Quantisation feasibility and performance of RSS-based secret key extraction in VANETs

Vehicular Ad Hoc Networks (VANETs) has emerged as a unique implementation of Mobile Ad Hoc Networks (MANETs). These networks promise to increase road safety and improve the driving experience by exploiting recent advances in wireless technologies for both intra-vehicle and inter-vehicle communications. Physical layer security is a promising alternative approach to secure communication in VANETs where physical and applications' constraints encourage the use of lightweight and fast cryptographic algorithms. Our work focuses on the quantisation stage of the secret generation process, by reviewing existing schemes in the public domain and associated performance metrics. Evaluations are done through simulation with the aid of a wireless channel model which includes three-dimensional scattering and scatterers' mobility. Preliminary findings show that RSS-based algorithms do not perform efficiently in the proposed vehicular stochastic wireless model. Hence they are not able to satisfy the typical low latency required in safety-related broadcasting messaging. We conclude that more research is desirable to design protocols capable of taking advantage from the nodes' high-mobility and the consequent variability of both coherence intervals and level crossing rates, to further improve secret bit extraction throughput.