Physical Layer Security - from Theory to Practice

In this article we present the evolutionary journey of physical layer security (PLS), starting from its theoretical foundations in wiretap coding and secret key generation followed by to the revolutionary advancements in authentication using physical unclonable functions (PUFs), localization and RF fingerprinting. Since the middle of last century the theory behind PLS has been constantly evolving, however, practical solutions are still scarce. Through a critical review, we identify the key hurdles hindering the widespread adoption of PLS. Moreover, we highlight important research directions and possible solutions that can bridge the gap between theory and practice.