可证安全的紧致无证书聚合签密方案

Provable Secure and Compact Certificateless Aggregate Signcryption Scheme

无证书聚合签密不仅可以保证信息传输的机密性和认证性,还可以降低密文的验证和通信开销。分析现有无证书聚合签密方案,发现它们的计算效率普遍较低。该文提出一个紧致的无证书聚合签密方案,方案聚合验证密文信息需要的双线性对个数固定,并且与签密用户个数无关。与已有无证书聚合签密方案相比,新方案减少了双线性对运算个数,提高了聚合验证效率。同时,在随机预言模型下,基于双线性Diffie-Hellman困难问题和计算Diffie-Hellman困难问题,证明方案满足机密性和不可伪造性。

Certificateless aggregate signcryption not only can ensure the confidentiality and authentication of information transmission, but also can reduce the cost of data communication and the verification of ciphertexts.Through analyzing some existing certificateless aggregate signcryption schemes, it is found that their efficiencies are much lower. A provable secure certificateless compact aggregate signcryption scheme is proposed in this paper.In the new scheme, the pairing numbers, not depending on the number of signcryption users, are constant when aggregate ciphertexts are verified. Compared with the existing certificateless aggregate signcryption schemes, the new scheme decreases pairing numbers and raise the efficiency of verification. Moreover, based on the assumption of bilinear Diffie-Hellman and computational Diffie-Hellman, in the random oracle model, it is proved that the new scheme satisfies the properties of confidentiality and unforgeability.