Most emulation subreddits (r/Citra, r/Roms) will ban you instantly if you ask for or share a pre-made aes_keys.txt . You must dump it yourself from a hacked 3DS.

Since you cannot download the keys legitimately from the developers anymore, the "correct" technical method to obtain an updated aes_keys.txt is:

: Download a specialized GodMode9 script (often named dumpkeys.gm9 ) and place it in the sd:/gm9/scripts folder on your SD card.