Secure Pairing-Free Certificate-Based Online/Offline Signcryption Scheme With Conditional Privacy Preserving for VANETs

In vehicular ad hoc networks (VANETs), the core feature lies in the secure and prompt exchange of information between vehicles. To further enhance this feature, many signcryption schemes adopted to VANETs are proposed. However, most existing schemes still suffer from security or efficiency drawbacks. In this article, we propose a pairing-free certificate-based online/offline signcryption scheme constructed by elliptic curve, aiming to make the communication system of VANETs more lightweight and more secure. It not only ensures data confidentiality and unforgeability within one logic step but also eliminates the need of secure channels for key distribution. When deployed in VANETs, it can precompute many intricate operations in the offline phase and support batch verification of multiple messages. Moreover, our deployment provides pseudonym-based conditional privacy preserving for vehicles and its traceability results about malicious behaviors can be publicly verified, guaranteeing accountability. It also considers common attacks involved in VANETs, including but not limited to impersonation attacks, collusion attacks, and man-in-the-middle attacks. These advantages of our construction make it highly practical for VANETs, which have been demonstrated in our simulation experiments.