See these previous analysis https://forum.exetools.com/showthread.php?t=17472 https://yingtongli.me/blog/2018/11/16/drm1-1.html https://github.com/ME3Explorer/ME3Explorer/tree/v2.0.10/ME3Explorer/PAREditor Thank you very much. The second link did it with the hint that only every 4th byte is used. ;)

Sadly, noone is willing to help, right?

Noone? :( In your tool, the following two different contents result in the same checksum. So this is obviously no CRC32 as it would also change with every byte that changed... [Base] ContentId = 1001288 ProductTitle = "Command and Conquer Red Alert" InstalledDistro = RequiredToPlayV1,Acces...

Make sure your CRC32 algorithm works with polynomial 0x04C11DB7 I used that. Look at the file I attached. The checksum in the file is 0x31E360B3, but when I calculate the CRC32, I get 0xBDC63D58 (polynomial 0x00000000) or 0xDCB13237 (polynomial 0x04C11DB7). So what's wrong? I don't get it. :( RA95L...

Ekey wrote: ↑Thu Nov 21, 2019 2:42 pm This is CRC32 of encrypted data

It doesn't seem to be CRC32. I already checked that. That's why I'm asking.
I took a par file, removed the first 4 bytes and the CRC32 doesn't match the hash I removed before.

Hmm, sadly none of the creators is reachable anymore.

How are the first 4 bytes calculated actually? Can anyone tell?