public static int Encrypt(byte[] plaintext, int offset, int len, byte[] additionalData, byte[] nonce, byte[] key, byte[] outBuffer)
{
lock (mutex) {
if (cipher == null)
{
cipher = new ChaCha7539Engine();
}
else
{
cipher.Reset();
}
if (_encryptKey == null)
{
_encryptKey = new KeyParameter(key);
}
else
{
_encryptKey.Reset();
_encryptKey.SetKey(key);
}
if (_temp_Params == null)
{
_temp_Params = new ParametersWithIV(_encryptKey, nonce);
}
else
{
_temp_Params.Reset();
_temp_Params.Set(_encryptKey, nonce);
}
cipher.Init(true, _temp_Params);
byte[] firstBlock = BufferPool.GetBuffer(64);
KeyParameter macKey = GenerateRecordMacKey(cipher, firstBlock);
cipher.ProcessBytes(plaintext, offset, len, outBuffer, 0);
byte[] mac = BufferPool.GetBuffer(16);
int macsize = CalculateRecordMac(macKey, additionalData, outBuffer, 0, len, mac);
Array.Copy(mac, 0, outBuffer, len, macsize);
BufferPool.ReturnBuffer(mac);
BufferPool.ReturnBuffer(firstBlock);
return(len + 16);
}
}
protected static KeyParameter GenerateRecordMacKey(IStreamCipher cipher, byte[] firstBlock)
{
cipher.ProcessBytes(firstBlock, 0, firstBlock.Length, firstBlock, 0);
if (_macKey == null)
{
_macKey = new KeyParameter(firstBlock, 0, 32);
}
else
{
_macKey.Reset();
_macKey.SetKey(firstBlock, 0, 32);
}
Arrays.Fill(firstBlock, (byte)0);
return(_macKey);
}
public static int Decrypt(byte[] ciphertext, int offset, int len, byte[] additionalData, byte[] nonce, byte[] key, byte[] outBuffer)
{
lock (mutex) {
if (cipher == null)
{
cipher = new ChaCha7539Engine();
}
else
{
cipher.Reset();
}
if (_decryptKey == null)
{
_decryptKey = new KeyParameter(key);
}
else
{
_decryptKey.Reset();
_decryptKey.SetKey(key);
}
if (_temp_Params == null)
{
_temp_Params = new ParametersWithIV(_decryptKey, nonce);
}
else
{
_temp_Params.Reset();
_temp_Params.Set(_decryptKey, nonce);
}
cipher.Init(false, _temp_Params);
byte[] firstBlock = BufferPool.GetBuffer(64);
KeyParameter macKey = GenerateRecordMacKey(cipher, firstBlock);
int plaintextLength = len - 16;
byte[] calculatedMac = BufferPool.GetBuffer(16);
CalculateRecordMac(macKey, additionalData, ciphertext, offset, plaintextLength, calculatedMac);
byte[] receivedMac = BufferPool.GetBuffer(16);
Array.Copy(ciphertext, offset + plaintextLength, receivedMac, 0, receivedMac.Length);
if (!Arrays.ConstantTimeAreEqual(calculatedMac, receivedMac))
{
BufferPool.ReturnBuffer(calculatedMac);
BufferPool.ReturnBuffer(receivedMac);
BufferPool.ReturnBuffer(firstBlock);
throw new TlsFatalAlert(AlertDescription.bad_record_mac);
}
BufferPool.ReturnBuffer(calculatedMac);
BufferPool.ReturnBuffer(receivedMac);
BufferPool.ReturnBuffer(firstBlock);
cipher.ProcessBytes(ciphertext, offset, plaintextLength, outBuffer, 0);
return(plaintextLength);
}
}
