1 files changed, 95 insertions, 0 deletions
diff --git a/crypto/src/tls/TlsECDHKeyExchange.cs b/crypto/src/tls/TlsECDHKeyExchange.cs
new file mode 100644
index 000000000..45e83f8ad
--- /dev/null
+++ b/crypto/src/tls/TlsECDHKeyExchange.cs
@@ -0,0 +1,95 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Tls.Crypto;
+
+namespace Org.BouncyCastle.Tls
+{
+    /// <summary>(D)TLS ECDH key exchange (see RFC 4492).</summary>
+    public class TlsECDHKeyExchange
+        : AbstractTlsKeyExchange
+    {
+        private static int CheckKeyExchange(int keyExchange)
+        {
+            switch (keyExchange)
+            {
+            case KeyExchangeAlgorithm.ECDH_ECDSA:
+            case KeyExchangeAlgorithm.ECDH_RSA:
+                return keyExchange;
+            default:
+                throw new ArgumentException("unsupported key exchange algorithm", "keyExchange");
+            }
+        }
+
+        protected TlsCredentialedAgreement m_agreementCredentials;
+        protected TlsCertificate m_ecdhPeerCertificate;
+
+        public TlsECDHKeyExchange(int keyExchange)
+            : base(CheckKeyExchange(keyExchange))
+        {
+        }
+
+        public override void SkipServerCredentials()
+        {
+            throw new TlsFatalAlert(AlertDescription.internal_error);
+        }
+
+        public override void ProcessServerCredentials(TlsCredentials serverCredentials)
+        {
+            this.m_agreementCredentials = TlsUtilities.RequireAgreementCredentials(serverCredentials);
+        }
+
+        public override void ProcessServerCertificate(Certificate serverCertificate)
+        {
+            this.m_ecdhPeerCertificate = serverCertificate.GetCertificateAt(0).CheckUsageInRole(ConnectionEnd.server,
+                TlsCertificateRole.ECDH);
+        }
+
+        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.ecdsa_fixed_ecdh, ClientCertificateType.rsa_fixed_ecdh };
+        }
+
+        public override void SkipClientCredentials()
+        {
+            throw new TlsFatalAlert(AlertDescription.unexpected_message);
+        }
+
+        public override void ProcessClientCredentials(TlsCredentials clientCredentials)
+        {
+            this.m_agreementCredentials = TlsUtilities.RequireAgreementCredentials(clientCredentials);
+        }
+
+        public override void GenerateClientKeyExchange(Stream output)
+        {
+            // In this case, the Client Key Exchange message will be sent, but will be empty.
+        }
+
+        public override void ProcessClientCertificate(Certificate clientCertificate)
+        {
+            this.m_ecdhPeerCertificate = clientCertificate.GetCertificateAt(0).CheckUsageInRole(ConnectionEnd.client,
+                TlsCertificateRole.ECDH);
+        }
+
+        public override void ProcessClientKeyExchange(Stream input)
+        {
+            // For ecdsa_fixed_ecdh and rsa_fixed_ecdh, the key arrived in the client certificate
+        }
+
+        public override bool RequiresCertificateVerify
+        {
+            get { return false; }
+        }
+
+        public override TlsSecret GeneratePreMasterSecret()
+        {
+            return m_agreementCredentials.GenerateAgreement(m_ecdhPeerCertificate);
+        }
+    }
+}