A Novel and Provably Secure Certificateless Aggregate Signature Scheme

Aggregate signature scheme can aggregate n signatures on n distinct messages from n different signers into a single signature, the resulting aggregate signature can convince the verifier that the n signers did indeed sign the n messages, i.e., n verification equations can be reduced to one. Certificateless public key cryptography overcomes the complicated certificate management in traditional public key cryptography and key escrow problem in identity based cryptography. It is because of the advantages of aggregate signature scheme and certificateless public key cryptography that certificateless aggregate signature schemes become a research hotspot. In this paper, an efficient certificateless aggregate signature scheme based on bilinear pairings is presented. In the random oracle model, it is proven existentially unforgeable against adaptive chosen message attacks(EUF-CLAS-CMA) without Fork Lemma under the computational Diffie-Hellman assumption. The aggregate signature is only composed of two group elements, and the signature verification only needs four pairings(constant order of magnitude) and n scalar multiplications computations. Compared with the existing certificateless aggregate signature(CLAS) schemes, the proposed new scheme improves the efficiency of communication and computation, and it is more suitable for the applications in resource-constrained environment.