You're thinking a few OSI layers too high. Any such radio communications from similar systems have one-way broadcast as the physical layer.
If you don't include a radio receiver, then there is no capability to receive a single bit, much less negotiate encryption; the system throws out a waveform and the rest of the world may figure out what to do with it if they manage to receive it.
If you don't include a radio receiver, then there is no capability to receive a single bit, much less negotiate encryption; the system throws out a waveform and the rest of the world may figure out what to do with it if they manage to receive it.