Gameloft ZIP Unscrambler

Programs that are related to this or that game.
Post Reply
User avatar
GMMan
veteran
Posts: 139
Joined: Fri Nov 05, 2010 10:14 pm
Been thanked: 53 times

Gameloft ZIP Unscrambler

Post by GMMan » Tue May 20, 2014 10:48 pm

It seems some newer Gameloft games, such as N.O.V.A. 3, use scrambled ZIP files instead of the traditional CustomPak. It took me forever banging my head against the CustomPak reader until I realized that it was probably not a CustomPak. Somehow it also escaped my attention until today that all files of this type starts with "SB". Well, anyway, here's a program to descramble the files. Have fun with it. Source code is included, as always. I haven't written my DRM wrapper yet, so I guess iOS app hacking noobs will be all over this soon.

Download at the blog: blog/?p=1177

Format notes
It's basically a ZIP file, but with different signatures and encrypted file headers. Instead of "PK\x03\x04" for each file header, you've got "SB" followed by a short of the header length. Not sure why they did it that way, but that's how it works. Oddly enough, the compressed data is not encrypted, so just copy that verbatim. Near the end you'll find the central ZIP directory, which starts with "SDIR", and goes on until the end of the file. Note this directory is a single block instead of the many repeating blocks you find in a normal .zip file. Everything after the "SDIR" is encrypted, so to get this block back just write "PK\x01\x02" to your output and dump the decrypted block to it. No need to differentiate between a central directory entry and the end-of-central-directory block. Regarding the encryption, it's just scrolling XOR, with the file name being the key.

Version History
[1.0.0.0 2014-05-20]
  • Initial release
Currently researching: Alpha Prime scripting (AI and mods)
Queued: EE .cache repacking, CustomPak repacking, Gameloft Scrambled Zip multitool, GRAF Extractor Skeleton repacking, Gun Metal filenames CRC

User avatar
cra0
ultra-veteran
ultra-veteran
Posts: 431
Joined: Fri Apr 27, 2012 9:37 am
Has thanked: 29 times
Been thanked: 182 times
Contact:

Re: Gameloft ZIP Unscrambler

Post by cra0 » Wed May 21, 2014 1:40 am

Zing zing zing haha i knew it was xor ill take a look at the binary in IDA seems interesting once again good work man
yeah you're right lol

Image

Post Reply