package org.bouncycastle.crypto.generators;
import java.math.BigInteger;
import java.security.SecureRandom;
import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
import org.bouncycastle.crypto.AsymmetricCipherKeyPairGenerator;
import org.bouncycastle.crypto.KeyGenerationParameters;
import org.bouncycastle.crypto.params.ECDomainParameters;
import org.bouncycastle.crypto.params.ECKeyGenerationParameters;
import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.math.ec.ECConstants;
import org.bouncycastle.math.ec.ECPoint;
public class ECKeyPairGenerator
implements AsymmetricCipherKeyPairGenerator, ECConstants
{
ECDomainParameters params;
SecureRandom random;
public void init(
KeyGenerationParameters param)
{
ECKeyGenerationParameters ecP = (ECKeyGenerationParameters)param;
this.random = ecP.getRandom();
this.params = ecP.getDomainParameters();
}
/**
* Given the domain parameters this routine generates an EC key
* pair in accordance with X9.62 section 5.2.1 pages 26, 27.
*/
public AsymmetricCipherKeyPair generateKeyPair()
{
BigInteger n = params.getN();
int nBitLength = n.bitLength();
BigInteger d;
do
{
d = new BigInteger(nBitLength, random);
}
while (d.equals(ZERO) || (d.compareTo(n) >= 0));
ECPoint Q = params.getG().multiply(d);
return new AsymmetricCipherKeyPair(
new ECPublicKeyParameters(Q, params),
new ECPrivateKeyParameters(d, params));
}
}