Secure Control Protocol Research Articles

Secure group consensus of nonlinear multi‐agent systems with multiple attacks under periodic event‐triggered control

SummaryIn this paper, the secure group consensus is investigated via periodic event‐triggered output feedback control for nonlinear multi‐agent systems subject to multiple attacks, where replay attacks and denial‐of‐service attacks are considered simultaneously. To avoid uninterrupted communication between agents, a novel fixed/switching continuous‐discrete compensator is first put forward by introducing a discrete‐time triggering mechanism in relative output signals. Then, with the help of the gain control technique, a compensator‐based periodic event‐triggered secure control protocol is established, which includes a triggering mechanism and an output feedback controller that both are discrete‐time. Particularly, Zeno behavior and continuous monitoring of the triggering function are naturally avoided compared with existing event‐triggered control protocols. Further, by combining the Lyapunov‐Krasovskii functional approach with switching topology theory, the secure group consensus is successfully achieved under the designed secure control protocol, meanwhile, the negative effect of multiple attacks on the system is compensated. Finally, two simulation examples are applied to verify the effectiveness of proposed control protocols.

Observer-based impulsive consensus control of nonlinear multi-agent systems under denial-of-service attacks

This paper is concerned with the distributed impulsive consensus problem for nonlinear multi-agent systems (MASs) subject to denial-of-service (DoS) attacks, where the information of agent states is not fully available in the impulsive control design. To reconstruct the states of MASs and guarantee secure average consensus, a novel observer-based impulsive secure control protocol is put forward, and some sufficient conditions are derived by means of linear matrix inequality (LMI) technique and Lyapunov method. It should be pointed out that both the proposed state observer and control protocol adjust the state value abruptly at some discrete instants in an impulsive manner. Moreover, the considered asynchronous DoS attack model can allow jam each channel independently, under which the decay rates of different attack modes are estimated. Finally, two simulation examples, including a practical control system, verify the effectiveness of the proposed consensus algorithm.

Anti-Attack Event-Triggered Control for Nonlinear Multi-Agent Systems With Input Quantization.

In this article, an anti-attack event-triggered secure control scheme for a class of nonlinear multi-agent systems with input quantization is developed. With the help of neural networks approximating unknown nonlinear functions, unknown states are obtained by designing an adaptive neural state observer. Then, a relative threshold event-triggered control strategy is introduced to save communication resources including network bandwidth and computational capabilities. Furthermore, a quantizer is employed to provide sufficient accuracy under the requirement of a low transmission rate, which is represented by the so-called a hysteresis quantizer. Meanwhile, to resist attacks in the multi-agent network, a predictor is designed to record whether an edge is attacked or not. Through the Lyapunov analysis, the proposed secure control protocol can ensure that all the closed-loop signals remain bounded under attacks. Finally, the effectiveness of the designed scheme is verified by simulation results.

Estimator-based event-triggered leader–following consensus of multiagent systems under denial-of-service attacks

The leader–following consensus issue is investigated for multiagent systems under external disturbances and denial-of-service (DoS) attacks. DoS attacks are considered to be designed according to an unknown attack strategy and would block the communication network. First, a novel triggering mechanism is designed to save communication resources during normal communication periods by event-triggered strategy and to detect the end of attack periods by time-triggered strategy. Then, a set of estimators is constructed to predict the states of the agent itself and its neighbors when the attack occurs. The estimators do not contain the control signals, which only correct the prediction when the actual system states are received. As a result, a distributed switching controller is designed that includes event-triggered states during normal communication periods and predicted states during attack periods. Finally, the proposed secure control protocol is proven to ensure that the system states are eventually consensus and the Zeno behavior is not exhibited. Moreover, a simulation example is given to illustrate the effectiveness of the presented strategy.

