A secure Certificateless Aggregate Signature Scheme

Aggregate signatures allow n signatures on n distinct messages from n distinct signers to be aggregated into a single signature that convinces any verifier that n signers do indeed sign the n messages, respectively. The major advantage of utilizing aggregate signatures is to address the security of data and save bandwidth and computations in sensor networks. Recently, people discuss aggregate signature in certificateless public key setting. But some existing certificateless aggregate signature schemes are not secure. In this paper, we analyze the security of Zhang et al. 's certificateless aggregate signature schemes, and propose a new certificateless aggregate signature schemes, and prove the new scheme is existentially unforgeable under adaptive chosen-message attacks under the assumption that computational Diffie Hellman problem is hard. Furthermore, in signing equation of the proposed scheme user's partial private key and secret value are directly combined with the signed message. So, the scheme is also secure against some inside forgery attack.