Secure CLS and CL-AS schemes designed for VANETs

Vehicular Ad hoc Network (VANET) is a part of intelligent transport system facing the problem of limited bandwidth. Certificateless aggregate signature (CL-AS) scheme gives an efficient solution of solving the limitation of bandwidth and also reduces the computation overhead. Aggregate signature (AS) allows integrating n number of individual signatures on n distinct messages from n distinct users into one single short signature where any signer out of n signers can generate the signature. We propose efficient CLS and CL-AS schemes for VANET. We demonstrate that our CL-AS scheme preserves the conditional privacy, in which message generated by a vehicle is mapped to a distinct pseudo-identity. The security of the proposed scheme is proved in the random oracle model against adaptive chosen-message attacks with the hardness of computational Diffie-Hellman Problem.