Biblio

This paper studies the sensor placement problem in a networked control system for improving its security against cyber-physical attacks. The problem is formulated as a zero-sum game between an attacker and a detector. The attacker's decision is to select f nodes of the network to attack whereas the detector's decision is to place f sensors to detect the presence of the attack signals. In our formulation, the attacker minimizes its visibility, defined as the system L2 gain from the attack signals to the deployed sensors' outputs, and the detector maximizes the visibility of the attack signals. The equilibrium strategy of the game determines the optimal locations of the sensors. The existence of Nash equilibrium for the attacker-detector game is studied when the underlying connectivity graph is a directed or an undirected tree. When the game does not admit a Nash equilibrium, it is shown that the Stackelberg equilibrium of the game, with the detector as the game leader, can be computed efficiently. Our results show that, under the optimal sensor placement strategy, an undirected topology provides a higher security level for a networked control system compared with its corresponding directed topology.

NEMESIS provides powerful and cost-effective defenses against extreme Distributed Denial of Service (DDos) attacks through a number of network maneuvers. However, selection of which maneuvers to deploy when and with what parameters requires great care to achieve optimal outcomes in the face of overwhelming attack. Analytical wargaming allows game theoretic optimal Courses of Action (COA) to be created real-time during live operations, orders of magnitude faster than packet-level simulation and with equivalent outcomes to even expert human hand-crafted COAs.

Cryptography is a method of storing and transmitting data in a particular form. Only those for whom it is intended can read, use it, and return it back to the original data by using various techniques. The International Data Encryption Algorithm "IDEA" is a block cipher that works with 64-bit plaintext block and ciphertext blocks and it has a 128-bit input key. This paper describe the designing and implementation of a modified key schedule operation of IDEA called GISKOP. It uses the same number of rounds and output transformation that operates using 128 bit user input plaintext and a modified way of key scheduling operation of 256 bit keys. The modified algorithm uses Serpent key scheduling operation to derive the different sub keys to be used in each rounds. The algorithm was implemented to provide better security on user's password within the Document Management System to protect user's data within the cloud database. It has gone through initial testing and evaluations with very encouraging results.

Advancement in communication technologies and the Internet of Things (IoT) is driving adoption in smart cities that aims to increase operational efficiency and improve the quality of services and citizen welfare, among other potential benefits. The privacy, reliability, and integrity of communications must be ensured so that actions can be appropriate, safe, accurate, and implemented promptly after receiving actionable information. In this work, we present a multi-tier methodology consisting of an authentication and trust-building/distribution framework designed to ensure the safety and validity of the information exchanged in the system. Blockchain protocols and Radio Frequency-Distinct Native Attributes (RF-DNA) combine to provide a hardware-software codesigned system for enhanced device identity and overall system trustworthiness. Our threat model accounts for counterfeiting, breakout fraud, and bad mouthing of one entity by others. Entity trust (e.g., IoT devices) depends on quality and level of participation, quality of messages, lifetime of a given entity in the system, and the number of known "bad" (non-consensus) messages sent by that entity. Based on this approach to trust, we are able to adjust trust upward and downward as a function of real-time and past behavior, providing other participants with a trust value upon which to judge information from and interactions with the given entity. This approach thereby reduces the potential for manipulation of an IoT system by a bad or byzantine actor.

P2P applications deployment on MANETs is motivated by the popularity of these applications, coupled with the widespread use of mobile devices. P2P applications and MANETs have common features such as decentralization, self organization, and the absence of dedicated servers or infrastructure. The deployment often faces specific performance challenges resulting from topological overlay and underlay mismatch, limited bandwidth constraint and dynamic topology changes. Hierarchical MANETs are a special type of MANETs where some nodes have specific routing roles to allow inter- cluster communications. Such topologies (typical for tactical networks) render a successful P2P deployment more challenging. We developed a novel approach for P2P deployment in such networks by bringing topology-awareness into the overlay, mapping the underlay topology (structure) to the logical overlay and building a hierarchically-structured logical overlay on top of the hierarchical underlay. Simulation results demonstrated a significant performance advantage of our proposed deployment solution vs. a flat logical overlay using different configurations and mobility scenarios.

