How to use

ConcatKDFBytesGenerator

in

io.yggdrash.common.crypto

@Test
public void testKDF() {
  ConcatKDFBytesGenerator kdf = new ConcatKDFBytesGenerator(new SHA256Digest());
  kdf.init(new KDFParameters("Hello".getBytes(), new byte[0]));
  byte[] bytes = new byte[2];
  kdf.generateBytes(bytes, 0, bytes.length);
  assertArrayEquals(new byte[] {-66, -89}, bytes);
}

  private static EthereumIESEngine makeIESEngine(boolean isEncrypt, ECPoint pub, BigInteger prv, byte[] IV) {
    AESEngine aesFastEngine = new AESEngine();

    EthereumIESEngine iesEngine = new EthereumIESEngine(
        new ECDHBasicAgreement(),
        new ConcatKDFBytesGenerator(new SHA256Digest()),
        new HMac(new SHA256Digest()),
        new SHA256Digest(),
        new BufferedBlockCipher(new SICBlockCipher(aesFastEngine)));

    byte[] d = new byte[] {};
    byte[] e = new byte[] {};

    IESParameters p = new IESWithCipherParameters(d, e, KEY_SIZE, KEY_SIZE);
    ParametersWithIV parametersWithIV = new ParametersWithIV(p, IV);

    iesEngine.init(isEncrypt, new ECPrivateKeyParameters(prv, CURVE), new ECPublicKeyParameters(pub, CURVE), parametersWithIV);
    return iesEngine;
  }
}

public static byte[] decrypt(ECPoint ephem, BigInteger prv, byte[] IV, byte[] cipher, byte[] macData) throws InvalidCipherTextException {
  AESEngine aesFastEngine = new AESEngine();
  EthereumIESEngine iesEngine = new EthereumIESEngine(
      new ECDHBasicAgreement(),
      new ConcatKDFBytesGenerator(new SHA256Digest()),
      new HMac(new SHA256Digest()),
      new SHA256Digest(),
      new BufferedBlockCipher(new SICBlockCipher(aesFastEngine)));
  byte[] d = new byte[] {};
  byte[] e = new byte[] {};
  IESParameters p = new IESWithCipherParameters(d, e, KEY_SIZE, KEY_SIZE);
  ParametersWithIV parametersWithIV =
      new ParametersWithIV(p, IV);
  iesEngine.init(false, new ECPrivateKeyParameters(prv, CURVE), new ECPublicKeyParameters(ephem, CURVE), parametersWithIV);
  return iesEngine.processBlock(cipher, 0, cipher.length, macData);
}

private static EthereumIESEngine makeIESEngine(boolean isEncrypt, ECPoint pub, BigInteger prv, byte[] IV) {
  AESEngine aesFastEngine = new AESEngine();
  EthereumIESEngine iesEngine = new EthereumIESEngine(
      new ECDHBasicAgreement(),
      new ConcatKDFBytesGenerator(new SHA256Digest()),
      new HMac(new SHA256Digest()),
      new SHA256Digest(),
      new BufferedBlockCipher(new SICBlockCipher(aesFastEngine)));
  byte[] d = new byte[] {};
  byte[] e = new byte[] {};
  IESParameters p = new IESWithCipherParameters(d, e, KEY_SIZE, KEY_SIZE);
  ParametersWithIV parametersWithIV = new ParametersWithIV(p, IV);
  iesEngine.init(isEncrypt, new ECPrivateKeyParameters(prv, curve), new ECPublicKeyParameters(pub, curve), parametersWithIV);
  return iesEngine;
}