The ‘no encryption’ rule in ham radio is intended to encourage experimentation and openness. Ham radio has always been about exploring, learning, and sharing knowledge, much like open-source software. If transmissions are encrypted, it becomes nearly impossible for others to decode, learn from, or experiment with them. The idea is that anyone with the right knowledge of the protocol should be able to communicate with anyone else on the airwaves, supporting the spirit of why this spectrum is reserved.
That said, balancing this with modern needs for security and privacy is a real challenge. Good communication protocols today are designed with these protections in mind, and the inability to use encryption arguably limits what amateur radio enthusiasts can do with newer radio technologies.
Privacy, however, has traditionally not been part of ham radio—this is why you’re required to identify yourself with a call sign, and contact info is publicly available. The identity of the sender is expected to be open. Maybe there’s room to allow for some privacy around the content of the message itself, but the sender’s identity should still be clear. I’m not sure what the right balance is, but simply allowing complete encryption that hides the message, the transmitter’s identity, and the transmission protocol itself doesn’t seem to align with the purpose of amateur radio.
The ‘trash bands’ (ISM bands) are probably a much better place for experimenting with full-bore encryption and privacy. From these experiments, we might learn a balanced approach that could be backported to the amateur spectrum, preserving the spirit of why these bands exist while adapting to modern privacy needs.