RIS-Aided Robust Secure Beamforming Design Against Pilot Spoofing Attack

The pilot spoofing attack is one kind of active eavesdropping activities conducted by an adversary during the channel training phase, which manipulates the channel estimation outcome and brings new challenges to physical layer secure transmission. In this paper, we propose a novel two-way training-based scheme to detect the pilot spoofing attack where the reconfigurable intelligent surface (RIS) is turned off in the uplink training phase and turned on in the downlink training phase, respectively. Furthermore, based on the estimated and statistical channel state information of the legitimate and eavesdropping links, we propose the secrecy outage probability constrained robust secure beamforming design with the assistance of RIS. The active beamforming and RIS passive beamforming are jointly optimized based on the alternating optimization algorithm to maximize the achievable secrecy rate of the legitimate user. Finally, simulation results show that our proposed RIS-aided robust secure beamforming design is capable of efficiently improving the achievable secrecy rate compared with different baseline schemes.