Whenever one accesses a computer system there are three essential security issues involved: identification, authentication and authorization. The identification process enables recognition of an entity, which may be either a human, a machine, or another asset - e.g. software program. Two complementary mechanisms are used for determining who can access those systems: authentication and authorization. To address the authentication process, various solutions have been proposed in the literature, from a simple password to newer technologies based on biometrics or RFID (Radio Frequency Identification). This paper presents a novel scalable multi-factor authentication method, applicable to computer systems with no need of any hardware/software changes.

Air-gapped computers are hermetically isolated from the Internet to eliminate any means of information leakage. In this paper we present HOTSPOT - a new type of airgap crossing technique. Signals can be sent secretly from air-gapped computers to nearby smartphones and then on to the Internet - in the form of thermal pings. The thermal signals are generated by the CPUs and GPUs and intercepted by a nearby smartphone. We examine this covert channel and discuss other work in the field of air-gap covert communication channels. We present technical background and describe thermal sensing in modern smartphones. We implement a transmitter on the computer side and a receiver Android App on the smartphone side, and discuss the implementation details. We evaluate the covert channel and tested it in a typical work place. Our results show that it possible to send covert signals from air-gapped PCs to the attacker on the Internet through the thermal pings. We also propose countermeasures for this type of covert channel which has thus far been overlooked.

This research concerns the detection of unauthorised access within hospital networks through the real-time analysis of audit logs. Privacy is a primary concern amongst patients due to the rising adoption of Electronic Patient Record (EPR) systems. There is growing evidence to suggest that patients may withhold information from healthcare providers due to lack of Trust in the security of EPRs. Yet, patient record data must be available to healthcare providers at the point of care. Ensuring privacy and confidentiality of that data is challenging. Roles within healthcare organisations are dynamic and relying on access control is not sufficient. Through proactive monitoring of audit logs, unauthorised accesses can be detected and presented to an analyst for review. Advanced data analytics and visualisation techniques can be used to aid the analysis of big data within EPR audit logs to identify and highlight pertinent data points. Employing a human-in-the-loop model ensures that suspicious activity is appropriately investigated and the data analytics is continuously improving. This paper presents a system that employs a Human-in-the-Loop Machine Learning (HILML) algorithm, in addition to a density-based local outlier detection model. The system is able to detect 145 anomalous behaviours in an unlabelled dataset of 1,007,727 audit logs. This equates to 0.014% of the EPR accesses being labelled as anomalous in a specialist Liverpool (UK) hospital.

The condition of road surface has a significant role in land transportation. Due to poor road conditions, the logistics and supply chain industry face a drastic loss in their business. Unmaintained roads can cause damage to goods and accidents. The existing routing techniques do not consider factors like shock, temperature and tilt of goods etc. but these factors have to be considered for the logistics and supply chain industry. This paper proposes a recommender system which target management of goods in logistics. A 3 axis accelerometer is used to measure the road surface conditions. The pothole location is obtained using Global Positioning System (GPS). Using these details a hybrid recommender system is built. Hybrid recommender system combines multiple recommendation techniques to develop an effective recommender system. Here content-based and collaborative-based techniques is combined to build a hybrid recommender system. One of the popular Multiple Criteria Decision Making (MCDM) method, The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is used for content based filtering and normalised Euclidean distance and KNN algorithm is used for collaborative filtering. The best route recommended by the system will be displayed to the user using a map application.

Air-gap attacks and mimic defense are two emerging techniques in the field of network attack and defense, respectively. However, direct confrontation between them has not yet appeared in the real world. Who will be the winner, if air-gap attacks encounter mimic defense? To this end, a preliminary analysis is conducted for exploring the possible the strategy space of game according to the core principles of air-gap attacks and mimic defense. On this basis, an architecture model is proposed, which combines some detectors for air-gap attacks and mimic defense devices. First, a Dynamic Heterogeneous Redundancy (DHR) structure is employed to be on guard against malicious software of air-gap attacks. Second, some detectors for air-gap attacks are used to detect some signal sent by air-gap attackers' transmitter. Third, the proposed architecture model is obtained by organizing the DHR structure and the detectors for air-gap attacks with some logical relationship. The simulated experimental results preliminarily confirm the power of the new model.

