package org.bouncycastle.crypto.generators;
import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
import org.bouncycastle.crypto.AsymmetricCipherKeyPairGenerator;
import org.bouncycastle.crypto.KeyGenerationParameters;
import org.bouncycastle.crypto.params.GOST3410KeyGenerationParameters;
import org.bouncycastle.crypto.params.GOST3410Parameters;
import org.bouncycastle.crypto.params.GOST3410PrivateKeyParameters;
import org.bouncycastle.crypto.params.GOST3410PublicKeyParameters;
import java.math.BigInteger;
import java.security.SecureRandom;
/**
* a GOST3410 key pair generator.
* This generates GOST3410 keys in line with the method described
* in GOST R 34.10-94.
*/
public class GOST3410KeyPairGenerator
implements AsymmetricCipherKeyPairGenerator
{
private static final BigInteger ZERO = BigInteger.valueOf(0);
private GOST3410KeyGenerationParameters param;
public void init(
KeyGenerationParameters param)
{
this.param = (GOST3410KeyGenerationParameters)param;
}
public AsymmetricCipherKeyPair generateKeyPair()
{
BigInteger p, q, a, x, y;
GOST3410Parameters GOST3410Params = param.getParameters();
SecureRandom random = param.getRandom();
q = GOST3410Params.getQ();
p = GOST3410Params.getP();
a = GOST3410Params.getA();
do
{
x = new BigInteger(256, random);
}
while (x.equals(ZERO) || x.compareTo(q) >= 0);
//
// calculate the public key.
//
y = a.modPow(x, p);
return new AsymmetricCipherKeyPair(
new GOST3410PublicKeyParameters(y, GOST3410Params),
new GOST3410PrivateKeyParameters(x, GOST3410Params));
}
}