public static void DecryptPass(uint seed, Span <byte> input, Span <byte> output, int size)
{
uint one = CRC32.CRC32UInt(seed);
uint two = CRC32.CRC32UInt(one);
uint three = CRC32.CRC32UInt(two);
uint four = CRC32.CRC32UInt(three);
if (size == 0)
{
return;
}
// CryptDataChunk
one &= 0x1ffff;
two &= 0x7ffff;
three &= 0x7fffff;
four &= 0x1fffffff;
for (int i = 0; i < size; i++)
{
output[i] = (byte)((byte)three ^ (byte)four ^ (byte)one ^ (byte)two ^ input[i]);
one = (one & 0xff) << 0x9 | one >> 0x08;
two = (two & 0xff) << 0xb | two >> 0x08;
three = (three & 0xff) << 0xf | three >> 0x08;
four = (four & 0xff) << 0x15 | four >> 0x08;
}
}
public static uint CRCXor(Span <uint> input, uint input2)
{
uint crc = CRC32.CRC32UInt(input2);
uint old = input[0];
input[0] ^= crc;
return(old);
}
/// <summary>
/// Key computing GT5P JP Demo
/// </summary>
/// <param name="seed"></param>
/// <returns></returns>
private uint[] PrepareKeyOld(uint seed)
{
var keysetSeedCrc = ~CRC32.CRC32_0x04C11DB7(_keys.Magic, 0);
uint one = CRC32.CRC32UInt(seed ^ keysetSeedCrc);
uint two = CRC32.CRC32UInt(one);
uint three = CRC32.CRC32UInt(two);
uint four = CRC32.CRC32UInt(three);
uint[] keys = new uint[4];
keys[0] = one & 0x1FFFF;
keys[1] = two & 0x7ffff;
keys[2] = three & 0x7fffff;
keys[3] = four & 0x1fffffff;
return(keys);
}