In this paper, we propose the first traffic monitoring and labeling system for iOS devices, named iMonitor, which not just captures mobile network traffic in .pcap files, but also provides comprehensive APP-related and user-related information of captured packets. Through further analysis, one can obtain the exact APP or device where each packet comes from. The labeled traffic can be used in many research areas for mobile security, such as privacy leakage detection and user profiling. Given the implementation methodology of NetworkExtension framework of iOS 9+, APP labels of iMonitor are reliable enough so that labeled traffic can be regarded as training data for any traffic classification methods. Evaluations on real iPhones demonstrate that iMonitor has no notable impact upon user experience even with slight packet latency. Also, the experiment result supports our motivation that mobile traffic monitoring for iOS is absolutely necessary, as traffic generated by different OSes like Android and iOS are different and unreplaceable in researches.

Health Information Technology Systems (HITS) are increasingly used to improve the quality of patient care while reducing costs. These systems have been developed in response to the changing models of care to an ongoing relationship between patient and care team, supported by the use of technology due to the increased instance of chronic disease. However, the use of HITS may increase the risk to patient safety and security. While standards can be used to address and manage these risks, significant communication problems exist between experts working in different departments. These departments operate in silos often leading to communication breakdowns. For example, risk management stakeholders who are not clinicians may struggle to understand, define and manage risks associated with these systems when talking to medical professionals as they do not understand medical terminology or the associated care processes. In order to overcome this communication problem, we propose the use of the “Three Amigos” approach together with the use of the SIMPLE tool that has been developed to assist patients in understanding medical terms. This paper examines how the “Three Amigos” approach and the SIMPLE tool can be used to improve estimation of severity of risk by non-clinical risk management stakeholders and provides a practical example of their use in a ten step risk management process.

Deep learning has undergone tremendous advancements in computer vision studies. The training of deep learning neural networks depends on a considerable amount of ground truth datasets. However, labeling ground truth data is a labor-intensive task, particularly for large-volume video analytics applications such as video surveillance and vehicles detection for autonomous driving. This paper presents a rapid and accurate method for associative searching in big image data obtained from security monitoring systems. We developed a semi-automatic moving object annotation method for improving deep learning models. The proposed method comprises three stages, namely automatic foreground object extraction, object annotation in subsequent video frames, and dataset construction using human-in-the-loop quick selection. Furthermore, the proposed method expedites dataset collection and ground truth annotation processes. In contrast to data augmentation and data generative models, the proposed method produces a large amount of real data, which may facilitate training results and avoid adverse effects engendered by artifactual data. We applied the constructed annotation dataset to train a deep learning you-only-look-once (YOLO) model to perform vehicle detection on street intersection surveillance videos. Experimental results demonstrated that the accurate detection performance was improved from a mean average precision (mAP) of 83.99 to 88.03.

Peer-to-Peer networks are designed to rely on the resources of their own users. Therefore, resource management plays an important role in P2P protocols. Early P2P networks did not use proper mechanisms to manage fairness. However, after seeing difficulties and rise of freeloaders in networks like Gnutella, the importance of providing fairness for users have become apparent. In this paper, we propose an incentive-based security model which leads to a network infrastructure that lightens the work of Seeders and makes Leechers to contribute more. This method is able to prevent betrayals in Leecher-to-Leecher transactions and helps Seeders to be treated more fairly. This is what other incentive methods such as Bittorrent are incapable of doing. Additionally, by getting help from cryptography and combining it with our method, it is also possible to achieve secure channels, immune to spying, next to a fair network. This is the first protocol designed for P2P networks which has separated Leechers and Seeders without the need to a central server. The simulation results clearly show how our proposed approach can overcome free-riding issue. In addition, our findings revealed that our approach is able to provide an appropriate level of fairness for the users and can decrease the download time.

The paper shows the influence of deactivated agents in social networks: switching between French-De Groot models and Friedkin-Johnsen model.

