  This paper studies the physical layer security (PLS) of a vehicular network
employing reconfigurable intelligent surfaces (RISs). RIS technologies are
emerging as an important paradigm for the realisation of next-generation smart
radio environments, where large numbers of small, low-cost and passive
elements, reflect the incident signal with an adjustable phase shift without
requiring a dedicated energy source. Inspired by the promising potential of
RIS-based transmission, we investigate the PLS of two vehicular network system
models: One with vehicle-to-vehicle communication with the source employing a
RIS-based access point, and the other is in the form of a vehicular adhoc
network (VANET), with a RIS-based relay deployed on a building; both models
assume the presence of an eavesdropper. The performance of the proposed systems
are evaluated in terms of the average secrecy capacity (ASC) and the secrecy
outage probability (SOP). We present accurate analytical expressions for the
two performance metrics and study the impact of various system parameters on
the overall performance of the two considered system configurations.
Monte-Carlo simulations are provided throughout to validate the results. The
results show that performance of the system in terms of the ASC and SOP is
affected by the location of the RIS-relay as well as the number of RIS cells.
Moreover, upto an order magnitude gain could be achieved within certain regions
when the number of RIS cells are doubled, clearly indicating the benefit of
employing a RIS configuration.
