dhkeypairgenerator.java

来自「一个非常好的ssh客户端实现」· Java 代码 · 共 73 行

/******************************************************************************
 *
 * Copyright (c) 1999-2003 AppGate Network Security AB. All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code as
 * defined in and that are subject to the MindTerm Public Source License,
 * Version 2.0, (the 'License'). You may not use this file except in compliance
 * with the License.
 * 
 * You should have received a copy of the MindTerm Public Source License
 * along with this software; see the file LICENSE.  If not, write to
 * AppGate Network Security AB, Otterhallegatan 2, SE-41118 Goteborg, SWEDEN
 *
 *****************************************************************************/

package com.mindbright.security.publickey;

import java.math.BigInteger;

import com.mindbright.jca.security.KeyPair;
import com.mindbright.jca.security.KeyPairGenerator;
import com.mindbright.jca.security.SecureRandom;
import com.mindbright.jca.security.InvalidAlgorithmParameterException;
import com.mindbright.jca.security.spec.AlgorithmParameterSpec;

import com.mindbright.jce.crypto.spec.DHParameterSpec;

public class DHKeyPairGenerator extends KeyPairGenerator {

    protected DHParameterSpec params;
    protected SecureRandom    random;

    public DHKeyPairGenerator() {
	super("DH");
    }

    public void initialize(int keysize, SecureRandom random) {
	throw new Error("Not implemented: " +
			"'DHKeyPairGenerator.initialize(int, SecureRandom)'");
    }

    public void initialize(AlgorithmParameterSpec params, SecureRandom random)
	throws InvalidAlgorithmParameterException
    {
	if(!(params instanceof DHParameterSpec)) {
	    throw new InvalidAlgorithmParameterException("Invalid params: " +
							 params);
	}
	this.params = (DHParameterSpec)params;
	this.random = random;
    }

    public KeyPair generateKeyPair() {
	BigInteger g = params.getG();
	BigInteger p = params.getP();
	int        l = params.getL();

	if(l == 0) {
	    l = p.bitLength();
	}

	if(random == null) {
	    random = new SecureRandom();
	}

	BigInteger x = DiffieHellman.generateX(p, l, random);
	BigInteger y = DiffieHellman.generateY(x, g, p);

	return new KeyPair(new DHPublicKey(y, p, g), new DHPrivateKey(x, p, g));
    }

}