Protecting Files

[Kaen]

So far I'm using the archive resource to protect my files:

Code: Select all

build.classify("game/**", "archive")

Though I'd like to know if there is a way to protect the game files better so it's more difficult to gain access to them (specially the image files).

[xela]

None that would be useful to you.

[Kaen]

What do you mean xela? Feel free to share if you want.

[Asceai]

You're fighting a losing battle. Once the files are on someone's machine, they can and will be able to gain access to them. You can't make it possible for the game to open them but not possible for anyone else.

Anyway, for protecting image files specifically, I guess I'd suggest this process (note that none of this code is available and I'm not writing it, but so you're aware of what's involved...):
- Create a missing image handler to replace image access in your application. This is the way JCC works
- Determine a way to construct a series of steps to obscure the image that can be reconstructed using image manipulators. This will slow down image loading in your game
- I'd suggest the process for obscuring images would be to first seed a random.Random instance using the image path as seed.
- Then you could try splitting images in a deterministic way that works in all cases, possibly decided by the random number generator. You might just decide to split all images above a certain size into a grid of images, with one randomly-selected image being unusually tall / short / wide / thin. Then shuffle the images, again using the random number generator, apply undoable image manipulator transforms like flip, matrix operations etc., creating randomly-generated filenames for these images and then dumping them in the directory.
- Note that you can't save images from Ren'Py, so I'd suggest writing a separate tool in pillow to do the obfuscation and using the image manipulators in your Ren'Py game to reverse the task.
- Then you just need to do the same stuff, but in the opposite order in your game when loading images using the missing image handler.
- Once your game is filled with these garbage-named files that are scrambled, miscoloured and flipped chunks of images not really useful to anyone, you can exclude the original images from distribution

That will only make things very slightly harder for anyone to attack. Like I said, losing battle.

[LVUER]

No reason not to make it harder though... Archive your files but never think your files will be safe forever. It's always good to archive your files but when people want it, they will break it. Even AAA game protection could be broken by hackers.

[Asceai]

The other thing I thought about, which is only a very weak 'security through obscurity' modification is to make a slight alteration to the Ren'Py code, putting a little bit of data at the start of the .rpa archives and ignoring it when reading. Then package and distribute using your modified Ren'Py. This will protect you from existing tools until someone notices your little trick.

[xela]

What do you mean xela? Feel free to share if you want.

Asceai explained in detail exactly what I've meant

[Asceai]

You can also obscure your scripts a little bit (actually, just the text in them) by creating a custom font which is whatever your regular font is, but with the codepoints shuffled. You could make the font contain a ton of duplicates of characters (unicode has codepoints to spare) and when you write a tool to obscure your scripts, just randomly pick from the duplicates. This kind of protection would be annoying to get around (because the information about the sequence is encoded in the font, rather than in an easily-reversed script packaged with the game) but it's only useful for protecting the text in your scripts, which is rarely the most important thing to people.

[Kaen]

Thank you everyone for your suggestions.

While taking a look at Uncle Mugen's DSE I noticed that most of the files are encrypted (?) as a Thumbs.db file.

Does anyone know what exactly is this and how to do this?

[Asceai]

Thank you everyone for your suggestions.

While taking a look at Uncle Mugen's DSE I noticed that most of the files are encrypted (?) as a Thumbs.db file.

Does anyone know what exactly is this and how to do this?

Nope, thumbs.db is just a file Windows automatically creates to store thumbnails of image files. renpy never uses it.

[Ran08]

I archive my files too, hahaha, especially the scripts. I tend to have weird ##comments## in there. Lol. But I think it doesn't matter much. After all, like what the others have said, if someone wants to open your files, they'll find ways to do it. Plus, I think there's a benefit to leaving your scripts open.