What compression/encryption algorithm used in illusion games

[shekofte]

these game series are so great in human anatomy research ...

SB3Utility is an excellent tool for working with the archives used in games developed by Illusion .
since it accompanied with the source code , may you take a look into it and Identify which compressions or encryption methods applied in them ?

may be the first step for writing BMS scripts for each games individually ...

[aluigi]

The source uses "System.IO.Compression" (gzip/deflate/zip) but apparently all the compression and decompression code is handled by JchStream.cs at lines 150 (from 399) and 313.

[shekofte]

this is about the game プレミアムプレイ (Premium Play Darkness)

for everyone that want follow or for comparison of similarity between these games i will show you the directory :

these contain 3d data (.xx 3d models and .xa animations ) , textures , images

Code: Select all

prpr_00_00.pp        878,907,319 
prpr_00_01.pp      1,282,203,820 
prpr_00_02.pp      1,587,975,756 
prpr_01_00.pp         44,776,918 
prpr_01_01.pp      1,417,289,346 
prpr_02_00.pp      1,627,758,708 
prpr_03_00.pp         35,761,133 
prpr_04_00.pp         68,530,095 
prpr_05_00.pp         16,146,318 
prpr_05_01.pp        868,424,681 
prpr_06_00.pp        239,925,442 

Clipboard.jpg

pure .wav files

Code: Select all

prpr_07_01.pp        167,820,645 
prpr_07_02.pp        187,762,613 
prpr_07_03.pp        181,855,083 
prpr_07_04.pp        160,030,733 
prpr_07_05.pp        193,868,143 
prpr_07_06.pp        187,129,083 
prpr_07_07.pp        203,494,145 

pure .ogg files

Code: Select all

prpr_08_01.pp        177,549,890 
prpr_08_02.pp        148,569,749 
prpr_08_03.pp        143,926,305 
prpr_08_04.pp        162,089,625 
prpr_08_05.pp        147,557,909 
prpr_08_06.pp        133,804,536 
prpr_08_07.pp        146,040,734 
prpr_08_08.pp        141,469,501 
prpr_08_09.pp        134,293,106 

first i tried to discover the structure of header that seem simple , but nothing ...
since the significant amount of bytes in header as showed in the following plot , have a repeating pattern that every value after 2048 bytes interval is the same !

2048.gif

i am so eager to see how do you miraculously extract the readable data from them ?

the first 4 mb of an archive that contains only wave files is available here :
https://www.zeta-uploader.com/1359167685

grazie mille

[aluigi]

Exept for the "[PPVER]" string at the beginning, all the rest is probably obfuscated.