public void Decrypt(byte[] content, byte[] sectorId)
{
var aes = AesXts.Create(false, 0x20, true);
var enc = aes.CreateDecryptor(new byte[0x20], sectorId);
enc.TransformBlock(content, 0, content.Length, content, 0);
}
public void XtsContextTest()
{
var aes = AesXts.Create(false, 0x20, true);
var enc = aes.CreateEncryptor(new byte[0x20], new byte[0x10]);
var dec = aes.CreateDecryptor(new byte[0x20], new byte[0x10]);
var content = new byte[0x10];
enc.TransformBlock(content, 0, content.Length, content, 0);
dec.TransformBlock(content, 0, content.Length, content, 0);
Assert.IsTrue(new byte[0x10].SequenceEqual(content));
}
public XtsStream(Stream input, byte[] key, byte[] sectorId, bool advanceSectorId, bool littleEndianId, int sectorSize)
{
if (key.Length / 4 < 4 || key.Length / 4 > 8 || key.Length % 4 > 0)
{
throw new InvalidOperationException("Key has invalid length.");
}
if (sectorId.Length != BlockSize)
{
throw new InvalidOperationException("SectorId has invalid length.");
}
if (input.Length % BlockSize != 0)
{
throw new InvalidOperationException($"Stream needs to have a length dividable by {BlockSize}.");
}
if (sectorSize % BlockSize != 0)
{
throw new InvalidOperationException($"SectorSize needs to be dividable by {BlockSize}");
}
_baseStream = input;
_internalLength = _baseStream.Length;
_lastBlockBuffer = new byte[BlockSize];
_littleEndianId = littleEndianId;
_advanceSectorId = advanceSectorId;
_sectorSize = sectorSize;
_initialId = new byte[sectorId.Length];
Array.Copy(sectorId, _initialId, sectorId.Length);
_currentId = new byte[sectorId.Length];
Array.Copy(sectorId, _currentId, sectorId.Length);
var xts = AesXts.Create(littleEndianId, sectorSize, advanceSectorId);
_encryptor = (AesXtsCryptoTransform)xts.CreateEncryptor(key, _initialId);
_decryptor = (AesXtsCryptoTransform)xts.CreateDecryptor(key, _initialId);
}
