The key factor accelerating the development of intelligent transportation and reduced traffic congestion is the vehicle ad hoc network (VANET). However, the swift upsurge in the diversity of vehicles puts the development of the vehicle network's safety system through plentiful glitches. To receive the messages promptly, attain the confidentiality of vehicle identity, and authentication swiftly in VANET, we present a new identity-based aggregate signature (IBAGS) system using the lattices. The proposed lattice-based method presented in this article combines the batch verification and aggregate signature scheme (ASS), which finishes the authentication of several vehicular units and aggregates multiple users' signatures into a single (compact) signature. This boosts the competence of the verification process. Furthermore, the vehicle pseudo-identities are also utilized to meet the goals of vehicle identity and privacy protection. Finally, dependable cloud storage technology efficiently enables the secure storing of message signatures. This article demonstrates the lower storage overhead and increases authentication efficiency while maintaining security compared to similar competing schemes