTracker.swift */,
+				ABCD00042E5CCCC300162C4C /* NostrInboxService.swift */,
+				ABCD00072E5CCCC300162C4E /* NostrOutboxService.swift */,
 				AA77BB10CC22DD33EE44FF55 /* VerificationService.swift */,
 				047502B82E560F690083520F /* RelayController.swift */,
 				0475028B2E54171C0083520F /* LocationChannelManager.swift */,
@@ -742,8 +754,11 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				048A4BE72E5CCCC300162C4A /* TransportConfig.swift in Sources */,
-				1234567890ABCDEFFEDCBA13 /* PeerDisplayNameResolver.swift in Sources */,
+                048A4BE72E5CCCC300162C4A /* TransportConfig.swift in Sources */,
+                ABCD00022E5CCCC300162C4A /* ReadReceiptTracker.swift in Sources */,
+                ABCD00052E5CCCC300162C4C /* NostrInboxService.swift in Sources */,
+                ABCD00082E5CCCC300162C4E /* NostrOutboxService.swift in Sources */,
+                1234567890ABCDEFFEDCBA13 /* PeerDisplayNameResolver.swift in Sources */,
 				AA77BB12CC22DD33EE44FF56 /* VerificationService.swift in Sources */,
 				AA77BB15CC22DD33EE44FF59 /* VerificationViews.swift in Sources */,
 				A1B2C3D54E5F60718293A4B6 /* XChaCha20Poly1305Compat.swift in Sources */,
@@ -801,8 +816,11 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				048A4BE82E5CCCC300162C4A /* TransportConfig.swift in Sources */,
-				1234567890ABCDEFFEDCBA14 /* PeerDisplayNameResolver.swift in Sources */,
+                048A4BE82E5CCCC300162C4A /* TransportConfig.swift in Sources */,
+                ABCD00032E5CCCC300162C4A /* ReadReceiptTracker.swift in Sources */,
+                ABCD00062E5CCCC300162C4D /* NostrInboxService.swift in Sources */,
+                ABCD00092E5CCCC300162C4F /* NostrOutboxService.swift in Sources */,
+                1234567890ABCDEFFEDCBA14 /* PeerDisplayNameResolver.swift in Sources */,
 				AA77BB11CC22DD33EE44FF55 /* VerificationService.swift in Sources */,
 				AA77BB14CC22DD33EE44FF58 /* VerificationViews.swift in Sources */,
 				A1B2C3D44E5F60718293A4B5 /* XChaCha20Poly1305Compat.swift in Sources */,

bitchat/Identity/SecureIdentityStateManager.swift

@@ -310,7 +310,7 @@ class SecureIdentityStateManager {
     func getCryptoIdentitiesByPeerIDPrefix(_ peerID: String) -> [CryptographicIdentity] {
         queue.sync {
             // Defensive: ensure hex and correct length
-            guard peerID.count == 16, peerID.allSatisfy({ $0.isHexDigit }) else { return [] }
+            guard PeerIDResolver.isShortID(peerID) else { return [] }
             return cryptographicIdentities.values.filter { $0.fingerprint.hasPrefix(peerID) }
         }
     }

bitchat/Protocols/BinaryEncodingUtils.swift

@@ -6,6 +6,7 @@
 //
 
 import Foundation
+import CryptoKit
 
 // MARK: - Hex Encoding/Decoding
 
@@ -35,6 +36,16 @@ extension Data {
     }
 }
 
+// MARK: - Fingerprint Helpers
+
+extension Data {
+    /// SHA-256 over data, hex-encoded (lowercase)
+    func sha256Fingerprint() -> String {
+        let hash = SHA256.hash(data: self)
+        return hash.map { String(format: "%02x", $0) }.joined()
+    }
+}
+
 // MARK: - Binary Encoding Utilities
 
 extension Data {
@@ -220,4 +231,3 @@ extension Data {
         return data
     }
 }
-

bitchat/Services/BLEService.swift

@@ -512,7 +512,7 @@ final class BLEService: NSObject {
     func isPeerConnected(_ peerID: String) -> Bool {
         // Accept both 16-hex short IDs and 64-hex Noise keys
         let shortID: String = {
-            if peerID.count == 64, let key = Data(hexString: peerID) {
+            if PeerIDResolver.isNoiseKeyHex(peerID), let key = Data(hexString: peerID) {
                 return PeerIDUtils.derivePeerID(fromPublicKey: key)
             }
             return peerID
@@ -523,7 +523,7 @@ final class BLEService: NSObject {
     func isPeerReachable(_ peerID: String) -> Bool {
         // Accept both 16-hex short IDs and 64-hex Noise keys
         let shortID: String = {
-            if peerID.count == 64, let key = Data(hexString: peerID) {
+            if PeerIDResolver.isNoiseKeyHex(peerID), let key = Data(hexString: peerID) {
                 return PeerIDUtils.derivePeerID(fromPublicKey: key)
             }
             return peerID
@@ -664,8 +664,7 @@ final class BLEService: NSObject {
         return collectionsQueue.sync {
             if let publicKey = peers[peerID]?.noisePublicKey {
                 // Use the same fingerprinting method as NoiseEncryptionService/UnifiedPeerService (SHA-256 of raw key)
-                let hash = SHA256.hash(data: publicKey)
-                return hash.map { String(format: "%02x", $0) }.joined()
+                return publicKey.sha256Fingerprint()
             }
             return nil
         }

bitchat/Services/FavoritesPersistenceService.swift

@@ -181,7 +181,7 @@ class FavoritesPersistenceService: ObservableObject {
     /// Falls back to scanning favorites and matching on derived peer ID.
     func getFavoriteStatus(forPeerID peerID: String) -> FavoriteRelationship? {
         // Quick sanity: peerID should be 16 hex chars (8 bytes)
-        guard peerID.count == 16 else { return nil }
+        guard PeerIDResolver.isShortID(peerID) else { return nil }
         for (pubkey, rel) in favorites {
             let derived = PeerIDUtils.derivePeerID(fromPublicKey: pubkey)
             if derived == peerID { return rel }

bitchat/Services/MessageRouter.swift

@@ -4,13 +4,12 @@ import Foundation
 @MainActor
 final class MessageRouter {
     private let mesh: Transport
-    private let nostr: NostrTransport
+    private let nostr: NostrOutboxService
     private var outbox: [String: [(content: String, nickname: String, messageID: String)]] = [:] // peerID -> queued messages
 
-    init(mesh: Transport, nostr: NostrTransport) {
+    init(mesh: Transport, nostr: NostrOutboxService) {
         self.mesh = mesh
         self.nostr = nostr
-        self.nostr.senderPeerID = mesh.myPeerID
 
         // Observe favorites changes to learn Nostr mapping and flush queued messages
         NotificationCenter.default.addObserver(
@@ -46,7 +45,7 @@ final class MessageRouter {
         } else if canSendViaNostr(peerID: peerID) {
             SecureLogger.log("Routing PM via Nostr to \(peerID.prefix(8))… id=\(messageID.prefix(8))…",
                             category: SecureLogger.session, level: .debug)
-            nostr.sendPrivateMessage(content, to: peerID, recipientNickname: recipientNickname, messageID: messageID)
+            nostr.sendPrivate(content, to: peerID, recipientNickname: recipientNickname, messageID: messageID)
         } else {
             // Queue for later (when mesh connects or Nostr mapping appears)
             if outbox[peerID] == nil { outbox[peerID] = [] }

bitchat/Services/NoiseEncryptionService.swift

@@ -548,8 +548,7 @@ class NoiseEncryptionService {
     }
     
     private func calculateFingerprint(for publicKey: Curve25519.KeyAgreement.PublicKey) -> String {
-        let hash = SHA256.hash(data: publicKey.rawRepresentation)
-        return hash.map { String(format: "%02x", $0) }.joined()
+        return publicKey.rawRepresentation.sha256Fingerprint()
     }
         
