Experimental Validation of Provably Covert Communication Using Software-Defined Radio

2025-08-11

AI Summary

Provable covert communication based on the square-root law (SRL) remains experimentally unvalidated in the radio-frequency (RF) domain; existing demonstrations are confined to optical channels. Method: This work presents the first RF implementation of a mathematically provable covert communication system using software-defined radio (SDR), achieving high-precision time–frequency synchronization and ultra-low-power modulation under strict SRL constraints. Contribution/Results: Experimental results closely match information-theoretic predictions, empirically validating the SRL’s applicability in RF environments and refuting the conventional assumption that standard RF links are inherently unsuitable for covert transmission. By bridging the gap between theory and practice, this study establishes the first empirical foundation for RF-based low-probability-of-detection (LPD) communication, providing both critical experimental evidence and a practical technical pathway toward real-world deployment.

Technology Category

• Machine Learning: Privacy
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Cognitive Modeling & Cognitive Systems: Neural Spike Coding

Application Category

• Security and Privacy: Large-scale security measurements
• Responsible Web: Measurement, analysis, and circumvention of Web censorship
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments

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 $Lsqrt{n}$ 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.

Problem

• Validating provably covert RF communication using SDRs
• Overcoming hardware constraints of square root law
• Exploring practical implementation of LPD/LPI systems

Innovation

• Software-defined radios enable covert RF communication
• Experimental validation of square root law
• Provably-secure low probability detection communication