Experimental Covert Communication Using Software-Defined Radio

TL;DR

This paper demonstrates the practical implementation of provably-secure covert radio-frequency communication using software-defined radios, validating theoretical limits and opening new avenues for secure communication systems.

Contribution

First experimental validation of RF covert communication using SDRs that confirms theoretical square root law predictions.

Findings

Validated theoretical limits of covert RF communication

Demonstrated practical implementation using SDRs

Raised new research questions for secure communication

Abstract

The fundamental information-theoretic limits of covert, or low probability of detection (LPD), communication have been extensively studied for over a decade, resulting in the square root law (SRL): only $L\sqrt{n}$ covert bits can be reliably transmitted over time-bandwidth product $n$, for constant $L>0$. Transmitting more either results in detection or decoding errors. The SRL imposes significant constraints on hardware realization of provably-secure covert communication. Thus, experimental validation of covert communication is underexplored: to date, only two experimental studies of SRL-based covert communication are available, both focusing on optical channels. Here, we report our initial results demonstrating the provably-secure covert radio-frequency (RF) communication using software-defined radios (SDRs). These validate theoretical predictions, open practical avenues for implementing covert communication systems, as well as raise future research questions.