The Research On Verifiable Search Over Encrypted Data In Cloud Environment

In recent years,the technology of cloud computing has continued to develop and become mature.Now it is popular among enterprises and individuals.Users outsource data resources to cloud server storage and enjoy the convenience brought by cloud computing while saving computing and storage costs.However,cloud computing servers are accompanied by various risks when they collect a large amount of data.Not only are cloud servers vulnerable to external attacks,but the malicious behavior of cloud server providers themselves may sometimes lead to data damage or leakage.In order to prevent the risk of private data leakage,it is a feasible method to encrypt data before outsourcing to cloud servers.In this context,searchable encryption technology emerges as the times require.Searchable encryption technology can ensure data privacy while ensuring data privacy and the availability of data is improved,but it cannot guarantee the integrity of the search results returned by the cloud server.Therefore,it is necessary to verify the search results in a cloud computing environment.At present,verifiable ciphertext search technology has become a research hotspot,and it is an important way to ensure the security and integrity of keyword retrieval in the cloud environment.In this thesis,the following researches are carried out on the problems faced in the verifiable keyword ciphertext retrieval technology in the cloud environment:(1)Efficient Verifiable Search Scheme over Encrypted Cloud Data(EVSS): This method solves the problems of data privacy protection and integrity verification of search results in the cloud environment.The method extracts keywords from the document set,and constructs a RAP-tree index after generating evidence and authentication.In the RAP-tree,each path from the root node to the terminal node corresponds to a token of a keyword,and each terminal node stores an inverted list and an authentication corresponding to the keyword.After the user starts a query,the cloud server will return the retrieved ciphertext together with the authentication to the user,and the user can verify the integrity of the search result by reconstructing the evidence.The index of RAP-tree has a high search rate,and the RSA accumulator can ensure the integrity of the search results,and the additional communication cost brought by the authentication information is low.Through security analysis,it is proved that the EVSS scheme meets the requirements of data confidentiality and verifiability,and the feasibility and superiority of the scheme are proved through experimental analysis.(2)Dynamic Verifiable Search Scheme over Encrypted Cloud Data(DYVS): This method proposes a solution for the more realistic data dynamic update problem,and the method adds the update operation to the document set.By adding update record code and update record value to realize the verification of search results after the document set is updated,the update record code is saved by the data owner and shared with the data user,and the update record value is stored in the index.After a query is started,the update record value is returned to the user together with the search result.The update record code and the update record value of the corresponding keyword are recalculated each time the document set is updated,which are used to assist the verification of the search result after the document set is updated.Through security analysis and experimental result analysis,it is proved that DYVS scheme can realize safe and efficient verifiable keyword ciphertext retrieval function.Finally,by analyzing the specific requirements of the prototype system,the prototype system is designed and implemented according to the algorithms and modules.