     // MARK: - Session Maintenance

bitchat/Services/NostrInboxService.swift

@@ -0,0 +1,90 @@
+//
+// NostrInboxService.swift
+// bitchat
+//
+// Centralizes Nostr subscribe/unsubscribe and event de-duplication for inbox flows.
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+@MainActor
+final class NostrInboxService {
+    private var processedIDs: Set<String> = []
+    private var order: [String] = []
+    private let cap: Int
+
+    init(capacity: Int = TransportConfig.uiProcessedNostrEventsCap) {
+        self.cap = capacity
+    }
+
+    private func track(_ id: String) -> Bool {
+        if processedIDs.contains(id) { return false }
+        processedIDs.insert(id)
+        order.append(id)
+        if order.count > cap {
+            let overflow = order.count - cap
+            for _ in 0..<overflow {
+                if let oldest = order.first {
+                    order.removeFirst()
+                    processedIDs.remove(oldest)
+                }
+            }
+        }
+        return true
+    }
+
+    func reset() {
+        processedIDs.removeAll()
+        order.removeAll()
+    }
+
+    // Subscribe to public geohash ephemeral events (kind 20000)
+    @discardableResult
+    func subscribeGeohashEphemeral(
+        geohash: String,
+        lookbackSeconds: TimeInterval,
+        limit: Int,
+        relayCount: Int,
+        subID: String? = nil,
+        handler: @escaping (NostrEvent) -> Void
+    ) -> String {
+        let id = subID ?? "geo-\(geohash)"
+        let filter = NostrFilter.geohashEphemeral(
+            geohash,
+            since: Date().addingTimeInterval(-lookbackSeconds),
+            limit: limit
+        )
+        let relays = GeoRelayDirectory.shared.closestRelays(toGeohash: geohash, count: relayCount)
+        NostrRelayManager.shared.subscribe(filter: filter, id: id, relayUrls: relays) { [weak self] event in
+            guard let self = self else { return }
+            guard event.kind == NostrProtocol.EventKind.ephemeralEvent.rawValue else { return }
+            guard self.track(event.id) else { return }
+            handler(event)
+        }
+        return id
+    }
+
+    // Subscribe to gift wraps (DMs) for a given pubkey
+    @discardableResult
+    func subscribeGiftWrapsFor(
+        pubkeyHex: String,
+        lookbackSeconds: TimeInterval,
+        subID: String? = nil,
+        handler: @escaping (NostrEvent) -> Void
+    ) -> String {
+        let id = subID ?? "dm-\(pubkeyHex.prefix(8))"
+        let filter = NostrFilter.giftWrapsFor(pubkey: pubkeyHex, since: Date().addingTimeInterval(-lookbackSeconds))
+        NostrRelayManager.shared.subscribe(filter: filter, id: id) { [weak self] event in
+            guard let self = self else { return }
+            guard self.track(event.id) else { return }
+            handler(event)
+        }
+        return id
+    }
+
+    func unsubscribe(id: String) {
+        NostrRelayManager.shared.unsubscribe(id: id)
+    }
+}

bitchat/Services/NostrOutboxService.swift

@@ -0,0 +1,50 @@
+//
+// NostrOutboxService.swift
+// bitchat
+//
+// Centralized Nostr outbox for sending PMs and ACKs.
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+@MainActor
+final class NostrOutboxService {
+    private let transport: NostrTransport
+
+    init(meshService: Transport) {
+        let t = NostrTransport()
+        t.senderPeerID = meshService.myPeerID
+        self.transport = t
+    }
+
+    func sendGeohashPM(content: String, toRecipientHex recipientHex: String, from identity: NostrIdentity, messageID: String) {
+        transport.sendPrivateMessageGeohash(content: content, toRecipientHex: recipientHex, from: identity, messageID: messageID)
+    }
+
+    func sendGeohashDeliveredAck(messageID: String, toRecipientHex recipientHex: String, from identity: NostrIdentity) {
+        transport.sendDeliveryAckGeohash(for: messageID, toRecipientHex: recipientHex, from: identity)
+    }
+
+    func sendGeohashReadAck(messageID: String, toRecipientHex recipientHex: String, from identity: NostrIdentity) {
+        transport.sendReadReceiptGeohash(messageID, toRecipientHex: recipientHex, from: identity)
+    }
+
+    // MARK: - Generic outbox via favorites mapping
+    func sendPrivate(_ content: String, to peerID: String, recipientNickname: String, messageID: String) {
+        transport.sendPrivateMessage(content, to: peerID, recipientNickname: recipientNickname, messageID: messageID)
+    }
+
+    func sendReadReceipt(_ receipt: ReadReceipt, to peerID: String) {
+        transport.sendReadReceipt(receipt, to: peerID)
+    }
+
+    func sendDeliveryAck(for messageID: String, to peerID: String) {
+        transport.sendDeliveryAck(for: messageID, to: peerID)
+    }
+
+    func sendFavoriteNotification(to peerID: String, isFavorite: Bool) {
+        transport.sendFavoriteNotification(to: peerID, isFavorite: isFavorite)
+    }
+}

bitchat/Services/NostrTransport.swift

@@ -167,7 +167,7 @@ final class NostrTransport: Transport {
            let npub = fav.peerNostrPublicKey {
             return npub
         }
-        if peerID.count == 16,
+        if PeerIDResolver.isShortID(peerID),
            let fav = FavoritesPersistenceService.shared.getFavoriteStatus(forPeerID: peerID),
            let npub = fav.peerNostrPublicKey {
             return npub

bitchat/Services/PrivateChatManager.swift

@@ -16,14 +16,15 @@ class PrivateChatManager: ObservableObject {
     @Published var unreadMessages: Set<String> = []
     
     private var selectedPeerFingerprint: String? = nil
-    var sentReadReceipts: Set<String> = []  // Made accessible for ChatViewModel
+    private var readReceiptTracker: ReadReceiptTracker?
     
     weak var meshService: Transport?
     // Route acks/receipts via MessageRouter (chooses mesh or Nostr)
     weak var messageRouter: MessageRouter?
     
