Asynchronous Attacks Research Articles

A variable threshold weight approach to dynamic event-triggered consensus control for leader-following multi-agent systems under asynchronous DoS attacks

This paper is concerned with the event-triggered consensus problem for leader-following multi-agent systems under asynchronous denial-of-service (DoS) attacks. Since the asynchronous attacks on different edges may enlarge the defense burden, the topology connectivity is employed to reveal the effectiveness of attacks and determine the unhealthy time periods. Relying on the internal system state, a dynamic event-triggered mechanism is built to regulate the information transmission between agents. In this mechanism, a variable threshold weight composed of the deviations of the relative neighboring errors and historical state errors is proposed to adaptively schedule the triggering thresholds with systems running stages. To guarantee secure consensus performance even during the triggering intervals, the local estimation of the neighboring information is integrated into the controller such that sufficient conditions to obtain the control parameters and the tolerable attack parameters are established without any Zeno behavior. The proposed method is validated by a simulation study.

Adaptive memory event-triggered observer-based pinning synchronization control for complex dynamical networks under asynchronous attacks

This article addresses the security synchronization issue of complex dynamical networks under asynchronous cyber and physical attacks within the context of cyber-physical systems. An observer is devised to estimate the system's state using the measured outputs of partial nodes. The integration of a buffer for storing historical information enhances the accuracy of state estimation under asynchronous attacks, enabling the observer-based control scheme to generate more precise control signals during attacks. The robustness against external disturbances is reinforced by introducing disturbance compensation for both the observer and the controller. Additionally, an adaptive memory event-triggered mechanism is designed to conserve network resources. Then, a sufficient condition for the synchronization of complex dynamical networks against asynchronous attacks is obtained, and the gains of the observer and controller are computed based on the linear matrix inequality technique. Finally, a simulated example demonstrates the effectiveness of the suggested strategy.

A Lightweight and Privacy-Preserving Authentication Protocol for Healthcare in an IoT Environment

In Internet of Things (IoT)-based healthcare, sensor nodes are deployed to detect the patient’s physiological data in a wireless sensor network. In order to prevent unwarranted users from accessing the sensor network to obtain patients’ data, designing lightweight and privacy-preserving authentication protocols plays a crucial role. Many lightweight authentication protocols for IoT-based healthcare have been proposed in recent years, but most of them may suffer from one or more security problems. In particular, few protocols can resist sensor node-captured attacks and achieve n-factor secrecy, which leads to unauthorized personnel being able to access the patient’s physiological data and obtain patients’ privacy. Therefore, a lightweight and privacy-preserving authentication protocol for healthcare based on elliptic curve cryptography (ECC) and physical unclonable function (PUF) is proposed to surmount the above obstacles. We design a dynamic anonymity strategy to achieve users’ anonymity and unlinkability and use PUF to protect information stored in users’ devices and sensor nodes. In addition, higher security features such as three-factor secrecy, perfect forward secrecy, resistance to sensor node-captured attacks, and update asynchronous attacks are guaranteed. The proposed protocol is proven to be secure under the random oracle model and maintains lightweight computing efficiency.

Hybrid Dynamic Event-Triggered Control for Networked Control Systems Subject to Asynchronous DoS Attacks

Hybrid Dynamic Event-Triggered Control for Networked Control Systems Subject to Asynchronous DoS Attacks

Dynamic-Memory Event-Based Asynchronous Attack Detection Filtering for a Class Of Nonlinear Cyber-Physical Systems.

In this article, we endeavor to address the problem of asynchronous attack detection for a class of nonlinear cyber-physical system (CPS) under the dynamic-memory event-triggered transmission protocol (DMETP). Malicious attacks under consideration are composed of the parameter-dependent false data-injection (FDI) attacks and the multichannel deception attacks with the time delay. Meanwhile, we attempt to employ the T-S fuzzy singular Semi-Markov jump linear parameter-varying (SS-MJLPV) systems to describe the stochastic jump characteristics and nonlinear time-varying characteristics of CPSs. Then, the DMETP is proposed for the first time, which can not only relieve the bandwidth pressure but also obtain the key released packets at the crest or trough of the curve. By augmenting the states of the original system and the asynchronous attacks detection filter, the issue of attacks detection is converted into an auxiliary dissipative filtering for the CPS. Moreover, sufficient conditions for the existence of the attacks detection filter are obtained. Finally, the effectiveness of the proposed scheme is verified via the networked truck-trailer reversing system.

A Novel RFID Authentication Protocol Based on Reconfigurable RRAM PUF.