Observer-Based Secure Event-Triggered Bipartite Consensus Control of Linear Multiagent Systems Subject to Denial-of-Service Attacks

This brief deals with the secure bipartite consensus problem for linear multi-agent systems (MASs) with Denial-of-Service (DoS) attacks subject to an observer-based dynamic event-triggered strategy (OBDES). Two event-triggered strategies involved with dynamic threshold are developed in controller and observer channels. Based on the connected structurally balanced signed graph, a new observer-based secure control protocol integrated of OBDES and relative output measurements of neighboring agents is proposed. The control strategy with dynamic coupling gains is fully distributed, which only requires to obtain the observer information from neighboring agents. Then, some criteria for secure bipartite consensus under DoS attacks are established. In addition, it is demonstrated that the Zeno behavior cannot not occur. At last, a numerical simulation is provided to verify the effectiveness of the proposed controller.

Event-based secure consensus of multiple AUVs under DoS attacks

In this paper, the event-based triggering method is adopted to investigate the secure consensus issue of multiple autonomous underwater vehicles (AUVs) under denial-of-service (DoS) attacks. DoS attack is a form of time-sequence-based cyber attack, which can destroy the normal service of the control target or network. First, based on an event-triggered mechanism, a novel secure control protocol is proposed. Second, the upper bounds of attack duration and attack frequency are given to ensure that multiple AUVs under DoS attacks can reach consensus. Third, an event-triggered mechanism with exponential variables is developed to avoid the continuous update of the controller, thereby reducing the burdens of communication and calculation. Zeno behavior can be strictly ruled out for each AUV under this triggering mechanism. Finally, the simulation results illustrate the feasibility of the proposed scheme.

Cooperative Output-Feedback Secure Control of Distributed Linear Cyber-Physical Systems Resist Intermittent DoS Attacks.

This article studies a cooperative output-feedback secure control problem for distributed cyber-physical systems over an unreliable communication interaction, which is to achieve coordination tracking in the presence of intermittent denial-of-service (DoS) attacks. Under the switching communication network environment, first, a distributed secure control method for each subsystem is proposed via neighborhood information, which includes the local state estimator and cooperative resilient controller. Second, based on the topology-dependent Lyapunov function approach, the design conditions of secure control protocol are derived such that cooperative tracking errors are uniformly ultimately bounded. Interestingly, by exploiting the topology-allocation-dependent average dwell-time (TADADT) technique, the stability analysis of closed-loop error dynamics is presented, and the proposed coordination design conditions can relax time constraints on interaction topology switching. Finally, two numerical examples are presented to demonstrate the effectiveness of the theoretical results.

Secure control protocol for universal serial bus mass storage devices

The universal serial bus (USB) has some advantages like high transmission speed, plug-and-play and hot swapping, and has become the most popular interface standard for peripheral connections. However, such features also make it easier for a malicious user to extract confidential files from computer systems via USB ports. Consequently, to control the potential security risks of USB interface, many workplace and commercial corporations have directly forbidden their employees from using USB devices. To provide a flexible way of using USB without compromising security, this study proposes a novel secure control protocol for USB storage devices. The device and the server are required to complete mutual authentication and establish a session key used to encrypt the transferred files. The details of each phase of the new protocol are given. Security analysis demonstrates that the proposed protocol conquers those security pitfalls existing in the available protocols and can resist various attacks. Performance discussion indicates that the new protocol is also efficient enough for practical applications.

A secure control protocol for USB mass storage devices

The Universal Serial Bus (USB) has become the most popular interface standard for hardware connection, and there has been an explosion in the number of USB peripheral devices. External USB storage devices, in particular, are finding widespread application. Unfortunately, because USB affords high transmission speeds and is extremely convenient, many workplaces and businesses have prohibited the use of USB devices to prevent confidential data from being extracted from computer systems via USB ports. However, this compromises the convenience of the USB connection and demonstrates a lack of flexibility in management. Therefore, finding a way to take the considerations of both convenience and management into account has become a significant issue. This study proposes a secure control protocol which provides mutual authentication and key agreement between client and server to solve this problem.