Research On Lattice-based Cloud Storage Integrity Checking Schemes

With the rapid development of cloud computing and the continuous growth of data,more and more individuals and organizations choose to store data in the cloud.However,due to the existence of some security risks in cloud storage services,data may be damaged or missing,resulting in data integrity damage.In order to check the integrity of cloud data,cloud storage integrity checking schemes should be used urgently.At present,many cloud storage integrity checking schemes are based on traditional hardness problems such as discrete logarithm and factorization,but these problems are threatened by the coming quantum computer.As a cryptosystem that can resist quantum computation,lattice-based public key cryptography has high security,relatively efficient implementation.However,there are still security and efficiency problems in the existing lattice-based cloud storage integrity checking schemes.To overcome these problems,the research on lattice-based public cloud storage integrity checking schemes is carried out in the thesis,and the following research results are achieved:(1)Aiming at the security and efficiency problems of existing identity-based cloud storage integrity checking schemes,a new identity-based cloud storage integrity checking scheme is constructed by using the short integer solution problem over ideal lattices in the thesis,and it is proven to be secure against the adaptive identity attacks of clouds in the random oracle model.Compared with the scheme over general lattices,the lengths of the system parameters and the user's private key in the scheme are reduced by O(n)times,in which n is the security parameter.The experimental results show that the communication overhead of this scheme is higher than that of the traditional scheme,but compared with the two existing schemes,the online file-storing time of the scheme is reduced by 88.32%~93.74%,and the proof verification time is reduced by 98.81%~99.73%.(2)To further improve the efficiency of lattice-based cloud storage integrity checking schemes and provide stronger security guarantees,by using the learning problem with errors and the short integer solution problem over rings,an efficient public cloud storage integrity checking scheme over lattices based on public key infrastructure is constructed in the thesis.The audit proof of the scheme is proven to be unforgeable in the random oracle model,and the retrievability of the scheme is proved on the polynomial ring over the rational number field.By using the commutativity of polynomial rings,coefficients in audit challenge are set as polynomials instead of single integers,so the norm growths of homomorphic authenticator and aggregate block are slowed down,and the communication overhead is also reduced.The experimental results show that compared with the two existing schemes based on pairing and RSA,the communication overhead of this scheme is larger,but the time of file-storing and proof verification is reduced by 93.97%~95% and 58.73%~74.43% respectively.