public BlockAlgorithmKeyWrapTransform(SymmetricAlgorithm symmetricAlgorithm, Salt salt, KeyWrapDirection keyWrapDirection)
{
if (symmetricAlgorithm == null)
{
throw new ArgumentNullException("symmetricAlgorithm");
}
if (salt == null)
{
throw new ArgumentNullException("salt");
}
if (salt.Length != 0 && salt.Length < symmetricAlgorithm.Key().Length)
{
throw new InternalErrorException("Salt is too short. It must be at least as long as the algorithm key, or empty for no salt.");
}
_algorithm = symmetricAlgorithm;
byte[] saltedKey = _algorithm.Key();
saltedKey.Xor(salt.GetBytes().Reduce(saltedKey.Length));
_algorithm.SetKey(saltedKey);
_algorithm.Mode = CipherMode.ECB;
_algorithm.Padding = PaddingMode.None;
BlockLength = _algorithm.BlockSize / 8;
_transform = keyWrapDirection == KeyWrapDirection.Encrypt ? _algorithm.CreateEncryptingTransform() : _algorithm.CreateDecryptingTransform();
}
