Potential radio comms security(calling all computer geeks)

OK, I’ve some questions for the more technically savvy among us. How hard would it be to integrate something like THIS(don’t get too excited, it’s pretty much vaporware) into an HT’s speaker mic or a PTT wiring? What might building something similar using a Raspberry PI Zero entail? A small USB power bank should provide ample juice for a day+ and I’m assuming a sound card would also be needed if going that route.

People have built repeater controllers using Pi’s, so it definitely not an issue setting one up to key a radio. I know for sure there are a few programs that can convert analog audio to an encrypted digital sound also available for Pi’s. Two more questions are how to go about syncing the encrypted radios and what type of encryption to use. Program via USB before handing them out? Some kind of number pad to enter a key? One key programmed each day? Rolling encryption based on time or number of transmissions?

Preferably I’m thinking something no bigger than a 20rnd AR magazine in a somewhat hardened case with a built in power supply. When I’m wearing a carrier in some classes, a radio is in one of the elastic mag slots of my cummerbund just behind my left arm. Since I never carry mags in the cummerbund anyway, there is plenty of room for a device such as I’m envisioning as well.

There is already a product along those lines for .gov with the addition of a GPS tracker. I don’t see a need for the GPS capabilities but, in a true ‘Poop hits the impeller’ situation, the possibility to secure radio comms from nearly anyone would be highly beneficial*{1}*.
{1} I know encryption is not legal an amateur/GMRS/FRS bands and this is not proposed for ‘good times’ use. I’m also aware there are radios that are already capable of some form of encryption. Those are all digital radios that require a license or 1W 900Mhz unlicensed radios with no range. I’m thinking more along the lines of a plug and play solution that will fit any radio with a Kenwood K1 speaker/mic jack(Baofeng/Wouxun/TYT/etc). This way people can use their legal analog radio as is to become proficient with it and simply add an encryptor in times of need.