Compiling with PCK encryption key

The export dialog gives you the option to encrypt your PCK file with an 256bit AES key, when releasing your game. This will make sure your scenes, scripts and other resources are not stored in plain text and can not easily be ripped by some script kiddie. Of course the key needs to be stored in the binary, but if it's compiled, optimized and without symbols, it would take some effort to find it.

For this to work, you need to build the export templates from source, with that same key.

Step by step

  1. Generate a 256bit AES key in HEX. You can use the aes-256-cbc variant from this service.

    Alternatively, you can generate it yourself by using OpenSSL:

    openssl rand -hex 32 > godot.gdkey
    

    The output in godot.gdkey should be similar to:

    aeb1bc56aaf580cc31784e9c41551e9ed976ecba10d315db591e749f3f64890f
    

    You can generate the key without redirecting the output to a file, but that way you can minimize the risk of exposing the key.

  2. Set this key as environment variable in the console that you will use to compile Godot, like this:

    export SCRIPT_AES256_ENCRYPTION_KEY="your_generated_key"
    
  3. Compile Godot export templates and set them as custom export templates in the export preset options.

  4. Set the encryption key in the Encryption tab of the export preset:

    ../../_images/encryption_key.png
  5. Add filters for the files/folders to encrypt. By default, include filters are empty and nothing will be encrypted.

  6. Export the project. The game should run with the files encrypted now.

Possible Errors

If you get an error like below, it means the key wasn't properly included in your Godot build. Godot is encrypting PCK file during export, but can't read it at runtime.

ERROR: open_and_parse: Condition "String::md5(md5.digest) != String::md5(md5d)" is true. Returning: ERR_FILE_CORRUPT
   At: core/io/file_access_encrypted.cpp:103