1 files changed, 115 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/tls/TlsDHEKeyExchange.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/tls/TlsDHEKeyExchange.java
new file mode 100644
index 000000000..fa4bd98f1
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/tls/TlsDHEKeyExchange.java
@@ -0,0 +1,115 @@
+package org.spongycastle.crypto.tls;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Vector;
+
+import org.spongycastle.crypto.Digest;
+import org.spongycastle.crypto.Signer;
+import org.spongycastle.crypto.params.DHParameters;
+import org.spongycastle.util.io.TeeInputStream;
+
+public class TlsDHEKeyExchange
+    extends TlsDHKeyExchange
+{
+    protected TlsSignerCredentials serverCredentials = null;
+
+    public TlsDHEKeyExchange(int keyExchange, Vector supportedSignatureAlgorithms, DHParameters dhParameters)
+    {
+        super(keyExchange, supportedSignatureAlgorithms, dhParameters);
+    }
+
+    public void processServerCredentials(TlsCredentials serverCredentials)
+        throws IOException
+    {
+        if (!(serverCredentials instanceof TlsSignerCredentials))
+        {
+            throw new TlsFatalAlert(AlertDescription.internal_error);
+        }
+
+        processServerCertificate(serverCredentials.getCertificate());
+
+        this.serverCredentials = (TlsSignerCredentials)serverCredentials;
+    }
+
+    public byte[] generateServerKeyExchange()
+        throws IOException
+    {
+        if (this.dhParameters == null)
+        {
+            throw new TlsFatalAlert(AlertDescription.internal_error);
+        }
+
+        DigestInputBuffer buf = new DigestInputBuffer();
+
+        this.dhAgreeServerPrivateKey = TlsDHUtils.generateEphemeralServerKeyExchange(context.getSecureRandom(),
+            this.dhParameters, buf);
+
+        /*
+         * RFC 5246 4.7. digitally-signed element needs SignatureAndHashAlgorithm from TLS 1.2
+         */
+        SignatureAndHashAlgorithm signatureAndHashAlgorithm;
+        Digest d;
+
+        if (TlsUtils.isTLSv12(context))
+        {
+            signatureAndHashAlgorithm = serverCredentials.getSignatureAndHashAlgorithm();
+            if (signatureAndHashAlgorithm == null)
+            {
+                throw new TlsFatalAlert(AlertDescription.internal_error);
+            }
+
+            d = TlsUtils.createHash(signatureAndHashAlgorithm.getHash());
+        }
+        else
+        {
+            signatureAndHashAlgorithm = null;
+            d = new CombinedHash();
+        }
+
+        SecurityParameters securityParameters = context.getSecurityParameters();
+        d.update(securityParameters.clientRandom, 0, securityParameters.clientRandom.length);
+        d.update(securityParameters.serverRandom, 0, securityParameters.serverRandom.length);
+        buf.updateDigest(d);
+
+        byte[] hash = new byte[d.getDigestSize()];
+        d.doFinal(hash, 0);
+
+        byte[] signature = serverCredentials.generateCertificateSignature(hash);
+
+        DigitallySigned signed_params = new DigitallySigned(signatureAndHashAlgorithm, signature);
+        signed_params.encode(buf);
+
+        return buf.toByteArray();
+    }
+
+    public void processServerKeyExchange(InputStream input)
+        throws IOException
+    {
+        SecurityParameters securityParameters = context.getSecurityParameters();
+
+        SignerInputBuffer buf = new SignerInputBuffer();
+        InputStream teeIn = new TeeInputStream(input, buf);
+
+        ServerDHParams params = ServerDHParams.parse(teeIn);
+
+        DigitallySigned signed_params = DigitallySigned.parse(context, input);
+
+        Signer signer = initVerifyer(tlsSigner, signed_params.getAlgorithm(), securityParameters);
+        buf.updateSigner(signer);
+        if (!signer.verifySignature(signed_params.getSignature()))
+        {
+            throw new TlsFatalAlert(AlertDescription.decrypt_error);
+        }
+
+        this.dhAgreeServerPublicKey = TlsDHUtils.validateDHPublicKey(params.getPublicKey());
+    }
+
+    protected Signer initVerifyer(TlsSigner tlsSigner, SignatureAndHashAlgorithm algorithm, SecurityParameters securityParameters)
+    {
+        Signer signer = tlsSigner.createVerifyer(algorithm, this.serverPublicKey);
+        signer.update(securityParameters.clientRandom, 0, securityParameters.clientRandom.length);
+        signer.update(securityParameters.serverRandom, 0, securityParameters.serverRandom.length);
+        return signer;
+    }
+}