A Lightweight Certificateless Aggregation Signature Scheme With Provably Security in the Standard Model

Abstract

In an aggregate signature scheme, $n$ signatures on $n$ different messages from $n$ users can be combined into a single signature. By verifying the signature, the verifier believes that $n$ users did generate the $n$ corresponding signatures. In the recent decade, numerous certificateless aggregate signature (CLAS) schemes have been introduced. There are two issues with these schemes. First, it was in the random oracles model (ROM) that the security proofs of these schemes were given. ROM is an idealized model. A signature scheme is not necessarily secure in real life even if it has proven to be safe in ROM. Second, the number of hash-to-point operations increases linearly with the number of signers in these schemes, so that are not suited for the computation-constrained devices (such as mobile devices). In this article, a new certificateless signature scheme is constructed. Based on it, a new CLAS scheme is proposed. Under the hypothesis that it is hard to solve a computation Diffie–Hellman problem, two schemes are proved to be secure in the standard model. The CLAS scheme needs only three pairing operations and does not need a hash-to-point operation, taken into account the computation cost, it is more efficient than previous CLAS schemes.