1 files changed, 106 insertions, 0 deletions
diff --git a/sshlib/src/main/java/com/trilead/ssh2/crypto/dh/EcDhExchange.java b/sshlib/src/main/java/com/trilead/ssh2/crypto/dh/EcDhExchange.java
new file mode 100644
index 0000000..870a3b4
--- /dev/null
+++ b/sshlib/src/main/java/com/trilead/ssh2/crypto/dh/EcDhExchange.java
@@ -0,0 +1,106 @@
+/**
+ *
+ */
+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.interfaces.ECPrivateKey;
+import java.security.interfaces.ECPublicKey;
+import java.security.spec.ECParameterSpec;
+import java.security.spec.ECPoint;
+import java.security.spec.ECPublicKeySpec;
+import java.security.spec.InvalidKeySpecException;
+
+import javax.crypto.KeyAgreement;
+
+import com.trilead.ssh2.signature.ECDSASHA2Verify;
+
+/**
+ * @author kenny
+ *
+ */
+public class EcDhExchange extends GenericDhExchange {
+	private ECPrivateKey clientPrivate;
+	private ECPublicKey clientPublic;
+	private ECPublicKey serverPublic;
+
+	@Override
+	public void init(String name) throws IOException {
+		final ECParameterSpec spec;
+
+		if ("ecdh-sha2-nistp256".equals(name)) {
+			spec = ECDSASHA2Verify.EllipticCurves.nistp256;
+		} else if ("ecdh-sha2-nistp384".equals(name)) {
+			spec = ECDSASHA2Verify.EllipticCurves.nistp384;
+		} else if ("ecdh-sha2-nistp521".equals(name)) {
+			spec = ECDSASHA2Verify.EllipticCurves.nistp521;
+		} else {
+			throw new IllegalArgumentException("Unknown EC curve " + name);
+		}
+
+		KeyPairGenerator kpg;
+		try {
+			kpg = KeyPairGenerator.getInstance("EC");
+			kpg.initialize(spec);
+			KeyPair pair = kpg.generateKeyPair();
+			clientPrivate = (ECPrivateKey) pair.getPrivate();
+			clientPublic = (ECPublicKey) 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() {
+		return ECDSASHA2Verify.encodeECPoint(clientPublic.getW(), clientPublic.getParams()
+				.getCurve());
+	}
+
+	@Override
+	protected byte[] getServerE() {
+		return ECDSASHA2Verify.encodeECPoint(serverPublic.getW(), serverPublic.getParams()
+				.getCurve());
+	}
+
+	@Override
+	public void setF(byte[] f) throws IOException {
+
+		if (clientPublic == null)
+			throw new IllegalStateException("DhDsaExchange not initialized!");
+
+		final KeyAgreement ka;
+		try {
+			KeyFactory kf = KeyFactory.getInstance("EC");
+			ECParameterSpec params = clientPublic.getParams();
+			ECPoint serverPoint = ECDSASHA2Verify.decodeECPoint(f, params.getCurve());
+			this.serverPublic = (ECPublicKey) kf.generatePublic(new ECPublicKeySpec(serverPoint,
+																					params));
+
+			ka = KeyAgreement.getInstance("ECDH");
+			ka.init(clientPrivate);
+			ka.doPhase(serverPublic, true);
+		} catch (NoSuchAlgorithmException e) {
+			throw (IOException) new IOException("No ECDH key agreement method").initCause(e);
+		} catch (InvalidKeyException e) {
+			throw (IOException) new IOException("Invalid ECDH key").initCause(e);
+		} catch (InvalidKeySpecException e) {
+			throw (IOException) new IOException("Invalid ECDH key").initCause(e);
+		}
+
+		sharedSecret = new BigInteger(1, ka.generateSecret());
+	}
+
+	@Override
+	public String getHashAlgo() {
+		return ECDSASHA2Verify.getDigestAlgorithmForParams(clientPublic.getParams());
+	}
+}