Intelligent reflecting surface-aided physical layer security of wireless communications

Existing physical layer security (PLS) techniques are generally channel-adaptive, the achievable secrecy performance of which is severely constrained by the wireless propagation environment. In order to break through the technical bottleneck, intelligent reflecting surface (IRS) provides a new engine for PLS enhancement for the next generation wireless networks by smartly reconfiguring the wireless channels. In this chapter, we collect recent research fruits on the IRS-aided PLS, putting an emphasis on four scenarios, namely, the multi-input multi-output system, the pattern index modulation system, the integrated sensing and communication system, and the artificial intelligence-driven communication system. For each case, we describe the system model, formulate the optimization problem, build the design framework, and provide numerical results. We also present several interesting and challenging open-ended issues for future research works.