Research And Implementation Of Network Isolation And Data Exchange-based Security Systems

The problem of computer security was almost born with the presence of computer, and especially with presence and rapid development of the computer network, it takes on more and more important.when we developed the project The network management information system of the college of continuing education of Guangdong University of Technology, such a problem was faced: students inquire about scores via extranet, and teachers enter scores into intranet via extranet ,the security of the important data in intranet must be ensured once the firewall, etc. is void. Therefore, there must be a mechanism to ensure the isolation and exchanging data between intranet and extranet.In this paper based on the solution of that problem, a multilevel defense system is researched and implemented. The system ensures the extranet by traditional technology, such as IDS and filtering the packet, and ensures the internet by installing a set (called isolation & exchange set)between intranet and extranet , which is the core of the system and isolates networks & automatically exchanges data between intranet and extranet. The core part doesn't use the protocol of TCP/IP, and it transfers especial format data defined by myself by a serial port/parallel port or a USB port with driver software researched by myself and keeps isolated state which is equal to physical disconnect when one side exchanges data with the part of the core by the circuit locking each other. To ensure the efficiency and availability of data, the system transfer data at fixed time. At the same time, the data of the score must be with signature of a teacher when it is printed on the paper that is saved.Finally, a security mechanism the teacher enters data via the Internet is finally put forward to ensure the security of transferring data.A system which indubitably resolves the isolation between intranet and extranet and exchanging data was not found by research. The system was successfully used on The network management information system of the college of continuing education ofGuangdong University of Technology and will be used on Guangzhou Wangfujin Electronic Commerce System and Guangdong Electronic Appliances Market Electronic Commerce System. In fact, any project system involved in network security and isolation between intranet and extranet can use the system directly or with little modification. The system is very advanced, and it has practicability and generalization.