/*
* SSHTools - Java SSH2 API
*
* Copyright (C) 2002-2003 Lee David Painter and Contributors.
*
* Contributions made by:
*
* Brett Smith
* Richard Pernavas
* Erwin Bolwidt
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package com.sshtools.j2ssh.transport.publickey.dsa;
import com.sshtools.j2ssh.io.ByteArrayReader;
import com.sshtools.j2ssh.io.ByteArrayWriter;
import com.sshtools.j2ssh.transport.publickey.InvalidSshKeyException;
import com.sshtools.j2ssh.transport.publickey.InvalidSshKeySignatureException;
import com.sshtools.j2ssh.transport.publickey.SshPrivateKey;
import com.sshtools.j2ssh.transport.publickey.SshPublicKey;
import com.sshtools.j2ssh.util.SimpleASNReader;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.io.IOException;
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.Signature;
import java.security.interfaces.DSAPrivateKey;
import java.security.interfaces.DSAPublicKey;
import java.security.spec.DSAPrivateKeySpec;
import java.security.spec.DSAPublicKeySpec;
class SshDssPrivateKey extends SshPrivateKey {
private static Log log = LogFactory.getLog(SshDssPrivateKey.class);
DSAPrivateKey prvkey;
/**
* Creates a new SshDssPrivateKey object.
*
* @param prvkey
*/
public SshDssPrivateKey(DSAPrivateKey prvkey) {
this.prvkey = prvkey;
}
/**
* Creates a new SshDssPrivateKey object.
*
* @param key
*
* @throws InvalidSshKeyException
*/
public SshDssPrivateKey(byte[] key) throws InvalidSshKeyException {
try {
DSAPrivateKeySpec dsaKey;
// Extract the key information
ByteArrayReader bar = new ByteArrayReader(key);
String header = bar.readString();
if (!header.equals(getAlgorithmName())) {
throw new InvalidSshKeyException();
}
BigInteger p = bar.readBigInteger();
BigInteger q = bar.readBigInteger();
BigInteger g = bar.readBigInteger();
BigInteger x = bar.readBigInteger();
dsaKey = new DSAPrivateKeySpec(x, p, q, g);
KeyFactory kf = KeyFactory.getInstance("DSA");
prvkey = (DSAPrivateKey) kf.generatePrivate(dsaKey);
} catch (Exception e) {
throw new InvalidSshKeyException();
}
}
/**
*
*
* @param obj
*
* @return
*/
public boolean equals(Object obj) {
if (obj instanceof SshDssPrivateKey) {
return prvkey.equals(((SshDssPrivateKey) obj).prvkey);
}
return false;
}
/**
*
*
* @return
*/
public int hashCode() {
return prvkey.hashCode();
}
/**
*
*
* @return
*/
public String getAlgorithmName() {
return "ssh-dss";
}
/**
*
*
* @return
*/
public int getBitLength() {
return prvkey.getX().bitLength();
}
/**
*
*
* @return
*/
public byte[] getEncoded() {
try {
ByteArrayWriter baw = new ByteArrayWriter();
baw.writeString("ssh-dss");
baw.writeBigInteger(prvkey.getParams().getP());
baw.writeBigInteger(prvkey.getParams().getQ());
baw.writeBigInteger(prvkey.getParams().getG());
baw.writeBigInteger(prvkey.getX());
return baw.toByteArray();
} catch (IOException ioe) {
return null;
}
}
/**
*
*
* @return
*/
public SshPublicKey getPublicKey() {
try {
DSAPublicKeySpec spec = new DSAPublicKeySpec(getY(),
prvkey.getParams().getP(), prvkey.getParams().getQ(),
prvkey.getParams().getG());
KeyFactory kf = KeyFactory.getInstance("DSA");
return new SshDssPublicKey((DSAPublicKey) kf.generatePublic(spec));
} catch (Exception e) {
return null;
}
}
/**
*
*
* @param data
*
* @return
*
* @throws InvalidSshKeySignatureException
*/
public byte[] generateSignature(byte[] data)
throws InvalidSshKeySignatureException {
try {
Signature sig = Signature.getInstance("SHA1withDSA");
sig.initSign(prvkey);
/*java.util.Random rnd = new java.util.Random();
byte[] buffer = new byte[20];
rnd.nextBytes(buffer);
sig.update(buffer);
byte[] test = sig.sign();*/
sig.update(data);
byte[] signature = sig.sign();
byte[] decoded = new byte[40];
SimpleASNReader asn = new SimpleASNReader(signature);
asn.getByte();
asn.getLength();
asn.getByte();
byte[] r = asn.getData();
asn.getByte();
byte[] s = asn.getData();
if (r.length >= 20) {
System.arraycopy(r, r.length - 20, decoded, 0, 20);
} else {
System.arraycopy(r, 0, decoded, 20 - r.length, r.length);
}
if (s.length >= 20) {
System.arraycopy(s, s.length - 20, decoded, 20, 20);
} else {
System.arraycopy(s, 0, decoded, 20 + (20 - s.length), s.length);
}
if (log.isDebugEnabled()) {
log.debug("s length is " + String.valueOf(s.length));
log.debug("r length is " + String.valueOf(r.length));
String str = "";
for (int i = 0; i < signature.length; i++) {
str += (Integer.toHexString(signature[i] & 0xFF) + " ");
}
log.debug("Java signature is " + str);
str = "";
for (int i = 0; i < decoded.length; i++) {
str += (Integer.toHexString(decoded[i] & 0xFF) + " ");
}
log.debug("SSH signature is " + str);
}
ByteArrayWriter baw = new ByteArrayWriter();
baw.writeString(getAlgorithmName());
baw.writeBinaryString(decoded);
return baw.toByteArray();
} catch (Exception e) {
throw new InvalidSshKeySignatureException(e);
}
}
private BigInteger getY() {
return prvkey.getParams().getG().modPow(prvkey.getX(),
prvkey.getParams().getP());
}
}