Achieving Adaptive Linkability for Cellular V2X Group Communications in 5G

Cellular vehicle-to-everything (C-V2X) in 5G enables device-to-device (D2D) group communications to support a variety of proximity-based services. While D2D group communication can improve mobile network spectrum efficiency and user experience by offloading local traffic and extending the coverage of cellular base stations, it has also raised new privacy challenges on balancing UE anonymity and message linkability. In this paper, we first identify the limitations of current standardization and literature on addressing this issue. Then, we design a Service-oriented Authentication Framework (SAF) that supports secure service delegation and anonymous message authentication. Specifically, a UE-controlled linking method is introduced to support adaptive linkability for different V2X use cases. Security analysis demonstrates the SAF is secure under cryptographic assumptions. Moreover, we conduct extensive simulations based on Vissim and NS3 to show that the SAF is more efficient compared with the state-or-art literature and is feasible for 3GPP standardized V2X group communications.