Research On Searchable Encryption Technology In Cloud Storage

With the rapid development of information technology,the big data deeply associ-ated with companies and individuals has increased powerfully,and such a large amount of data makes it difficult to store for users due to storage resource restricted.Fortunately,cloud storage technology,as an important service mode of cloud computing,enables data owners to store such data conveniently and efficiently at remote cloud servers.However,data privacy leakage and server attacks occur frequently,when data owners conveniently use cloud storage services to store data.For these users,the biggest concern they care about is the privacy of the data they store in the cloud.Therefore,in order to store their data safely,data owners always encrypt the data to be stored and then store the ciphertext data to the cloud server.In addition to facilitating the safe storage of their data,data own-ers can also retrieve their own stored data on the cloud server for an indefinite period or provide efficient retrieval services for other authorized data users by cloud servers.Differ-ent from the traditional plaintext retrieval technology,how can the cloud server perform data retrieval service on the ciphertext for users(data owners or data users),searchable encryption is such a technology that can provide a technical solution.Scholars have done a lot of research on searchable encryption technology and created many specific technical solutions to realize this emerging technology.Among them,the keyword-based searchable encryption technology becomes the mainstream of research work.This technology scheme can return the search results related to the given query keywords from a data user.At present,the keyword-based searchable encryption technol-ogy schemes mainly consist of single-keyword search,multi-keyword search,conjunc-tive keyword search,and fuzzy keyword search,etc.At the same time,the keyword-based search schemes have rich corresponding performance,such as the keyword rank search and keyword verifiability search.Considering the problems existing in the current keyword-based searchable encryption schemes,like the keyword privacy disclosure and enhanced fine-grained access control for data sharing,this paper tries to give solutions to these two main problems on the basis of summaries of the existing relevant schemes.The following is the main research content:(1)In keyword-based searchable encryption schemes,the secure construction of index is very important for keyword privacy preserving.In this part,a global index pair is designed to solve the problem of keyword privacy leakage caused by the access pattern and search pattern in the keyword-based searchable encryption scheme.Additionally,this scheme supports k-nearest neighbour search,k-NN.(2)Based on the part(1),this paper constructs an enhanced fine-grained conjunctive keyword search scheme.Combined with the global index pair constructed in(1)and the attribute-based encryption technology,this part presents a ciphertext searchable scheme which supports enhanced fine-grained access control for data sharing.This scheme can realize such an application scenario that users with different attribute permissions may not receive the same search results,even if they use the same query keywords.Our scheme makes up the defect that the relevant attribute-based keyword searchable encryp-tion schemes cannot flexibly meet the search requests of users with different roles and resists the privacy leakage resulted from access pattern and search pattern simultaneously.