Need help decoding Friday The 13th savefiles

Reading, editing and everything related to the files created by games to contain savegames and configurations
nnvt
Posts: 6
Joined: Sat Jul 07, 2018 9:48 pm

Need help decoding Friday The 13th savefiles

Post by nnvt »

Hi there!

I'm trying to decode/decrypt the following savefile: https://drive.google.com/file/d/14MycmmP8Hkf_xRwJ58dvZjU61RVxZxjA/view?usp=sharing

At the top there seems to be some sort of key (look similar to the key for the main pak): 53729557affce487c97c5b98c585800d032b9337bb8c00d09ae7f79169552dae

I can't seem to decrypt the file with this key though. I know some parts are not encrypted so I looped over the file in c# and skipped a byte every time to try and find the starting point of the encrypted part but I didn't find anything.

Can anyone help me figure this out?

Thanks!
aluigi
Site Admin
Posts: 12984
Joined: Wed Jul 30, 2014 9:32 pm

Re: Need help decoding Friday The 13th savefiles

Post by aluigi »

The data at offset 0x59 is compressed, offzip -a can do the extraction automatically.
nnvt
Posts: 6
Joined: Sat Jul 07, 2018 9:48 pm

Re: Need help decoding Friday The 13th savefiles

Post by nnvt »

aluigi wrote:The data at offset 0x59 is compressed, offzip -a can do the extraction automatically.



OK Thanks, I managed to extract the file and reimport the modified bit. The game can't use the new file though, it just generates a new one.

EDIT: the "key" at the top also changes every time the game modifies the file, seems to be some sort of signature.

EDIT 2: it seems to be a SHA256 hash but I can't seem to find where it came from. (Generating a hash of the files never returns the same hash)