Attack of Two Certificateless Aggregate Signature Schemes Based on VANET

The Vehicular Ad-hoc Network is the fundamental of smart transportation system in the future. The rapid development of wireless communication technology makes it possible to communicate between vehicles and vehicles, between vehicles and roadside infrastructures. Wang et al. and Hong et al. proposed a certificateless aggregate signature algorithm for Vehicular Ad-hoc Network respectively, and proved the algorithm to be safe under the random oracle model. In this paper, these two programs are analyzed in depth, and it is found that the two solutions both have security problems. The scheme of Wang et al. cannot resist the attack of type II attacker, while the scheme of Hong et al. can neither resist the attack of type I attacker nor the attack of type II attacker. This paper details the attack process of the two schemes, analyzes reasons for the signature forgery of each algorithm and gives improvement measures. This work provides an idea for designing a more secure and efficient certificateless aggregate signature scheme based on Vehicular Ad-hoc Network.