1 files changed, 93 insertions, 0 deletions
diff --git a/sshlib/src/main/java/com/trilead/ssh2/crypto/dh/GenericDhExchange.java b/sshlib/src/main/java/com/trilead/ssh2/crypto/dh/GenericDhExchange.java
new file mode 100644
index 0000000..039ff75
--- /dev/null
+++ b/sshlib/src/main/java/com/trilead/ssh2/crypto/dh/GenericDhExchange.java
@@ -0,0 +1,93 @@
+
+package com.trilead.ssh2.crypto.dh;
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.math.BigInteger;
+
+import com.trilead.ssh2.crypto.digest.HashForSSH2Types;
+import com.trilead.ssh2.log.Logger;
+
+
+/**
+ * DhExchange.
+ *
+ * @author Christian Plattner, plattner@trilead.com
+ * @version $Id: DhExchange.java,v 1.2 2008/04/01 12:38:09 cplattne Exp $
+ */
+public abstract class GenericDhExchange
+{
+	private static final Logger log = Logger.getLogger(GenericDhExchange.class);
+
+	/* Shared secret */
+
+	BigInteger sharedSecret;
+
+	protected GenericDhExchange()
+	{
+	}
+
+	public static GenericDhExchange getInstance(String algo) {
+		if (algo.startsWith("ecdh-sha2-")) {
+			return new EcDhExchange();
+		} else {
+			return new DhExchange();
+		}
+	}
+
+	public abstract void init(String name) throws IOException;
+
+	/**
+	 * @return Returns the e (public value)
+	 * @throws IllegalStateException
+	 */
+	public abstract byte[] getE();
+
+	/**
+	 * @return Returns the server's e (public value)
+	 * @throws IllegalStateException
+	 */
+	protected abstract byte[] getServerE();
+
+	/**
+	 * @return Returns the shared secret k.
+	 * @throws IllegalStateException
+	 */
+	public BigInteger getK()
+	{
+		if (sharedSecret == null)
+			throw new IllegalStateException("Shared secret not yet known, need f first!");
+
+		return sharedSecret;
+	}
+
+	/**
+	 * @param f
+	 */
+	public abstract void setF(byte[] f) throws IOException;
+
+	public byte[] calculateH(byte[] clientversion, byte[] serverversion, byte[] clientKexPayload,
+			byte[] serverKexPayload, byte[] hostKey) throws UnsupportedEncodingException
+	{
+		HashForSSH2Types hash = new HashForSSH2Types(getHashAlgo());
+
+		if (log.isEnabled())
+		{
+			log.log(90, "Client: '" + new String(clientversion, "ISO-8859-1") + "'");
+			log.log(90, "Server: '" + new String(serverversion, "ISO-8859-1") + "'");
+		}
+
+		hash.updateByteString(clientversion);
+		hash.updateByteString(serverversion);
+		hash.updateByteString(clientKexPayload);
+		hash.updateByteString(serverKexPayload);
+		hash.updateByteString(hostKey);
+		hash.updateByteString(getE());
+		hash.updateByteString(getServerE());
+		hash.updateBigInt(sharedSecret);
+
+		return hash.getDigest();
+	}
+
+	public abstract String getHashAlgo();
+}