An efficient certificateless aggregate signature with conditional privacy-preserving for vehicular sensor networks

Certificateless public key cryptography was introduced to solve the complicated certificate management problem in traditional public key cryptography and the key escrow problem in identity-based cryptography. The aggregate signature concept is useful in special areas where the signatures on many different messages generated by many different users need to be compressed. This feature is very attractive for authentication in a resource constrained environment because it allows large bandwidth and computation time savings. This paper proposes a new certificateless signature scheme. A new certificateless aggregate signature scheme for vehicle-to-infrastructure communication in vehicular ad hoc networks based on the new certificateless signature scheme is presented. We demonstrate that the proposed certificateless aggregate signature scheme can also achieve conditional privacy preservation, in which each traffic message launched by a vehicle is mapped to a distinct pseudo identity. A legal authority can retrieve the real identity from any pseudo identity for any dispute event. In addition, the proposed scheme is provably secure against existential forgery on adaptively chosen message attack in the random oracle model assuming the computational Diffie-Hellman problem is hard. Furthermore, the proposed scheme presents efficient computational overhead with the existing well-known schemes and is suitable for practical use.