Efficient and Provably Secure Offline/Online Heterogeneous Signcryption Scheme for VANETs

With the rapid advancement of wireless communication and autonomous driving technology, vehicular ad hoc networks (VANETs) has emerged as a robust network facilitating interactive communication among vehicles, roadside infrastructure, and the surrounding environment. However, VANETs face challenges regarding traffic information security and vehicle identity privacy during wireless transmission. Vehicles require reliable technology to communicate efficiently and securely with roadside infrastructure, especially at high speeds. To address these issues in VANETs environments characterized by diverse nature of vehicles and roadside units (RSUs), we propose an enhanced certificateless and identity-based offline/online heterogeneous signcryption (CLIOOHSC) scheme for VANETs, aiming to achieve confidentiality, integrity, authentication and identity anonymity simultaneously in a unified step. The CLIOOHSC scheme enables vehicles in certificateless cryptography (CLC) environment to transmit messages to RSU in identity-based cryptography (IBC) environment. In the online phase, scalar multiplication operations are omitted since they are performed in the offline phase, significantly reducing the computational load. Then, through security proofs, we demonstrate that the proposed scheme can achieve the expected security properties. The performance analysis shows that our scheme is superior to other schemes in terms of computation and communication costs and is suitable for scenarios where vehicles communicate across cryptosystems.