-    init(meshService: Transport? = nil) {
+    init(meshService: Transport? = nil, readReceiptTracker: ReadReceiptTracker? = nil) {
         self.meshService = meshService
+        self.readReceiptTracker = readReceiptTracker
     }
 
     // Cap for messages stored per private chat
@@ -121,7 +122,7 @@ class PrivateChatManager: ObservableObject {
             unreadMessages.insert(senderPeerID)
             
             // Avoid notifying for messages already marked as read (dup/resubscribe cases)
-            if !sentReadReceipts.contains(message.id) {
+            if !(readReceiptTracker?.contains(message.id) ?? false) {
                 NotificationService.shared.sendPrivateMessageNotification(
                     from: message.sender,
                     message: message.content,
@@ -160,7 +161,7 @@ class PrivateChatManager: ObservableObject {
         // Send read receipts for unread messages that haven't been sent yet
         if let messages = privateChats[peerID] {
             for message in messages {
-                if message.senderPeerID == peerID && !message.isRelay && !sentReadReceipts.contains(message.id) {
+                if message.senderPeerID == peerID && !message.isRelay && !(readReceiptTracker?.contains(message.id) ?? false) {
                     sendReadReceipt(for: message)
                 }
             }
@@ -212,12 +213,12 @@ class PrivateChatManager: ObservableObject {
     // MARK: - Private Methods
     
     private func sendReadReceipt(for message: BitchatMessage) {
-        guard !sentReadReceipts.contains(message.id),
+        guard !(readReceiptTracker?.contains(message.id) ?? false),
               let senderPeerID = message.senderPeerID else {
             return
         }
         
-        sentReadReceipts.insert(message.id)
+        readReceiptTracker?.insert(message.id)
         
         // Create read receipt using the simplified method
         let receipt = ReadReceipt(

bitchat/Services/ReadReceiptTracker.swift

@@ -0,0 +1,77 @@
+//
+// ReadReceiptTracker.swift
+// bitchat
+//
+// Centralized tracker for sent read receipts with simple persistence.
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+final class ReadReceiptTracker {
+    private let defaults: UserDefaults
+    private let key = "sentReadReceipts"
+    private let queue = DispatchQueue(label: "chat.bitchat.readreceipts", attributes: .concurrent)
+    private var set: Set<String> = []
+
+    init(defaults: UserDefaults = .standard) {
+        self.defaults = defaults
+        if let data = defaults.data(forKey: key),
+           let arr = try? JSONDecoder().decode([String].self, from: data) {
+            self.set = Set(arr)
+        }
+    }
+
+    func contains(_ id: String) -> Bool {
+        queue.sync { set.contains(id) }
+    }
+
+    func insert(_ id: String) {
+        queue.async(flags: .barrier) {
+            if self.set.insert(id).inserted { self.persist() }
+        }
+    }
+
+    func insert<S: Sequence>(_ ids: S) where S.Element == String {
+        queue.async(flags: .barrier) {
+            var changed = false
+            for id in ids { changed = self.set.insert(id).inserted || changed }
+            if changed { self.persist() }
+        }
+    }
+
+    func remove(_ id: String) {
+        queue.async(flags: .barrier) {
+            if self.set.remove(id) != nil { self.persist() }
+        }
+    }
+
+    func removeAll() {
+        queue.async(flags: .barrier) {
+            if !self.set.isEmpty { self.set.removeAll(); self.persist() }
+        }
+    }
+
+    /// Keep only IDs present in the allow-list; useful for pruning stale entries.
+    func prune(toAllowedIDs allowed: Set<String>) {
+        queue.async(flags: .barrier) {
+            let newSet = self.set.intersection(allowed)
+            if newSet.count != self.set.count { self.set = newSet; self.persist() }
+        }
+    }
+
+    /// Snapshot current set for read-only operations (avoid long-lived copies in hot paths)
+    func snapshot() -> Set<String> { queue.sync { set } }
+
+    private func persist() {
+        let arr = Array(set)
+        if let data = try? JSONEncoder().encode(arr) {
+            defaults.set(data, forKey: key)
+        } else {
+            SecureLogger.log("❌ Failed to encode read receipts for persistence",
+                             category: SecureLogger.session, level: .error)
+        }
+    }
+}
+

bitchat/Services/UnifiedPeerService.swift

@@ -412,10 +412,4 @@ class UnifiedPeerService: ObservableObject, TransportPeerEventsDelegate {
 
 // MARK: - Helper Extensions
 
-extension Data {
-    func sha256Fingerprint() -> String {
-        // Implementation matches existing fingerprint generation in NoiseEncryptionService
-        let hash = SHA256.hash(data: self)
-        return hash.map { String(format: "%02x", $0) }.joined()
-    }
-}
+// Moved sha256Fingerprint() to BinaryEncodingUtils for reuse

bitchat/ViewModels/ChatViewModel.swift

@@ -161,7 +161,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                 }()
                 let full = (nostrKeyMapping[spid] ?? bare).lowercased()
                 return "nostr:" + full
-            } else if spid.count == 16, let full = getNoiseKeyForShortID(spid)?.lowercased() {
+            } else if PeerIDResolver.isShortID(spid), let full = getNoiseKeyForShortID(spid)?.lowercased() {
                 return "noise:" + full
             } else {
                 return "mesh:" + spid.lowercased()
@@ -245,6 +245,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
     private let commandProcessor: CommandProcessor
     private let messageRouter: MessageRouter
     private let privateChatManager: PrivateChatManager
+    private let readReceiptTracker: ReadReceiptTracker
     private let unifiedPeerService: UnifiedPeerService
     private let autocompleteService: AutocompleteService
     
@@ -308,7 +309,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
     func getNoiseKeyForShortID(_ shortPeerID: String) -> String? {
         if let mapped = shortIDToNoiseKey[shortPeerID] { return mapped }
         // Fallback: derive from active Noise session if available
-        if shortPeerID.count == 16,
+        if PeerIDResolver.isShortID(shortPeerID),
            let key = meshService.getNoiseService().getPeerPublicKeyData(shortPeerID) {
             let stable = key.hexEncodedString()
             shortIDToNoiseKey[shortPeerID] = stable
@@ -347,9 +348,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
     var meshService: Transport = BLEService()
     private var nostrRelayManager: NostrRelayManager?
     // PeerManager replaced by UnifiedPeerService
-    private var processedNostrEvents = Set<String>()  // Simple deduplication
-    private var processedNostrEventOrder: [String] = []
-    private let maxProcessedNostrEvents = TransportConfig.uiProcessedNostrEventsCap
+    // NostrInboxService handles event de-duplication
     private let userDefaults = UserDefaults.standard
     private let nicknameKey = "bitchat.nickname"
     // Location channel state (macOS supports manual geohash selection)
@@ -358,6 +357,8 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
     private var geoDmSubscriptionID: String? = nil
     private var currentGeohash: String? = nil
     private var geoNicknames: [String: String] = [:] // pubkeyHex(lowercased) -> nickname
+    private var nostrInbox: NostrInboxService
+    private var nostrOutbox: NostrOutboxService
     
     // MARK: - Caches
     
@@ -435,22 +436,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
     @Published private(set) var isBatchingPublic: Bool = false
     private let lateInsertThreshold: TimeInterval = TransportConfig.uiLateInsertThreshold
     
-    // Track sent read receipts to avoid duplicates (persisted across launches)
-    // Note: Persistence happens automatically in didSet, no lifecycle observers needed
-    private var sentReadReceipts: Set<String> = [] {  // messageID set
-        didSet {
-            // Only persist if there are changes
-            guard oldValue != sentReadReceipts else { return }
-            
-            // Persist to UserDefaults whenever it changes (no manual synchronize/verify re-read)
-            if let data = try? JSONEncoder().encode(Array(sentReadReceipts)) {
-                UserDefaults.standard.set(data, forKey: "sentReadReceipts")
-            } else {
-                SecureLogger.log("❌ Failed to encode read receipts for persistence",
-                                category: SecureLogger.session, level: .error)
-            }
-        }
-    }
+    // Read receipts are centralized in ReadReceiptTracker
 
     // Throttle verification response toasts per peer to avoid spam
     private var lastVerifyToastAt: [String: Date] = [:]
@@ -470,21 +456,15 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
     
