protected override void initCipher(byte[] iv, bool isCipher)
{
base.initCipher(iv, isCipher);
IntPtr ctx = Marshal.AllocHGlobal(MbedTLS.cipher_get_size_ex());
if (isCipher)
{
_encryptCtx = ctx;
}
else
{
_decryptCtx = ctx;
}
byte[] realkey;
if (_method.StartsWith("rc4-"))
{
byte[] temp = new byte[keyLen + ivLen];
realkey = new byte[keyLen];
Array.Copy(_key, 0, temp, 0, keyLen);
Array.Copy(iv, 0, temp, keyLen, ivLen);
realkey = MbedTLS.MD5(temp);
}
else
{
realkey = _key;
}
MbedTLS.cipher_init(ctx);
if (MbedTLS.cipher_setup(ctx, MbedTLS.cipher_info_from_string(getInfo().name)) != 0)
{
throw new Exception("Cannot initialize mbed TLS cipher context");
}
/*
* MbedTLS takes key length by bit
* cipher_setkey() will set the correct key schedule
* and operation
*
* MBEDTLS_AES_{EN,DE}CRYPT
* == MBEDTLS_BLOWFISH_{EN,DE}CRYPT
* == MBEDTLS_CAMELLIA_{EN,DE}CRYPT
* == MBEDTLS_{EN,DE}CRYPT
*
*/
if (MbedTLS.cipher_setkey(ctx, realkey, keyLen * 8,
isCipher ? MbedTLS.MBEDTLS_ENCRYPT : MbedTLS.MBEDTLS_DECRYPT) != 0)
{
throw new Exception("Cannot set mbed TLS cipher key");
}
if (MbedTLS.cipher_set_iv(ctx, iv, ivLen) != 0)
{
throw new Exception("Cannot set mbed TLS cipher IV");
}
if (MbedTLS.cipher_reset(ctx) != 0)
{
throw new Exception("Cannot finalize mbed TLS cipher context");
}
}
protected override void cipherUpdate(bool isCipher, int length, byte[] buf, byte[] outbuf)
{
// C# could be multi-threaded
if (_disposed)
{
throw new ObjectDisposedException(this.ToString());
}
if (MbedTLS.cipher_update(isCipher ? _encryptCtx : _decryptCtx,
buf, length, outbuf, ref length) != 0)
{
throw new Exception("Cannot update mbed TLS cipher context");
}
}
protected void bytesToKey(byte[] password, byte[] key)
{
byte[] result = new byte[password.Length + 16];
int i = 0;
byte[] md5sum = null;
while (i < key.Length)
{
if (i == 0)
{
md5sum = MbedTLS.MD5(password);
}
else
{
md5sum.CopyTo(result, 0);
password.CopyTo(result, md5sum.Length);
md5sum = MbedTLS.MD5(result);
}
md5sum.CopyTo(key, i);
i += md5sum.Length;
}
}
protected byte[] GetPasswordHash()
{
byte[] inputBytes = Encoding.UTF8.GetBytes(Password);
byte[] hash = MbedTLS.MD5(inputBytes);
return(hash);
}