For many Nintendo 3DS users looking to unlock the full potential of their handheld—ranging from homebrew development to custom firmware (CFW) management—the term aeskeys.txt is frequently encountered. Often cited as a necessary file for decryption and emulation, the is a small but critical piece of the puzzle.
If your game dumps are already fully decrypted, Citra does not actually need the aes_keys.txt file to play them. However, keeping the file in your directory ensures compatibility across all types of game dumps. How the Keys Work Inside the File 3ds aeskeystxt work