基于802.1x协议的无线网认证技术安全分析和研究

在简述802.11认证技术的基础上,重点介绍了新一代WLAN安全标准802.11i中使用的认证协议802.1x的工作机理,同时分析了802.1x在无线网中使用时存在的一些安全问题,提出了相应的解决办法。     

DoS攻击减缓技术

首先简单介绍了DoS攻击减缓技术的概念,然后对主要的DoS攻击减缓技术的原理及适用情况进行了分析。     

Sampled-data bipartite consensus control of nonlinear multi-agent systems under denial-of-service attacks

This article concentrates on the sampled-data secure bipartite consensus problem for a class of nonlinear multiagent systems under intermittent denial-of-service attacks. The network communication channels are destroyed when the attacks occur, which causes all the system states to be unavailable. A novel distributed sampled-data output feedback control protocol is developed by using the discontinuous sensor data. It is proved by the Lyapunov stability analysis that the considered nonlinear multiagent systems can achieve bipartite consensus exponentially in light of the designed control protocol. Then, the control algorithm is extended to systems with both state and input delay. Finally, a simulation example is presented to verify the effectiveness of the proposed control protocol.     

An Immutable Framework for Smart Healthcare Using Blockchain Technology

The advancements in sensing technologies, information processing, and communication schemes have revolutionized the healthcare sector. Electronic Healthcare Records (EHR) facilitate the patients, doctors, hospitals, and other stakeholders to maintain valuable data and medical records. The traditional EHRs are based on cloud-based architectures and are susceptible to multiple cyberattacks. A single attempt of a successful Denial of Service (DoS) attack can compromise the complete healthcare system. This article introduces a secure and immutable blockchain-based framework for the Internet of Medical Things (IoMT) to address the stated challenges. The proposed architecture is on the idea of a lightweight private blockchain-based network that facilitates the users and hospitals to perform multiple healthcare-related operations in a secure and trustworthy manner. The efficacy of the proposed framework is evaluated in the context of service execution time and throughput. The experimental outcomes indicate that the proposed design attained lower service execution time and higher throughput under different control parameters.     

Event-triggered model predictive control of switched systems with denial-of-service attacks

Observer-based model predictive control (MPC) for the discrete-time switched systems suffered by event-triggered mechanism and denial-of-service (DoS) attacks is discussed in this paper. We assume that the switch is slow enough and the attacker's energy is limited. To save network resources, an event-triggered mechanism is designed based on dwell time and triggered error. Under the coupled influence of attack and trigger, a complex mismatch of system mode and controller mode occurs, which brings difficulties to the transformation of MPC optimization problem. To address this problem, a new performance index coefficient is designed by using the increasing/decreasing law of Lyapunov function. On this basis, the transformation of the optimization problem is realized. Then, the controller gain and observer gain for the attack-free case are designed to guarantee the exponential convergence of the closed-loop system. In the presence of attacks, we obtain the upper bound of attack duty cycle, below which the exponential convergence of the system can still be archived. An example is illustrated at last to verify the validity of the main results.     

Optimal control strategy by tracking and compensation for ICPS under the DoS attack

To solve the security problem of industrial cyber-physical systems (ICPS) suffering from the Denial of Service (DoS) attack, this paper proposes an optimal control strategy with functions of tracking and compensation control. The system model, being depicted as a discrete linear time-invariant system combined with an improved Bernoulli model, is established to describe the system under DoS attacks by using the feedback control theory. The optimal control strategy is completed by designing linear quadratic Gaussian (LQG) controller consisting of a tracking regulator and a Kalman filter to achieve tracking control of ICPS whose equilibrium state is neither zero state nor zero output, where a periodic event-triggered mechanism is adopted for ensuring the system's stability. The compensation control strategy is completed by designing a compensator to compensate the system to a certain extent through the multistep state prediction compensation strategy after a DoS attack being detected, where the ${\chi }^2$ detector is adopted to detect the DoS attack based on the measurement residual obtained by the Kalman filter. The simulation test is conducted by using Simulink/True Time tool with a ball-beam system as the physical object, whose results show that the tracking regulator can achieve the tracking control of ICPS; compensation strategy can reduce the impact of the attack on the system to a certain extent.