public static byte[] Decrypt(byte[] data, C25519Key key)
{
var size = data[1] & 127;
var sizeLength = 0;
var hasFieldSize = (data[1] & 128) != 0;
if (hasFieldSize)
{
sizeLength = size;
size = (int)new BigInteger(data.Skip(2).Take(sizeLength).ToArray(), true, true);
}
var step = 2 + sizeLength;
var asymmetricCipher = data.Skip(step).Take(32 * 3).ToArray();
var asymmetricPlain = key.Decrypt(asymmetricCipher);
step += AsymmetricSize;
if (size == 200)
{
return(UnPad32(asymmetricPlain));
}
var symmetricKey = AesSherableKey.Parse(asymmetricPlain);
return(symmetricKey.Decrypt(data.Skip(step).ToArray()));
}
public AesSherableKey GenKey(AesKey key) => AesSherableKey.Parse(key.Hash(ToByteArray()));