As of 2025, (the fork that replaced Citra) has a modernized key handling system. Instead of aes-keys.txt , Azahar uses a keys.txt file placed in [User Folder]/load/ . You can generate this via the Azahar Key Generator tool, which asks you to input data from your own 3DS.
The Citra community and similar emulator projects often provide guidelines on how to obtain and use these keys legally. They emphasize using keys obtained from your own console to ensure you're not infringing on copyright laws.
On a physical Nintendo 3DS, games are encrypted using . To run these games, the hardware uses specific "keys" stored in its firmware to unlock the data. Because these keys are copyrighted by Nintendo, they cannot be bundled with Citra.
Place the file in the Citra user folder (usually located at %AppData%\Citra\sysdata\ on Windows).