Secure certificateless signcryption scheme without bilinear pairing

Message confidential vulnerability and signature selective forgery vulnerability exist in most of the existing no pairing certificateless signcryption schemes.To solve these vulnerabilities,based on discrete logarithm problem in limited multiplication Abel group,this paper proposed a certificateless signcryption scheme without bilinear pairing,and analysed the security of the proposed scheme.This paper pointed out that the proof methods of the random oracle model might ignore the attacks which did not solve the discrete logarithm problem,the model could not prove that the difficulty of cracking the signcryption scheme was equal to solving the discrete logarithm problem.By mathematical analysis of the parameters,the necessary condition of cracking the proposed signcryption scheme is solving the discrete logarithm problem,there is no existed not solving the discrete logarithm problem polynomial time attacking algorithm aimed at the proposed signcryption scheme.Compared to all known schemes,the security of the proposed scheme is higher.