A Lightweight Zone Authentication Scheme with Auto-Refreshing Pseudonyms for C-V2X

Vehicular communications are bringing a wave of privacy issues in the boom of Cellular Vehicle-to-Everything (C- V2X), one of which is privacy-preserving authentication. Thus we propose the concept of zone authentication. Zone authentication is an approach to transmitting Vehicle-to-Everything (V2X) data in an authentic and confidential manner, where the vehicles and authorization authorities generate pseudonymous key pairs to further sign and verify messages associated to static geographic zones close to their location. To help the resourceconstrained devices fit in the C-V2X environment more preferably, we were motivated to lessen the overhead and heighten the efficiency of zone authentication. For this purpose, we designed a scheme of lightweight zone authentication with auto-refreshing pseudonyms. The proposed scheme not only enables authorization authorities to work hierarchically in line with the geographic division of the zones, but also allows vehicles to transmit zone-associated parameters in accordance with universal hash function family (UHF). Considering the characteristics of zone authentication, we computed the pseudonymous parameters concerning both time epochs and zones, which guarantees the confidentiality of the communication process. As a consequence, the performance analysis on the basis of computation time cost, storage cost, and the number of operations demonstrates that our zone authentication scheme performs better than existing schemes.