A Study on Malicious Attacks for RIS-Aided Wireless Systems

Reconfigurable intelligent surfaces (RIS) aim to reconfigure the random channel between the source and the destination, thus directing the transmitted signals toward the destination. The potential gains of RIS-aided systems compared to legacy systems are an increase in rate, energy efficiency, and energy transfer. A RIS should be low-complex and quasi-passive, therefore, does not have a high computational capability. The source configures the phases of the RIS elements by sending a signal to its controller to maximize the required metrics, such as the received power, the rate, the signal-to-noise ratio (SNR), etc. However, the channel between the source and the RIS controller is vulnerable. In this paper, we discuss the security issues in RIS-aided wireless systems. We focus on the channel between the source and the RIS controller. We show that a severe decrease in the destination rate, to a value lower than the one of the system without RIS, can be made by controlling the phase shifts of the RIS. With a realistic 3GPP channel model and an RIS with 100 elements, the rate can be decreased from 4.55 bps/Hz to only 0.08 bps/Hz by selecting the RIS phase shifts to minimize the received power (power loss around 26 dB). Future directions and challenges are also discussed, such as energy deviation, multiple RISs, and multiple operators.