On the other hand it annoys some of the most insufferable humans on the planet. As a ham who’s not a boomer who would gladly die with the airwaves silent but compliant with rules and regulations established assuming usage of the spectrum would grown instead of dwindle I encourage it. Fuck ‘em.

>the US rules are that you can use digital protocols but you must publish the specs so anyone can, in principle, decode the signal.

This restriction does not appear to actually be enforced, eg, if I recall correctly the VARA HF/FM modes do not have published specs anywhere near sufficient to decode them, to the point where there are projects trying to reverse engineer them.

Depends on your jurisdiction. In Canada it's allowed if you publish your keys.

https://www.rac.ca/encryption/