The fifth generation (5G) networks exhibit extremely low latency, extremely high bandwidth, and high density connections that are salient features for the support of vehicle to everything (V2X) services. Although a lot of research efforts have been directed towards addressing 5G technical issues for the support of V2X communications, these researches only concentrate on synchronization, physical layer structure or resource allocation. Very little research has been carried out on how to uphold message security as well as user privacy in V2X networks and as such, these networks still face a number challenges relating to privacy and secure payload exchanges. For instance, to facilitate cooperative driving, road conditions as well as vehicle status is shared among all neighbor autonomous vehicles. This is accomplished via periodical generation of notification messages. As such, message authentication is essential to prevent attacks and boost reliability in an autonomous platoon. Unfortunately, existing authentication protocols incur high computational and communication costs during the authentication process. Moreover, although novel access validation and key agreement schemes have been suggested, secure and efficient mobility management still faces many challenges owing to the high number of recurrent handovers and massive vehicular communications. To address these challenges, this paper sought to develop an efficient and secure protocol that was shown to have average communication and computational costs and also robust against impersonation, MitM, replay and eavesdropping attacks.