Research On Secure Group Data Sharing Scheme In Cloud Environment

Group data sharing provides users a feasible means to publish and share data in cloud environment.However,using public clouds for group data sharing and users' cross-domain access cause a risk of information leakage against cloud service providers,such as important private data and user identity.There are some limitations on the existing group data sharing security mechanism,such as single-point bottleneck,poor scalability and adaptability.How to effectively protect user private information,and how to achieve a secure and efficient group data sharing scheme is still an important part of data sharing in cloud.Aimed at the poor scalability and adaptability of user management and bottleneck of system performance in the existing group data sharing scheme,we proposes a threshold multi-manager group data sharing scheme by introducing multiple managers in cloud.The mangers in our system includes a group manager and multiple key managers.To well solve the master key's security matters of key managers and reduce group manager's burden,the master key is hidden from view by introducing(t,n)threshold during system initialization of key parameters.To reduce the verification cost increasing linearly with the number of revoked users,we introduce a token verification mechanism and hash table.The comparison of token parameters replaces the sequential verification of revocation list by using hash table.To improve the system performance,we also provide signature batch verification algorithm by modifying the parameters and verification procedures of the original signature algorithm.The security comparisons show the proposed scheme is better than Mona and Atgds.For the system computation cost and performance of file accessing,the scheme greatly reduce the computation cost by 30 percent on the access control.The computation cost on data key generation is close or better than others.The performance of file uploading and downloading increase 5.3% and 6.9%,respectively.