NOnion: minor refactoring

Renamed IdentityKey type to Fingerprint as technically this is
the digest of identity key.

Author: webwarrior-ws

NOnion.Tests/CircuitHelper.cs

@@ -25,7 +25,7 @@ static private CircuitNodeDetail ConvertToCircuitNodeDetail(ServerDescriptorEntr
             var endpoint = IPEndPoint.Parse($"{server.Address.Value}:{server.OnionRouterPort.Value}");
             return CircuitNodeDetail.NewCreate(endpoint, 
                                                new NTorOnionKey(nTorOnionKeyBytes), 
-                                               new IdentityKey(fingerprintBytes));
+                                               new Fingerprint(fingerprintBytes));
         }
 
         /* It's possible that the router returned by GetRandomFallbackDirectory

NOnion.Tests/TorDirectoryTests.cs

@@ -56,7 +56,7 @@ private async Task ReturnRandomRouter()
             TorDirectory directory = await TorDirectory.BootstrapAsync(FallbackDirectorySelector.GetRandomFallbackDirectory(), cachePath);
             var (endPoint, router) = await directory.GetRouterAsync(RouterType.Normal);
             Assert.IsTrue(router.IsCreate);
-            Assert.IsFalse(((CircuitNodeDetail.Create)router).IdentityKey.ToByteArray().All(x => x == 0));
+            Assert.IsFalse(((CircuitNodeDetail.Create)router).Fingerprint.ToByteArray().All(x => x == 0));
             Assert.IsFalse(((CircuitNodeDetail.Create)router).NTorOnionKey.ToByteArray().All(x => x == 0));
             Assert.IsNotNull(((CircuitNodeDetail.Create)router).EndPoint);
             Assert.That(endPoint, Is.EqualTo(((CircuitNodeDetail.Create)router).EndPoint));

NOnion/Constants.fs

@@ -32,7 +32,7 @@ module Constants =
     let KdfLength = 92
 
     [<Literal>]
-    let IdentityKeyLength = 20
+    let FingerprintLength = 20
 
     [<Literal>]
     let Ed25519PrivateKeyLength = 32

NOnion/Directory/TorDirectory.fs

@@ -277,7 +277,7 @@ type TorDirectory =
                     CircuitNodeDetail.Create(
                         endpoint,
                         NTorOnionKey nTorOnionKeyBytes,
-                        IdentityKey fingerprintBytes
+                        Fingerprint fingerprintBytes
                     )
         }
 

NOnion/KeyTypes.fs

@@ -57,12 +57,13 @@ type NTorOnionKey(bytes: array<byte>) =
     member self.ToByteArray() =
         bytes
 
-type IdentityKey(bytes: array<byte>) =
+/// Digest of identity key.
+type Fingerprint(bytes: array<byte>) =
     do
-        if bytes.Length <> Constants.IdentityKeyLength then
+        if bytes.Length <> Constants.FingerprintLength then
             failwithf
-                "Invalid identity key length, expected %d, got %d"
-                Constants.IdentityKeyLength
+                "Invalid fingerprint (identity key digest) length, expected %d, got %d"
+                Constants.FingerprintLength
                 bytes.Length
 
     member self.ToByteArray() =

NOnion/Network/TorCircuit.fs

@@ -26,7 +26,7 @@ type CircuitNodeDetail =
     | Create of
         EndPoint: IPEndPoint *
         NTorOnionKey: NTorOnionKey *
-        IdentityKey: IdentityKey
+        Fingerprint: Fingerprint
 
     member self.GetIdentityKey() =
         match self with

NOnion/Network/TorGuard.fs

@@ -49,7 +49,7 @@ type TorGuard
     (
         client: TcpClient,
         sslStream: SslStream,
-        fingerprintOpt: Option<IdentityKey>
+        fingerprintOpt: Option<Fingerprint>
     ) =
     let shutdownToken = new CancellationTokenSource()
 
@@ -116,7 +116,7 @@ type TorGuard
 
     static member private InnerNewClient
         (ipEndpoint: IPEndPoint)
-        (fingerprintOpt: Option<IdentityKey>)
+        (fingerprintOpt: Option<Fingerprint>)
         =
         async {
             let tcpClient = new TcpClient()

NOnion/Services/TorServiceClient.fs

@@ -373,7 +373,7 @@ type TorServiceClient =
                                     CircuitNodeDetail.Create(
                                         endpointSpecifier,
                                         introductionPoint.OnionKey.Value,
-                                        IdentityKey identityKey
+                                        Fingerprint identityKey
                                     )
 
                         return

NOnion/Services/TorServiceHost.fs

@@ -31,7 +31,7 @@ type IntroductionPointInfo =
         AuthKey: AsymmetricCipherKeyPair
         MasterPublicKey: Ed25519PublicKeyParameters
         NTorOnionKey: NTorOnionKey
-        Fingerprint: IdentityKey
+        Fingerprint: Fingerprint
     }
 
 type TorServiceHost
@@ -234,7 +234,7 @@ type TorServiceHost
                     |> Seq.tryExactlyOne
 
                 match linkSpecifierOpt with
-                | Some linkSpecifier -> IdentityKey linkSpecifier.Data
+                | Some linkSpecifier -> Fingerprint linkSpecifier.Data
                 | None -> failwith "No rendezvous fingerprint found!"
 
             let connectToRendezvousJob =

NOnion/TorHandshakes/NTorHandshake.fs

@@ -15,13 +15,13 @@ type NTorHandshake =
         {
             RandomClientPrivateKey: X25519PrivateKeyParameters
             RandomClientPublicKey: X25519PublicKeyParameters
-            IdentityDigest: IdentityKey
+            IdentityDigest: Fingerprint
             NTorOnionKey: X25519PublicKeyParameters
         }
 
 
     static member Create
-        (identityDigest: IdentityKey)
+        (identityDigest: Fingerprint)
         (nTorOnionKey: NTorOnionKey)
         =