protected override void initCipher(byte[] iv, bool isCipher)
{
base.initCipher(iv, isCipher);
IntPtr ctx;
if (isCipher)
{
if (_encryptCtx == IntPtr.Zero)
{
ctx = Marshal.AllocHGlobal(_cipherInfo[3]);
_encryptCtx = ctx;
}
else
{
ctx = _encryptCtx;
}
}
else
{
if (_decryptCtx == IntPtr.Zero)
{
ctx = Marshal.AllocHGlobal(_cipherInfo[3]);
_decryptCtx = ctx;
}
else
{
ctx = _decryptCtx;
}
}
byte[] realkey;
if (_method == "rc4-md5")
{
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 = MD5.Create().ComputeHash(temp);
}
else
{
realkey = _key;
}
if (_cipher == CIPHER_AES)
{
PolarSSL.aes_init(ctx);
// PolarSSL takes key length by bit
// since we'll use CFB mode, here we both do enc, not dec
PolarSSL.aes_setkey_enc(ctx, realkey, keyLen * 8);
}
else if (_cipher == CIPHER_RC4)
{
PolarSSL.arc4_init(ctx);
// PolarSSL RC4 takes key length by byte
PolarSSL.arc4_setup(ctx, realkey, keyLen);
}
}
protected virtual void Dispose(bool disposing)
{
lock (this)
{
if (_disposed)
{
return;
}
_disposed = true;
}
if (disposing)
{
}
if (_encryptCtx != IntPtr.Zero)
{
switch (_cipher)
{
case CIPHER_AES:
PolarSSL.aes_free(_encryptCtx);
break;
case CIPHER_RC4:
PolarSSL.arc4_free(_encryptCtx);
break;
}
Marshal.FreeHGlobal(_encryptCtx);
_encryptCtx = IntPtr.Zero;
}
if (_decryptCtx != IntPtr.Zero)
{
switch (_cipher)
{
case CIPHER_AES:
PolarSSL.aes_free(_decryptCtx);
break;
case CIPHER_RC4:
PolarSSL.arc4_free(_decryptCtx);
break;
}
Marshal.FreeHGlobal(_decryptCtx);
_decryptCtx = IntPtr.Zero;
}
}
protected override void cipherUpdate(bool isCipher, int length, byte[] buf, byte[] outbuf)
{
// C# could be multi-threaded
if (_disposed)
{
throw new ObjectDisposedException(this.ToString());
}
byte[] iv;
int ivOffset;
IntPtr ctx;
if (isCipher)
{
iv = _encryptIV;
ivOffset = _encryptIVOffset;
ctx = _encryptCtx;
}
else
{
iv = _decryptIV;
ivOffset = _decryptIVOffset;
ctx = _decryptCtx;
}
switch (_cipher)
{
case CIPHER_AES:
PolarSSL.aes_crypt_cfb128(ctx, isCipher ? PolarSSL.AES_ENCRYPT : PolarSSL.AES_DECRYPT, length, ref ivOffset, iv, buf, outbuf);
if (isCipher)
{
_encryptIVOffset = ivOffset;
}
else
{
_decryptIVOffset = ivOffset;
}
break;
case CIPHER_RC4:
PolarSSL.arc4_crypt(ctx, length, buf, outbuf);
break;
}
}