标准模型下可证安全的基于身份的门限环签密方案

Provably Secure Identity-based Threshold Ring Signcryption Scheme in Standard Model

签密是一个能够同时提供认证性和保密性的密码学术语,而它却比分别签名和加密具有更低的计算成本。环签密除具有签密的一般属性外,还具有匿名性。为了设计基于身份的门限环签密方案,利用秘密共享和双线性对技术,提出了一种标准模型下基于身份的门限环签密方案,并对方案的安全性进行了分析。最后,通过计算Diffie-Hell-man问题和判定性Diffie-Hellman问题的困难性,证明了该方案在适应性选择消息和身份攻击下的不可伪造性以及在适应性选择密文攻击下的不可区分性。

Signcryption is a cryptographic primitive which can provide authentication and confidentiality simultaneously with a computational cost lower than signing and encryption respectively,while the ring signcryption has anonymity in addition to authentication and confidentiality. In order to design an identity-based threshold ring signcryption, this paper presented an efficient identity-based threshold ring signcryption scheme without random oracles by means of secret sha- ring and bilinear pairing technique, and gave security analysis of the scheme. At last, we proved this scheme satisfies in- distinguishability against adaptive chosen ciphertext attacks and existential unforgeability against adaptive chosen mes- sage and identity attacks in terms of the hardness of DBDH problem and CDH problem.