对一个基于身份签密方案的分析与改

基于身份的签密方案计算开销小，密钥管理简单，适用于保证信息的保密性和认证性。Zhang等提出了一个高效的基于身份签密方案，并在随机预言模型下证明了该方案的安全性。通过分析发现Zhang等的签密方案存在缺陷，针对缺陷提出了相应的改进方案，并且基于随机预言模型证明了新方案的安全性。理论分析和实验仿真证明，所提方案计算复杂度低，适合于实际应用。

Analysis and improvement of an identity-based signcryption

Identity-based signcryption was a cryptography scheme with low computation cost and simple key management, which was suitable to guarantee the confidentiality and authentication of information. Zhang, et al proposed an efficient identity-based signcryption scheme, and provided security provement in the random oracle model. Through analysis, it was found out that Zhang’s signcryption scheme was imperfect. To avoid the defect, a new identity-based signcryption scheme was proposed, whose security was proved in the random orcale model. Both the theoretical analysis and the experimental results show that proposed scheme is efficient and suitable for practical application.