A secure Certificateless Aggregate Signature Scheme
Certificateless public key cryptography can solve the key escrow problem without any digital certificates to bind users and their public keys. Meanwhile, aggregate signature can efficiently lower the cost of computations and communications. Hence it is of interest to construct a certificateless aggregate signature scheme by taking advantages of the two methods. Though great progress has been made in this area, certificateless aggregate signature schemes available today cannot simultaneously achieve the objectives of being secure against both types of super adversaries and being efficient in operation. This paper puts forward a construction of certificateless aggregate signature scheme with stronger security by using pairings and introducing state information. The state information is used to hold partial information on a given hard problem in the random oracle model. The results show that the presented scheme, based on the infeasibility of the computational Diffie Hellman (CDH) problem, is secure against both super adversaries. At the same time, the new scheme needs only four pairings during the processes of individual signature and verification for an aggregate signature by making good use of public information and the properties of bilinear maps. Furthermore, after knowing the same state information, a user in the scheme can perform individual signature operations in a non interactive manner, which allows any users in the system to join dynamically for generating an