Research On Forward And Backward Secure Multi-keyword Ranked Retrieval Supporting Semantic Extension Scheme

Data is transmitted quickly with 5G technology between things and networks,networks and networks to facilitate human's life.The birth of cloud services has solved the problem of massive data storage and reduced the cost.However,people still have to face the problem of data security.These data contain all kinds of information about people.At the same time,most ECs are honest and curious;Some cloud servers are even completely untrusted.To protect data security and ensure that people's privacy is not leaked,data encryption becomes inevitable.However,after data encryption,users' search becomes complex and inconvenient.Searchable encryption technology is used to search the encrypted data.The existing multi keyword sorting and retrieval schemes do not support dynamic data updating.Although some schemes support dynamic data updating,their security or efficiency are slightly insufficient.Moreover,among the existing multi keyword retrieval schemes,multi keyword strict matching schemes account for the majority.Of course,there are some schemes that support multi keyword fuzzy matching.These schemes ignore the semantic relationship between keywords,which will lead to the search results not comprehensive and accurate enough.Facing the above problems,this paper has done the following three aspects:1.Firstly,a sort retrieval scheme supporting dynamic data update is proposed.In this scheme,the index structure of balanced binary tree is adopted.In addition to the dynamic updating of data,parallel retrieval is also realized.Spatial vector model and TF-IDF,as the key technologies of constructing index vector and query vector,encrypt index vector and query vector through secure k-nearest neighbor algorithm,which not only protects the privacy of data,but also ensures forward and backward security while dynamically updating data.2.Secondly,semantic query is applied to the retrieval scheme in this paper,so that our scheme supports dynamic data updating and ranks.Through the semantic relationship diagram to show the relationship between keywords,the semantic expansion of the queried keywords is achieved.Compared with some retrieval schemes that strictly match keywords,the retrieval results of this scheme are more comprehensive.In addition,the location information of keywords in the document is also explained,which also improves the accuracy of retrieval.3.Finally,the security and efficiency of this scheme are compared with several existing schemes.The efficiency and security of this scheme are improved.This scheme realizes parallel retrieval,so the retrieval efficiency is improved compared with the previous scheme;And forward security and backward security are also guaranteed in this scheme.