internal static Guid GPRCK(Guid keyId, byte[] keySeed)
{
    byte[] b = new byte[0x10];
    byte[] destinationArray = new byte[30];
    Array.Copy(keySeed, destinationArray, destinationArray.Length);
    byte[] inputBuffer = keyId.ToByteArray();
    using (SHA256Managed managed = new SHA256Managed())
    {
        using (SHA256Managed managed2 = new SHA256Managed())
        {
            using (SHA256Managed managed3 = new SHA256Managed())
            {
                managed.TransformBlock(destinationArray, 0, destinationArray.Length, destinationArray, 0);
                managed.TransformFinalBlock(inputBuffer, 0, inputBuffer.Length);
                byte[] hash = managed.Hash;
                managed2.TransformBlock(destinationArray, 0, destinationArray.Length, destinationArray, 0);
                managed2.TransformBlock(inputBuffer, 0, inputBuffer.Length, inputBuffer, 0);
                managed2.TransformFinalBlock(destinationArray, 0, destinationArray.Length);
                byte[] buffer5 = managed2.Hash;
                managed3.TransformBlock(destinationArray, 0, destinationArray.Length, destinationArray, 0);
                managed3.TransformBlock(inputBuffer, 0, inputBuffer.Length, inputBuffer, 0);
                managed3.TransformBlock(destinationArray, 0, destinationArray.Length, destinationArray, 0);
                managed3.TransformFinalBlock(inputBuffer, 0, inputBuffer.Length);
                byte[] buffer6 = managed3.Hash;
                for (int i = 0; i < 0x10; i++)
                {
                    b[i] = Convert.ToByte((int) (((((hash[i] ^ hash[i + 0x10]) ^ buffer5[i]) ^ buffer5[i + 0x10]) ^ buffer6[i]) ^ buffer6[i + 0x10]));
                }
            }
        }
    }
    return new Guid(b);
}