Cryptanalysis and improvement of an efficient certificateless signature scheme

Abstract

In this paper, an efficient certificateless signature scheme which is recently proposed by Fengyin LI and Peiyu LIU, is analyzed but the scheme turns out to be insecure. Concretely, the proposed certificateless signature scheme can suffer from the public key replacement attack so that any one can forge a valid signature on any message. Then, to overcome this flaw, a comprehensive and improved scheme is proposed, whose security is based on the CDH assumption. Furthermore, the improved scheme can achieve the same trust level (Level 3) as that of the traditional PKI. In considering the precomputation, the efficiency of the improved scheme is almost the same as the original scheme. © Springer-Verlag Berlin Heidelberg 2012.