GameMaker 8.1 Decompiler Released

on June 14, 2011 - 29233 Views

GameMaker decompilerThe file format of executable games created using GameMaker 8.1 has been cracked and a GameMaker 8.1 decompiler has been released.

Until now games created using GameMaker 8.1, which promised “new, more secure .EXE encryption”, were “safe” from having their source code revealed.

This latest release is actually an updated version of the original Game Maker 8 decompiler. I would imagine that the decompiler could quickly be rendered useless thanks to the system used by YoYo Games to push out regular updates to GameMaker 8.1 users.  Or a more speedy game of cat and mouse could ensue.

Writing on Twitter prior to 8.1’s release GameMaker developer Mike Dailly described the new encryption as “nothing amazing” but added that it “should block things for a little while” and that he “could even change it with each release”.

The most recently released GameMaker decompiler was able to turn iOS apps released by YoYo Games into a computer editable Game Maker file.  That was developed as a stepping stone in a project working towards developing a, subsequently abandoned, Game Maker iOS compiler which could attach YoYo Games’ iOS runner on to any editable Game Maker file.

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31 Responses to GameMaker 8.1 Decompiler Released

  1. A disgruntled pig. says:

    Are you aware that sometimes the decompiled games have errors, or some features missing? I had to reconstruct quite a bit of one of my more complicated projects. Is there any way to fix that issue in a future release?

  2. Cosmic says:

    Blue :Obsfucating is not really the solution. There are (mainly) two kind of people who decompile games(or better people have 2 kind of intentions with decompiling):
    1 — They decompile your game because they are interested in how you made your game, and want to learn.
    2 — They decompile your game, edit it, and release it, as if it was their own.
    I don’t see the second one a lot, but they exist.

    For this reason, I always like to hide additional credits in my projects where most people would never find them. Usually the types of people who do this aren’t intelligent enough to make their own complex games, which also usually means that even if they knew I had hidden credits somewhere else in the file, they wouldn’t be able to find them.

    This is by no means a method of prevention, though it is nice to be able to prove to people after this occurs that someone’s work is not their own, without the need to bother scrambling to provide old topics and dates as evidence.

  3. master higgins says:

    God d**n it! I lost the usb stick where I was storing the source code of my game and now that I learn there’s a decompiler for GM8.1 there are no links anywhere!!! How am I supposed to make sure this decompiler works if there isn’t any link?????. Google sucks at getting any download links for this tool (ò_Ó). See to believe…

  4. KarjamP says:

    Maybe GMAPI can be ported to GM8.1 now? 😉

  5. Adolf says:

    Wheres the downloadlink?

  6. Random Worried Guest says:

    There’s no active link. May I have one real quick?

  7. Ray says:

    Awesome. Thank you, and thanks to x2048 you dudes r cool.

  8. Ray says:

    I’ve used decompilers in the past to study games, and also once to save my bacon on an older game of mine that I lost the source code to.

    Why are some so afraid of these? You can still protect your graphic and sound assets in other ways and that’s what most of the a$$hole copy-cats steal anyway.

    So where’s the release at? The Google maze didn’t yield a link yet…

  9. Rohan says:

    GM never alters your code. It should. Maybe if I get time and nobody releases an obfuscator, I could make one. Most likely I wont, since that would involve using Zach’s poorly programmed GMK library (torll).

    • Schwiggy says:

      Decompilers can be great learning tools. We all should know how beneficial working source code is to a starting programmer. If anyone wanted to ‘steal’ code through it the chances of it fitting perfectly with their architecture are slim – and other resources are so obvious when stolen that I don’t think they would get far.

      I would still be really thankful for whoever makes an obfuscator though 😛

    • Joseph McDanger says:

      OROHAN ^^ You’re so silly. But Zach did have quite a few issues with that library, didn’t he? O-o.

  10. Someone says:

    I do understand that Yoyogames is working on an anti-decompiler patch for game maker. I really am not sure who is going to win this race.

  11. MMs says:

    What a bad luck! Just when a bought a copy of game maker a few weeks ago 🙁

    • Joseph McDanger says:

      We (the x2048 guys) have actually urged Charlie to update his Anti Decompiler (because we feel that if somebody truly wants to protect their game, they can, but we also wanted to provide a tool to recover game sources in the case of an accident, etc.), but he has no interest in it. There are a few individuals who are working on writing their own anti decompiler solutions, so maybe you didn’t waste your cash.

  12. Rex says:

    Philip Gamble :That’s a very good idea. I hadn’t even considered that but makes sense given the history of new file formats being “cracked”.

    There’s actually been an obfuscator for GM for a while, but as far as I know it doesn’t yet work with GM 8: http://gmc.yoyogames.com/index.php?showtopic=373402 I was just wondering if YoYo had added anything like that to GM 8.1.

    • xot says:

      From what I understand, a GM8 version should be coming soon. It’s certainly being worked on. I don’t have any information on when exactly it will be released.

  13. ugriffin says:

    Typical.

    I don’t really understand what’s the point of the decompiler anymore. Originally it was to raise awareness of GM’s huge security flaw.

    Now, I fear that it’s just a bunch of trolls.

    • Zach says:

      Not trolling, just having fun. And honestly I try to keep the tool up to date somewhat because I’ve seen it used for legitimate reasons. I’ve asked Charlie to update his anti-decompiler tool but he cbf’d to.

      Plus, this is still pointing out security flaws in GM, although YYG’s has done a pretty good job with GM since 8.1.

  14. Rex says:

    Unfortunately, even if YoYo does keep tweaking the EXE format to keep one step ahead of decompilers, it won’t be of any use to a game that’s already been released and has lots of copies out there on the internet. They can’t all be called back in for recompiling.

    Does anyone know if GM 8.1 at least obfuscates the source code, such as removing comments, changing variable names, etc? That would be a pretty easy thing to do and it would at least prevent people from getting usable source code.

    • That’s a very good idea. I hadn’t even considered that but makes sense given the history of new file formats being “cracked”.

    • Blue says:

      Obsfucating is not really the solution. There are (mainly) two kind of people who decompile games(or better people have 2 kind of intentions with decompiling):

      1 – They decompile your game because they are interested in how you made your game, and want to learn.
      2 – They decompile your game, edit it, and release it, as if it was their own.

      I don’t see the second one a lot, but they exist:
      http://gmc.yoyogames.com/index.php?showtopic=478789
      http://gmc.yoyogames.com/index.php?showtopic=506888

      Personally, I don’t care if someone decompiles my game and learns from the source.
      However, the second category .. Well, that’s obvious.

      Obsfucating only works against the first group. They simply can’t read your code, and can’t learn from it.

      But the second group .. They just browse throught your code until they find the credits, and change them.

      Obsfucating misses the goal.

    • Rex says:

      I guess if someone is just planning on copying your game outright without making any changes (other than the credits), then obfuscating doesn’t make much a difference. But at least in that case, the copy of your work is easier to spot because its identical.

      I do think looking at code is a valuable way to learn, but I also think it should be up to the author whether to release their source code or not.

  15. Gamemakeraddict says:

    How did you recieve this information?

  16. Joseph McDanger says:

    A lot of people who upgraded are going to feel screwed.

  17. Rohan says:

    Well, it did block things for a little while.

  18. Sam Whited says:

    Looks good; I can confirm that GM does not obfuscate code or remove comments.
    Thanks for the release, this is a useful tool to have.

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