This paper explores a new cyber-attack vector targeting Industrial Control Systems (ICS), particularly focusing on water treatment facilities. Developing a new multi-agent Deep Reinforcement Learning (DRL) approach, adversaries craft stealthy, strategically timed, wear-out attacks designed to subtly degrade product quality and reduce the lifespan of field actuators. This sophisticated method leverages DRL methodology not only to execute precise and detrimental impacts on targeted infrastructure but also to evade detection by contemporary AI-driven defence systems. By developing and implementing tailored policies, the attackers ensure their hostile actions blend seamlessly with normal operational patterns, circumventing integrated security measures. Our research reveals the robustness of this attack strategy, shedding light on the potential for DRL models to be manipulated for adversarial purposes. Our research has been validated through testing and analysis in an industry-level setup. For reproducibility and further study, all related materials, including datasets and documentation, are publicly accessible.

Package delivery is a critical aspect of various industries, but it often incurs high financial costs and inefficiencies when relying solely on human resources. The last-mile transport problem, in particular, contributes significantly to the expenditure of human resources in major companies. Robot-based delivery systems have emerged as a potential solution for last-mile delivery to address this challenge. However, robotic delivery systems still face security and privacy issues, like impersonation, replay, man-in-the-middle attacks (MITM), unlinkability, and identity theft.In this context, we propose a privacy-preserving multi-factor authentication scheme specifically designed for robot delivery systems. Additionally, AI-assisted robotic delivery systems are susceptible to machine learning-based attacks (e.g. FGSM, PGD, etc.). We introduce the first transformer-based audio-visual fusion defender to tackle this issue, which effectively provides resilience against adversarial samples. Furthermore, we provide a rigorous formal analysis of the proposed protocol and also analyse the protocol security using a popular symbolic proof tool called ProVerif and Scyther. Finally, we present a real-world implementation of the proposed robotic system with the computation cost and energy consumption analysis. Code and pre-trained models are available at: https://github.com/YYangNUS/TIFS RobotMFA.

Digital Twin (DT) is a revolutionary technology changing how a smart manufacturing industry carries out its day-to-day activities. DT can provide numerous advantages such as real-time synchronised functioning, monitoring and data analysis. However, security and privacy issues in DT have not been thoroughly investigated. This article proposes a user-empowerment-based privacy-preserving authentication protocol for a cloud-based Digital Twin using a Decentralised Identifier (DID) and Verifiable Credential (VC). Here, user empowerment provides full control to users over their identities, and with the help of VC, users can prove their authenticity and preserve their privacy. Although DID has emerged as a promising technology for introducing user empowerment, it suffers from some fundamental problems such as usability and auditability. Here we address all these issues and propose a user-revocation-enabled security solution for the DT. A security analysis of the proposed scheme shows that it is secured against significant security threats. With the help of performance analysis, we prove that the proposed work effectively ensures security and privacy in DT.

In the current artificial intelligence (AI) era, the scale and quality of the dataset play a crucial role in training a high-quality AI model. However, good data is not a free lunch and is always hard to access due to privacy regulations like the General Data Protection Regulation (GDPR). A potential solution is to release a synthetic dataset with a similar distribution to that of the private dataset. Nevertheless, in some scenarios, it has been found that the attributes needed to train an AI model belong to different parties, and they cannot share the raw data for synthetic data publication due to privacy regulations. In PETS 2023, Xue et al. [29] proposed the first generative adversary network-based model, VertiGAN, for vertically partitioned data publication. However, after thoroughly investigating, we found that VertiGAN is less effective in preserving the correlation among the attributes of different parties. This article proposes a Vertical Federated Learning-based Generative Adversarial Network, VFLGAN, for vertically partitioned data publication to address the above issues. Our experimental results show that compared with VertiGAN, VFLGAN significantly improves the quality of synthetic data. Taking the MNIST dataset as an example, the quality of the synthetic dataset generated by VFLGAN is 3.2 times better than that generated by VertiGAN w.r.t. the Frechet Distance. We also designed a more efficient and effective Gaussian mechanism for the proposed VFLGAN to provide the synthetic dataset with a differential privacy guarantee. On the other hand, differential privacy only gives the upper bound of the worst-case privacy guarantee. This article also proposes a practical auditing scheme that applies membership inference attacks to estimate privacy leakage through the synthetic dataset.

Underwater Acoustic Sensor Networks (UW-ASNs) are predominantly used for underwater environments and find applications in many areas. However, a lack of security considerations, the unstable and challenging nature of the underwater environment, and the resource-constrained nature of the sensor nodes used for UW-ASNs (which makes them incapable of adopting security primitives) make the UW-ASN prone to vulnerabilities. This paper proposes an Adaptive decentralised Intrusion Detection and Prevention System called AIDPS for UW-ASNs. The proposed AIDPS can improve the security of the UW-ASNs so that they can efficiently detect underwater-related attacks (e.g., blackhole, grayhole and flooding attacks). To determine the most effective configuration of the proposed construction, we conduct a number of experiments using several state-of-the-art machine learning algorithms (e.g., Adaptive Random Forest (ARF), light gradient-boosting machine, and K-nearest neighbours) and concept drift detection algorithms (e.g., ADWIN, kdqTree, and Page-Hinkley). Our experimental results show that incremental ARF using ADWIN provides optimal performance when implemented with One-class support vector machine (SVM) anomaly-based detectors. Furthermore, our extensive evaluation results also show that the proposed scheme outperforms state-of-the-art bench-marking methods while providing a wider range of desirable features such as scalability and complexity.

