How to use

ECIESCoder

in

io.yggdrash.common.crypto

public static byte[] decrypt(BigInteger privKey, byte[] cipher, byte[] macData) throws IOException, InvalidCipherTextException {
  byte[] plaintext;
  ByteArrayInputStream is = new ByteArrayInputStream(cipher);
  byte[] ephemBytes = new byte[2 * ((CURVE.getCurve().getFieldSize() + 7) / 8) + 1];
  is.read(ephemBytes);
  ECPoint ephem = CURVE.getCurve().decodePoint(ephemBytes);
  byte[] IV = new byte[KEY_SIZE / 8];
  is.read(IV);
  byte[] cipherBody = new byte[is.available()];
  is.read(cipherBody);
  plaintext = decrypt(ephem, privKey, IV, cipherBody, macData);
  return plaintext;
}

public static byte[] encrypt(ECPoint toPub, byte[] plaintext) {
  return encrypt(toPub, plaintext, null);
}

@Test  // encrypt decrypt round trip
public void test2() {
  BigInteger privKey = new BigInteger("5e173f6ac3c669587538e7727cf19b782a4f2fda07c1eaa662c593e5e85e3051", 16);
  byte[] payload = Hex.decode("1122334455");
  ECKey ecKey = ECKey.fromPrivate(privKey);
  ECPoint pubKeyPoint = ecKey.getPubKeyPoint();
  byte[] cipher = new byte[0];
  try {
    cipher = ECIESCoder.encrypt(pubKeyPoint, payload);
  } catch (Throwable e) {
    log.error(e.getMessage());
  }
  log.debug(Hex.toHexString(cipher));
  byte[] decrypted_payload = new byte[0];
  try {
    decrypted_payload = ECIESCoder.decrypt(privKey, cipher);
  } catch (Throwable e) {
    log.error(e.getMessage());
  }
  log.debug(Hex.toHexString(decrypted_payload));
}

public static byte[] encrypt(ECPoint toPub, byte[] plaintext, byte[] macData) {
  ECKeyPairGenerator eGen = new ECKeyPairGenerator();
  SecureRandom random = new SecureRandom();
  KeyGenerationParameters gParam = new ECKeyGenerationParameters(CURVE, random);
  eGen.init(gParam);
  byte[] IV = new byte[KEY_SIZE / 8];
  new SecureRandom().nextBytes(IV);
  AsymmetricCipherKeyPair ephemPair = eGen.generateKeyPair();
  BigInteger prv = ((ECPrivateKeyParameters) ephemPair.getPrivate()).getD();
  ECPoint pub = ((ECPublicKeyParameters) ephemPair.getPublic()).getQ();
  EthereumIESEngine iesEngine = makeIESEngine(true, toPub, prv, IV);
  ECKeyGenerationParameters keygenParams = new ECKeyGenerationParameters(CURVE, random);
  ECKeyPairGenerator generator = new ECKeyPairGenerator();
  generator.init(keygenParams);
  ECKeyPairGenerator gen = new ECKeyPairGenerator();
  gen.init(new ECKeyGenerationParameters(ECKey.CURVE, random));
  byte[] cipher;
  try {
    cipher = iesEngine.processBlock(plaintext, 0, plaintext.length, macData);
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    bos.write(pub.getEncoded(false));
    bos.write(IV);
    bos.write(cipher);
    return bos.toByteArray();
  } catch (InvalidCipherTextException | IOException e) {
    throw new RuntimeException(e);
  }
}

@Test // decrypt cpp data
public void test1() {
  BigInteger privKey = new BigInteger("5e173f6ac3c669587538e7727cf19b782a4f2fda07c1eaa662c593e5e85e3051", 16);
  byte[] cipher = Hex.decode("049934a7b2d7f9af8fd9db941d9da281ac9381b5740e1f64f7092f3588d4f87f5ce55191a6653e5e80c1c5dd538169aa123e70dc6ffc5af1827e546c0e958e42dad355bcc1fcb9cdf2cf47ff524d2ad98cbf275e661bf4cf00960e74b5956b799771334f426df007350b46049adb21a6e78ab1408d5e6ccde6fb5e69f0f4c92bb9c725c02f99fa72b9cdc8dd53cff089e0e73317f61cc5abf6152513cb7d833f09d2851603919bf0fbe44d79a09245c6e8338eb502083dc84b846f2fee1cc310d2cc8b1b9334728f97220bb799376233e113");
  byte[] payload = new byte[0];
  try {
    payload = ECIESCoder.decrypt(privKey, cipher);
  } catch (Throwable e) {
    log.error(e.getMessage());
  }
  Assert.assertEquals("802b052f8b066640bba94a4fc39d63815c377fced6fcb84d27f791c9921ddf3e9bf0108e298f490812847109cbd778fae393e80323fd643209841a3b7f110397f37ec61d84cea03dcc5e8385db93248584e8af4b4d1c832d8c7453c0089687a700",
      Hex.toHexString(payload));
}