One thing that I picked up on the spec sheet there which you shouldn't really have in a ham radio is a scrambler. I don't know if they really mean something like DTS/CTCSS which isn't actually encryption, but the word encryption shows up in the user manual, though this might just be a troubled translation.
I'm curious if anyone who has one of these has any further clarity on what exactly that feature is.
It's "voice inversion" [1] which conceptually is just flipping the baseband signal's spectrum around a mutually-agreed upon frequency, which serves as the key. The resulting audio is difficult to understand. The UV-K5 is only capable of selecting a single key frequency; more clever schemes will have some sort of rolling code/hopping.
This is separate from CTCSS/DCS which this radio also supports, and is not a method for obscuring meaning.
You are correct that it is illegal to use on ham frequencies (which can't obscure meaning), but I wanna say it's legal to use on FRS. Of course, this radio is not type-certified for FRS, so technically that would also be illegal (although many people don't care so much about type-certification for FRS). You are correct, it has no completely legal use on this particular radio.
People should be able to have encryption if they want it. The rules are absolutely unenforceable either way and there isn't actually any drawback. I'm a ham but most hams like to freak out about it because they think it'll cause companies to suddenly start using ham bands with impunity. The reality is, we need to enforce the existing rules about IDing in the clear periodically and then send whatever you want after that. You already can't decode most of the common digital modes without significant effort because they rely on proprietary vocoders so it's not like encryption would change anything.
To be fair there are a large number of people that think the AMBE vocoders should be removed from the ham bands too. Personally I don't think they run afoul of the rules since the intent is not to obscure meaning.
I think encryption is a terrible idea for amateur radio not because of companies doing things (they have ample land mobile allocations), but because it would be filled with cryptoshit scams in no time at all. I know of at least one RF-based cryptocurrency already. I'd also be worried about high speed traders on the HF bands since they're already trying to get licenses in the shortwave broadcast bands as it is. Not to mention I've yet to hear of a legit use case for encryption in the amateur bands that isn't served just as well by other licensed (and licensed-by-rule) services.
My belief is that the core purpose of ham radio is experimentation, so playing with modern protocols, modulation schemes and techniques is really important for it to remain relevant in the future. It can't forever exist as an HF/VHF AM/FM service forever. The future is AES/RSA, DSSS/CSS, internet access, and mobile mesh systems.
All that said, if we went to allowing it with a cleartext ID, how do you think the crypto scams would defeat that in a scalable way?
People can use encryption all they want. They just have to do it in some part of the spectrum that wasn't explicitly set aside for more "open" kinds of communication. Use the ISM bands, or get a license for commercial spectrum. It's really not a big restriction.
It could be a mistranslation and just refer to DTS/CTCSS. The cpu isn't powerful enough to implement real AES encryption and the datasheet doesn't mention a hardware crypto module. It could be an inversion scrambler, that's not difficult to implement in software and even if it doesn't have that stock someone could implement it. But scramblers have limited utility now. They are really only useful to annoy others, they are trivial to defeat. Undocumented encryption capabilities are also not unheard of with Chinese made ham radios either. Seems the FCC really only cares when people make a menace of themselves and draw their attention.
I'm curious if anyone who has one of these has any further clarity on what exactly that feature is.