"What we need is ... blah blah blah ... technology" is rarely what you want when you start on this path. In my company (I'm the MD), salary info is pretty open

"What we need is ... blah blah blah ... technology" is rarely what you want when you start on this path. In my company (I'm the MD), salary info is pretty open and I believe income is proudly and publicly published in Sweden for all individuals but I do understand your reticence. Do you actually need encryption or even a computer to get the message across? What about whispering? If you want to ensure confidentiality then you need to agree on your standards with your partners. You have no choice in this matter. Rapidly you are in a technical debate on standards. Apart from the channel, are you sure you are safely getting the data in and out? Think about things like side channel attacks eg someone listening to your keyboard. Get the tin foil out! I'll give you this for free, right now: TLS is a very decent way of creating a tunnel between you and your partner. So is IPSEC and probably WireGuard, also a SSL tunnel. There is no such thing as a simple way to do confidential comms, just like there is no simple way to build a suspension bridge. I studied Civil Engineering at Plymouth Polytechnic in Devon and the building industry collapsed in the UK as I graduated in 1991. Building a bridge is quite complicated but for the end user it is a piece of piss to drive their car across it. You say that self-signed is broken but all browsers and modern OS's allow you to import CA certs. You can generate a CA cert with a one liner with openssl and if you are careful you can be pretty sure things are secure. I trust my own CAs far more than anyone else's. You cannot have simple solutions for confidential comms. If there was such a thing then James Bond would use it too, and he doesn't.