Every piece of technology emits radio waves. It is only a matter of figuring out the frequency and amplitude modulation of those waves, for us to be to be able to translate in to information.

For instance, I have a powerful condenser microphone, and I often hear faint sounds of the radio when recording. This is because my microphone is translating the audio in to a wave, while a radio station is simultaneously sending out a wave of the same frequency.

While this is scary to some, there is simply too much overlap for someone to accurately translate these frequencies effectively. So if someone is trying to steal your information they are more than likely just getting a lot of static.

Also, while radio waves cannot be encrypted themselves, the information stored on them can be encrypted. Like wifi.