The ongoing digitalization of the power distribution grid will improve the operational support and automation which is believed to increase the system reliability. However, in an integrated and interdependent cyber-physical system, new threats appear which must be understood and dealt with. Of particular concern, in this paper, is the causes of an inconsistent view between the physical system (here power grid) and the Information and Communication Technology (ICT) system (here Distribution Management System). In this paper we align the taxonomy used in International Electrotechnical Commission (power eng.) and International Federation for Information Processing (ICT community), define a metric for inconsistencies, and present a modelling approach using Stochastic Activity Networks to assess the consequences of inconsistencies. The feasibility of the approach is demonstrated in a simple use case.

This is an extension of an ongoing research project on Fully Homomorphic Encryption. Arithmetic Circuit Homomorphic Encryption (ACHE) [1] was implemented based on (TFHE) Fast Fully Homomorphic Encryption over the Torus. Just like many Homomorphic Encryption methods, ACHE does not integrate with any authentication method. Thus, this was an issue that this paper attempts to resolve. This paper will focus on the implementation method of integrating RFC7664 [2] into ACHE. Next, the paper will further discuss latency incurred due to key generation, the latency of transmission of public and private keys. Last but not least, the paper will also discuss the key size generated and its significance.

The safety management is an important and fundamental task in the construction and operation of pumped-storage power stations. However, because of the traditional technical framework, the relevant systems are separated from each other, leading to a lot of disadvantages in application and performance. In order to meet the requirements of smart pumped-storage power stations, an integrated safety management system (ISMS) based on ubiquitous internet of things in electricity is proposed in this paper. The ISMS is divided into five layers including data display layer, data manipulation layer, data processing layer, data transmission layer and data acquisition layer. It consists of six modules, i.e., central control module, cave access control and personnel location module, video and security monitoring module, emergency broadcasting and communication module, geological warning module, and fall protection module. All modules are integrated into a unified information platform.

With the rapid deployment of Cyber-Physical Systems (CPS), security has become a more critical problem than ever before, as such devices are interconnected and have access to a broad range of critical data. A well-known attack is ReturnOriented Programming (ROP) which can diverge the control flow of a program by exploiting the buffer overflow vulnerability. To protect a program from ROP attacks, a useful method is to instrument code into the protected program to do runtime control flow checking (known as Control Flow Integrity, CFI). However, instrumented code brings extra execution time, which has to be properly handled, as most CPS systems need to behave in a real-time manner. In this paper, we present a technique to efficiently compute an execution plan, which maximizes the number of executions of instrumented code to achieve maximal defense effect, and at the same time guarantees real-time schedulability of the protected task system with a new response time analysis. Simulation-based experimental results show that the proposed method can yield good quality execution plans, but performs orders of magnitude faster than exhaustive search. We also built a prototype in which a small auto-drive car is defended against ROP attacks by the proposed method implemented in FreeRTOS. The prototype demonstrates the effectiveness of our method in real-life scenarios.

Individuals may change their opinion in effect of a wide range of factors like interaction with peer groups, governmental policies and personal intentions. Works in this area mainly focus on individuals in social network and their interactions while neglect other factors. In this paper we have introduced an opinion formation model that consider the internal tendency as a personal feature of individuals in social network. In this model agents may trust, distrust or be neutral to their neighbors. They modify their opinion based on the opinion of their neighbors, trust/distrust to them while considering the internal tendency. The results of simulation show that this model can predict the opinion of social network especially when the average of nodal degree and clustering coefficient are high enough. Since this model can predict the preferences of individuals in market, it can be used to define marketing and production strategy.

The tremendous advances in information and communications technology (ICT), as well as the embedded systems, have been led to the emergence of the novel concept of the internet of things (IoT). Enjoying IoT-based technologies, many objects and components can be connected to each other through the internet or other modern communicational platforms. Embedded systems which are computing machines for special purposes like those utilized in high-tech devices, smart buildings, aircraft, and vehicles including advanced controllers, sensors, and meters with the ability of information exchange using IT infrastructures. The phrase "internet", in this context, does not exclusively refer to the World Wide Web rather than any type of server-based or peer-to-peer networks. In this study, the application of IoT in smart grids is addressed. Hence, at first, an introduction to the necessity of deployment of IoT in smart grids is presented. Afterwards, the applications of IoT in three levels of generation, transmission, and distribution is proposed. The generation level is composed of applications of IoT in renewable energy resources, wind and solar in particular, thermal generation, and energy storage facilities. The deployment of IoT in transmission level deals with congestion management in power system and guarantees the security of the system. In the distribution level, the implications of IoT in active distribution networks, smart cities, microgrids, smart buildings, and industrial sector are evaluated.

