Research And Implementation Of Group Signature Scheme With Revocable Mechanism

With the rapid development of computers and the wide popularity of the Internet,people pay more and more attention to the protection of their privacy information.In spite of many schemes of revocable group signature proposed in recent years,there are problems of the performance evaluations and security in the revocable and backward security group signatures.According to the problems mentioned above,the dissertation carries on wide research of revocable group signatures.First,based on the current analysis of the group signatures at home and abroad,there are defects of efficiency,revocability and security in the scheme of the revocable group signatures.In the application of group signatures,the proposed scheme adopts the distributed group signature mode available to massive users,including trusted authority,group manager,group members,verifier and so on.This mode can enlarge the range of application on group signatures.In addition,it optimizes the algorithm of the operation in signature and verification by the BBS + signature for the algorithm itself.Secondly,the proposed scheme gives the trusted authority to the management of the revocable list in terms of the revoked members.The Complete Subtree method of the NNL framework,being used to the change of the revocable list,increases the function of algorithm compared to the traditional one,which can be degreed to the level of O(log(n)).In terms of security,it defines four attributes of security :backward security,non-frameability,traceability and anonymity,and under the random prediction model it proves the security based on the XDH,DL,q-SDH assumptions.Last,in terms of performance evaluations and security,the dissertation optimizes the two algorithms of signature and verification in the simulation environment at first.Obtaining the running time optimize,it is superior to the scheme of revocable group signatures at present in comparison.In terms of security,the proposed scheme has four attributes of security: backward security,non-frameability,traceability and anonymity.However,the existing schemes have different deficiency in security attributes.