Signal masking for secure backscattered communication

A method comprising:

• receiving, via a primary RF signal receiver of an RF device, a RF carrier signal sent from a base station;
• receiving, via a secondary signal receiver of the RF device, a masking audio signal from the base station;
• generating, via a signal mixer of the RF device, a response signal based at least on the RF carrier signal;
• generating, via the signal mixer of the RF device, a mixed signal by mixing the response signal and the masking audio signal;
• and
• broadcasting the mixed signal via a transmitter of the RF device, via backscattering, as a masked backscattered signal.

A battery-free RF device, comprising:

• a primary RF signal receiver configured to receive a RF carrier signal sent from a base station positioned on a shared substrate with the battery-free RF device;
• an energy harvester configured to harvest energy from the RF carrier signal;
• a secondary signal receiver configured to receive a masking audio signal from the base station through the shared substrate;
• a signal mixer configured to generate a response signal based at least on the RF carrier signal and generate a mixed signal by mixing the response signal and the masking audio signal;
• and
• a transmitter configured to broadcast the mixed signal, via backscattering, as a masked backscattered signal using the energy harvested from the RF carrier signal.