Create dedicated KeyExchangeECCurve25519 BclImpl

Author: scott-xu

src/Renci.SshNet/Security/KeyExchangeECCurve25519.BclImpl.cs

@@ -0,0 +1,57 @@
+#if NET
+using System.Security.Cryptography;
+
+namespace Renci.SshNet.Security
+{
+    internal abstract partial class KeyExchangeECCurve25519
+    {
+        protected sealed class BclImpl : Impl
+        {
+            private readonly ECCurve _curve;
+            private readonly ECDiffieHellman _clientECDH;
+
+            public BclImpl(ECCurve curve)
+            {
+                _curve = curve;
+                _clientECDH = ECDiffieHellman.Create();
+            }
+
+            public override byte[] GenerateClientECPoint()
+            {
+                _clientECDH.GenerateKey(_curve);
+
+                var q = _clientECDH.PublicKey.ExportParameters().Q;
+
+                return q.X;
+            }
+
+            public override byte[] CalculateAgreement(byte[] serverECPoint)
+            {
+                var parameters = new ECParameters
+                {
+                    Curve = _curve,
+                    Q = new ECPoint
+                    {
+                        X = serverECPoint,
+                        Y = new byte[serverECPoint.Length]
+                    },
+                };
+
+                using var serverECDH = ECDiffieHellman.Create(parameters);
+
+                return _clientECDH.DeriveRawSecretAgreement(serverECDH.PublicKey);
+            }
+
+            protected override void Dispose(bool disposing)
+            {
+                base.Dispose(disposing);
+
+                if (disposing)
+                {
+                    _clientECDH.Dispose();
+                }
+            }
+        }
+    }
+}
+#endif

src/Renci.SshNet/Security/KeyExchangeEC.BclImpl.cs renamed to src/Renci.SshNet/Security/KeyExchangeECDH.BclImpl.cs

@@ -4,7 +4,7 @@
 
 namespace Renci.SshNet.Security
 {
-    internal abstract partial class KeyExchangeEC
+    internal abstract partial class KeyExchangeECDH
     {
         protected sealed class BclImpl : Impl
         {