help decrypting simple encryption for unity assetbundles

[Jenny_1367]

my friend found this game made with unity and every code in the .bundles is same to normal assetbundles format
except the header, no cab in the file
instead there is a bundle_index.txt file and I wonder if it is possible to use it to decrypt the .bundle?
versions and stuff seems to be in the .bundle files (2018.4.21?) but I am just not sure what to do

any help will be much appreciated!!
(it seems a lot easier than the other game decryption
thanks a lot in advance!
here's the sample files: https://mega.nz/folder/gPwygAJB#lSq_aZyieulbFzSUnN46hA

[aluigi]

I don't know how is the header encrypted/obfuscated, but at least you can decompress the lz4 content:

Code: Select all

comtype lz4
math OFFSET = 0x74
get SIZE asize
math SIZE - OFFSET
xmath XSIZE "SIZE * 4"
get NAME filename
string NAME + ".unpack"
clog NAME OFFSET SIZE XSIZE

Maybe someone else can help you in building a proper UnityFS header for opening the content with the usual tools.

Please remember to EVER specify the name of the game.

[Jenny_1367]

I don't know how is the header encrypted/obfuscated, but at least you can decompress the lz4 content:

Code: Select all

comtype lz4
math OFFSET = 0x74
get SIZE asize
math SIZE - OFFSET
xmath XSIZE "SIZE * 4"
get NAME filename
string NAME + ".unpack"
clog NAME OFFSET SIZE XSIZE

Maybe someone else can help you in building a proper UnityFS header for opening the content with the usual tools.

Please remember to EVER specify the name of the game.

Tyvm! however what file do I use it on? I can't seem to get any outputs with .bundle..(the game is 梦间集天鹅座, sorry I didn't note it at the start)