1 files changed, 93 insertions, 0 deletions
diff --git a/crypto/src/tls/TlsDHKeyExchange.cs b/crypto/src/tls/TlsDHKeyExchange.cs
new file mode 100644
index 000000000..a00ed67b7
--- /dev/null
+++ b/crypto/src/tls/TlsDHKeyExchange.cs
@@ -0,0 +1,93 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Tls.Crypto;
+
+namespace Org.BouncyCastle.Tls
+{
+    /// <summary>(D)TLS DH key exchange.</summary>
+    public class TlsDHKeyExchange
+        : AbstractTlsKeyExchange
+    {
+        private static int CheckKeyExchange(int keyExchange)
+        {
+            switch (keyExchange)
+            {
+            case KeyExchangeAlgorithm.DH_DSS:
+            case KeyExchangeAlgorithm.DH_RSA:
+                return keyExchange;
+            default:
+                throw new ArgumentException("unsupported key exchange algorithm", "keyExchange");
+            }
+        }
+
+        protected TlsCredentialedAgreement m_agreementCredentials;
+        protected TlsCertificate m_dhPeerCertificate;
+
+        public TlsDHKeyExchange(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_dhPeerCertificate = serverCertificate.GetCertificateAt(0).CheckUsageInRole(ConnectionEnd.server,
+                TlsCertificateRole.DH);
+        }
+
+        public override short[] GetClientCertificateTypes()
+        {
+            return new short[]{ ClientCertificateType.dss_fixed_dh, ClientCertificateType.rsa_fixed_dh };
+        }
+
+        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)
+        {
+            /*
+             * RFC 2246 7.4.7.2 If the client certificate already contains a suitable Diffie-Hellman
+             * key, then Yc is implicit and does not need to be sent again. In this case, the Client Key
+             * Exchange message will be sent, but will be empty.
+             */
+        }
+
+        public override void ProcessClientCertificate(Certificate clientCertificate)
+        {
+            this.m_dhPeerCertificate = clientCertificate.GetCertificateAt(0).CheckUsageInRole(ConnectionEnd.client,
+                TlsCertificateRole.DH);
+        }
+
+        public override void ProcessClientKeyExchange(Stream input)
+        {
+            // For dss_fixed_dh and rsa_fixed_dh, the key arrived in the client certificate
+        }
+
+        public override bool RequiresCertificateVerify
+        {
+            get { return false; }
+        }
+
+        public override TlsSecret GeneratePreMasterSecret()
+        {
+            return m_agreementCredentials.GenerateAgreement(m_dhPeerCertificate);
+        }
+    }
+}