ABSTRACT
In recent years, networks have received considerable attention with the rapid development of network technologies. It has become an inevitable trend for combining networks with control systems. At present, NCSs have been widely applied in strategic and significant infrastructure fields such as electrical power systems, chemical industry, manufacturing industry, natural gas systems, etc [54, 183]. Equipped with networks, control systems have many advantages in mobility and flexibility. However, the introduced networks also bring some new challenging problems on control systems. Although it reduces costs to transmit control commands or measurement signals via public networks, inherent closeness of control systems is inevitably broken. Traditional control systems adopted dedicated signal transmission protocols. At present, standard transmission protocols and commercial operation systems are used for control systems, which will seriously increase attacked abilities. Since control systems have high requirements for real time and availability, a lot of control systems ignore or even deliberately decrease security protection from security protection perspective. From external environment perspective, attacked means and techniques gain increasing developments. Attacks aiming at industry control systems are emerging in an endless stream now [194, 141].
