Add ServerDHParams and refactor DHE key exchange code

1 files changed, 4 insertions, 17 deletions

diff --git a/core/src/main/java/org/bouncycastle/crypto/tls/TlsDHEKeyExchange.java b/core/src/main/java/org/bouncycastle/crypto/tls/TlsDHEKeyExchange.java
index ed654730..66f3e170 100644
--- a/core/src/main/java/org/bouncycastle/crypto/tls/TlsDHEKeyExchange.java
+++ b/core/src/main/java/org/bouncycastle/crypto/tls/TlsDHEKeyExchange.java
@@ -3,15 +3,12 @@ package org.bouncycastle.crypto.tls;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.math.BigInteger;
 import java.util.Vector;
 
 import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
 import org.bouncycastle.crypto.Digest;
 import org.bouncycastle.crypto.Signer;
-import org.bouncycastle.crypto.generators.DHKeyPairGenerator;
 import org.bouncycastle.crypto.io.SignerInputStream;
-import org.bouncycastle.crypto.params.DHKeyGenerationParameters;
 import org.bouncycastle.crypto.params.DHParameters;
 import org.bouncycastle.crypto.params.DHPrivateKeyParameters;
 import org.bouncycastle.crypto.params.DHPublicKeyParameters;
@@ -49,16 +46,8 @@ public class TlsDHEKeyExchange
 
         ByteArrayOutputStream buf = new ByteArrayOutputStream();
 
-        DHKeyPairGenerator kpg = new DHKeyPairGenerator();
-        kpg.init(new DHKeyGenerationParameters(context.getSecureRandom(), this.dhParameters));
-        AsymmetricCipherKeyPair kp = kpg.generateKeyPair();
-        this.dhAgreeServerPrivateKey = (DHPrivateKeyParameters)kp.getPrivate();
-
-        BigInteger Ys = ((DHPublicKeyParameters)kp.getPublic()).getY();
-
-        TlsDHUtils.writeDHParameter(dhParameters.getP(), buf);
-        TlsDHUtils.writeDHParameter(dhParameters.getG(), buf);
-        TlsDHUtils.writeDHParameter(Ys, buf);
+        this.dhAgreeServerPrivateKey = TlsDHUtils.generateEphemeralServerKeyExchange(context.getSecureRandom(),
+            this.dhParameters, buf);
 
         byte[] digestInput = buf.toByteArray();
 
@@ -88,9 +77,7 @@ public class TlsDHEKeyExchange
         Signer signer = initVerifyer(tlsSigner, securityParameters);
         InputStream sigIn = new SignerInputStream(input, signer);
 
-        BigInteger p = TlsDHUtils.readDHParameter(sigIn);
-        BigInteger g = TlsDHUtils.readDHParameter(sigIn);
-        BigInteger Ys = TlsDHUtils.readDHParameter(sigIn);
+        ServerDHParams serverDHParams = ServerDHParams.parse(sigIn);
 
         byte[] sigBytes = TlsUtils.readOpaque16(input);
         if (!signer.verifySignature(sigBytes))
@@ -98,7 +85,7 @@ public class TlsDHEKeyExchange
             throw new TlsFatalAlert(AlertDescription.decrypt_error);
         }
 
-        this.dhAgreeServerPublicKey = validateDHPublicKey(new DHPublicKeyParameters(Ys, new DHParameters(p, g)));
+        this.dhAgreeServerPublicKey = TlsDHUtils.validateDHPublicKey(serverDHParams.getPublicKey());
     }
 
     protected Signer initVerifyer(TlsSigner tlsSigner, SecurityParameters securityParameters)