Multi-keyword Searchable Encryption Via Blind Storage

With the advent of big data Era,the cloud storage becomes more and more widely.Compared with the traditional storage mode,cloud storage provides a good solution for users to share data between different devices,it has flexibility,scalability and ease of management.However,cloud storage brings convenience to users while also causing the separation of data ownership and management rights.Thus it cause users to worry about the security of the data being threatened rather than using cloud storage services,this greatly affects the development of cloud storage services.Security considerations for data in the cloud storage are primarily Availability,Confidentiality,and Integrity.And often the confidentiality of data is the most important factor.Therefore,in order to effectively protect the confidentiality of the data,the effective way is to encrypt the data.But the data will lose its original characteristics in encrypted form,this will lead to the user not to search on the encrypted data.Thus,it greatly reduces the availability of data.So how to effectively search the encrypted data stored in the cloud server has become an important problem to be solved urgently.On the basis of the research of searchable encryption,this paper proposes a multi-keyword searchable encryption via blind storage method,for the case where most searchable encryption schemes only support single keyword search and the security model is weak.And in the guarantee of file data confidentiality at the same time,allow the user to carry out a multi keyword search on the encrypted data.In order to ensure the zero leakage of access mode in the search process of the encrypted data,we first give a blind storage scheme for cloud data,the scheme allow users to store sensitive data on untrusted servers,and use the blind technology to ensure that the server will not be informed of the user's access mode,the scheme provides functions such as uploading files,downloading files,and updating files.The security analysis shows that the scheme satisfies dynamic adaptive security.Based on this scheme,this paper constructs a multi-keyword searchable encryption scheme via blind storage.This scheme uses the Paillier homomorphic encryption method to generate security index,and bases on private set intersection techenique to implement multi-keyword ciphertext.The security analysis shows that the scheme has the semantic security of searchable encryption.Finally,a prototype system is designed and implemented.The system consists of two entities:the client and the server,the system mainly includes:file access and keyword search functions.For the number of files,file size,dictionary size and other aspects of the performance of the system in a detailed test,the results show that the system has good computational cost.