Research And Application Of Data Security Based On Hidden Search And Access Pattern

Dynamic searchable encryption methods allow a client to perform searches and updates over encrypted data stored in the cloud,greatly reducing the cost of data management and maintenance.But search patterns and access pattern are often leaked in the search and update process.Recent schemes enable secure searching over an encrypted database stored in a server,but these schemes only focus on hiding the access pattern using ORAM.Although the traditional Oblivious Random Access Machine(ORAM)can hide the access pattern,which refers to the set of documents that match the client’s queries,it also incurs significant communication overhead and cannot hide the search pattern.Existing researches show that the general dynamic searchable symmetric encryption(DSSE)scheme is vulnerable to statistical attacks due to the leakage of both search patterns and access patterns.Therefore hiding the access pattern is not enough,it is essential to hide both access patterns and search patterns with high efficiency.In order to overcome this limitation,this paper mainly studies how to hide search and access patterns efficiently,and conducts performance analysis and security analysis of this scheme.(1)In order to solve the problem of high communication overhead of the ORAM scheme,this paper presents a scheme for efficient and oblivious access to encrypted databases through encrypted indexes.This scheme is a hybrid ORAM scheme,which utilizes semi-homomorphic encryption to perform calculations in the ciphertext domain,overcoming the limitations of the huge overhead associated with Path-ORAM.For excessive amounts of data,semi-homomorphic encryption can significantly reduce communication and storage overhead.Our scheme can achieve high-security encrypted search and update operations at the same time.Moreover,the execution speed of ODS-Tree is 2-8x faster than that of ORAM-based schemes.In addition,the proposed scheme reduces the data block transmission and storage costs compared to existing frameworks..(2)In order to solve the problem of ORAM will incur additional cost,a DSSE scheme called obliviously shuffled incidence matrix DSSE(OSM-DSSE)is proposed in this paper to access the encrypted data obliviously without using ORAM.The OSM-DSSE scheme realizes efficient search and update operations based on an incidence matrix,In particular,a shuffling algorithm using Paillier encryption combines the 1-out-of-n obliviously transfer(OT)protocol to hide access pattern and an optimized padding scheme to obfuscate the search pattern with low storage overhead.Besides,Simulation results and security analysis confirm that OSM-DSSE scheme achieves high security and efficient searches.Also,this scheme provides adaptive security against malicious attacks by adversaries.Furthermore,OSM-DSSE is capable of searching for a keyword out of 9×1010 keyword-file pairs within 2.19s which is 3-4x better execution efficiency than the state-of-art solutions.(3)We conduct experimental evaluation on the performance of the scheme to ensure the high efficiency of the scheme.We used the Enron dataset to extract file-keyword pairs and used them to evaluate our scheme.The simulation results confirmed that the scheme in this paper achieves efficient search.At the same time,we also conducted a security analysis on this schemes,which proved that this scheme has achieved high security.Furthermore,the scheme provides adaptive security against adversary malicious attacks.At the same time,the application method of our scheme is pointed out.