Design And Implementation Of One-way File Transfer System Based On Physical Isolation

The rapid development of information and communication technology and Internet technology changed the way of people's live and work and improving the efficiency of our work. But it also brings many serious security issues, such as information leakage, viruses, and so on. This is a great threat to information security of enterprises and institutions. The Chinese government attaches great importance to the protection of information security. According to the principles of the State Secrecy Bureau, computer information systems of secret units must be physically isolated from the outside network. Traditional information security technologies just control data transmission at the level of software, cannot meeting physical isolation requirements between the non-classified secret external networks and secret internal network. To solve the problem of inefficient and laborious way of data files transferring between the non-classified secret external networks and secret internal network, a file transfer system that can guarantee the complete one-way transmission in was designed and implemented.Based on the practical application, one-way physical transmission channel firstly was designed based on the common optical fiber adapter, optical splitter and optical fiber, and it can physically guarantee the one-way transmission of data. Different from electrical signals, light has the property of one-way transmission. The sending module and receiving module of the optical fiber network function is single and irreversible and the former is only responsible for sending optical signals, the latter only responsible for receiving optical signals and it will not form a loop. So, it can guarantee the complete one-way transmission of data. According to the unidirectional transmission channel, the data encapsulation format, transmission protocol and reliable transmission mechanism are proposed and the definition of the package of the transmission package, the file property package, the file block packet, the structure definition of the packet and the synchronization signal packet are the main modules. And on this basis, the software channel of the file transferring from the external unsafe network to the internal security network is realized by using Qt software development technology.The article has carried on the detailed functional testing and performance testing of the system. According to the analysis of test results, the system can effectively complete the file unidirectional transmission from the non-secret network to the classified network safely and reliably.