public static Pair<IV, int> extractIVFromContent(BufferReference content)
{
if (content.Length < 1 || content.Length < content[0] + 1)
throw new InternalError("Failed to extract IV from encrypted block.");
var ivBytes = content[0];
var iv = new byte[content[0]];
content.copy(1, iv, 0, ivBytes);
return Pair.make(new IV(iv), 1 + ivBytes);
}
public BufferReference decrypt(BufferReference content)
{
Pair<IV, int> ivInfo = extractIVFromContent(content);
var iv = ivInfo.First;
var ivPrefixLength = ivInfo.Second;
_provider.IV = iv.Data;
using (var encryptor = _provider.CreateDecryptor())
{
_outputStream.SetLength(0);
using (var stream = new CryptoStream(_outputStream, encryptor, CryptoStreamMode.Write))
{
stream.Write(content.Buffer, content.Offset + ivPrefixLength, content.Length - ivPrefixLength);
stream.FlushFinalBlock();
return _outputStream.asBufferReference();
}
}
}
public BufferReference encrypt(IV iv, BufferReference content)
{
_provider.IV = iv.Data;
// don't see a way how we can reuse MemoryStream / CryptoStream here, need
// to implement based on TransFormBlock, but even then we need to create the
// Encryptor for each instance.
_outputStream.SetLength(0);
writeIV(_provider.IV, _outputStream);
using (var encryptor = _provider.CreateEncryptor())
{
// note: cryptostream closes our output stream, which is fine for us!)
using (var stream = new CryptoStream(_outputStream, encryptor, CryptoStreamMode.Write))
{
stream.Write(content.Buffer, content.Offset, content.Length);
stream.FlushFinalBlock();
return _outputStream.asBufferReference();
}
}
}
public override void link(Linker usr)
{
buffer = createBuffer(Name, width, height);
}
protected override void doLink(Linker user)
{
buffer = createBuffer(name);
targ = user.getTarget(name);
}
// Return decrypted data by using DecryptionService and the given serialized Key
public static BufferReference decrypt(string serializedKey, BufferReference encrypted)
{
return decrypt(Key.deserialize(serializedKey), encrypted);
}
// Return decrypted data by using DecryptionService and the given Key
public static BufferReference decrypt(Key key, BufferReference content)
{
using (var service = new DecryptionService(key))
{
return service.decrypt(content);
}
}
public static BufferReference encrypt(Key key, IV? iv_, BufferReference content)
{
using (var service = new EncryptionService(key))
{
var iv = iv_ ?? service.createRandomIV();
return service.encrypt(iv, content);
}
}
public static BufferReference encrypt(Key key, BufferReference content)
{
return encrypt(key, null, content);
}
public static BufferReference encrypt(string serializedKey, IV? iv_, BufferReference content)
{
return encrypt(Key.deserialize(serializedKey), iv_, content);
}
