1 files changed, 141 insertions, 0 deletions
diff --git a/crypto/src/tls/TlsECDheKeyExchange.cs b/crypto/src/tls/TlsECDheKeyExchange.cs
new file mode 100644
index 000000000..ab83036d9
--- /dev/null
+++ b/crypto/src/tls/TlsECDheKeyExchange.cs
@@ -0,0 +1,141 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Tls.Crypto;
+using Org.BouncyCastle.Utilities.IO;
+
+namespace Org.BouncyCastle.Tls
+{
+    /// <summary>(D)TLS ECDHE key exchange (see RFC 4492).</summary>
+    public class TlsECDheKeyExchange
+        : AbstractTlsKeyExchange
+    {
+        private static int CheckKeyExchange(int keyExchange)
+        {
+            switch (keyExchange)
+            {
+            case KeyExchangeAlgorithm.ECDHE_ECDSA:
+            case KeyExchangeAlgorithm.ECDHE_RSA:
+                return keyExchange;
+            default:
+                throw new ArgumentException("unsupported key exchange algorithm", "keyExchange");
+            }
+        }
+
+        protected TlsECConfig m_ecConfig;
+
+        protected TlsCredentialedSigner m_serverCredentials = null;
+        protected TlsCertificate m_serverCertificate = null;
+        protected TlsAgreement m_agreement;
+
+        public TlsECDheKeyExchange(int keyExchange)
+            : this(keyExchange, null)
+        {
+        }
+
+        public TlsECDheKeyExchange(int keyExchange, TlsECConfig ecConfig)
+            : base(CheckKeyExchange(keyExchange))
+        {
+            this.m_ecConfig = ecConfig;
+        }
+
+        public override void SkipServerCredentials()
+        {
+            throw new TlsFatalAlert(AlertDescription.internal_error);
+        }
+
+        public override void ProcessServerCredentials(TlsCredentials serverCredentials)
+        {
+            this.m_serverCredentials = TlsUtilities.RequireSignerCredentials(serverCredentials);
+        }
+
+        public override void ProcessServerCertificate(Certificate serverCertificate)
+        {
+            this.m_serverCertificate = serverCertificate.GetCertificateAt(0);
+        }
+
+        public override bool RequiresServerKeyExchange
+        {
+            get { return true; }
+        }
+
+        public override byte[] GenerateServerKeyExchange()
+        {
+            DigestInputBuffer digestBuffer = new DigestInputBuffer();
+
+            TlsEccUtilities.WriteECConfig(m_ecConfig, digestBuffer);
+
+            this.m_agreement = m_context.Crypto.CreateECDomain(m_ecConfig).CreateECDH();
+
+            GenerateEphemeral(digestBuffer);
+
+            TlsUtilities.GenerateServerKeyExchangeSignature(m_context, m_serverCredentials, digestBuffer);
+
+            return digestBuffer.ToArray();
+        }
+
+        public override void ProcessServerKeyExchange(Stream input)
+        {
+            DigestInputBuffer digestBuffer = new DigestInputBuffer();
+            Stream teeIn = new TeeInputStream(input, digestBuffer);
+
+            this.m_ecConfig = TlsEccUtilities.ReceiveECDHConfig(m_context, teeIn);
+
+            byte[] point = TlsUtilities.ReadOpaque8(teeIn, 1);
+
+            TlsUtilities.VerifyServerKeyExchangeSignature(m_context, input, m_serverCertificate, digestBuffer);
+
+            this.m_agreement = m_context.Crypto.CreateECDomain(m_ecConfig).CreateECDH();
+
+            ProcessEphemeral(point);
+        }
+
+        public override short[] GetClientCertificateTypes()
+        {
+            /*
+             * RFC 4492 3. [...] The ECDSA_fixed_ECDH and RSA_fixed_ECDH mechanisms are usable with
+             * ECDH_ECDSA and ECDH_RSA. Their use with ECDHE_ECDSA and ECDHE_RSA is prohibited because
+             * the use of a long-term ECDH client key would jeopardize the forward secrecy property of
+             * these algorithms.
+             */
+            return new short[]{ ClientCertificateType.dss_sign, ClientCertificateType.ecdsa_sign,
+                ClientCertificateType.rsa_sign };
+        }
+
+        public override void ProcessClientCredentials(TlsCredentials clientCredentials)
+        {
+            TlsUtilities.RequireSignerCredentials(clientCredentials);
+        }
+
+        public override void GenerateClientKeyExchange(Stream output)
+        {
+            GenerateEphemeral(output);
+        }
+
+        public override void ProcessClientKeyExchange(Stream input)
+        {
+            byte[] point = TlsUtilities.ReadOpaque8(input, 1);
+
+            ProcessEphemeral(point);
+        }
+
+        public override TlsSecret GeneratePreMasterSecret()
+        {
+            return m_agreement.CalculateSecret();
+        }
+
+        protected virtual void GenerateEphemeral(Stream output)
+        {
+            byte[] point = m_agreement.GenerateEphemeral();
+
+            TlsUtilities.WriteOpaque8(point, output);
+        }
+
+        protected virtual void ProcessEphemeral(byte[] point)
+        {
+            TlsEccUtilities.CheckPointEncoding(m_ecConfig.NamedGroup, point);
+
+            this.m_agreement.ReceivePeerValue(point);
+        }
+    }
+}