Research On Technology Of Efficient Multi-Keyword Searchable Encryption Based On Inner-Product Functional Encryption

With highly development of cloud computing,people are generating more and more data.However,due to computational and storage resource,data owners wish to outsource their data to cloud server and share his archives to data users through the cloud server.In order to protect the privacy of sensitive information,they should be encrypted before being uploaded to the cloud server.However,in this way,it is hard to find data in encrypted form according to search criticisms.To solve this problem,searchable encryption has merged.In this paper,we mainly focus on multi-keyword searchable encryption under single-owner/mluti-user setting.The specific research contents are as follows:First,we propose an efficient multi-keyword searchable encryption scheme based on multi-input inner product functional encryption(referred to as EMKS scheme).In some multi-keyword searchable encryption schemes,it first finds the files including the low frequency keywords data user wants to search and checks whether these files include other keywords.However,for scenes that the number of keywords is limited but the number of files is huge such as sharing a comprehensive knowledge base of a certain field,search efficiency is reduced.So we propose a scheme mainly applicable to the above scenes.In EMKS scheme,by tactfully leveraging multi-input inner-product functional encryption,the cloud server is able to complete search processes with search tokens which consist of constant items.Besides,by using an inverted index structure and super-incremental sequence,our schemes achieve efficient multi-keyword search.In addition,the schemes avoids per-query interaction between the data owner and data users.On the other hand,the schemes also achieves index indistinguishable security and token indistinguishable security at the same time.Then,we propose a verifiable multi-keyword searchable encryption scheme(referred to as VEMKS scheme).It adds verification functionality in EMKS for circumstances in which the cloud server is malicious and return incorrect results to users.Besides,VEMKS scheme also has the advantage that search tokens consist of constant items.Finally,we propse a ranked multi-keyword searchable encryption scheme(referred to as REMKS scheme).This scheme ranks the search results by calculating the degree of relevance of keywords and the documents.And then returns the most relevant top-k documents to the user.In addidtion,this scheme constructs a tree-based keyword index structure and uses a pruning depth-first search method to improve search efficiency.