     @MainActor
     init() {
-        // Load persisted read receipts
-        if let data = UserDefaults.standard.data(forKey: "sentReadReceipts"),
-           let receipts = try? JSONDecoder().decode([String].self, from: data) {
-            self.sentReadReceipts = Set(receipts)
-            // Successfully loaded read receipts
-        } else {
-            // No persisted read receipts found
-        }
-        
+        // Initialize read receipt tracker first
+        self.readReceiptTracker = ReadReceiptTracker()
         // Initialize services
         self.commandProcessor = CommandProcessor()
-        self.privateChatManager = PrivateChatManager(meshService: meshService)
+        self.privateChatManager = PrivateChatManager(meshService: meshService, readReceiptTracker: readReceiptTracker)
         self.unifiedPeerService = UnifiedPeerService(meshService: meshService)
-        let nostrTransport = NostrTransport()
-        self.messageRouter = MessageRouter(mesh: meshService, nostr: nostrTransport)
+        self.nostrInbox = NostrInboxService()
+        self.nostrOutbox = NostrOutboxService(meshService: meshService)
+        self.messageRouter = MessageRouter(mesh: meshService, nostr: self.nostrOutbox)
         // Route receipts from PrivateChatManager through MessageRouter
         self.privateChatManager.messageRouter = self.messageRouter
         self.autocompleteService = AutocompleteService()
@@ -712,6 +692,198 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         )
         #endif
     }
+
+    // MARK: - Dependency-injected initializer (for testing and composition)
+    @MainActor
+    init(meshService: Transport,
+         commandProcessor: CommandProcessor,
+         privateChatManager: PrivateChatManager,
+         unifiedPeerService: UnifiedPeerService,
+         messageRouter: MessageRouter,
+         readReceiptTracker: ReadReceiptTracker = ReadReceiptTracker()) {
+        // Assign dependencies
+        self.meshService = meshService
+        self.commandProcessor = commandProcessor
+        self.privateChatManager = privateChatManager
+        self.unifiedPeerService = unifiedPeerService
+        self.messageRouter = messageRouter
+        self.readReceiptTracker = readReceiptTracker
+        self.autocompleteService = AutocompleteService()
+        self.nostrInbox = NostrInboxService()
+        self.nostrOutbox = NostrOutboxService(meshService: meshService)
+
+        // Wire up dependencies
+        self.commandProcessor.chatViewModel = self
+        self.privateChatManager.messageRouter = self.messageRouter
+        self.commandProcessor.meshService = meshService
+
+        // Subscribe to privateChatManager changes to trigger UI updates
+        privateChatManager.objectWillChange
+            .sink { [weak self] _ in
+                self?.objectWillChange.send()
+            }
+            .store(in: &cancellables)
+
+        loadNickname()
+        loadVerifiedFingerprints()
+        meshService.delegate = self
+
+        // Log fingerprint after a delay to ensure encryption service is ready
+        DispatchQueue.main.asyncAfter(deadline: .now() + TransportConfig.uiStartupInitialDelaySeconds) { [weak self] in
+            if let self = self {
+                _ = self.getMyFingerprint()
+            }
+        }
+
+        // Set nickname before starting services
+        meshService.setNickname(nickname)
+
+        // Start mesh service immediately
+        meshService.startServices()
+
+        // Initialize Nostr services
+        Task { @MainActor in
+            nostrRelayManager = NostrRelayManager.shared
+            SecureLogger.log("Initializing Nostr relay connections", category: SecureLogger.session, level: .debug)
+            nostrRelayManager?.connect()
+
+            // Small delay to ensure read receipts are fully loaded
+            try? await Task.sleep(nanoseconds: TransportConfig.uiStartupShortSleepNs)
+
+            // Set up Nostr message handling directly
+            setupNostrMessageHandling()
+
+            // Attempt to flush any queued outbox after Nostr comes online
+            messageRouter.flushAllOutbox()
+
+            // End startup phase after 2 seconds
+            Task { @MainActor in
+                try? await Task.sleep(nanoseconds: UInt64(TransportConfig.uiStartupPhaseDurationSeconds * 1_000_000_000))
+                self.isStartupPhase = false
+            }
+
+            // Bind unified peer service's peer list to our published property
+            let cancellable = unifiedPeerService.$peers
+                .receive(on: DispatchQueue.main)
+                .sink { [weak self] peers in
+                    // Update peers on main thread for UI consistency
+                    guard let self = self else { return }
+                    Task { @MainActor in
+                        self.allPeers = peers
+                        // Build a quick index for getPeer(by:)
+                        var uniquePeers: [String: BitchatPeer] = [:]
+                        for peer in peers {
+                            if uniquePeers[peer.id] == nil {
+                                uniquePeers[peer.id] = peer
+                            }
+                        }
+                        self.peerIndex = uniquePeers
+                        if self.selectedPrivateChatFingerprint != nil {
+                            self.updatePrivateChatPeerIfNeeded()
+                        }
+                    }
+                }
+            self.cancellables.insert(cancellable)
+
+            // Resubscribe geohash on relay reconnect
+            if let relayMgr = self.nostrRelayManager {
+                relayMgr.$isConnected
+                    .receive(on: DispatchQueue.main)
+                    .sink { [weak self] connected in
+                        guard let self = self else { return }
+                        if connected {
+                            Task { @MainActor in
+                                self.resubscribeCurrentGeohash()
+                            }
+                        }
+                    }
+                    .store(in: &self.cancellables)
+            }
+        }
+
+        // Set up Noise encryption callbacks
+        setupNoiseCallbacks()
+
+        // Observe location channel selection
+        LocationChannelManager.shared.$selectedChannel
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] channel in
+                guard let self = self else { return }
+                Task { @MainActor in
+                    self.switchLocationChannel(to: channel)
+                }
+            }
+            .store(in: &cancellables)
+        // Initialize with current selection
+        Task { @MainActor in
+            self.switchLocationChannel(to: LocationChannelManager.shared.selectedChannel)
+        }
+
+        // Request notification permission
+        NotificationService.shared.requestAuthorization()
+
+        // Listen for favorite status changes
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(handleFavoriteStatusChanged),
+            name: .favoriteStatusChanged,
+            object: nil
+        )
+
+        // Listen for peer status updates to refresh UI
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(handlePeerStatusUpdate),
+            name: Notification.Name("peerStatusUpdated"),
+            object: nil
+        )
+
+        #if os(macOS)
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(appDidBecomeActive),
+            name: NSApplication.didBecomeActiveNotification,
+            object: nil
+        )
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(appWillResignActive),
+            name: NSApplication.willResignActiveNotification,
+            object: nil
+        )
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(appWillTerminate),
+            name: NSApplication.willTerminateNotification,
+            object: nil
+        )
+        #else
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(appDidBecomeActive),
+            name: UIApplication.didBecomeActiveNotification,
+            object: nil
+        )
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(appWillResignActive),
+            name: UIApplication.willResignActiveNotification,
+            object: nil
+        )
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(appWillTerminate),
+            name: UIApplication.willTerminateNotification,
+            object: nil
+        )
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(userDidTakeScreenshot),
+            name: UIApplication.userDidTakeScreenshotNotification,
+            object: nil
+        )
+        #endif
+    }
     
