On the Potential of RIS in the Context of PLA in Wireless Communication Systems

Re-configurable Intelligent Surfaces (RIS) technology has proven itself a promising candidate for the next generation of wireless networks through its enhanced performance in terms of throughput, spectral, and energy efficiency. However, the broadcast nature of RIS-assisted wireless communication makes it vulnerable to malicious attacks at the physical layer. On the other hand, physical layer authentication is an emerging area in the security domain to thwart different attacks such as cloning, spoofing, and impersonation by using the random features of the physical layer. In this paper, we investigate RIS-assisted wireless communication systems to unlock the potential of using RIS for physical layer authentication (PLA). Specifically, we exploit two distinct features of the physical layer: pathloss and channel impulse response (CIR) for PLA in RIS-assisted wireless communication. We construct hypothesis tests for the estimated features and derive the closed-form errors' expressions. Further, we chose the critical error, i.e., missed detection as our objective function for minimization by optimizing the phase shift of the RIS pannel. We compare the performance of our proposed mechanisms with baseline mechanisms which are PLA schemes using the same features but with no RIS assistance. Furthermore, we thoroughly evaluate our proposed schemes using performance metrics such as the probability of false alarm (PFA), the probability of missed detection (PMD), and the receiver operating characteristic (ROC) curves. The results demonstrate the significant positive impact of RIS on PLA, as it effectively reduces PMD values to zero when determining the optimal phase shift.