> what about allowing authentication, rather than encryption? like, let people send MAC-protected checksums and signatures to make plaintext verifiable. That's

> what about allowing authentication, rather than encryption? like, let people send MAC-protected checksums and signatures to make plaintext verifiable. That's already allowed, and commonly done. 97.113(a)(4) doesn't say "no cryptography", it says (in part): >> No amateur station shall transmit [...] messages encoded for the purpose of obscuring their meaning. The scheme you're describing doesn't obscure the meaning of your transmissions, so it is perfectly legal. https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-97 https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D...