/*
* Copyright (C)2009 - SSHJ Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.schmizz.sshj.transport.kex;
import net.schmizz.sshj.common.Factory;
import net.schmizz.sshj.common.SSHRuntimeException;
import net.schmizz.sshj.common.SecurityUtils;
import net.schmizz.sshj.transport.random.Random;
import javax.crypto.spec.DHParameterSpec;
import javax.crypto.spec.DHPublicKeySpec;
import java.math.BigInteger;
import java.security.GeneralSecurityException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.PublicKey;
import java.security.spec.AlgorithmParameterSpec;
/** Diffie-Hellman key generator. */
public class DH extends DHBase {
private BigInteger p;
private BigInteger g;
public DH() {
super("DH", "DH");
}
@Override
public void init(AlgorithmParameterSpec params, Factory<Random> randomFactory) throws GeneralSecurityException {
if (!(params instanceof DHParameterSpec)) {
throw new SSHRuntimeException("Wrong algorithm parameters for Diffie Hellman");
}
this.p = ((DHParameterSpec) params).getP();
this.g = ((DHParameterSpec) params).getG();
generator.initialize(params);
final KeyPair kp = generator.generateKeyPair();
agreement.init(kp.getPrivate());
setE(((javax.crypto.interfaces.DHPublicKey) kp.getPublic()).getY().toByteArray());
}
@Override
void computeK(byte[] f) throws GeneralSecurityException {
final KeyFactory keyFactory = SecurityUtils.getKeyFactory("DH");
final PublicKey yourPubKey = keyFactory.generatePublic(new DHPublicKeySpec(new BigInteger(f), p, g));
agreement.doPhase(yourPubKey, true);
setK(new BigInteger(1, agreement.generateSecret()));
}
public BigInteger getP() {
return p;
}
public BigInteger getG() {
return g;
}
}