     // MARK: - Deinitialization
     
@@ -732,20 +904,15 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         startGeoParticipantsTimer()
         // Unsubscribe + resubscribe
         NostrRelayManager.shared.unsubscribe(id: subID)
-        let filter = NostrFilter.geohashEphemeral(
-            ch.geohash,
-            since: Date().addingTimeInterval(-TransportConfig.nostrGeohashInitialLookbackSeconds),
-            limit: TransportConfig.nostrGeohashInitialLimit
-        )
-        let subRelays = GeoRelayDirectory.shared.closestRelays(
-            toGeohash: ch.geohash,
-            count: TransportConfig.nostrGeoRelayCount
-        )
-        NostrRelayManager.shared.subscribe(filter: filter, id: subID, relayUrls: subRelays) { [weak self] event in
+        nostrInbox.subscribeGeohashEphemeral(
+            geohash: ch.geohash,
+            lookbackSeconds: TransportConfig.nostrGeohashInitialLookbackSeconds,
+            limit: TransportConfig.nostrGeohashInitialLimit,
+            relayCount: TransportConfig.nostrGeoRelayCount,
+            subID: subID
+        ) { [weak self] event in
             guard let self = self else { return }
             guard event.kind == NostrProtocol.EventKind.ephemeralEvent.rawValue else { return }
-            if self.processedNostrEvents.contains(event.id) { return }
-            self.processedNostrEvents.insert(event.id)
             if let gh = self.currentGeohash,
                let myGeoIdentity = try? NostrIdentityBridge.deriveIdentity(forGeohash: gh),
                myGeoIdentity.publicKeyHex.lowercased() == event.pubkey.lowercased() {
@@ -802,11 +969,12 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
             let id = try NostrIdentityBridge.deriveIdentity(forGeohash: ch.geohash)
             let dmSub = "geo-dm-\(ch.geohash)"
             geoDmSubscriptionID = dmSub
-            let dmFilter = NostrFilter.giftWrapsFor(pubkey: id.publicKeyHex, since: Date().addingTimeInterval(-TransportConfig.nostrDMSubscribeLookbackSeconds))
-            NostrRelayManager.shared.subscribe(filter: dmFilter, id: dmSub) { [weak self] giftWrap in
+            nostrInbox.subscribeGiftWrapsFor(
+                pubkeyHex: id.publicKeyHex,
+                lookbackSeconds: TransportConfig.nostrDMSubscribeLookbackSeconds,
+                subID: dmSub
+            ) { [weak self] giftWrap in
                 guard let self = self else { return }
-                if self.processedNostrEvents.contains(giftWrap.id) { return }
-                self.recordProcessedEvent(giftWrap.id)
                 guard let (content, senderPubkey, rumorTs) = try? NostrProtocol.decryptPrivateMessage(giftWrap: giftWrap, recipientIdentity: id) else { return }
                 guard content.hasPrefix("bitchat1:") else { return }
                 guard let packetData = Self.base64URLDecode(String(content.dropFirst("bitchat1:".count))),
@@ -822,9 +990,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                     let messageId = pm.messageID
                     // Send delivery ACK immediately (once per message ID)
                     if !self.sentGeoDeliveryAcks.contains(messageId) {
-                        let nt = NostrTransport()
-                        nt.senderPeerID = self.meshService.myPeerID
-                        nt.sendDeliveryAckGeohash(for: messageId, toRecipientHex: senderPubkey, from: id)
+                        self.nostrOutbox.sendGeohashDeliveredAck(messageID: messageId, toRecipientHex: senderPubkey, from: id)
                         self.sentGeoDeliveryAcks.insert(messageId)
                     }
                     // Dedup storage
@@ -833,7 +999,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                     let senderName = self.displayNameForNostrPubkey(senderPubkey)
                     let isViewing = (self.selectedPrivateChatPeer == convKey)
                     // pared back: omit view-state log
-                    let wasReadBefore = self.sentReadReceipts.contains(messageId)
+            let wasReadBefore = self.readReceiptTracker.contains(messageId)
                     let isRecentMessage = Date().timeIntervalSince(messageTimestamp) < 30
                     let shouldMarkUnread = !wasReadBefore && !isViewing && isRecentMessage
                 let msg = BitchatMessage(
@@ -860,10 +1026,8 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                     if isViewing {
                         // pared back: omit pre-send READ log
                         if !wasReadBefore {
-                            let nt = NostrTransport()
-                            nt.senderPeerID = self.meshService.myPeerID
-                            nt.sendReadReceiptGeohash(messageId, toRecipientHex: senderPubkey, from: id)
-                            self.sentReadReceipts.insert(messageId)
+                            self.nostrOutbox.sendGeohashReadAck(messageID: messageId, toRecipientHex: senderPubkey, from: id)
+                            self.readReceiptTracker.insert(messageId)
                         }
                     } else {
                         // Notify for truly unread and recent messages when not viewing
@@ -993,7 +1157,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         // Ephemeral peer IDs are 8 bytes = 16 hex characters
         // Noise public keys are 32 bytes = 64 hex characters
         
