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package org.spongycastle.crypto.ec.test;
import java.math.BigInteger;
import java.security.SecureRandom;
import org.spongycastle.crypto.ec.ECDecryptor;
import org.spongycastle.crypto.ec.ECElGamalDecryptor;
import org.spongycastle.crypto.ec.ECElGamalEncryptor;
import org.spongycastle.crypto.ec.ECEncryptor;
import org.spongycastle.crypto.ec.ECPair;
import org.spongycastle.crypto.params.ECDomainParameters;
import org.spongycastle.crypto.params.ECPrivateKeyParameters;
import org.spongycastle.crypto.params.ECPublicKeyParameters;
import org.spongycastle.crypto.params.ParametersWithRandom;
import org.spongycastle.math.ec.ECConstants;
import org.spongycastle.math.ec.ECCurve;
import org.spongycastle.math.ec.ECPoint;
import org.spongycastle.util.encoders.Hex;
import org.spongycastle.util.test.SimpleTest;
public class ECElGamalTest
extends SimpleTest
{
public String getName()
{
return "ECElGamal";
}
public void performTest()
throws Exception
{
BigInteger n = new BigInteger("6277101735386680763835789423176059013767194773182842284081");
ECCurve.Fp curve = new ECCurve.Fp(
new BigInteger("6277101735386680763835789423207666416083908700390324961279"), // q
new BigInteger("fffffffffffffffffffffffffffffffefffffffffffffffc", 16), // a
new BigInteger("64210519e59c80e70fa7e9ab72243049feb8deecc146b9b1", 16), // b
n, ECConstants.ONE);
ECDomainParameters params = new ECDomainParameters(
curve,
curve.decodePoint(Hex.decode("03188da80eb03090f67cbf20eb43a18800f4ff0afd82ff1012")), // G
n);
ECPublicKeyParameters pubKey = new ECPublicKeyParameters(
curve.decodePoint(Hex.decode("0262b12d60690cdcf330babab6e69763b471f994dd702d16a5")), // Q
params);
ECPrivateKeyParameters priKey = new ECPrivateKeyParameters(
new BigInteger("651056770906015076056810763456358567190100156695615665659"), // d
params);
ParametersWithRandom pRandom = new ParametersWithRandom(pubKey, new SecureRandom());
doTest(priKey, pRandom, BigInteger.valueOf(20));
BigInteger rand = new BigInteger(pubKey.getParameters().getN().bitLength() - 1, new SecureRandom());
doTest(priKey, pRandom, rand);
}
private void doTest(ECPrivateKeyParameters priKey, ParametersWithRandom pRandom, BigInteger value)
{
ECPoint data = priKey.getParameters().getG().multiply(value);
ECEncryptor encryptor = new ECElGamalEncryptor();
encryptor.init(pRandom);
ECPair pair = encryptor.encrypt(data);
ECDecryptor decryptor = new ECElGamalDecryptor();
decryptor.init(priKey);
ECPoint result = decryptor.decrypt(pair);
if (!data.equals(result))
{
fail("point pair failed to decrypt back to original");
}
}
public static void main(String[] args)
{
runTest(new ECElGamalTest());
}
}
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