Unify SHA256 hash and hex usages (#687)

bitchat/Services/BLEService.swift

@@ -264,8 +264,7 @@ final class BLEService: NSObject {
     // MARK: - Helpers: IDs, selection, and write backpressure
     private func makeMessageID(for packet: BitchatPacket) -> String {
         let senderID = packet.senderID.hexEncodedString()
-        let digest = SHA256.hash(data: packet.payload)
-        let digestPrefix = digest.prefix(4).map { String(format: "%02x", $0) }.joined()
+        let digestPrefix = packet.payload.sha256Hash().prefix(4).hexEncodedString()
         return "\(senderID)-\(packet.timestamp)-\(packet.type)-\(digestPrefix)"
     }
 
@@ -777,12 +776,7 @@ final class BLEService: NSObject {
     
     func getPeerFingerprint(_ peerID: String) -> String? {
         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 nil
+            return peers[peerID]?.noisePublicKey?.sha256Fingerprint()
         }
     }
 
@@ -1705,17 +1699,12 @@ final class BLEService: NSObject {
         }
 
         // Persist cryptographic identity and signing key for robust offline verification
-        do {
-            // Derive fingerprint from Noise public key
-            let hash = SHA256.hash(data: announcement.noisePublicKey)
-            let fingerprint = hash.map { String(format: "%02x", $0) }.joined()
-            identityManager.upsertCryptographicIdentity(
-                fingerprint: fingerprint,
-                noisePublicKey: announcement.noisePublicKey,
-                signingPublicKey: announcement.signingPublicKey,
-                claimedNickname: announcement.nickname
-            )
-        }
+        identityManager.upsertCryptographicIdentity(
+            fingerprint: announcement.noisePublicKey.sha256Fingerprint(),
+            noisePublicKey: announcement.noisePublicKey,
+            signingPublicKey: announcement.signingPublicKey,
+            claimedNickname: announcement.nickname
+        )
 
         // Record this announce for lightweight rebroadcast buffer (exclude self)
         if peerID != myPeerID {

bitchat/Services/NoiseEncryptionService.swift

@@ -272,8 +272,7 @@ final class NoiseEncryptionService {
     
     /// Get our identity fingerprint
     func getIdentityFingerprint() -> String {
-        let hash = SHA256.hash(data: staticIdentityPublicKey.rawRepresentation)
-        return hash.map { String(format: "%02x", $0) }.joined()
+        staticIdentityPublicKey.rawRepresentation.sha256Fingerprint()
     }
     
     /// Get peer's public key data
@@ -554,7 +553,7 @@ final class NoiseEncryptionService {
     
     private func handleSessionEstablished(peerID: String, remoteStaticKey: Curve25519.KeyAgreement.PublicKey) {
         // Calculate fingerprint
-        let fingerprint = calculateFingerprint(for: remoteStaticKey)
+        let fingerprint = remoteStaticKey.rawRepresentation.sha256Fingerprint()
         
         // Store fingerprint mapping
         serviceQueue.sync(flags: .barrier) {
@@ -572,11 +571,6 @@ final 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()
-    }
         
     // MARK: - Session Maintenance
     

bitchat/Services/UnifiedPeerService.swift

@@ -10,7 +10,6 @@ import BitLogger
 import Foundation
 import Combine
 import SwiftUI
-import CryptoKit
 
 /// Single source of truth for peer state, combining mesh connectivity and favorites
 @MainActor
@@ -389,13 +388,3 @@ final 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()
-    }
-}

bitchat/Services/VerificationService.swift

@@ -1,5 +1,4 @@
 import Foundation
-import CryptoKit
 
 /// QR verification scaffolding: schema, signing, and basic challenge/response helpers.
 final class VerificationService {
@@ -95,7 +94,7 @@ final class VerificationService {
                                     nickname: payload.nickname,
                                     ts: payload.ts,
                                     nonceB64: payload.nonceB64,
-                                    sigHex: sig.map { String(format: "%02x", $0) }.joined())
+                                    sigHex: sig.hexEncodedString())
         let out = signed.toURLString()
         Cache.last = (nickname, npub, Date(), out)
         return out