Generative Covert Communication: Leveraging Signal Coupling for Secret Data Transmission

摘要

With the rapid advancement of communication technologies, wireless data transmissions have become pervasive. However, the open nature of the wireless medium makes these transmissions vulnerable to attacks, such as malicious detection and eavesdropping. Importantly, the prerequisite for these threats is the attackers’ ability to detect the existence of legitimate transmissions. Covert communication (CovCom), a physical-layer security (PLS) technique designed to conceal legitimate transmissions from detection by attackers, serves as a fundamental security measure unlike other PLS schemes. Nevertheless, most existing CovCom schemes rely on covering signals that are independent of the covert signals themselves. This independence allows attackers to enhance their signal processing capabilities to separate the covert signal from the covering signal, ultimately extracting the original signal. Furthermore, the necessity for dedicated covering signal generation incurs additional power and hardware costs. To address these deficiencies, we propose a novel scheme called Generative Covert Communication (GCC), aimed at achieving covert data transmissions. GCC leverages interactions among covering signals; by adjusting their power and/or phases, a desired secret signal intended for the covert receiver (Rx) can be produced. Since the covert signals are derived from covering signals, they become coupled, and hence prevent attackers from decoupling them and detecting the existence of, as well as the content carried by, the secret transmissions. We design two GCC schemes: Power Control GCC (PC-GCC) and Phase Control GCC (${\mathbb{F}}$C-GCC). We utilize (1) the Universal Software Radio Peripheral (USRP) platform for experimental validation of GCC’s feasibility and (2) comprehensive MATLAB simulations to demonstrate its effectiveness in achieving covert and secure data transmissions.