The Research On Data Integrity Verification Scheme In Cloud Storage Based On RMHT

In the cloud storage environment,users' data are stored remotely on the cloud servers without data backups.Thus,it is an important research to ensure the integrity of data storage in this situation.The audit of dynamic data is more important in practical applications.Therefore,it is indispensable to design an efficient dynamic auditing scheme in the cloud storage environment.When the user updates the data,the cloud storage server uses the hash value of the file to establish MHT structure and send the generated data integrity audit evidence to the user.The user can verify whether the stored data is updated correctly by this method.Existing MHT-based integrity auditing scheme can only update one file block at a time,and users cannot update concurrently when the update file is large.This makes the overall auditing efficiency lower.When the files are out of order,different insertion positions will result in different amounts of verification evidence.Choosing an appropriate insertion position can reduce the amount of evidence and the MHT update calculation.In addition,the user needs to specify the file block number during the insertion and deletion process.Each insertion and deletion will result in a large number of file sequence numbers being updated.Based on these issues,this paper works as follows:To address the problem of multiple file blocks inserted in the same position,this paper proposes an RMHT inserting algorithm,which aggregates multiple file blocks into an RMHT subtree and then inserts the subtree into the specified position.The proposed algorithm can insert multiple file blocks into one MHT update,while the general RMHT algorithm requires each file block to be inserted in sequence.Moreover,an RMHT Multi-file deletion algorithm is proposed to resolve the problem of multiple file blocks deletion consecutively.This algorithm determines whether all the leaf nodes under a parent node need to be deleted so as to delete multiple file blocks at one time.The deletion or insertion algorithm proposed in this paper implements MHT concurrent update and data integrity audit under specific circumstances,which can effectively reduce the auxiliary information AAI(auxiliary authentication information)required for RMHT update.We take the number of required AAIs as the standard,and simulate the algorithm using updating the number of file blocks and the total number of file blocks as variables.The simulation results show that the number of AAIs for the insertion or deletion of the proposed algorithm RMHT is less,and the number of AAIs for next updates is reduced.Therefore,the proposed algorithm is more efficient.An optimal insertion position searching algorithm is proposed to resolve the problem of the nonsequential file.Generally,MHT often has inconsistencies in the structure of the left and right subtrees during the update process,which causes a large number of evidence.In the verification process,the proposed algorithm can reduce the amount of evidence through inserting a file block into the low depth subtree.Furthermore,the technique of sequential numbering is not suitable for the disorder of file blocks.To address these issues,this paper proposes a fixed numbering algorithm,which uses the position of the corresponding node of the file block in the MHT structure to determine its numerical value.The proposed algorithm improves the deletion and insertion method and does not affect other node numbers.We simulate our algorithm by taking the number of required AAIs as the standard.The number of inserted file blocks and the total number of file blocks are used as variables.The simulation results show that the proposed algorithm can reduce the number of required AAI in the process of RMHT updating,and the number of required AAI will be less in the future updating.