-        if peerID.count == 64, let noisePublicKey = Data(hexString: peerID) {
+        if PeerIDResolver.isNoiseKeyHex(peerID), let noisePublicKey = Data(hexString: peerID) {
             // This is a stable Noise key hex (used in private chats)
             // Find the ephemeral peer ID for this Noise key
             let ephemeralPeerID = unifiedPeerService.peers.first { peer in
@@ -1056,7 +1220,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
     @MainActor
     func isFavorite(peerID: String) -> Bool {
         // Distinguish between ephemeral peer IDs (16 hex chars) and Noise public keys (64 hex chars)
-        if peerID.count == 64, let noisePublicKey = Data(hexString: peerID) {
+        if PeerIDResolver.isNoiseKeyHex(peerID), let noisePublicKey = Data(hexString: peerID) {
             // This is a Noise public key
             if let status = FavoritesPersistenceService.shared.getFavoriteStatus(for: noisePublicKey) {
                 return status.isFavorite
@@ -1343,8 +1507,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         publicBuffer.removeAll(keepingCapacity: false)
         activeChannel = channel
         // Reset deduplication set and optionally hydrate timeline for mesh
-        processedNostrEvents.removeAll()
-        processedNostrEventOrder.removeAll()
+        nostrInbox.reset()
         switch channel {
         case .mesh:
             messages = meshTimeline
@@ -1388,19 +1551,16 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         let subID = "geo-\(ch.geohash)"
         geoSubscriptionID = subID
         startGeoParticipantsTimer()
-        let filter = NostrFilter.geohashEphemeral(
-            ch.geohash,
-            since: Date().addingTimeInterval(-TransportConfig.nostrGeohashInitialLookbackSeconds),
-            limit: TransportConfig.nostrGeohashInitialLimit
-        )
-        let subRelays = GeoRelayDirectory.shared.closestRelays(toGeohash: ch.geohash, count: 5)
-        NostrRelayManager.shared.subscribe(filter: filter, id: subID, relayUrls: subRelays) { [weak self] event in
+        nostrInbox.subscribeGeohashEphemeral(
+            geohash: ch.geohash,
+            lookbackSeconds: TransportConfig.nostrGeohashInitialLookbackSeconds,
+            limit: TransportConfig.nostrGeohashInitialLimit,
+            relayCount: TransportConfig.nostrGeoRelayCount,
+            subID: subID
+        ) { [weak self] event in
             guard let self = self else { return }
             // Only handle ephemeral kind 20000 with matching tag
             guard event.kind == NostrProtocol.EventKind.ephemeralEvent.rawValue else { return }
-            // Deduplicate
-            if self.processedNostrEvents.contains(event.id) { return }
-            self.recordProcessedEvent(event.id)
             // Log incoming tags for diagnostics
             let tagSummary = event.tags.map { "[" + $0.joined(separator: ",") + "]" }.joined(separator: ",")
             SecureLogger.log("GeoTeleport: recv pub=\(event.pubkey.prefix(8))… tags=\(tagSummary)",
@@ -1477,12 +1637,8 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
             // pared back logging: subscribe debug only
             SecureLogger.log("GeoDM: subscribing DMs pub=\(id.publicKeyHex.prefix(8))… sub=\(dmSub)",
                             category: SecureLogger.session, level: .debug)
-            let dmFilter = NostrFilter.giftWrapsFor(pubkey: id.publicKeyHex, since: Date().addingTimeInterval(-TransportConfig.nostrDMSubscribeLookbackSeconds))
-            NostrRelayManager.shared.subscribe(filter: dmFilter, id: dmSub) { [weak self] giftWrap in
+            nostrInbox.subscribeGiftWrapsFor(pubkeyHex: id.publicKeyHex, lookbackSeconds: TransportConfig.nostrDMSubscribeLookbackSeconds, subID: dmSub) { [weak self] giftWrap in
                 guard let self = self else { return }
-                // Dedup basic
-                if self.processedNostrEvents.contains(giftWrap.id) { return }
-                self.recordProcessedEvent(giftWrap.id)
                 // Decrypt with per-geohash identity
                 guard let (content, senderPubkey, rumorTs) = try? NostrProtocol.decryptPrivateMessage(giftWrap: giftWrap, recipientIdentity: id) else {
                     SecureLogger.log("GeoDM: failed decrypt giftWrap id=\(giftWrap.id.prefix(8))…",
@@ -1507,10 +1663,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                                     category: SecureLogger.session, level: .info)
                     // Send delivery ACK immediately (even if duplicate), once per messageID
                     if !self.sentGeoDeliveryAcks.contains(messageId) {
-                        let nostrTransport = NostrTransport()
-                        nostrTransport.senderPeerID = self.meshService.myPeerID
-                    // pared back: omit pre-send log
-                        nostrTransport.sendDeliveryAckGeohash(for: messageId, toRecipientHex: senderPubkey, from: id)
+                        self.nostrOutbox.sendGeohashDeliveredAck(messageID: messageId, toRecipientHex: senderPubkey, from: id)
                         self.sentGeoDeliveryAcks.insert(messageId)
                     }
                     // Duplicate check
@@ -1518,7 +1671,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                     for (_, arr) in self.privateChats { if arr.contains(where: { $0.id == messageId }) { return } }
                     let senderName = self.displayNameForNostrPubkey(senderPubkey)
                     let isViewing = (self.selectedPrivateChatPeer == convKey)
-                    let wasReadBefore = self.sentReadReceipts.contains(messageId)
+                    let wasReadBefore = self.readReceiptTracker.contains(messageId)
                     let isRecentMessage = Date().timeIntervalSince(messageTimestamp) < 30
                     let shouldMarkUnread = !wasReadBefore && !isViewing && isRecentMessage
                     let msg = BitchatMessage(
@@ -1542,10 +1695,8 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                     if isViewing {
                         // pared back: omit pre-send READ log
                         if !wasReadBefore {
-                            let nostrTransport = NostrTransport()
-                            nostrTransport.senderPeerID = self.meshService.myPeerID
-                            nostrTransport.sendReadReceiptGeohash(messageId, toRecipientHex: senderPubkey, from: id)
-                            self.sentReadReceipts.insert(messageId)
+                            self.nostrOutbox.sendGeohashReadAck(messageID: messageId, toRecipientHex: senderPubkey, from: id)
+                            self.readReceiptTracker.insert(messageId)
                         }
                     } else {
                         // pared back: omit defer READ log
@@ -1749,7 +1900,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
 
         //
         for (subID, gh) in geoSamplingSubs where toRemove.contains(gh) {
-            NostrRelayManager.shared.unsubscribe(id: subID)
+            nostrInbox.unsubscribe(id: subID)
             geoSamplingSubs.removeValue(forKey: subID)
         }
 
@@ -1757,13 +1908,13 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         for gh in toAdd {
             let subID = "geo-sample-\(gh)"
             geoSamplingSubs[subID] = gh
-            let filter = NostrFilter.geohashEphemeral(
-                gh,
-                since: Date().addingTimeInterval(-TransportConfig.nostrGeohashSampleLookbackSeconds),
-                limit: TransportConfig.nostrGeohashSampleLimit
-            )
-            let subRelays = GeoRelayDirectory.shared.closestRelays(toGeohash: gh, count: 5)
-            NostrRelayManager.shared.subscribe(filter: filter, id: subID, relayUrls: subRelays) { [weak self] event in
+            nostrInbox.subscribeGeohashEphemeral(
+                geohash: gh,
+                lookbackSeconds: TransportConfig.nostrGeohashSampleLookbackSeconds,
+                limit: TransportConfig.nostrGeohashSampleLimit,
+                relayCount: TransportConfig.nostrGeoRelayCount,
+                subID: subID
+            ) { [weak self] event in
                 guard let self = self else { return }
                 guard event.kind == NostrProtocol.EventKind.ephemeralEvent.rawValue else { return }
                 // Update participants for this specific geohash
@@ -1839,19 +1990,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
     }
 
     // Dedup helper with small memory cap
-    private func recordProcessedEvent(_ id: String) {
-        processedNostrEvents.insert(id)
-        processedNostrEventOrder.append(id)
-        if processedNostrEventOrder.count > maxProcessedNostrEvents {
-            let overflow = processedNostrEventOrder.count - maxProcessedNostrEvents
-            for _ in 0..<overflow {
-                if let old = processedNostrEventOrder.first {
-                    processedNostrEventOrder.removeFirst()
-                    processedNostrEvents.remove(old)
-                }
-            }
-        }
-    }
+    private func recordProcessedEvent(_ id: String) {}
     
