Cryptanalysis of a Certificateless Signature Scheme without Bilinear Pairings

During these years, the research field of certificateless signature (CLS) scheme without bilinear pairings is promptly investigated as the key escrow problem in identity-based cryptography can be solved via such concept. In this paper, we demonstrate that a certificateless signature scheme proposed by Gong and Li cannot fulfill its security claims. The authors argued that their proposed certificateless signature scheme is able to resist to the super adversary. However, this security argument can be improved. We present a series of attack processes to point out that Gong and Li’s scheme is insecure against a super type I adversary.