标准模型下基于身份的广义签密方案*

首次对标准模型下基于身份广义签密体制进行了研究。利用双线性对，提出了基于身份的广义签密方案, 并在标准模型下证明了方案的安全性。结果表明，方案的保密性在DBDH假设下是适应性选择密文攻击下不可区分的，在CDHP假设下方案是适应性选择消息攻击下存在性不可伪造的。与其他两个基于身份广义签密方案相比，本方案效率较高，且是在标准模型下可证明是安全的。

Identity-based generalized signcryption in standard model

This paper conducted a research on identity-based gengeralized signcryption under the standard model for the first time. It proposed an identity-based generalized signcryption scheme and gave its security proof in the standard model. It shows that the confidentiality satisfies the semantic security notion IND-CCA2 under the decisional bilinear Diffie-Hellman assumption and the unforgeability against adaptive chosen message attack derives under the computational Diffie-Hellman assumption. Compare with the two identity-based generalized signcryption schemes, the proposed one is comparably efficient and provably secure under standard model.