Radio frequency identification technology (RFID) has empowered a wide variety of automation industries. Aiming at the current light-weight RFID encryption scheme with limited information protection methods, combined with the physical unclonable function (PUF) composed of resistive random access memory (RRAM), a new type of high-efficiency reconfigurable strong PUF circuit structure is proposed in this paper. Experimental results show that the proposed PUF shows an almost ideal value (50%) of inter-chip hamming distance (HD) (µ/ = 0.5001/0.0340) among 1000 PUF keys, and intra-chip HD results are very close to the ideal value (0). The bit error rate (BER) is as low as across one million challenges. Based on the RRAM PUF, we propose and implement a light weight RFID authentication protocol. By virtue of RRAM’s model ability, the protocol replaces the One-way Hash Function with a response chain mutual encryption algorithm. The results of test and analysis show that the protocol can effectively resist multiple threats such as physical attacks, replay attacks, tracking attacks and asynchronous attacks, and has good stability. At the same time, based on RRAM’s unique resistance variability, PUF also has the advantage of being reconfigurable, providing good security for RFID tags.

Remote observer-based robust control for cyber-physical systems under asynchronous DoS attacks: an intelligent approach

In this paper, the input-to-state stability (ISS) control problem is studied for cyber-physical systems (CPSs) in the presence of asynchronous denial-of-service (DoS) attacks. To enhance the exponential ISS, an intelligent packet-based control method with buffering is proposed by introducing the acknowledgement signal (ACK), in which the trial transmission attempts of the control packet are intelligently determined by the situation (successful or failed) of its last sampling transmission instant after identifying the unnecessary transmission points and the necessary transmission points. Then, inspired by the packet-based control technology with buffering, the sufficient condition for attempting transmission of the control packet is given, in which the exponential ISS with maximum robustness index can be preserved. Compared with the existing method with a fixed transmission rate for the control packet, it is shown that the considered framework improves the exponential ISS performance with equal or less communication resource costs.

Observer-based synchronization control for complex networks against asynchronous attacks

Under the framework of cyber-physical systems (CPSs), this paper investigates the secure synchronization control problem of complex networks against asynchronous attacks. Different from the previous works that considered either connection attack on network connections or denial-of-service (DoS) attack in control (controller-to-actuator) channels, the asynchronous case of both types of attacks in complex networks is taken into account here. Besides, to overcome the difficulty that system states are not available for controllers, the pinning-nodes-based observer is designed to estimate all system states only using the measurements of pinning nodes rather than all ones. Such an observer is very realistic, especially for large-scale complex systems. By establishing a piecewise Lyapunov function, the secure synchronization criteria of complex networks under the considered asynchronous attacks are obtained. Finally, a numerical example and its simulations are exhibited to confirm the availability of the developed theoretical outcomes.

Why Botnets Work: Distributed Brute-Force Attacks Need No Synchronization

In September 2017, the McAfee Labs quarterly report estimated that brute-force attacks represent 20% of total network attacks, making them the most prevalent type of attack ex-aequo with browser-based vulnerabilities. These attacks have sometimes catastrophic consequences, and understanding their fundamental limits may play an important role in the risk assessment of password-secured systems and in the design of better security protocols. While some solutions exist to prevent online brute-force attacks that arise from one single IP address, attacks performed by botnets are more challenging. In this paper, we analyze these distributed attacks by using a simplified model. Our aim is to understand the impact of distribution and asynchronization on the overall computational effort necessary to breach a system. Our result is based on guesswork, a measure of the number of queries (guesses) before a correct sequence, such as a password, is found in an optimal attack. Guesswork is a direct surrogate for time and computational effort of guessing a sequence from a set of sequences with the associated likelihoods. We model the lack of synchronization by a worst-case optimization in which the queries made by multiple adversarial agents are received in the worst possible order for the adversary, resulting in a min–max formulation. We show that, even without synchronization, and for sequences of growing length, the asymptotic optimal performance is achievable by using randomized guesses drawn from an appropriate distribution. Therefore, randomization is key for the distributed asynchronous attacks. In other words, asynchronous guessers can asymptotically perform brute-force attacks as efficiently as synchronized guessers.

Multiple Binary Images Watermarking in Spatial and Frequency Domains

Watermarking is used for the protection of intellectual property, data integrity, and data authentication. This paper proposes a novel method for image watermarking based on embedding multiples watermarks in different domains of the image representation (spatial and DCT domains), without any distortion of the watermarked image. In the spatial domain, the processing method is based on study of segmentation by fuzzy c-means clustering method that outputs the zones of watermark embedding and respectively the associated appropriate embedding gain factors. However in the DCT domain a proper choice of the DCT coefficients based on the quantization JPEG table in the middle frequencies band is carried out. Several watermarks were embedded in these two domains in order to take advantage of the spatial domain robustness against different asynchronous attacks, associated to the DCT domain robustness against jpeg compression and some other signal processing distortions. Experimental results show that the proposed method is robust against a large set of synchronous and asynchronous image attacks such as filtering, lossy compression, cropping and rotation attack.