Research On Dynamic Searchable Symmetric Encryption With Forward Privacy And Application Of Encrypted Electronic Medical Record System

With the rapid development of cloud computing,more and more users choose to migrate their local data to the cloud server,so as to save local data management and system maintenance costs.However,due to some uncertain factors,such as improper operation of cloud server administrator and illegal intrusion by hackers,a large number of user information and private data are directly exposed.In order to ensure the confidentiality of data uploaded to the cloud server and retain the keyword retrieval ability of the cloud server,searchable encryption technology was proposed and has been extensively researched and developed by researchers in recent years.Dynamic searchable encryption enables users to update the outsourced database without losing the confidentiality and searchability of the data.However,with the operation of updating the database,the additional disclosure of information may pose a threat to the privacy of users.In order to eliminate the impact of additional information leakage caused by updating the database,the concept of forward privacy is proposed.Some recent attacks indicate that forward privacy has become a basic requirement for designing new dynamic searchable encryption schemes.Based on the research of the existing dynamic searchable encryption schemes,the specific work of this paper is as follows:1.From the perspective of expanding query capability and improving scheme efficiency,a forward secure conjunctive-keyword searchable symmetric encryption scheme is proposed.The scheme achieves forward privacy by updating the latest state of the local client,so that the newly added file can only be searched by the search token generated by the latest state,while the old search token cannot be searched for the newly added file.In addition,by means of the Shamir threshold secret sharing scheme,the scheme tests the result file matched to the query single keyword,to see whether the same secret value can be recovered,so as to determine whether the file contains multiple keywords of the query at the same time.2.Motivated by the universal phenomenon in data outsourcing that user’s data is often separately distributed,we propose a FBSSE-MDS scheme in the scenario of multiple data sources which also provides both forward privacy and BP-Ⅱ backward privacy to limit the leakage to the server when data sources perform update operation.3.Designed a traceable and forward secure searchable encrypted medical record system based on national secret algorithm.This system is mainly solve the problems of the patients’ privacy in electronic medical record system,involving the patient of important private data storage and transmission encryption processing modules,on the premise of guarantee security to provide fast and efficient processing.The whole system is based on C/S architecture,and its main functional modules include user management,patient registration,doctor reception,efficient query of diagnostic records,traceability authentication of diagnostic records,and key update of trusted center,etc.