refactor(hex+fingerprint): centralize SHA256 fingerprint helper; reuse PeerIDResolver in ID checks

- Move Data.sha256Fingerprint() to BinaryEncodingUtils for reuse; refactor NoiseEncryptionService to use it.\n- Replace manual short/full hex checks with PeerIDResolver in ChatViewModel, ContentView, and SecureIdentityStateManager.\n- Keep behavior identical; reduce ad-hoc string length/hex parsing.

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/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/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()
@@ -309,7 +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
@@ -970,7 +970,7 @@ 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
@@ -1033,7 +1033,7 @@ 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
@@ -3965,7 +3965,7 @@ 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
@@ -4519,7 +4519,7 @@ 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
@@ -5086,7 +5086,7 @@ 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)
         }
         
@@ -5484,7 +5484,7 @@ 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()
                 

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