Recently, cyber-attacks are increasingly targeting industrial control system facilities such as Stuxnet, Duke, and Flame. In order to protect these facilities from attacks, they separate industrial control systems from business network, and use a one-way data transmission technology for data transfer between each other systems. In this paper, we develop a unidirectional security gateway system, UNIWAY, which provides session management, packet loss prevention, access control, and malware detection for ensuring reliability and security of transfer data. To easily applying one-way technology, we use commercial Intel 82580EB NIC interface, and show 1Gbps data transfer throughput.