Timely and effective detection of malicious attacks is a primary problem in cyber-physical system security. This paper studies the detection of DoS (denial of service) attacks in identification of FIR (finite impulse response) systems with binary-valued observations. Based on the prior information of the system, an attack detection algorithm is designed, and its online form is given. The detectability is discussed for the ability of detection algorithm, and the necessary and sufficient condition for the attack strategy to be detectable is obtained. The concepts of the missed detection rate and false alarm rate are introduced, and their calculation methods and approximate formulas under large samples are provided. Furthermore, it is analyzed the influence of prior information of system parameters and data length on the performance of detection algorithm.The rationality of theoretical results is verified by numerical simulation.
KEYWORDSattack detection, DoS attack, FIR system, the false alarm rate, the missed detection rate
INTRODUCTIONCPS (cyber-physical system) is a complex system that combines environmental perception, network communication, data calculation, and control systems. It is widely used in various fields, such as biomedical monitoring records, efficient communication of transportation, and dispatch and distribution of smart grid, etc. [1-4]. In the process of integrating physical system with network, due to the openness of network and the frequency of data interaction, CPS is vulnerable to malicious network attacks. These attacks often disrupt the normal communication, affect the credibility of the data, and can produce damage to systems [5][6][7][8]. Therefore, research on the safety of the CPS is one of the great significance.There are dozens of attacks against CPS, among which FDI (false data injection) attacks, replay attacks, and DoS (denial of service) attacks are common [9]. The target object of FDI attack is generally the transmission channel or sensor, actuator, and other components of the system. By injecting false data, the attacker makes the control center receive data that does not match the actual situation