Physical layer security for Internet of Things via reconfigurable intelligent surface

Security countermeasures are considered one of the major concerns in the emerging Internet of Things (IoT) paradigm to guarantee an efficient network operation. To investigate the security problem in unauthorized access to sensitive IoT information and services, this paper, particularly, studies physical-layer security of a typical system model constituted by a reconfigurable intelligent surface (RIS) assisted access point (AP), legitimate user, and an eavesdropper. In this model, a RIS is deployed to increase the system secrecy and communication performances to deal with eavesdropping attacks. To measure the security performances, we firstly expose analytical results for the secrecy outage probability. We provide insights with asymptotic analysis to identify system parameters that significantly affect the secrecy performance of our proposed RIS-aided IoT systems. In particular, the findings show that by controlling the number of metasurface elements of the RIS and the average signal-to-noise ratios (SNR), system performances can be improved. We verify such a RIS-aided IoT system within many practical situations by conducting Monte-Carlo simulations in the Matlab simulation platform. We compared our analytical results with the Monte-Carlo simulations to evaluate the accuracy of the proposed closed-form expressions of secure performance metrics. Simulation results demonstrated that the secrecy performance in the IoT systems can be significantly improved by increasing the number of metasurfaces in the RIS and reducing channel quality approaching to eavesdroppers. (C) 2021 Elsevier B.V. All rights reserved.