Aeskeystxt Citra
Section 1201 prohibits "circumventing a technological measure that effectively controls access to a copyrighted work." The AES encryption on 3DS cartridges qualifies as such a measure. Therefore, distributing or using keys derived without authorization violates the DMCA.
If you are trying to run an encrypted .cia file, you may need a batch CIA 3DS decryptor if the keys alone do not work. aeskeystxt citra
Here’s a of that functionality: