public static void EncryptDecrypt(Stream input, Stream output, byte[] key, out byte[] digest)
{
byte[] header = new byte[0x20];
input.Read(header, 0, 0x20);
output.Write(header, 0, 0x20);
var length = BufferUtils.ToUInt32(header, 0x0c);
var data = new byte[length - 0x20];
input.Read(data, 0, data.Length);
var hash = XeCrypt.XeCryptHmacSha(key, header, 0x10, 0x10);
Array.Resize(ref hash, 0x10);
digest = new byte[0x10];
Buffer.BlockCopy(hash, 0, digest, 0, 0x10);
// Decrypt the data
var rc4 = XeCrypt.XeCryptRc4Key(hash);
XeCrypt.XeCryptRc4Ecb(rc4, ref data, 0, data.Length);
output.Write(data, 0, data.Length);
}
public void Decrypt(Stream output, byte[] key, out byte[] digest)
{
Stream.Seek(Origin, SeekOrigin.Begin);
byte[] header = new byte[0x20];
Stream.Read(header, 0, 0x20);
output.Write(header, 0, 0x20);
var data = new byte[length - 0x20];
Stream.Read(data, 0, data.Length);
var hash = XeCrypt.XeCryptHmacSha(key, header, 0x10, 0x10);
Array.Resize(ref hash, 0x10);
digest = new byte[0x10];
Buffer.BlockCopy(hash, 0, digest, 0, 0x10);
// Decrypt the data
var rc4 = XeCrypt.XeCryptRc4Key(hash);
XeCrypt.XeCryptRc4Ecb(rc4, ref data, 0, data.Length);
output.Write(data, 0, data.Length);
}
public byte[] GetDigestKey(byte[] key)
{
Stream.Seek(Origin + 0x10, SeekOrigin.Begin);
var hash = XeCrypt.XeCryptHmacSha(key, hmacSalt, 0, 0x10);
Array.Resize(ref hash, 0x10);
return(hash);
}