For example, GTA V modders could decrypt RPF files, so how could they do so?

Here are the possible reasons I can think of:

  • They are encrypted using weak encryption methods
  • They have been decrypted by expert hackers (which means they can hack other more critical systems)
  • They were insiders or were helped by insiders
  • Rockstar Games officially helped modders
  • \$\begingroup\$ After a quick search I found this. \$\endgroup\$
    – Mangata
    Jul 29, 2022 at 4:07
  • 1
    \$\begingroup\$ Related question: Is it worth it to encrypt data? \$\endgroup\$
    – Philipp
    Jul 29, 2022 at 10:14
  • 2
    \$\begingroup\$ Do you have evidence that these asset files were encrypted to begin with? It might just be that they're in a non-standard / undocumented format that required some reverse engineering and custom tools to be able to read and modify, or that checksums or hashes are used to detect tampering. Neither of these are "encrypted", just obscure, making them more challenging (but by no means impossible) to edit. \$\endgroup\$
    – DMGregory
    Jul 29, 2022 at 12:05
  • \$\begingroup\$ 5. Through careful inspection, they figured out how the game itself decrypts the assets, and did the same thing. \$\endgroup\$
    – mm201
    Aug 8, 2022 at 19:13
  • \$\begingroup\$ @DMGregory, please send references that game asset files are not encrypted. \$\endgroup\$
    – AZeed
    Aug 8, 2022 at 22:15

1 Answer 1


When you want to use encrypted asset files in a game you developed, then the game executable must be able to decrypt those files. That means that somewhere in your game exectuable you must embed both the algorithm and the decryption key to perform that decryption. When these are part of the exectuable, then a determined cracker can find them. It's not a question of "if", it's a question of "when". With a popular game like GTA V, there are lots and lots of people looking for this information in game files. So it's just a question of time until someone finds it and publishes it on the Internet.

  • \$\begingroup\$ But why are there some games that are still not moddable? \$\endgroup\$
    – AZeed
    Jul 29, 2022 at 8:16
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    \$\begingroup\$ @AZeed Because nobody found the time and energy yet to look into how to mod them. \$\endgroup\$
    – Philipp
    Jul 29, 2022 at 8:18
  • \$\begingroup\$ But why they did for games like GTA V? Does it depend on hardness or popularity? \$\endgroup\$
    – AZeed
    Jul 29, 2022 at 8:21
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    \$\begingroup\$ @AZeed It depends on both of that. Popular games attract more people who would like to mod them, and easier to mod games lower the bar of people who are qualified to do so. Which is why there are games like GTA V or Minecraft which were never designed to be moddable, but still have thriving modder communities. And why there are also relatively unknown indie games which are fully moddable, but nobody makes use of that, because it's not worth it for a game played by very few people. \$\endgroup\$
    – Philipp
    Jul 29, 2022 at 8:26

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