Abstract
A large spectrum of technologies are collectively dubbed as physical
layer security (PLS), ranging from wiretap coding, secret key generation
(SKG), authentication using physical unclonable functions (PUFs),
localization / RF fingerprinting, anomaly detection monitoring the
physical layer (PHY) and hardware. Despite the fact that the fundamental
limits of PLS have long been characterized, incorporating PLS in future
wireless security standards requires further steps in terms of channel
engineering and pre-processing. Reflecting upon the growing discussion
in our community, in this critical review paper, we ask some important
questions with respect to the key hurdles in the practical deployment of
PLS in 6G, but also present some research directions and possible
solutions, in particular our vision for context-aware 6G security that
incorporates PLS.