Multi-phrase Ranked Search Over Encrypted Data With Symmetric Searchable Encryption

As cloud computing becomes prevalent,more and more data owners are likely to outsource their data to a cloud server.However,to ensure privacy,the data should be encrypted before outsourcing.Symmetric searchable encryption allows users to retrieve keyword over encrypted data without decrypting the data.Many existing schemes that are based on symmetric searchable encryption only support single keyword search,conjunctive keywords search,multiple keywords search,single phrase search and so on.This article mainly focus on the research of phrase search in symmetric searchable encryption.However,users may want to search several phrases in a query request,and retrieve the Top-k files.Data owners may also want to update the outsourced data.For the above problems,we propose a multi-phrase ranked search over encrypted cloud data,which also supports dynamic update operations,such as adding or deleting files.We used an inverted index to record the locations of keywords and to judge whether the phrase appears.This index can search for keywords efficiently.In order to rank the results and protect the privacy of relevance score,the TF-IDF model is used in searching process on client-side.Also,the special construction of the index makes the scheme dynamic.In this article,we design the model of multi-phrase ranked search with symmetric searchable scheme,and describe the algorithm in detail.The experimental analysis is carried out in the actual data set,and the results of experiment demonstrate the efficiency of the proposed scheme.We also do security analyses in paper,and prove the safety of our scheme,the data privacy can be well protected,and the proposed scheme cannot reveal the files and keywords to adversaries.