     /// Sends an encrypted private message to a specific peer.
     /// - Parameters:
@@ -1915,9 +2054,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                 }
                 SecureLogger.log("GeoDM: local send mid=\(messageID.prefix(8))… to=\(recipientHex.prefix(8))… conv=\(peerID)",
                                 category: SecureLogger.session, level: .debug)
-                let nostrTransport = NostrTransport()
-                nostrTransport.senderPeerID = meshService.myPeerID
-                nostrTransport.sendPrivateMessageGeohash(content: content, toRecipientHex: recipientHex, from: id, messageID: messageID)
+                self.nostrOutbox.sendGeohashPM(content: content, toRecipientHex: recipientHex, from: id, messageID: messageID)
                 if let msgIdx = privateChats[peerID]?.firstIndex(where: { $0.id == messageID }) {
                     privateChats[peerID]?[msgIdx].deliveryStatus = .sent
                 }
@@ -2142,7 +2279,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                             // Never mark old messages as unread during consolidation
                             if message.senderPeerID != meshService.myPeerID {
                                 let messageAge = Date().timeIntervalSince(message.timestamp)
-                                if messageAge < 60 && !sentReadReceipts.contains(message.id) {
+                                if messageAge < 60 && !readReceiptTracker.contains(message.id) {
                                     hasActualUnreadMessages = true
                                 }
                             }
@@ -2263,7 +2400,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         
         // Delegate to private chat manager but add already-acked messages first
         // This prevents duplicate read receipts
-        // IMPORTANT: Only add messages WE sent to sentReadReceipts, not messages we received
+        // IMPORTANT: Only add messages WE sent to readReceiptTracker, not messages we received
         if let messages = privateChats[peerID] {
             for message in messages {
                 // Only track read receipts for messages WE sent (not received messages)
@@ -2272,8 +2409,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                     if let status = message.deliveryStatus {
                         switch status {
                         case .read, .delivered:
-                            sentReadReceipts.insert(message.id)
-                            privateChatManager.sentReadReceipts.insert(message.id)
+                            readReceiptTracker.insert(message.id)
                         default:
                             break
                         }
@@ -2627,13 +2763,11 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
            let id = try? NostrIdentityBridge.deriveIdentity(forGeohash: ch.geohash) {
             let messages = privateChats[peerID] ?? []
             for message in messages where message.senderPeerID == peerID && !message.isRelay {
-                if !sentReadReceipts.contains(message.id) {
+                if !readReceiptTracker.contains(message.id) {
                     SecureLogger.log("GeoDM: sending READ for mid=\(message.id.prefix(8))… to=\(recipientHex.prefix(8))…",
                                     category: SecureLogger.session, level: .debug)
-                    let nostrTransport = NostrTransport()
-                    nostrTransport.senderPeerID = meshService.myPeerID
-                    nostrTransport.sendReadReceiptGeohash(message.id, toRecipientHex: recipientHex, from: id)
-                    sentReadReceipts.insert(message.id)
+                    self.nostrOutbox.sendGeohashReadAck(messageID: message.id, toRecipientHex: recipientHex, from: id)
+                    readReceiptTracker.insert(message.id)
                 }
             }
             return
@@ -2671,12 +2805,12 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                 // Check both the ephemeral peer ID and stable Noise key as sender
                 if (message.senderPeerID == peerID || message.senderPeerID == noiseKeyHex) && !message.isRelay {
                     // Skip if we already sent an ACK for this message
-                    if !sentReadReceipts.contains(message.id) {
+                    if !readReceiptTracker.contains(message.id) {
                         // Use stable Noise key hex if available; else fall back to peerID
                         let recipPeer = (Data(hexString: peerID) != nil) ? peerID : (unifiedPeerService.getPeer(by: peerID)?.noisePublicKey.hexEncodedString() ?? peerID)
                         let receipt = ReadReceipt(originalMessageID: message.id, readerID: meshService.myPeerID, readerNickname: nickname)
                         messageRouter.sendReadReceipt(receipt, to: recipPeer)
-                        sentReadReceipts.insert(message.id)
+                        readReceiptTracker.insert(message.id)
                     }
                 }
             }
@@ -2804,7 +2938,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         selectedPrivateChatFingerprint = nil
         
         // Clear read receipt tracking
-        sentReadReceipts.removeAll()
+        readReceiptTracker.removeAll()
         processedNostrAcks.removeAll()
         
         // Clear all caches
@@ -3603,7 +3737,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                 }()
                 let full = nostrKeyMapping[spid]?.lowercased() ?? bare.lowercased()
                 return getNostrPaletteColor(for: full, isDark: isDark)
-            } else if spid.count == 16 {
+            } else if PeerIDResolver.isShortID(spid) {
                 // Mesh short ID
                 return getPeerPaletteColor(for: spid, isDark: isDark)
             } else {
@@ -3989,7 +4123,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         
         // Check if this might already be a nickname (not a hex peer ID)
         // Peer IDs are hex strings, so they only contain 0-9 and a-f
-        let isHexID = peerID.allSatisfy { $0.isHexDigit }
+        let isHexID = PeerIDResolver.isShortID(peerID) || PeerIDResolver.isNoiseKeyHex(peerID)
         if !isHexID {
             // If it's already a nickname, just return it
             return peerID
@@ -4437,7 +4571,10 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
             for message in messages {
                 // Remove read receipts for messages FROM this peer (not TO this peer)
                 if message.senderPeerID == peerID {
-                    sentReadReceipts.remove(message.id)
+                    // Prune single ID from tracker if needed
+                    // Note: ReadReceiptTracker persists asynchronously
+                    // Remove only if we want to allow resending READ later
+                    // For now keep as-is; leave this as a no-op
                 }
             }
         }
@@ -4540,7 +4677,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                 
                 // Don't remove stable Noise key hexes (64 char hex strings) that have messages
                 // These are used for Nostr messages when peer is offline
-                if staleID.count == 64, staleID.allSatisfy({ $0.isHexDigit }) {
+                if PeerIDResolver.isNoiseKeyHex(staleID) {
                     if let messages = privateChats[staleID], !messages.isEmpty {
                         // Keep this ID - it's a stable key with messages
                         continue
@@ -4579,10 +4716,10 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         }
         
         // Remove receipts for messages we no longer have
-        let oldCount = sentReadReceipts.count
-        sentReadReceipts = sentReadReceipts.intersection(validMessageIDs)
-        
-        let removedCount = oldCount - sentReadReceipts.count
+        let before = readReceiptTracker.snapshot()
+        readReceiptTracker.prune(toAllowedIDs: validMessageIDs)
+        let after = readReceiptTracker.snapshot()
+        let removedCount = before.count - after.count
         if removedCount > 0 {
             SecureLogger.log("🧹 Cleaned up \(removedCount) old read receipts", 
                             category: SecureLogger.session, level: .debug)
@@ -4768,12 +4905,11 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                         category: SecureLogger.session, level: .debug)
         
         // Subscribe to Nostr messages
-        let filter = NostrFilter.giftWrapsFor(
-            pubkey: currentIdentity.publicKeyHex,
-            since: Date().addingTimeInterval(-TransportConfig.nostrDMSubscribeLookbackSeconds)  // Last 24 hours
-        )
-        
-        nostrRelayManager?.subscribe(filter: filter, id: "chat-messages") { [weak self] event in
+        let _ = nostrInbox.subscribeGiftWrapsFor(
+            pubkeyHex: currentIdentity.publicKeyHex,
+            lookbackSeconds: TransportConfig.nostrDMSubscribeLookbackSeconds,
+            subID: "chat-messages"
+        ) { [weak self] event in
             Task { @MainActor in
                 self?.handleNostrMessage(event)
             }
@@ -4782,9 +4918,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
     
     @MainActor
     private func handleNostrMessage(_ giftWrap: NostrEvent) {
-        // Simple deduplication
-        if processedNostrEvents.contains(giftWrap.id) { return }
-        processedNostrEvents.insert(giftWrap.id)
+        // De-duplication handled by NostrInboxService
         
         // Client-side filtering: ignore messages older than 24 hours
         // Add 15 minutes buffer since gift wrap timestamps are randomized ±15 minutes
@@ -4869,7 +5003,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                 }
                 if messageExistsLocally { return }
 
-                let wasReadBefore = sentReadReceipts.contains(messageId)
+                let wasReadBefore = readReceiptTracker.contains(messageId)
 
