Post-Quantum PHY-Layer Authentication for Secure Initial Access in V2X Communications

One of the greatest challenges in vehicle-to-everything(V2X) communications lies in protecting vehicle authentication during initial access against advanced quantum cyber-physical attack (CPA), as well as maintaining ultra-reliable low-latency communications with each other and the infrastructure. In this paper, we propose a vehicle initial access authentication system which exploits post-quantum encryption and signal processing technique to defend against both active and passive quantum CPA. The system encodes/decodes the physical layer bits of messages using quasi-cyclic moderate-density parity-check code to avoid quantum passive cyber attacks while eliminating the influence of high-power active cyber attacks on bits by employing the independent component analysis based signal separation technique. We define the system failure probability to measure the reliability, by considering both the cyber and physical plane influence, such as asynchronous access delay caused by mobility and communications, wireless channel fading and the uncertain bit generation induced by traffic hazards. Simulations show the effectiveness of our proposed system against attacks and indicate how the adverse cyber-physical effects, either being intentional or unintentional, can be avoided subtly to reduce system failures.