Research On Secure Group Signature Scheme And Security Analysis

In recent network, information and digitization society, it is very important to invent a kind of technologies which can be used for identifying identity, data integrity and anti-denial, so the digital signature and certificate authentication arise at this historic moment. In order to satisfy the particularity application domain, different special digital signature technologies were proposed one after another. Amongst these special digital signatures, the research for group signature and the threshold group signature, in the management, the military, politics and the economy and so on many aspects have the widespread application. For instance, in public resource's management, important military order's signing and issuing, the important leader's election, electronic commerce, national news's issue, the financial contract signs and so on, the group signature may play an important role.A comprehensive research has made in the theoretical model and the security requirements for security group signature scheme. A forward security group signature scheme with effective member revoke was analyzed, some design mistakes and flaws in this scheme were pointed out. An improvement's forward security's group signature scheme was proposed in the improvement scheme, simultaneously some new security features were proposed, in improvement scheme, there is not only the forward security, but also there is ability to prevent the group member signing a valid signature which time is before the group member join group. The improvement scheme broke through the limit in the traditional forward security group signature scheme in which establish the fixed time periods, improvement scheme has the infinite time periods, no longer needed to reset system parameters and the member parameter after the time periods be used out. The improvement scheme can support member's effective revocation, any member can not sign a valid signature again when he is cancelled from group, simultaneously signatures signed before being abolished still maintained effective, and improvement scheme is a perfect group signature scheme which satisfies all security requirements.A comprehensive research has made in the application of elliptic curve based bilinear mapping in the group signature, security of bilinear mapping is established on the GAP group. Because the DDH problem is easy to solve in GAP, this fact results it is very difficult to design a bilinear mapping based group signature scheme which can satisfy anonymity and the tractability. Therefore in recent, the research about bilinear mapping based group signature is also at a start stage, there are no a bilinear mapping based group signature scheme obtains common recognition. There are some design defects in existing schemes, and the security is not very ideal. Though analyzed the existing schemes, a bilinear mapping based group signature scheme with multi-security strategies proposed, the proposed scheme satisfy the all security requirements for group signature completely.In the army, the government and some important organizations in which has the massive secret information, it is very important how to preserves the secrets safely. In some situations, the secret needs preserved by some person, each person preserves a secret share, when the necessity the secret can be restored by some person's cooperation, with this method, it may avoid the secret loss and tampered while by only one person preserving secret. The research achievement of secret sharing technology can satisfy this requirement very well. Simultaneously the secret sharing technology is also the fundamental of threshold group signature. A comprehensive research Has made in the theory of secret sharing technology, especially the threshold based secret sharing technology, summarizes the universal security problems threshold based secret sharing scheme, analyzed a multiple secret sharing authentication scheme, pointed out the mistakes and flaws in this scheme. A credible multiple secrets sharing authentication scheme was proposed, with the strict confirmation for each processes, scheme guaranteed that will detect all cheating in the secret recovery procedure, restored secret will have the very high confidence level.A comprehensive research has made in the theoretical model and the security requirements of threshold based group signature scheme. A threshold based group signature scheme with against conspiracy attack was analyzed. A few universal mistakes and flaws in threshold based group signature scheme were pointed out. Though the analysis and combining group signature technology to threshold based group signature scheme, a threshold based group signature scheme with against conspiracy attack was proposed.A comprehensive research has made in designing technologies of bilinear mapping based threshold group signature scheme. A bilinear mapping based chamellon threshold group signature and a forward security threshold group signature were analyzed, the mistakes and flaws in these schemes were pointed out. Though the analysis, taking different strategy according to the threshold signature synthetist's role, a bilinear mapping based threshold group signature scheme in which synthetist is a group member was proposed, as well as a bilinear mapping based threshold group signature scheme with forward security in which synthetist is security mediator was proposed. The proposed forward security threshold group signature scheme did not need to divide time into the time periods. Two schemes satisfy all secure requirements for threshold based group signature.Finally, summarize the major tasks in thesis and the research achievement, and the future work.