Research On Lattice-based Data Integrity Verification In Cloud Storage

With the rapid development of cloud computing technology,cloud storage services have been more and more widely used.While bringing convenience to cloud users,the integrity of user data in cloud storage is facing great challenges,for example: user data and identity information disclosure,user data tampered and other issues.Once the integrity of user's cloud data is corrupted,it will cause serious losses.Therefore,the data integrity checking in cloud storage is an essential work.At present,data auditing technology is mainly used to check data integrity,most cloud storage data auditing schemes are based on traditional public key cryptography.But with the raised algorithms such as quantum large number decomposition,their security is lost,while lattice-based cryptography is widely considered being able to effectively resist quantum attacks.Therefore,in view of data integrity verification in cloud storage and resistance to quantum attack,this thesis studies the lattice-based data integrity verification method in the cloud storage.The main work is as follows:(1)A lattice-based proxy-oriented medical data public auditing scheme in cloud-assisted wireless body area networks(WBANs)is proposed.Based on the Small Integer Solution(SIS)problem,using identity-based signature technology,this scheme implements the medical data integrity verification in WBAN.At the same time,the idea of proxy signature is introduced to reduce the computing and communication overhead of the users,which makes the scheme more efficient and practical.(2)An identity privacy protecting public auditing scheme for shared public medical data is proposed.Based on the extension Split-SIS problem,using the technology of ring signature,it realizes the data integrity checking of shared medical data,and effectively protects the data privacy and anonymity.Trace of malicious signer is using LWE public cryptography.The update key is generated by lattice basis delegate technology to avoid the threat caused by the disclosure of user key.(3)A lattice-based certificateless public auditing scheme is proposed by using refuse sampling technique.Combining the advantages of certificateless signature technology and aggregation signature technology,this scheme eliminates the peoblem of key escrow and certificate management,realizes batch auditing of data,and improves auditing efficiency.The three schemes in this thesis have been proved to be effective and secure in meeting the requirements of unforgability,privacy-protection and data integrity verification under the corresponding assumption.