Collective self-adaptive systems (CSAS) are distributed and interconnected systems composed of multiple agents that can perform complex tasks such as environmental data collection, search and rescue operations, and discovery of natural resources. By providing individual agents with learning capabilities, CSAS can cope with challenges related to distributed sensing and decision-making and operate in uncertain environments. This unique characteristic of CSAS enables the collective to exhibit robust behaviour while achieving system-wide and agent-specific goals. Although learning has been explored in many CSAS applications, selecting suitable learning models and techniques remains a significant challenge that is heavily influenced by expert knowledge. We address this gap by performing a multifaceted analysis of existing CSAS with learning capabilities reported in the literature. Based on this analysis, we introduce a 3D framework that illustrates the learning aspects of CSAS considering the dimensions of autonomy, knowledge access, and behaviour, and facilitates the selection of learning techniques and models. Finally, using example applications from this analysis, we derive open challenges and highlight the need for research on collaborative, resilient and privacy-aware mechanisms for CSAS.

Edge caching has received much attention as a promising technique to overcome the stringent latency and data hungry challenges in the future generation wireless networks. Meanwhile, full-duplex (FD) transmission can potentially double the spectral efficiency by allowing a node to receive and transmit simultaneously. In this paper, we study a cache-aided FD system via delivery time analysis and optimization. In the considered system, an edge node (EN) operates in FD mode and serves users via wireless channels. Two optimization problems are formulated to minimize the largest delivery time based on the two popular linear beamforming zero-forcing and minimum mean square error designs. Since the formulated problems are non-convex due to the self-interference at the EN, we propose two iterative optimization algorithms based on the inner approximation method. The convergence of the proposed iterative algorithms is analytically guaranteed. Finally, the impacts of caching and the advantages of the FD system over the half-duplex (HD) counterpart are demonstrated via numerical results.

Starting from our previous research where we in- troduced a general framework for supporting data-driven privacy-preserving big data management in distributed environments, such as emerging Cloud settings, in this paper we further and significantly extend our past research contributions, and provide several novel contributions that complement our previous work in the investigated research field. Our proposed framework can be viewed as an alternative to classical approaches where the privacy of big data is ensured via security-inspired protocols that check several (protocol) layers in order to achieve the desired privacy. Unfortunately, this injects considerable computational overheads in the overall process, thus introducing relevant challenges to be considered. Our approach instead tries to recognize the “pedigree” of suitable summary data representatives computed on top of the target big data repositories, hence avoiding computational overheads due to protocol checking. We also provide a relevant realization of the framework above, the so- called Data-dRIven aggregate-PROvenance privacy-preserving big Multidimensional data (DRIPROM) framework, which specifically considers multidimensional data as the case of interest. Extensions and discussion on main motivations and principles of our proposed research, two relevant case studies that clearly state the need-for and covered (related) properties of supporting privacy- preserving management and analytics of big data in modern distributed systems, and an experimental assessment and analysis of our proposed DRIPROM framework are the major results of this paper.

This paper presents a general model to assess the mixed-degradation profiles of critical components in a Cyber-Physical System (CPS) based on the reliability of its critical physical and software components. In the proposed assessment, the cyber aspect of a CPS was approached from a software reliability perspective. Although extensive research has been done on physical components degradation and software reliability separately, research for the combined physical-software systems is still scarce. The non-homogeneous Poisson Processes (NHPP) software reliability models are deemed to fit well with the real data and have descriptive and predictive abilities, which could make them appropriate to estimate software components reliability. To show the feasibility of the proposed approach, a case study for mixed-degradation profiles assessment is presented with n physical components and one major software component forming a critical subsystem in CPS. Two physical components were assumed to have different degradation paths with the dependency between them. Series and parallel structures were investigated for physical components. The software component failure data was taken from a wireless network switching center and fitted into a Weibull software reliability model. The case study results revealed that mix-degradation profiles of physical components, combined with software component profile, produced a different CPS reliability profile.