Reconfigurable Intelligent Surface-Assisted Passive Beamforming Attack

Recently, the reconfigurable intelligent surface (RIS), capable of adjusting the phase shifts (PSs) of the reflecting signals through its low-cost elements, has emerged as a promising technology for next-generation wireless communications. However, the RIS may be manipulated by an illegal passive attacker (Wyn) due to the shared nature of wireless channels. In this paper, a Wyn-controlled RIS is considered to attack multiple-input single-output (MISO) communications via passive beamforming based on existing localization and Rician factor estimation techniques. Specifically, we propose an alignment cancellation (AC) scheme to minimize the achievable rate (AR), where the closed-form expressions for location, reflecting element number, and PSs are derived. Furthermore, the computational complexity is quantified to evaluate the low-cost characteristics of this algorithm. Simulation results demonstrate that the proposed AC scheme outperforms other benchmark schemes in degrading the AR with efficient and low-complexity designs.