I have some file which are in cleartext except for the checksum that is appended to the end.
As I have to modify the content of these files I must learn how the checksum is calculated.
But though it is a simple algorithm (Even if the computer is slowed down to 1/1000 of it's normal speed it is calculated instantly) I didn't manage to find it.
I can generate files that only differ on 2 or 3 bytes (plus the checksum).
Is there any tool to do this kind of work? Or a way to proceed?