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对称群密钥协商方案的目的是协商一个只有群成员能够用来加解密消息的对称加解密密钥.为了满足网络通信的公开性,非对称群密钥协商方案在2009年被首次提出.非对称群密钥协商方案只需要协商出一个共享的群加密密钥,该加密密钥是公开的,且对应多个不同的解密密钥,即每个群成员都可以计算出一个对应于该加密密钥的解密密钥.任何人都可以利用公开信息计算加密密钥从而可以给群成员发消息,但只有群成员可以正确解密.本文基于无证书公钥密码体系提出一个无证书可认证的非对称群密钥协商方案.首先实现了对群成员身份的认证、对公开信息正确性,完整性的验证,保证了群成员间的安全通信.其次分析了群用户的加入和退出,在成员加入退出后更新密钥以保证前向安全性和后向安全性.最后对方案进行了安全性分析和效率分析,在随机预言机模型中证明了该方案满足选择明文安全,通过与其它方案的效率对比说明该方案在实现相同功能和满足相同安全性的情况下效率更高.
The purpose of symmetric group key agreement is to negotiate a symmetric encryption and decryption key that only group members can use to encrypt and decrypt messages.In order to satisfy the openness of network communication, asymmetric group key agreement scheme was first proposed in 2009. Symmetric group key agreement scheme only need to negotiate a shared group encryption key, which is public and corresponding to multiple different decryption keys, that is, each group member can calculate a corresponding to the encryption Key decryption key Anyone can use the public information to calculate the encryption key so that they can send messages to group members, but only members of the group can decrypt correctly.This paper presents a non-certificate-based public key cryptosystem Symmetric group key agreement scheme.Firstly, it authenticates the membership of the group, verifies the correctness and completeness of the public information and ensures the secure communication among the group members.Secondly, it analyzes the joining and withdrawing of group users, Exit after the update key to ensure the forward security and backward security.Finally, the program security analysis and efficiency analysis in the random oracle model card The safety program satisfies the selection plaintext, by contrast with the efficiency of other programs described in more efficient scheme case of performing the same function, and meet the same safety.