public byte[] Encrypt(PublicKey recipientPublicKey, byte[] plaintext, byte[] macData)
{
byte[] iv = _cryptoRandom.GenerateRandomBytes(KeySize / 8);
PrivateKey ephemeralPrivateKey = new PrivateKey(_cryptoRandom.GenerateRandomBytes(32));
ECPublicKeyParameters publicKeyParameters = BouncyCrypto.WrapPublicKey(recipientPublicKey);
ECPrivateKeyParameters ephemeralPrivateKeyParameters = BouncyCrypto.WrapPrivateKey(ephemeralPrivateKey);
EthereumIesEngine iesEngine = MakeIesEngine(true, publicKeyParameters, ephemeralPrivateKeyParameters, iv);
try
{
byte[] cipher = iesEngine.ProcessBlock(plaintext, 0, plaintext.Length, macData);
MemoryStream memoryStream = new MemoryStream();
memoryStream.Write(ephemeralPrivateKey.PublicKey.PrefixedBytes, 0, ephemeralPrivateKey.PublicKey.PrefixedBytes.Length);
memoryStream.Write(iv, 0, iv.Length);
memoryStream.Write(cipher, 0, cipher.Length);
return(memoryStream.ToArray());
}
catch (InvalidCipherTextException)
{
throw;
}
catch (IOException)
{
throw;
}
}
private byte[] Decrypt(PublicKey ephemeralPublicKey, PrivateKey privateKey, byte[] iv, byte[] ciphertextBody, byte[] macData)
{
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)));
IesParameters iesParameters = new IesWithCipherParameters(new byte[] { }, new byte[] { }, KeySize, KeySize);
ParametersWithIV parametersWithIV = new ParametersWithIV(iesParameters, iv);
ECPrivateKeyParameters privateKeyParameters = BouncyCrypto.WrapPrivateKey(privateKey);
ECPublicKeyParameters publicKeyParameters = BouncyCrypto.WrapPublicKey(ephemeralPublicKey);
iesEngine.Init(false, privateKeyParameters, publicKeyParameters, parametersWithIV);
return(iesEngine.ProcessBlock(ciphertextBody, 0, ciphertextBody.Length, macData));
}