dhparametersgenerator.java

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// Decompiled by Jad v1.5.8e2. Copyright 2001 Pavel Kouznetsov.
// Jad home page: http://kpdus.tripod.com/jad.html
// Decompiler options: packimports(3) fieldsfirst ansi space 
// Source File Name:   DHParametersGenerator.java

package org.bouncycastle.crypto.generators;

import java.math.BigInteger;
import java.security.SecureRandom;
import org.bouncycastle.crypto.params.DHParameters;

public class DHParametersGenerator
{

	private int size;
	private int certainty;
	private SecureRandom random;
	private static BigInteger ONE = BigInteger.valueOf(1L);
	private static BigInteger TWO = BigInteger.valueOf(2L);

	public DHParametersGenerator()
	{
	}

	public void init(int size, int certainty, SecureRandom random)
	{
		this.size = size;
		this.certainty = certainty;
		this.random = random;
	}

	public DHParameters generateParameters()
	{
		int qLength = size - 1;
		BigInteger p;
		BigInteger q;
		do
		{
			q = new BigInteger(qLength, certainty, random);
			p = q.multiply(TWO).add(ONE);
		} while (!p.isProbablePrime(certainty));
		BigInteger g;
		do
			g = new BigInteger(qLength, random);
		while (g.modPow(TWO, p).equals(ONE) || g.modPow(q, p).equals(ONE));
		return new DHParameters(p, g, q, 2);
	}

}