Comment by Animats
It's not encryption that's needed. It's authentication. How do you decide who's allowed to join your mesh if it runs on WiFi discovery?
It's not encryption that's needed. It's authentication. How do you decide who's allowed to join your mesh if it runs on WiFi discovery?
This is a general problem with all federated systems.
It's annoying that we don't have a decent solution to this even for home automation. You ought to be able to take a "house ID key", probably a Yubikey, and present it to all your devices to tell them "you're mine now". Then they can talk to each other.
There are military cryptosystems which have such hardware. There's a handheld device called the Simple Key Loader.[1] That's what's used to load secure voice keys into radios, encrypted GPS keys into GPS units, identify-friend-foe codes into aircraft, and such. It's 15 years old, runs Windows CE, has a screen with a pen, and is far too big. The Tactical Key Loader is smaller and simpler.[2] 7 buttons and a small screen. About the same size as a Flipper Zero, but ruggedized and expensive.
[1] https://info.publicintelligence.net/SKLInstructionGuide.pdf
[2] https://www.l3harris.com/all-capabilities/kik-11-tactical-ke...
Like others suggested a basic step would be to use a certificate based approach where a company (or basically any deployment) gives out certificates for robots allowed to join and you only communicate with them.