/// <summary>
/// Decrypts the encrypted data to the given stream
/// </summary>
/// <param name="outputPlaintextStream">The resulting plain text stream.</param>
public void DecryptTo(Stream outputPlaintextStream)
{
if (outputPlaintextStream == null)
{
throw new ArgumentNullException("outputPlaintextStream");
}
if (!PassphraseIsValid)
{
throw new InternalErrorException("Passphrase is not valid!");
}
using (Stream encryptedDataStream = CreateEncryptedDataStream())
{
encryptedDataStream.DecryptTo(outputPlaintextStream, DocumentHeaders.DataCrypto().DecryptingTransform(), DocumentHeaders.IsCompressed);
}
DocumentHeaders.Trailers(_reader);
if (DocumentHeaders.HmacCalculator.Hmac != DocumentHeaders.Hmac)
{
throw new Axantum.AxCrypt.Core.Runtime.IncorrectDataException("HMAC validation error.", ErrorStatus.HmacValidationError);
}
}
/// <summary>
/// Encrypt a stream with a given set of headers and write to an output stream. The caller is responsible for consistency and completeness
/// of the headers. Headers that are not known until encryption and compression are added here.
/// </summary>
/// <param name="outputDocumentHeaders"></param>
/// <param name="inputStream"></param>
/// <param name="outputStream"></param>
public void EncryptTo(Stream inputStream, Stream outputStream, AxCryptOptions options)
{
if (inputStream == null)
{
throw new ArgumentNullException("inputStream");
}
if (outputStream == null)
{
throw new ArgumentNullException("outputStream");
}
if (options.HasMask(AxCryptOptions.EncryptWithCompression) && options.HasMask(AxCryptOptions.EncryptWithoutCompression))
{
throw new ArgumentException("Invalid options, cannot specify both with and without compression.");
}
if (!options.HasMask(AxCryptOptions.EncryptWithCompression) && !options.HasMask(AxCryptOptions.EncryptWithoutCompression))
{
throw new ArgumentException("Invalid options, must specify either with or without compression.");
}
DocumentHeaders.IsCompressed = options.HasMask(AxCryptOptions.EncryptWithCompression);
V2HmacCalculator hmacCalculator = new V2HmacCalculator(new SymmetricKey(DocumentHeaders.GetHmacKey()));
V2HmacStream <Stream> outputHmacStream = V2HmacStream.Create(hmacCalculator, outputStream);
CryptoStreamBase encryptingStream = New <CryptoStreamBase>().Initialize(V2AxCryptDataStream.Create(outputHmacStream), DocumentHeaders.DataCrypto().EncryptingTransform(), CryptoStreamMode.Write);
DocumentHeaders.WriteStartWithHmac(outputHmacStream);
if (DocumentHeaders.IsCompressed)
{
using (ZOutputStream deflatingStream = new ZOutputStream(encryptingStream, -1))
{
deflatingStream.FlushMode = JZlib.Z_SYNC_FLUSH;
inputStream.CopyTo(deflatingStream);
deflatingStream.FlushMode = JZlib.Z_FINISH;
deflatingStream.Finish();
_plaintextLength = deflatingStream.TotalIn;
_compressedPlaintextLength = deflatingStream.TotalOut;
encryptingStream.FinalFlush();
DocumentHeaders.WriteEndWithHmac(hmacCalculator, outputHmacStream, _plaintextLength, _compressedPlaintextLength);
}
}
else
{
try
{
_compressedPlaintextLength = _plaintextLength = StreamExtensions.CopyTo(inputStream, encryptingStream);
encryptingStream.FinalFlush();
DocumentHeaders.WriteEndWithHmac(hmacCalculator, outputHmacStream, _plaintextLength, _compressedPlaintextLength);
}
finally
{
encryptingStream.Dispose();
}
}
}
