@Djeep @CattleBaron I didn't watched just skimmed chapters, but Meshtastic is the one of the things I recommend for local encrypted comms, but more importantly GPS location sharing (over local encrypted comms).
The other night when I made this post I was actually reviewing the cryptography (AES-CTR implementation) used by Meshtastic: https://noagendasocial.com/@eriner/111701641023919883