Analysis and Improvement of an Efficient Certificateless Aggregate Signature With Conditional Privacy Preservation in VANETs

Certificateless aggregate signature reduces the trust in key generation center and eases the inconvenience of certificate management at a low cost of communication and computation. Because of these merits, a lot of new certificateless aggregate signature schemes have been proposed to provide enough security and privacy in vehicular ad hoc networks (VANETs). However, many of these schemes are insecure against various attacks. In this article, we analyze the security of an efficient certificateless aggregate signature with conditional privacy preservation in Internet of vehicles. The results of the analysis show that it is insecure against forgery attack. In order to overcome the security vulnerability, we put forth an improved scheme. Then, the formal and informal security analysis of our improved scheme both are provided, which show that the improved scheme meets the expected security requirements and is secure against several known attacks in VANETs. Finally, performance evaluation shows that our improved scheme is feasible for the VANETs in terms of computation and communication overhead.