1 files changed, 132 insertions, 0 deletions
diff --git a/sshlib/src/main/java/com/trilead/ssh2/crypto/dh/DhExchange.java b/sshlib/src/main/java/com/trilead/ssh2/crypto/dh/DhExchange.java
new file mode 100644
index 0000000..3acde25
--- /dev/null
+++ b/sshlib/src/main/java/com/trilead/ssh2/crypto/dh/DhExchange.java
@@ -0,0 +1,132 @@
+/**
+ *
+ */
+package com.trilead.ssh2.crypto.dh;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.security.InvalidAlgorithmParameterException;
+import java.security.InvalidKeyException;
+import java.security.KeyFactory;
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+
+import javax.crypto.KeyAgreement;
+import javax.crypto.interfaces.DHPrivateKey;
+import javax.crypto.interfaces.DHPublicKey;
+import javax.crypto.spec.DHParameterSpec;
+import javax.crypto.spec.DHPublicKeySpec;
+
+/**
+ * @author kenny
+ *
+ */
+public class DhExchange extends GenericDhExchange {
+
+	/* Given by the standard */
+
+	private static final BigInteger P1 = new BigInteger(
+			  "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
+			+ "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
+			+ "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
+			+ "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
+			+ "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381"
+			+ "FFFFFFFFFFFFFFFF", 16);
+
+	private static final BigInteger P14 = new BigInteger(
+			  "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD1"
+			+ "29024E088A67CC74020BBEA63B139B22514A08798E3404DD"
+			+ "EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245"
+			+ "E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
+			+ "EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3D"
+			+ "C2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F"
+			+ "83655D23DCA3AD961C62F356208552BB9ED529077096966D"
+			+ "670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B"
+			+ "E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9"
+			+ "DE2BCBF6955817183995497CEA956AE515D2261898FA0510"
+			+ "15728E5A8AACAA68FFFFFFFFFFFFFFFF", 16);
+
+	private static final BigInteger G = BigInteger.valueOf(2);
+
+	/* Client public and private */
+
+	private DHPrivateKey clientPrivate;
+	private DHPublicKey clientPublic;
+
+	/* Server public */
+
+	private DHPublicKey serverPublic;
+
+	@Override
+	public void init(String name) throws IOException {
+		final DHParameterSpec spec;
+		if ("diffie-hellman-group1-sha1".equals(name)) {
+			spec = new DHParameterSpec(P1, G);
+		} else if ("diffie-hellman-group14-sha1".equals(name)) {
+			spec = new DHParameterSpec(P14, G);
+		} else {
+			throw new IllegalArgumentException("Unknown DH group " + name);
+		}
+
+		try {
+			KeyPairGenerator kpg = KeyPairGenerator.getInstance("DH");
+			kpg.initialize(spec);
+			KeyPair pair = kpg.generateKeyPair();
+			clientPrivate = (DHPrivateKey) pair.getPrivate();
+			clientPublic = (DHPublicKey) pair.getPublic();
+		} catch (NoSuchAlgorithmException e) {
+			throw (IOException) new IOException("No DH keypair generator").initCause(e);
+		} catch (InvalidAlgorithmParameterException e) {
+			throw (IOException) new IOException("Invalid DH parameters").initCause(e);
+		}
+	}
+
+	@Override
+	public byte[] getE() {
+		if (clientPublic == null)
+			throw new IllegalStateException("DhExchange not initialized!");
+
+		return clientPublic.getY().toByteArray();
+	}
+
+	@Override
+	protected byte[] getServerE() {
+		if (serverPublic == null)
+			throw new IllegalStateException("DhExchange not initialized!");
+
+		return serverPublic.getY().toByteArray();
+	}
+
+	@Override
+	public void setF(byte[] f) throws IOException {
+		if (clientPublic == null)
+			throw new IllegalStateException("DhExchange not initialized!");
+
+		final KeyAgreement ka;
+		try {
+			KeyFactory kf = KeyFactory.getInstance("DH");
+			DHParameterSpec params = clientPublic.getParams();
+			this.serverPublic = (DHPublicKey) kf.generatePublic(new DHPublicKeySpec(
+					new BigInteger(f), params.getP(), params.getG()));
+
+			ka = KeyAgreement.getInstance("DH");
+			ka.init(clientPrivate);
+			ka.doPhase(serverPublic, true);
+		} catch (NoSuchAlgorithmException e) {
+			throw (IOException) new IOException("No DH key agreement method").initCause(e);
+		} catch (InvalidKeyException e) {
+			throw (IOException) new IOException("Invalid DH key").initCause(e);
+		} catch (InvalidKeySpecException e) {
+			throw (IOException) new IOException("Invalid DH key").initCause(e);
+		}
+
+		sharedSecret = new BigInteger(ka.generateSecret());
+	}
+
+	@Override
+	public String getHashAlgo() {
+		return "SHA1";
+	}
+}