  The performance of physical-layer security of the classic Wyner's wiretap
model over Fisher-Snedecor F composite fading channels is considered in this
work. Specifically, the main channel (i.e., between the source and the
legitimate destination) and the eavesdropper's channel (i.e., between the
source and the illegitimate destination) are assumed to experience independent
quasi-static Fisher-Snedecor F fading conditions, which have been shown to be
encountered in realistic wireless transmission scenarios in conventional and
emerging communication systems. In this context, exact closed-form expressions
for the average secrecy capacity (ASC) and the probability of non-zero secrecy
capacity (PNSC) are derived. Additionally, an asymptotic analytical expression
for the ASC is also presented. The impact of shadowing and multipath fading on
the secrecy performance is investigated. Our results show that increasing the
fading parameter of the main channel and or the shadowing parameter of the
eavesdropper's channel improves the secrecy performance. The analytical results
are compared with Monte-Carlo simulations to validate the analysis.
