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广义签密和组合公钥密码都可以实现加密、签名和签密共用一对密钥,并且广义签密还可以实现三者共用一个算法.结合这两个概念,本文提出广义代理签密的概念.广义代理签密可以实现代理签名和代理签密共用一个算法和一对密钥.对于具有大量用户的系统、存储空间受限的系统或功能需求有变化的系统,它会带来效率的明显提高.本文给出了广义代理签密在基于身份的密码体制下的形式化定义和安全模型,并基于双线性对提出一个在标准模型中安全的基于身份的广义代理签密方案.方案具有在代理签密模式下可公开验证、防止代理密钥暴露攻击、可以自代理、具有较短的系统公开参数以及在原始签名(签密)者和代理签名(签密)者之间不需要安全信道的特点.本文方案在适应性选择密文、选择身份和选择授权攻击下的保密性安全性可以归结为DBDH困难问题;在适应性选择消息、选择身份和选择授权攻击下,本文方案的不可伪造性安全性可以归结为CDH困难问题.最后,本文对方案的效率进行了比较,结果表明它是属于高效的方案.
Generalized and combined public-key cryptography can both encrypt, share and encrypt a pair of keys, and generalized-signcryption can also implement a common algorithm among the three.Combined with these two concepts, this paper proposes the concept of generalized proxy signcryption Generalized proxy signcryption can share both an algorithm signature and a proxy signcryption algorithm and a pair of keys.For systems with a large number of users, systems with limited storage space or systems with changing functional requirements, it will bring about obvious efficiency This paper presents a formal definition and security model of generalized proxy signcryption in identity-based cryptosystem and proposes a secure identity-based generalized proxy signcryption scheme in standard model based on bilinear pairings.The scheme has In proxy signcryption mode, public authentication can be performed to prevent the proxy key from being exposed and can be protected from proxies, with short system public parameters and no need for security between the original signcryptor and the proxy signcryptor Channel characteristics.The security of the proposed scheme under adaptive selective ciphertext, selective identity and selective authorization attacks can be attributed to the difficulty of DBDH, The security of unforgeability of this scheme can be attributed to the difficulty of CDH under the information of choice message, choice of identity and choice of authorization attack.Finally, this paper compares the efficiency of the solution and shows that it is an efficient solution.