int privateValueSize,
BigInteger g,
BigInteger p)
throws Exception
{
DHParameterSpec elParams = new DHParameterSpec(p, g, privateValueSize);
int size = p.bitLength();
new BouncyCastleProvider().setParameter(ConfigurableProvider.DH_DEFAULT_PARAMS, elParams);
KeyPairGenerator keyGen = KeyPairGenerator.getInstance("ElGamal", "BC");
byte[] in = "This is a test".getBytes();
keyGen.initialize(p.bitLength());
KeyPair keyPair = keyGen.generateKeyPair();
new BouncyCastleProvider().setParameter(ConfigurableProvider.DH_DEFAULT_PARAMS, elParams);
SecureRandom rand = new SecureRandom();
checkKeySize(privateValueSize, keyPair);
Cipher cipher = Cipher.getInstance("ElGamal", "BC");
cipher.init(Cipher.ENCRYPT_MODE, keyPair.getPublic(), rand);
if (cipher.getOutputSize(in.length) != (size / 8) * 2)
{
fail("getOutputSize wrong on encryption");
}
byte[] out = cipher.doFinal(in);
cipher.init(Cipher.DECRYPT_MODE, keyPair.getPrivate());
if (cipher.getOutputSize(out.length) != (size / 8) - 1)
{
fail("getOutputSize wrong on decryption");
}
//
// No Padding - maximum length
//
byte[] modBytes = ((DHPublicKey)keyPair.getPublic()).getParams().getP().toByteArray();
byte[] maxInput = new byte[modBytes.length - 1];
maxInput[0] |= 0x7f;
cipher.init(Cipher.ENCRYPT_MODE, keyPair.getPublic(), rand);
out = cipher.doFinal(maxInput);
cipher.init(Cipher.DECRYPT_MODE, keyPair.getPrivate());
out = cipher.doFinal(out);
if (!areEqual(out, maxInput))
{
fail("NoPadding test failed on decrypt expected " + new String(Hex.encode(maxInput)) + " got " + new String(Hex.encode(out)));
}
//
// encrypt/decrypt
//
Cipher c1 = Cipher.getInstance("ElGamal", "BC");
Cipher c2 = Cipher.getInstance("ElGamal", "BC");
c1.init(Cipher.ENCRYPT_MODE, keyPair.getPublic(), rand);
byte[] out1 = c1.doFinal(in);
c2.init(Cipher.DECRYPT_MODE, keyPair.getPrivate());
byte[] out2 = c2.doFinal(out1);
if (!areEqual(in, out2))
{
fail(size + " encrypt test failed");
}
//
// encrypt/decrypt with update
//
int outLen = c1.update(in, 0, 2, out1, 0);
outLen += c1.doFinal(in, 2, in.length - 2, out1, outLen);
outLen = c2.update(out1, 0, 2, out2, 0);
outLen += c2.doFinal(out1, 2, out1.length - 2, out2, outLen);
if (!areEqual(in, out2))
{
fail(size + " encrypt with update test failed");
}
//
// public key encoding test
//
byte[] pubEnc = keyPair.getPublic().getEncoded();
KeyFactory keyFac = KeyFactory.getInstance("ElGamal", "BC");
X509EncodedKeySpec pubX509 = new X509EncodedKeySpec(pubEnc);
DHPublicKey pubKey = (DHPublicKey)keyFac.generatePublic(pubX509);
DHParameterSpec spec = pubKey.getParams();
if (!spec.getG().equals(elParams.getG()) || !spec.getP().equals(elParams.getP()))
{
fail(size + " bit public key encoding/decoding test failed on parameters");
}
if (!((DHPublicKey)keyPair.getPublic()).getY().equals(pubKey.getY()))
{
fail(size + " bit public key encoding/decoding test failed on y value");
}
//
// public key serialisation test
//
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
ObjectOutputStream oOut = new ObjectOutputStream(bOut);
oOut.writeObject(keyPair.getPublic());
ByteArrayInputStream bIn = new ByteArrayInputStream(bOut.toByteArray());
ObjectInputStream oIn = new ObjectInputStream(bIn);
pubKey = (DHPublicKey)oIn.readObject();
spec = pubKey.getParams();
if (!spec.getG().equals(elParams.getG()) || !spec.getP().equals(elParams.getP()))
{
fail(size + " bit public key serialisation test failed on parameters");
}
if (!((DHPublicKey)keyPair.getPublic()).getY().equals(pubKey.getY()))
{
fail(size + " bit public key serialisation test failed on y value");
}
//
// private key encoding test
//
byte[] privEnc = keyPair.getPrivate().getEncoded();
PKCS8EncodedKeySpec privPKCS8 = new PKCS8EncodedKeySpec(privEnc);
DHPrivateKey privKey = (DHPrivateKey)keyFac.generatePrivate(privPKCS8);
spec = privKey.getParams();
if (!spec.getG().equals(elParams.getG()) || !spec.getP().equals(elParams.getP()))
{
fail(size + " bit private key encoding/decoding test failed on parameters");
}
if (!((DHPrivateKey)keyPair.getPrivate()).getX().equals(privKey.getX()))
{
fail(size + " bit private key encoding/decoding test failed on y value");
}
//
// private key serialisation test
//
bOut = new ByteArrayOutputStream();
oOut = new ObjectOutputStream(bOut);
oOut.writeObject(keyPair.getPrivate());
bIn = new ByteArrayInputStream(bOut.toByteArray());
oIn = new ObjectInputStream(bIn);
privKey = (DHPrivateKey)oIn.readObject();
spec = privKey.getParams();
if (!spec.getG().equals(elParams.getG()) || !spec.getP().equals(elParams.getP()))
{
fail(size + " bit private key serialisation test failed on parameters");
}
if (!((DHPrivateKey)keyPair.getPrivate()).getX().equals(privKey.getX()))