The Research And Design Of Data Storage And Sharing Scheme Based On Blockchain

Recently,people use big data,artificial intelligence and other technologies to accurately analyze data,which not only brings efficient and objective data analysis,but also brings the challenge of data storage.With the characteristics of easy expansion and controllable resources,cloud storage can effectively provide convenient and low-cost storage services for big data.In terms of data management,Blockchain technology can realize the non-tampering of data and the credible circulation and sharing of data among multiple parties in a distributed and decentralized manner.Therefore,it is emerging in the field of big data.As massive amounts of data are stored on cloud storage servers,the requirement of data security is becoming more and more important.Since data leakage incidents emerge one after another,it is necessary to ensure the privacy and security of data.However,there are two key problems in existing cloud storage schemes:the first one is the lack of secure and reliable data exchange mechanism,resulting in the data cannot be shared.And the second one is the heavy cost of the data integrity verification.In this dissertation,we propose a data sharing scheme based on blockchain.The scheme is proved to be credible and confidential to achieve data sharing.At the same time,a blockchain based data integrity verification scheme is given.It can reduce the verification cost and ensure the security and credibility of the verification process.The specific research work of this thesis is as follows:(1)A ciphertext data sharing scheme based on blockchain is proposed.The scheme uses searchable encryption and blockchain in data sharing process.Firstly,the scheme uses searchable encryption to generate ciphertext index containing key words of data,and the index is stored on the honest and trustable blockchain.Therefore,the stored data is confidential and cannot be tampered.Secondly,the scheme adopts multi-keyword retrieval,which improves the accuracy of data searching.Finally,this scheme transfers the data retrieval behavior originally performed by the cloud server to the smart contract,which ensures the reliable retrieval of the stored data.Security analysis proves that the scheme can resist the attack of the adversary on the data information,and the efficiency analysis proves that the scheme is practical and feasible with low computational cost.In conclusion,this scheme realizes efficient and reliable data sharing through searching the ciphertext index,and the protection of data privacy makes this scheme more promising in application.(2)A blockchain based ciphertext data integrity verification scheme is presented.The method of probabilistic detection is used to cut the computation cost of data integrity verification.On one hand,the scheme store data into blocks and generates a corresponding merkle tree.At the same time,the online/offline cryptographic computing technology is used in the calculation stage of data verification tags,which improves the efficiency of the scheme execution.On the other hand,the scheme uses blockchain and smart contract to perform the verification process reliably and automatically.Without introducing untrusted third-party verifiers,the scheme avoids the denial behavior of dishonest participants.The security analysis shows that the proposed scheme can resist the internal attack to the correctness of the scheme and the external attack on the availability and data privacy.The data owner can verify the integrity of data accurately and reliably without a lot of local operations.And the balance between the accuracy of data integrity verification and the efficiency of verification overhead will also facilitate the integration of blockchain technology and cloud storage technology.