Wireless Physical-Layer Security: Lessons Learned from Information Theory

Physical-layer security utilizes resources of the transmission medium to guarantee secure communication against an adversary with unlimited computational power. Rooted in information theory, physical-layer security advocates for a foundational approach by requiring security of communicated information as well as its reliability at the outset. The past decade has seen an unprecedented effort in physical-layer security research resulting in promising new design insights. The majority of these advances has been in wireless communications security, well-motivated by the fact that most data at large, including those of sensitive nature, flow over wireless links that are more vulnerable to security breaches, e.g., eavesdropping. At the same time, the open broadcast nature of wireless brings possibilities of cooperation by the network entities for improving security, e.g., resistance to eavesdropping. This article aims to provide an overview of research results in information-theoretic security with multiple wireless transmitters, and focuses on distilling insights for designing wireless systems with confidentiality guarantees.