Survey on existing authentication issues for cellular-assisted V2X communication.

The integration of Internet of Things (IoT) into cellular network infrastructure is gaining much attention from the research community and standardisation groups, where new cellular-based enabling communication technologies are proposed to provide data links over existing cellular networks for IoT deployment. The Long Term Evolution (LTE) network and the emerging 5G system (New Radio) are widely acknowledged as the main driving forces for the connected-vehicle in the mobile network domain. On the other hand, vehicular networks are characterised by high mobility, high node density, dynamic network topology, time sensitivity and high transmission reliability. These unique characteristics of vehicular networks introduce new security implications and therefore, necessitate enhancement of existing LTE security or provision of new security techniques, in order to ensure fast, secure and reliable vehicular communications under mobile network. In this paper, an introduction to Vehicle to Everything (V2X) communications and services alongside the corresponding service requirement is presented. Then, the potential benefits of using cellular infrastructure for V2X services and the reference architectures for cellular-based V2X systems are described. We then focus on the security requirements of V2X in cellular network, specifically; on the authentication of V2X entities, as any violation or breach of authentication process can expose the entire network to serious consequences. The paper discusses common V2X threats and surveys existing V2X authentication solutions proposed in the literature. Finally, paper presents security issues related to V2X communication in cellular network leading towards possible research challenges.