Research On Cloud Data Integrity Verification Method Based On Blockchain

With the rapid development of cloud storage,data security issues on the cloud have attracted more and more attention.Traditional cloud data auditing schemes use third-party institutions to conduct integrity audits on user data,and believe that thirdparty institutions are absolutely credible,but in actual situations,third-party institutions are just as untrustworthy as cloud service providers.In view of this situation,this paper carries out the corresponding research on the cloud storage data integrity verification scheme,and puts forward the corresponding solutions combined with the blockchain technology.Firstly,aiming at the untrusted problem of the third-party audit institution in the traditional three-party verification model,the blockchain with the characteristics of decentralization and non-modification is used as the specific third-party audit platform to replace the trust-based centralized audit institution in the traditional scheme,and a trust model guaranteed by cryptography is constructed to improve the security of audit scheme.Then for the specific audit algorithm,this paper puts forward two different schemes.With the rapid development of quantum computing,the security of traditional cryptography is threatened.This paper proposes a lattice signature verification scheme combined with cuckoo filter.On the one hand,based on the small integer solution problem,the signature scheme can resist the threat of quantum computing and ensure the security of the scheme.Secondly,according to the characteristics of lattice signature and the requirements of data integrity verification in cloud storage scenario,the signature scheme and the cuckoo filter are combined to reduce the computational complexity of the user in the signature verification phase.At the same time,in order to meet the requirements of data dynamic modification,Merkel hash tree is introduced to support the data dynamic operation.The results of safety analysis and comparative experiments verify the feasibility and efficiency of the scheme.Since the traditional data audit schemes cannot recover the damaged data,this paper uses B + tree to improve the traditional Merkel tree structure,which supports the tracking and recovery of data modification,and improves the efficiency of data retrieval.Then the traditional audit algorithm based on bilinear mapping is analyzed and improved to reduce the computational complexity of the algorithm in the signature generation phase.Finally,combining the improved algorithm with Merkel tree structure based on B + tree,a dynamic data public audit scheme is realized.Theoretical analysis and experimental results verify the security and efficiency of the scheme.