Research On Forward And Backward Security Of Dynamic Symmtric Searchable Encryption Scheme

With the rapid growth of information,local storage and computing resources cannot fully meet people's needs.In this case,more and more data are concentrated on the cloud server.That brings issues about the data privacy.Searchable symmetric encryption is a useful cryptographic primitive that can encrypt the data to protect its confidentiality while keeping its searchability.Dynamic symmetric searchable encryption further provides data dynamics that allows the client to update data over the time without losing data confidentiality and searchability.However,many existing dynamic symmetric searchable encryption schemes suffer from attacks caused the by leakage.To resist these attacks,forward security and backward security are proposed.In this paper,we propose two dynamic symmetric searchable encryption schemes with forward and backward security.Our main contributions are as follows:1.To improving the query efficiency and reducing the storage,we construct a dynamic symmetric searchable encryption scheme with both forward and backward security.A binary tree is used as an inverted index in this scheme.The scheme achieves forward security by trapdoor permutations and achieves backward security based on puncturable encryption.The security analysis and proof show that our scheme is security.The efficiency and performance analysis of the scheme shows that the requirements of improving query efficiency and reducing space occupation are satisfied.2.From the perspective of improving the ability of query expression,we propose an extension scheme.This scheme is a dynamic symmetric searchable encryption scheme supporting multi-keyword query with forward and backward security.We still use a binary tree as the inverted index and trapdoor permutation and puncturable encryption to ensure forward security and backward security.Meanwhile,the scheme uses the minimum coverage of a tree and the relevance of keywords to implement the need for multiple keyword queries.The scheme meets the security requirement by the security proof.The efficiency and performance analysis of the scheme shows that the scheme supports multi-keyword query and improves the query expression ability.