Metasource-Based Secret Key: Physical Layer Security Guarantee for Future Wireless Networks

Physical-layer security (PLS) is a promising concept to complement upper-layer cryptographic technologies in wireless networks. Various channel- based approaches were conceived to exploit random channel characteristics in providing PLS, for example, through secret-key extraction, directional modulation, and artificial-noise injection. For overcoming the drawbacks associated with these approaches, legitimate channel-gain-mapped sources have recently been proposed to create a new family of physical-layer secret key generation techniques, herein referred to as metasource-based secret key (MBSK). In contrast to the channel-based approaches, the MBSK family not only promotes the actual realization of the PLS concept but also enables green communication infrastructure. The aim of this treatise is to elucidate the prominent MBSK techniques by delving into their fundamental principles, underlying mechanisms, and design rationales from a broad communications security perspective. Specifically, the latest advances and open issues in the MBSK realm are discussed to facilitate researchers who might be familiar with channel-based PLS approaches and would like to kick-start their understanding of the PLS frontiers established by MBSK.