Radio has a lot more to it than just keys. For example, frequency hopping is a big thing, and which frequencies it jumps between, when, and why (i.e. as some sort of anti jamming strategy) are all important details which could be established by inspecting the equipment.

That said, the mention of the Motorola programming software does make this sound more like a base security/policing problem than actual operational infrastructure.

Surely frequency hopping patterns is tied to the key and not hard coded? That would be pretty stupid.. but what do I know.

Wouldnt you just have another key as a seed for the hopping?

I don’t understand how this is security. Wouldn’t an adversary just listen on all channels and pick up the rest of the communication on the newly detected frequency?

Frequency hopping is actually not considered a secure communication method in military circles, nor is it designed to be. Frequency hopping is designed to provide robust communication during electronic warfare scenarios (jamming).

Military infrastructure isn't always as well-engineered as it should be all the time. It can be very costly and time consuming to deploy new encryption keys, especially for technologies like radios. It's not as simple as deploying a configuration file or running `ssh-keygen` and publishing a few artifacts. Many devices need to be rekeyed by hand, which can be labor intensive depending on the size of the inventory. Additionally, sometimes new hardware needs to be hand-delivered to the appropriate organizations for keys to function.

You're assuming OTA updates are available for legacy hardware.