The Study Of EMR System Based On Cloud Storage And Access Control Policy

With the advent of information era, medical informationization has become an inevitable trend of modern medical. As the core application of medical informationization and the main carrier of medical information, Electronic Medical Record (EMR) will play an increasingly important role in modern medical. Now EMR system used in most domestic medical institutions is embedded in Hospital Information System (HIS) based on local area network, which limits EMR to support a wide range of information sharing, medical service and other functions to achieve. At the same time as the patient's EMR contains his privacy information, there will be issues about improper access and disclosure of privacy information in realization of information sharing, which is a major factor hindering the development and popularization of EMR.In view of the above problems existing in the application of EMR, this paper builds an EMR system based on cloud storage, which improves existing systems mainly from generality and security aspects and realizes unified convenient secure EMR registration and usage services for patients and hospitals.The EMR system in this paper is composed of EMR storage cloud and credible third-party. The EMR storage cloud is composed of resource storage layer, foundation management layer, access control layer and EMR service layer. The former two layers use cloud storage technology, which is easy to extend and maintain. Access control layer is used to implement authentication and privilege management function, EMR service layer is used to provide unified EMR services for patients and hospitals. The credible third-party stores patients'real identity information apart from their EMR in the EMR storage cloud, in which way the importance of data stored in the cloud is reduced so that the possibility of illegal access is reduced and patients'privacy is enhanced in a certain extent.Based on EMR access control requirements and existing access control model, the paper designs the EMR access control model in detail. The model increases rights decision module based on EMR context sensitivity level and permission assignment strategies on the basic model of Rule-Based Role Based Access Control (RB-RBAC), which can realize automated role assignment and dynamic distribution of fine-grained permissions. The paper gives a detailed design of EMR logical structure as the basic model for sensitivity level setting and permission assignment strategies formulating. Then the paper designs the permission assignment strategies including basic permission assignment strategies pre-established by medical experts and temporary permission assignment strategy made by patients and chief doctors in a certain medical activity, which can achieve patient controlled permission assignment function with high security and availability.The paper also gives the PMI implement of EMR access control model, which is composed of information query component, attribute authority, policy authority and database. Then the paper makes detailed design and description of each module. As implementations of privilege management module in EMR access control layer, the PMI system can provide unified convenient access control and rights management function.