Research On The Key Technology Of Cloud Data Integrity Verification

Cloud storage,which enables cloud users to move their data from local storage systems to the cloud,is an important service offered by cloud computing.This new storage service provides users with affordable,location-independent,application transparent,scalable storage services.it can greatly reduce the burden of user data management and maintenance.Cloud storage has become a faster profit growth point in cloud computing,more and more individuals and enterprises to adopt cloud storage service.However,there is a security problem with the data storage model,the cloud server is vulnerable to malicious attacks and the cloud service providers are not fully trusted,the user's data security may not be guaranteed.Therefore,providing a mechanism that can detect the integrity of outsourced datas for user is necessary.In the real cloud storage environment,data deduplication has a strong practicality,there are many duplicates of data that users outsource to the cloud,so the cloud vendor wants to save storage space by storing a single copy of each data—no matter how many clients outsourced it.In addition,cloud users will often update the key in the cloud storage,if users by downloading all the files to calculate the file block tags,and then upload the file and update the label is not practical.How to achieve both integrity verification and data deduplication,and how to implement secure data integrity verification and key update operations simultaneous are challenges.This thesis researches this regard,including:1.Analyzed the security of existing cloud data integrity checking with deduplication scheme,Zheng's scheme is not only to achieve secure data deduplication,but also support for integrity verification.The defects is that use of a large number of random numbers in the program,the calculation process is more complex.Another flaw is that users' data information will be leaked during the audit process,can not achieve zero knowledge privacy protection.2.Analyzed the relationship between Provable Data Possession(PDP)and Proof of Ownership(POW),This thesis proposed a cloud data integrity checking with deduplication scheme.Based on aggregatable signature based broadcast encryption scheme,to achieve data integrity verification and deduplication actually co-exist within the same framework.Another bonus of our construction is privacy preserving,meaning that the third party auditor learns nothing about the stored data during the auditing process.3.This thesis proposed a privacy preserving cloud data auditing with key update,the scheme utilize a unidirectional proxy re-signature,when a user needs to chanage his/her public key due to private key is lost or expired,the user only to generate a new secret key as well as the re-signing key,then forwards the resigning key to the cloud server.This construction also has the desirable property of publicly verification and privacypreserving,This thesis gave the security proof of this protocol and analyzed the performance of this protocol by experiment.