Experimental Validation of Provably Covert Communication Using Software-Defined Radio

TL;DR

This paper demonstrates a practical, provably secure covert RF communication system using software-defined radios, validating theoretical limits and expanding experimental research beyond optical channels.

Contribution

First experimental validation of SRL-based covert communication in RF using SDRs, bridging theory and practical implementation.

Findings

Validated theoretical SRL limits in RF covert communication

Demonstrated secure covert communication with SDRs

Opened new avenues for practical covert systems

Abstract

The fundamental information-theoretic limits of covert, or low probability of detection/intercept (LPD/LPI), 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 mathematically-guaranteed covert communication. Indeed, they preclude using standard link maintenance operations that are taken for granted in non-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 a demonstration of provably-secure covert radio-frequency (RF) communication using software-defined radios (SDRs). This validates theoretical predictions, opens practical avenues for implementing covert communication systems, and raises further research questions.