Research And Implementation Of Integrity Verification Scheme Supporting Dynamic Data Updat

With the development of cloud storage technology,more and more users tend to use cloud storage service.Cloud storage service provides user with a cheap and flexible way to store data,alleviates shortage of user storage space and reduce the cost of data management for the user.However,cloud storage separates the ownership and usage rights of user data,so that user cannot ensure data integrity on the cloud in most cases.In order to enable user to verify the integrity of data on the cloud and to meet the needs of user to dynamically update data on the cloud,integrity verification schemes that support dynamic data update have been proposed one after another.After research,it is found that these schemes still have the following problems:(1)The dynamic structures to organize and update metadata of data blocks in these schemes have low update efficiency.(2)There is a risk of leaking user data in the design of these schemes.(3)These schemes generally introduce a Third-Party Audit(TPA)to perform integrity verification on behalf of the user,and assume that TPA is trusted.However,this assumption is sometimes too idealistic,and these schemes lack further consideration when TPA is not trusted.Aiming at above problems,this paper studies integrity verification schemes supporting dynamic data update,mainly including the following work:First,under the condition of TPA trusted,an integrity verification scheme using R-MMR is proposed.The improved R-MMR dynamic structure is used in the scheme to organize and update metadata of data blocks,which solves the problem of low update efficiency of dynamic structures in existing schemes.The scheme also introduces random masks to avoid leakage of user data.Second,considering the additional situation of TPA untrusted,a smart contract-based integrity verification scheme is proposed.In the scheme,the audit work of TPA is handed over to smart contracts on the blockchain for execution,which realizes decentralized auditing and ensures reasonableness and feasibility of the scheme when TPA is not trusted.Third,a prototype system for integrity verification based on smart contracts is designed and developed.The system can effectively realize the integrity verification scheme of decentralized auditing.