Intelligent Reflecting Surface for Wireless Communication Security and Privacy

Abstract

Intelligent reflection surface (IRS) is emerging as a promising technique for future wireless communications. Considering its excellent capability in customizing the channel conditions via energyfocusing and energy-nulling, it is an ideal technique for enhancing wireless communication security and privacy, through the theories of physical layer security and covert communications, respectively. In this article, we first present some results on applying IRS to improve the average secrecy rate in wiretap channels, to enable perfect communication covertness, and to deliberately create extra randomness in wireless propagations for hiding active wireless transmissions. Then, we identify multiple challenges for future research to fully unlock the benefits offered by IRS in the context of physical layer security and covert communications. With the aid of extensive numerical studies, we demonstrate the necessity of designing the amplitudes of the IRS elements in wireless communications with the consideration of security and privacy, where the optimal values are not always 1 as commonly adopted in the literature. Furthermore, we reveal the tradeoff between the achievable secrecy performance and the estimation accuracy of the IRS's channel state information (CSI) at both the legitimate and malicious users, which presents the fundamental resource allocation challenge in the context of IRS-aided physical layer security.Finally, a passive channel estimation methodology exploiting deep neural networks and scene images is discussed as a potential solution to enabling CSI availability without utilizing resource-hungry pilots.This methodology serves as a visible pathway to significantly improving the covert communication rate in IRS-aided wireless networks.

A Survey on Reconfigurable Intelligent Surface for Physical Layer Security of Next-Generation Wireless Communications

“…It increases with increase in accuracy of CSI availability upto a certain extent. Then it decreases since higher value of CSI accuracy will also enhance the Eve's decoding capability leading to rise in SOP as well [66]. Effective secrecy throughput can be defined as…”

A State-of-the-Art Survey on Reconfigurable Intelligent Surface-Assisted Non-Orthogonal Multiple Access Networks

“…1) Improving Secrecy Rate: Theoretically, by deploying the RIS in the vicinity of the legitimate NOMA users or the eavesdropper and by properly designing the passive RIS beamforming, the signals received from the direct and reflected paths can add up constructively at the users but destructively at the eavesdropper [74]- [77]. Therefore, the legitimate signal reception quality is enhanced, while the eavesdropping capability is degraded, and an increased secrecy rate for RIS-NOMA can be achieved.…”

A Survey on Channel Estimation and Practical Passive Beamforming Design for Intelligent Reflecting Surface Aided Wireless Communications

“…As IRS CSI acquisition (especially the CSI of eavesdroppers) may not be accurate in practice, it is necessary to design the robust IRS passive beamforming in IRS-aided PHY systems under the statistical (cascaded) CSI error model (see, e.g., [112], [119], [123], [132]). Besides, the authors in [233] employed the IRS to deliberately introduce extra randomness in the wireless propagation environment for hiding active wireless transmissions, and revealed the trade-off between the secrecy performance and CSI accuracy. Nevertheless, several practical issues in IRS-aided PHY systems have not been well tackled, e.g., the optimal design for detecting eavesdroppers, the trade-off between channel estimation and achievable secrecy performance, which deserve future studies.…”