Research On Securely Data Search For Cloud Storage

In cloud storage,users limited by resources can outsource data remotely.If the data is stored in plaintext,the privacy of users will be threatened.Searchable encryption technology not only provides the servers the ability of searching on encrypted data,but also protect the privacy of user data.There are two basic primitives: symmetric searchable encryption(SSE)and public key encryption with keyword search(PEKS).SSE primitives are efficient,but its security still need to be improved;asymmetric searchable encryptions has wide application scope and strong flexibility.This work focuses on DSSE and PEKS,solving problem of securely retrieving dynamic data in cloud storage,and the application of PEKS in novel cloud storage.The contents of this thesis mainly include the following aspects:For the problem of using dynamic searchable symmetric encryption(DSSE)to securely search data in cloud storage,the re-encryptability of symmetric puncturable(SPE)encryption is realized by the homomorphism of pseudorandom function(PRF),and the symmetric puncturable encryption with re-encryptability is obtained.The privacy of puncturable pseudorandom function(p PRF)is used to hide the deletion history without affecting the correct deletion,thus the correct file set can be obtained by searching.In the search process,users only need to interact with the server once,without sacrificing the efficiency of communication and calculation,and without increasing the amount of data stored by the client.Thus,a lightweight dynamic symmetric searchable encryption scheme is implemented,which achieves backward privacy with update pattern(UPBP)and does not use specific hardware such as random access memory(ORAM)or software guard extension(SGX).In order to improve the retrieval efficiency in cloud storage of decentralized anonymous payment(DAP)system,a PEKS scheme based on searchable public-key ciphertext with hidden structure(SPCHS)is proposed.A specific searchable public-key ciphertext with hidden structure for Zerocash payment(SPCHSZP)is designed,and its security is proved.By using SPCHSZP,this thesis improves the anonymous payment model and obtains an instantiated Zerocash payment scheme with efficient coin retrieval(ZPECR).The analysis shows that ZPECR has the same completeness and security as the Zerocash.Experiment shows that the efficiency of the proposed ZPECR is improved compared with the traditional Zerocash.