Cyber Physical Systems (CPSs) are considered as an integration of computing, networking, and physical processes. In such systems physical processes are monitored and controlled by the combination of computation, communication, and control technologies. Examples of CPSs include process control systems, medical devices, robots, and critical infrastructures such as water treatment plants, water distribution systems, and power grid. Often, these systems are vulnerable to attacks as the cyber components such as Supervisory Control and Data Acquisition (SCADA) workstations, Human Machine Interface (HMI), and Programmable Logic Controllers (PLCs) are potential targets for attackers. Replay attacks are easy to perform on such systems and can potentially lead to significant damages to the system. Therefore, timely detection of replay attacks is important to mitigate the attack consequences. In this work, we propose a practical watermarking technique to detect the attacks. Experiments are performed on a real WAter DIstribution system (WADI) to explore how to tackle the replay attacks using watermarking signal.

网络物理系统 (CPS) 被认为是计算、网络和物理过程的集成。在这样的系统中，物理过程通过计算、通信和控制技术的组合来监控和控制。CPS 的示例包括过程控制系统、医疗设备、机器人和关键基础设施，例如水处理厂、配水系统和电网。通常，这些系统容易受到攻击，因为监控和数据采集 (SCADA) 工作站、人机界面 (HMI) 和可编程逻辑控制器 (PLC) 等网络组件是攻击者的潜在目标。重放攻击很容易在此类系统上执行，并且可能对系统造成重大损害。所以，及时检测重放攻击对于减轻攻击后果很重要。在这项工作中，我们提出了一种实用的水印技术来检测攻击。在真实的水分配系统（WADI）上进行了实验，以探索如何使用水印信号解决重放攻击。