Considering the limited power and computational resources available, designing sufficiently secure systems for low-power devices is a difficult problem to tackle. With the ubiquitous adoption of the Internet of Things (IoT) not appearing to be slowing any time soon, resource-constrained security is more important than ever. Physical Unclonable Functions (PUFs) have gained momentum in recent years for their potential to enable strong security through the generation of unique identifiers based on entropy derived from unique manufacturing variations. Strong-PUFs, which are desirable for authentication protocols, have often been shown to be insecure to Machine Learning Modelling Attacks (ML-MA). Recently, some schemes have been proposed to enhance security against ML-MA through post-processing of the PUF; however, often, security is not sufficiently upheld, the scheme requires too large an additional overhead or key data must be insecurely stored in Non-Volatile Memory. In this work, we propose a generic framework for securing Strong-PUFs against ML-MA through obfuscation of challenge and response data by exploiting a DRAM-PUF to supplement a One-Way Function (OWF) which can be implemented using the available resources on an FPGA platform. Our proposed scheme enables reconfigurability, strong security and one-wayness. We conduct ML-MA using various classifiers to thoroughly evaluate the performance of our scheme across multiple 16-bit and 32-bit Arbiter-PUF (APUF) variants, showing our scheme reduces model accuracy to around 50% for each PUF (random guessing) and evaluate the properties of the final responses, demonstrating that ideal uniformity and uniqueness are maintained. Even though we demonstrate our proposal through a DRAM-PUF, our scheme can be extended to work with memory-based PUFs in general.

The overwhelmingly widespread use of Internet of Things (IoT) in different application domains brought not only benefits, but, alas, security concerns as a result of the increased attack surface and vectors. One of the most critical mechanisms in IoT infrastructure is key management. This paper reflects on the problems and challenges of existing key management systems, starting with the discussion of a recent real-world attack. We identify and elaborate on the drawbacks of security primitives based purely on physical variations and - after highlighting the problems of such systems - continue on to deduce an effective and cost-efficient key management solution for IoT systems extending the symbiotic security approach in a previous work. The symbiotic architecture combines software, firmware, and hardware resources for secure IoT while avoiding the traditional scheme of static key storage and generating entropy for key material on-the-fly via a combination of a Physical Unclonable Function (PUF) and pseudo-random bits pre-populated in firmware.

IPv6 over Low-powered Wireless Personal Area Networks (6LoWPAN) has grown in importance in recent years, with the Routing Protocol for Low Power and Lossy Networks (RPL) emerging as a major enabler. However, RPL can be subject to attack, with severe consequences. Most proposed IDSs have been limited to specific RPL attacks and typically assume a stationary environment. In this article, we propose the first adaptive hybrid IDS to efficiently detect and identify a wide range of RPL attacks (including DIO Suppression, Increase Rank, and Worst Parent attacks, which have been overlooked in the literature) in evolving data environments. We apply our framework to networks under various levels of node mobility and maliciousness. We experiment with several incremental machine learning (ML) approaches and various ‘concept-drift detection’ mechanisms (e.g. ADWIN, DDM, and EDDM) to determine the best underlying settings for the proposed scheme.

Low-power and Lossy Networks (LLNs) comprise nodes characterised by constrained computational power, memory, and energy resources. The LLN nodes empower ubiquitous connections amongst numerous devices (e.g. temperature, humidity, and turbidity sensors, together with motors, valves and other actuators) to sense, control and store properties of their environments. They are often deployed in hostile, unattended, and unfavourable conditions. Securing them often becomes very challenging. The extent of interconnected LLN devices poses a series of routing threats (e.g. wormhole, grayhole, DIO suppression, and increase rank attacks). Consequently, an efficient and effective intrusion detection system (IDS) is of utmost importance in identifying anomalous activities in the IPv6 over Low-powered Wireless Personal Area Networks (6LoWPAN). This article proposes a robust Adversarial Reinforcement Learning (ARL) framework to generate efficient IDSs for evolving data environments. The integration of ARL and incremental machine-learning facilitates the generation of resource-efficient and robust IDS detectors. We demonstrate in particular how such an approach, leveraging notions of ’concept drift’ detection and adaptation, can handle inevitable changes in the environment, giving the IDS best chances of detecting attacks in the current profile. The range of routing attacks considered is the most comprehensive to date. For the first time, Black-box and Grey-box ML-based adversaries aiming to destabilise the 6LoWPAN are distinguished and addressed.

The Routing Protocol for low power Lossy networks (RPL) is a critical operational component of low power wireless personal area networks using IPv6 (6LoWPANs). In this paper we propose a Reinforcement Learning (RL) based IDS to detect various attacks on RPL in 6LoWPANs, including several un-addressed by current research. The proposed scheme can also detect previously unseen attacks and the presence of mobile intruders. The scheme is well suited to the resource constrained environments of our target networks.