/// <summary>
/// Encrypts the stream under current security conditions.
/// </summary>
/// <param name="messageStream">Data to be encrypted.</param>
/// <param name="outputStream">Stream to write encrypted content to.</param>
/// <param name="sspiFeatureFlags">Requested features.</param>
public void EncryptMessage(Stream messageStream, GenuineChunkedStream outputStream, SspiFeatureFlags sspiFeatureFlags)
{
// get package sizes
lock (_secPkgContext_SizesLock)
{
if (!_secPkgContext_SizesInitialized)
{
SspiApi.QueryContextSizes(this._phContext, ref this._secPkgContext_Sizes);
_secPkgContext_SizesInitialized = true;
}
}
byte[] chunk = null;
int position = 0;
BinaryWriter outputWriter = new BinaryWriter(outputStream);
if ((sspiFeatureFlags & SspiFeatureFlags.Encryption) != 0)
{
// it'll write signature automatically as well as encrypt content
SspiApi.EncryptMessage(this._phContext, messageStream, outputWriter, ref this._secPkgContext_Sizes);
}
else if ((sspiFeatureFlags & SspiFeatureFlags.Signing) != 0)
{
// remember position to write signature size later
outputStream.WriteInt32AndRememberItsLocation(0, out chunk, out position);
long currentLength = outputStream.Length;
// anyway will have to read this into buffer
byte[] contentBuffer = new byte[(int)messageStream.Length];
GenuineUtility.ReadDataFromStream(messageStream, contentBuffer, 0, contentBuffer.Length);
// write signature
SspiApi.MakeSignature(this._phContext, contentBuffer, outputWriter, ref this._secPkgContext_Sizes);
// update signature size
MessageCoder.WriteInt32(chunk, position, (int)(outputStream.Length - currentLength));
// write the content
outputWriter.Write((int)contentBuffer.Length);
outputWriter.Write(contentBuffer, 0, contentBuffer.Length);
}
else
{
// just copy the source content
//outputWriter.Write( (int) messageStream.Length );
GenuineUtility.CopyStreamToStream(messageStream, outputStream);
}
}
/// <summary>
/// Decrypts the data.
/// </summary>
/// <param name="sourceStream">Stream containing encrypted data.</param>
/// <param name="sspiFeatureFlags">Requested SSPI features.</param>
/// <returns>Stream containing decrypted data.</returns>
public Stream DecryptMessage(Stream sourceStream, SspiFeatureFlags sspiFeatureFlags)
{
// get package sizes
lock (_secPkgContext_SizesLock)
{
if (!_secPkgContext_SizesInitialized)
{
SspiApi.QueryContextSizes(this._phContext, ref this._secPkgContext_Sizes);
_secPkgContext_SizesInitialized = true;
}
}
BinaryReader messageReader = new BinaryReader(sourceStream);
if ((sspiFeatureFlags & SspiFeatureFlags.Encryption) != 0)
{
// decrypt it
return(SspiApi.DecryptMessage(this._phContext, messageReader));
}
else if ((sspiFeatureFlags & SspiFeatureFlags.Signing) != 0)
{
// read signature
int signatureSize = messageReader.ReadInt32();
byte[] signature = new byte[signatureSize];
GenuineUtility.ReadDataFromStream(sourceStream, signature, 0, signatureSize);
// read content
int contentSize = messageReader.ReadInt32();
byte[] content = new byte[contentSize];
GenuineUtility.ReadDataFromStream(sourceStream, content, 0, contentSize);
// verify signature
SspiApi.VerifySignature(this._phContext, content, signature);
// return verified content
return(new MemoryStream(content, 0, content.Length, false, true));
}
return(sourceStream);
}
