Red key means un-encrypted key. The opposite would be black. Usually, the key does not need to be exposed. It would be stored in a very hard to break container

Red key means un-encrypted key. The opposite would be black. Usually, the key does not need to be exposed. It would be stored in a very hard to break container with some sort of self destruct mechanism. Communication with the box never involve the key itself. And to top it all, the key changes often. Additionally, protocols usually use the Diffie-Hellman algorithm (or something like it) to generate very short lived secret session keys. I would go and say (out of my ass) that recent military drones would have 2 or 3 different backup systems for everything, including positionning.