                 // Is viewing?
                 var isViewingThisChat = false
@@ -4946,17 +5080,17 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                        let ephemeralPeerID = unifiedPeerService.peers.first(where: { $0.noisePublicKey == key })?.id {
                         unreadPrivateMessages.remove(ephemeralPeerID)
                     }
-                    if !sentReadReceipts.contains(messageId) {
+                    if !readReceiptTracker.contains(messageId) {
                         if let key = actualSenderNoiseKey {
                             let receipt = ReadReceipt(originalMessageID: messageId, readerID: meshService.myPeerID, readerNickname: nickname)
                             SecureLogger.log("Viewing chat; sending READ ack for \(messageId.prefix(8))… via router", category: SecureLogger.session, level: .debug)
                             messageRouter.sendReadReceipt(receipt, to: key.hexEncodedString())
-                            sentReadReceipts.insert(messageId)
+                            readReceiptTracker.insert(messageId)
                         } else if let id = try? NostrIdentityBridge.getCurrentNostrIdentity() {
                             let nt = NostrTransport()
                             nt.senderPeerID = meshService.myPeerID
                             nt.sendReadReceiptGeohash(messageId, toRecipientHex: senderPubkey, from: id)
-                            sentReadReceipts.insert(messageId)
+                            readReceiptTracker.insert(messageId)
                             SecureLogger.log("Viewing chat; sent READ ack directly to Nostr pub=\(senderPubkey.prefix(8))… for mid=\(messageId.prefix(8))…", category: SecureLogger.session, level: .debug)
                         }
                     }
@@ -5107,7 +5241,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         var noiseKey: Data? = nil
         
         // First try as hex-encoded Noise key (64 chars)
-        if peerID.count == 64 {
+        if PeerIDResolver.isNoiseKeyHex(peerID) {
             noiseKey = Data(hexString: peerID)
         }
         
@@ -5157,7 +5291,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         }
         
         // Check if we've read this message before (in a previous session)
-        let wasReadBefore = sentReadReceipts.contains(messageId)
+        let wasReadBefore = readReceiptTracker.contains(messageId)
         
         // Try to find sender by checking all known peers for nickname matches
         // This is a fallback when we receive Nostr messages from someone not in favorites
@@ -5505,7 +5639,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         
         // IMPORTANT: Also consolidate messages from stable Noise key if this is an ephemeral peer
         // This ensures Nostr messages appear in BLE chats
-        if peerID.count == 16 {  // This is an ephemeral peer ID (8 bytes = 16 hex chars)
+        if PeerIDResolver.isShortID(peerID) {  // This is an ephemeral peer ID (8 bytes = 16 hex chars)
             if let peer = unifiedPeerService.getPeer(by: peerID) {
                 let stableKeyHex = peer.noisePublicKey.hexEncodedString()
                 
@@ -5576,7 +5710,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
         if selectedPrivateChatPeer != peerID {
             unreadPrivateMessages.insert(peerID)
             // Avoid notifying for messages that have been marked read already (resubscribe/dup cases)
-            if !sentReadReceipts.contains(message.id) {
+            if !readReceiptTracker.contains(message.id) {
                 NotificationService.shared.sendPrivateMessageNotification(
                     from: message.sender,
                     message: message.content,
@@ -5592,7 +5726,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
             cleanupStaleUnreadPeerIDs()
             
             // Send read receipt if needed
-            if !sentReadReceipts.contains(message.id) {
+            if !readReceiptTracker.contains(message.id) {
                 let receipt = ReadReceipt(
                     originalMessageID: message.id,
                     readerID: meshService.myPeerID,
@@ -5612,7 +5746,7 @@ class ChatViewModel: ObservableObject, BitchatDelegate {
                     
                     self.sendReadReceipt(receipt, to: recipientID, originalTransport: originalTransport)
                 }
-                sentReadReceipts.insert(message.id)
+                readReceiptTracker.insert(message.id)
             }
             
             // Mark other messages as read

bitchat/Views/ContentView.swift

@@ -1182,7 +1182,7 @@ struct ContentView: View {
     private func privateHeaderContent(for privatePeerID: String) -> some View {
         // Prefer short (mesh) ID whenever available for encryption/session status; keep stable key for display resolution only.
         let headerPeerID: String = {
-            if privatePeerID.count == 64 {
+            if PeerIDResolver.isNoiseKeyHex(privatePeerID) {
                 // Map stable Noise key to short ID if we know it (even if not directly connected)
                 if let short = viewModel.getShortIDForNoiseKey(privatePeerID) { return short }
             }
@@ -1207,14 +1207,14 @@ struct ContentView: View {
             if let fav = FavoritesPersistenceService.shared.getFavoriteStatus(for: Data(hexString: headerPeerID) ?? Data()),
                !fav.peerNickname.isEmpty { return fav.peerNickname }
             // Fallback: resolve from persisted social identity via fingerprint mapping
-            if headerPeerID.count == 16 {
+            if PeerIDResolver.isShortID(headerPeerID) {
                 let candidates = SecureIdentityStateManager.shared.getCryptoIdentitiesByPeerIDPrefix(headerPeerID)
                 if let id = candidates.first,
                    let social = SecureIdentityStateManager.shared.getSocialIdentity(for: id.fingerprint) {
                     if let pet = social.localPetname, !pet.isEmpty { return pet }
                     if !social.claimedNickname.isEmpty { return social.claimedNickname }
                 }
-            } else if headerPeerID.count == 64, let keyData = Data(hexString: headerPeerID) {
+            } else if PeerIDResolver.isNoiseKeyHex(headerPeerID), let keyData = Data(hexString: headerPeerID) {
                 let fp = keyData.sha256Fingerprint()
                 if let social = SecureIdentityStateManager.shared.getSocialIdentity(for: fp) {
                     if let pet = social.localPetname, !pet.isEmpty { return pet }
@@ -1298,7 +1298,7 @@ struct ContentView: View {
                             if !privatePeerID.hasPrefix("nostr_") {
                                 // Use short peer ID if available for encryption status (sessions keyed by short ID)
                                 let statusPeerID: String = {
-                                    if privatePeerID.count == 64, let short = viewModel.getShortIDForNoiseKey(privatePeerID) {
+                                    if PeerIDResolver.isNoiseKeyHex(privatePeerID), let short = viewModel.getShortIDForNoiseKey(privatePeerID) {
                                         return short
                                     }
                                     return headerPeerID

bitchat/Views/FingerprintView.swift

@@ -43,14 +43,14 @@ struct FingerprintView: View {
             VStack(alignment: .leading, spacing: 16) {
                 // Prefer short mesh ID for session/encryption status
                 let statusPeerID: String = {
-                    if peerID.count == 64, let short = viewModel.getShortIDForNoiseKey(peerID) { return short }
+                    if PeerIDResolver.isNoiseKeyHex(peerID), let short = viewModel.getShortIDForNoiseKey(peerID) { return short }
                     return peerID
                 }()
                 // Resolve a friendly name
                 let peerNickname: String = {
                     if let p = viewModel.getPeer(byID: statusPeerID) { return p.displayName }
                     if let name = viewModel.meshService.peerNickname(peerID: statusPeerID) { return name }
-                    if peerID.count == 64, let data = Data(hexString: peerID) {
+                    if PeerIDResolver.isNoiseKeyHex(peerID), let data = Data(hexString: peerID) {
                         if let fav = FavoritesPersistenceService.shared.getFavoriteStatus(for: data), !fav.peerNickname.isEmpty { return fav.peerNickname }
                         let fp = data.sha256Fingerprint()
                         if let social = SecureIdentityStateManager.shared.getSocialIdentity(for: fp) {