Design and Detection of Controller Manipulation Attack on RIS Assisted Communication

In recent years, research on signal and information theory from the electromagnetics viewpoint has drawn significant attention, mostly due to its potential use in various communication technologies such as multiple-input-multiple-output (MIMO) and Reconfigurable Intelligent Surface (RIS). In this paper, we introduce a new attack called controller manipulation attack (CMA) on a RIS assisted communication system between a transmitter and a receiver, and develop mathematical theory for its design and detection. An attacker has the capability to manipulate the RIS controller and modify the phase shift induced by the RIS elements on the incident electromagnetic signal. The goal of the attacker is to minimize the data rate at the receiver, subject to a constraint on the attack detection probability at the receiver. We consider a number of attack detection models: (i) composite hypothesis testing based attack detection in a given fading block for known channel gains, (ii) quickest detection of CMA in a given fading block for known channel gains, (iii) nonparametric hypothesis test to detect CMA for unknown channel gains over a fading block, and (iv) signal-to-noise-ratio (SNR) moment based detection over possibly multiple fading blocks. In the first case, we show that a simple energy detector is uniformly most powerful (UMP). In the second case, simplification of the standard CUSUM test and its performance bounds are obtained. In the third case, non-parametric Kolmogorov-Smirnov test is further simplified to a simple per-sample double threshold test. The optimal attack against these three detectors are designed via novel optimization formulations and semidefinite relaxation based solutions. In the fourth case, we consider threshold detection using moments of SNR; various SNR moments under no attack are obtained analytically for large RIS and then used to formulate the optimal attack design problem as a linear program. Finally, numerical results demonstrate the efficacy of the proposed schemes.