Efficient secure group communications for SCADA

Modern industrial facilities have command and control systems. These industrial command and control systems are commonly called supervisory control and data acquisition (SCADA). In the past, SCADA system has the closed operating environment, so this system were designed without security functionality. These days, as a demand for connecting the SCADA system to the open network increases, the study of SCADA system security is an issue. A key-management scheme is essential for secure SCADA communications. Several key-management schemes for SCADA also have been proposed. Recently, advanced SCADA key-management architecture (ASKMA) was proposed. While previous studies do not support message broadcasting and secure communications, ASKMA supports it. Although the overall performance of ASKMA has many advantages compared to previous studies, it can be less efficient during multicast. In this paper, we propose ASKMA+ which is a more efficient scheme that decreases the computational cost for multicast communication. ASKMA+ reduces the number of keys to be stored in a remote terminal unit and provides multicast and broadcast communications.