Actually a Raspi Pico

with and a Cassette player that can record would do, especially if that one has a audio jack port to record from a microphone. 

You'd hear a long beep sound only on the tape. 

Than, if you need due to industry failure, one recorder and a player the same Pico would be the In encrypter and Out decrypter either in-between source and mic-jack or player and headset. 

Being broke sucks. Drugged and powerless is worse... 

#gfyBKA