The Research And Realization On The Security Of Distributed Database System

Because of the rapid development of Internet and the technology of database, distributed database is widely used. Simultaneously the demand on the security of distributed database is strongly cried for. Due to the urgent demand on high-security DDBMS, it is significant to make research on secure DDBMS.The security problem of DDB has been researched deeply. The system can get its security character by secure audit, message tracing, collecting the access property of the users, putting in the relevant domain with the method of fuzzy control and the learning rules, and making decision whether modifying the firewall rules. The main points are as follows:1. Based on the analysis of current access control model: DAC, MAC and RBAC. In this thesis the realization of MAC in RBAC is discussed. The background database is designed based on the model that includes the design of database backup and resume, database access control and the management of the system users. 2. The design and development of database middleware based on the model is discussed in chapter 4 that mainly includes two modules: communication module and security module. In security module, the security technology of user authentication, message encryption, audit tracing and access control is used. Other more we have applied fuzzy control technology and expert system. We have used 64 bites DES in the message transaction online. In audit module the audit message that would be analyzed by the IP-based audit process and the user-based audit process is stored in database in the form of table. 3. The realization of the security of DDB. We realized the foreground in java and use the technology of socket to communicate with the middleware that was developed in C compiling environment in Linux.The system has realized the security of DDB by intrusion testing. It confirmed the feasibility of this scheme by using the secure technologies on the module of MAC applying in RBAC.