Certificateless short signature schemes can not only have the advantage of certificateless signature, but also provide a short signature size in communication. However, all existing certificateless short signature schemes only proven secure against a normal adversary which can only obtain the valid signature for the original public key rather than a super adversary which can obtain the valid signature for the replaced public key. Recently, Fan et al. proposed a certificateless short signature scheme which is very efficient, but we found it is still cannot against super adversary. In this paper, we first analysis their scheme, and then present an improved scheme which can against super adversaries. Furthermore, our scheme can provide both the strongest security level and the shortest signature size compared the existed provably secure certificateless short signature scheme.
A Provably Secure Ring Signature Scheme in Certificateless Cryptography
