CPBA: An Efficient Conditional Privacy-Preserving Batch Authentication Scheme for VANETs

The vehicular ad-hoc networks (VANETs) are the products of close integration of wireless communication technologies and modern automotive technologies, from which real-time traffic information and effective safety protections can be provided to managers and drivers respectively. Two major problems in VANETs are privacy protection and certificate revocation list management. With the exiting signature schemes, certificates provided by management center should be stored in vehicles and these vehicles need to check certificate revocation lists (CRLs) prior to message authentication. To realize the security and efficient authentication of information transmission between vehicle nodes in VANETs, we propose a new certificateless aggregate signature scheme (CLAS) that addresses the key escrow problem, supports batch verification and conditional privacy preservation. By using Chinese remainder theorem (CRT), the trusted authority (TA) generates and broadcasts new domain keys to the vehicles in the network dynamically, which means that vehicles can prevent false security information attacks from malicious vehicles without storing CRLs. The results show that the scheme can not just achieve these security properties, including anonymity, revocability, anti-forgery, and traceability, but can meet the requirements of real-time and efficiency for VANETs as well.