Uncrypt RPA?

[Amaku]

Hi! Ive got a problem, there are errors in my game and i have encrypted everything, how can i uncrypt the RPA package, please? Thanks

[F.I.A]

Last I know, you cannot decompress the rpa once you archived it.

Your only option is to track back to the "Archived" folder created after archiving, edit its files then place back into the game directory and rebuild the archive.

EDIT: @ Gau_Veldt: The "cannot" is as in "not able to access it easily." Anyone with sufficient knowledge in archiving should be able to open it.

[PyTom]

If you have the archived directory, everything is there. Building the archive again includes stuff from the archive as well as the game directory.

If you don't have anything else, send me the rpa and I can extract it for you.

[Gau_Veldt]

Hi! Ive got a problem, there are errors in my game and i have encrypted everything, how can i uncrypt the RPA package, please? Thanks

If you still have your game directory nothing is lost. Hopefully this is the case since undoing an RPA without the original files requires using parts of internal Ren'Py engine code to make a reverse-engineer of Ren'Py's loader. It can be done if you understand Python code and can look into Ren'Py's loader code. Any programmer would be able to read the loader code and have the obfuscation pretty much fall apart in doing so. The main key is Ren'Py itself has to be able to read the archive back in so that alone is the major cryptographic weakness. It's security by culture since anyone who publicly told you how to do so would get a big boo-hiss from the community here.

Morals of the story:
1. Don't ever delete your game directory.
2. If you put your social security number anywhere in a .rpa you may have your identity stolen.

[Gau_Veldt]

Last I know, you cannot decompress the rpa once you archived it.

Your only option is to track back to the "Archived" folder created after archiving, edit its files then place back into the game directory and rebuild the archive.

Depends on how you define 'cannot'. Ren'Py has to decompress the files in the archive to rerun the story after all.

[PyTom]

Yeah. Since Ren'Py can open the file, so can anyone who's willing to spend the time to understand how Ren'Py works internally. It's made easier because Ren'Py is open source... but if you look at how many games people are able to reverse-engineer in order to translate, it's not hard even in the closed-source case.

That's why I'm careful to call it "archiving" or "obfuscation", rather than something like "encryption" or "protection". It'll keep casual people out, that's all.

[Gau_Veldt]

Yeah. Since Ren'Py can open the file, so can anyone who's willing to spend the time to understand how Ren'Py works internally. It's made easier because Ren'Py is open source... but if you look at how many games people are able to reverse-engineer in order to translate, it's not hard even in the closed-source case.

That's why I'm careful to call it "archiving" or "obfuscation", rather than something like "encryption" or "protection". It'll keep casual people out, that's all.

I wrote a uncooker myself just to serve as a Mythbusters-style reminder about the myth of "security by obscurity". Took about 15 minutes of mythbusting to get a working unrpa.rpy. Myth of security by obscurity: Totally BUSTED.

[Amaku]

Thanks! I didnt realize the "Archive" folder was there ^^U Sorry for the trouble

[WinKi]

Hello. Some people here probably heard about our little Windows GUI toolkit called AnimED. It's written in a pure Object Pascal (no dynamically linked dlls or whatsoever). Current 0.6.8.406 build includes RPA 3.0 extraction support. It was hard to reimplement pickle behavior, but we did it. No repacking yet though.

P.S. The current build is known to correctly unpack the following titles:

* Higurashi Fun 1.0
* Katawa Shoujo: Act 1
* SFK Vol.1
* SFK Vol.3
* TFQ 1.7

Please see compatibility list for details.

P.P.S. Speaking about the legality - it's completely legal to create additional tools for Open Source engine. If you want your data to be protected and secure, do not use Open Source engines AND Open Source algorithms. Furthermore, if you DON'T want your code to be spreaded into public, forget about the Internets, seriously.

[mugenjohncel]

Unpack... RPA... packs?...

Now this I got to get my hands on this... so I can finally crack open "Final Week's" RPA files and steal err... I mean figure out how he did that quick save quick load thing...

So umm WinKi my friend... is this well... you know... already available?...

I swear on samu-kun's someone else's grave I won't use it for evil purposes... really (Puppy eyes)

"POOF" (Disappears)

[Samu-kun]

...just the sort of slimy business you'd have your hand in, Mugen...

Well... At least the law protects our assets... even if programming doesn't.

[killdream]

@WinKi:
Let me see... you're writing a graphical tool entirely in Object Pascal, which is a compiled language and takes more time to get something done than Python, to unpack Ren'Py's RPA files...

I wrote a script back in the time of Ren'Py 6.6.x that did the same thing, importing the internals of the engine, and it took 10 lines of code. Well, there's the blank lines and the code to force the directory structure when unpacking, imports and such, that I didn't count. But even so, the entire script is 30 lines of code.

@Mugen
Well... if you're talking about source code, the RPA files don't store them. But quick-saves and quick-loads are simple enough to do.

Code: Select all

label quick_save:    
    python hide:
        renpy.take_screenshot()
        # will save the current state on the "quicksave" file. This will overwrite any previous quicksaved game, of course                
        renpy.save("quicksave", extra_info=store.save_name)

label quick_load:
    python hide:
        # if we have some quicksaved game, we'll load it, otherwise this will do nothing
        if renpy.can_load("quicksave"):
                renpy.load("quicksave")

    return

[Vendor_Honyaku]

Great job, WinKi!
I wrote RPA-unpacker for translation projects, but it require Ren'Py. Your standalone tool is really great.

if you're talking about source code, the RPA files don't store them

Hmm, if we can unpack RPA-archive, we can find rpyc (and maybe rpy).
Next, rpyc is basically compressed with zlib. After extraction we can see code, fairly close to source (yes, some expression will be lost, but it's can be enough for analysis).

[F.I.A]

* SFK Vol.1
* SFK Vol.3

As far as I know, the two mentioned titles are commercials only. And last I heard, they are not open-source.

P.P.S. Speaking about the legality - it's completely legal to create additional tools for Open Source engine. If you want your data to be protected and secure, do not use Open Source engines AND Open Source algorithms. Furthermore, if you DON'T want your code to be spreaded into public, forget about the Internets, seriously.

I guess that's explains why there are plagiarisms on even open-source engines like M.U.G.E.N. Because there are those with enough time to mess with others' timeless efforts. If there isn't any rpy file lying in the game, give the maker a piece of mind, seriously.

Hmm, if we can unpack RPA-archive, we can find rpyc (and maybe rpy).

From what I know, rpyc files tend to be separated from rpa to allow re-patching. If there are rpy files in the rpa, it wouldn't allow any possible update to game itself.

[JinzouTamashii]

If there isn't any rpy file lying in the game, give the maker a piece of mind, seriously.

I don't understand what this means.

From what I know, rpyc files tend to be separated from rpa to allow re-patching. If there are rpy files in the rpa, it wouldn't allow any possible update to game itself.

You can make a patch for a released game? That's news to me.