Aggregate Signature without Pairing from Certificateless Cryptography

In some real-world applications, many messages must be processed at the same time with low computational costs. In an aggregate signature scheme, anyone can combine n signatures on n messages from n users into a single signature, the resulting signature can convince a verifier that the n users indeed signed the n corresponding messages. All of the aggregate signature schemes currently known used bilinear pairings, however, the computational cost of the pairing is much higher than that of the exponentiation in a RSA group and that of the scalar multiplication over the elliptic curve group. In this paper, we propose a certificateless aggregate signature based on RSA and discrete logarithm (DL) problem, and prove the security in the random oracle model. To the best of author's knowledge, the scheme is the first certificateless aggregate signature scheme without pairing.