public byte[] DecryptKey(byte[] cipherText)
{
string cacheKey = CreateCacheKey(cipherText, context: null);
byte[] result;
if (_lruCache.TryGet(cacheKey, out result))
{
return(result);
}
result = _actualDataKeyProvider.DecryptKey(cipherText);
_lruCache.Add(cacheKey, result);
return(result);
}
public Stream Decrypt(byte[] dataKey, Stream ciphertextStream, IDictionary <string, string> context)
{
byte[] plaintextKey = _dataKeyProvider.DecryptKey(dataKey, context);
var iv = new byte[IVBytes];
if (!TryFillBuffer(ciphertextStream, iv))
{
throw new CryptographicException("not enough data in input stream");
}
ISymmetricAlgorithm algo = null;
try
{
algo = _algorithmFactory.CreateAlgorithm(_config);
algo.Key = plaintextKey;
algo.IV = iv;
ICryptoTransform decryptor = algo.CreateDecryptor();
Stream cryptoStream = new CryptoStream(ciphertextStream, decryptor, CryptoStreamMode.Read);
// when this stream is disposed, the algo and decryptor will be, too.
return(new StreamWithDisposables(cryptoStream, new IDisposable[] { algo, decryptor }));
}
catch (Exception e)
{
// If we had trouble creating the stream, destroy the algorithm to prevent the key leaking.
if (algo != null)
{
try
{
algo.Dispose();
}
catch (Exception disposalException)
{
throw new AggregateException(e, disposalException);
}
}
throw;
}
}