613 research outputs found

    Efficient Model Checking: The Power of Randomness

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    Certificates for decision problems in temporal logic using context-based tableaux and sequent calculi.

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    115 p.Esta tesis trata de resolver problemas de Satisfactibilidad y Model Checking, aportando certificados del resultado. En ella, se trabaja con tres lógicas temporales: Propositional Linear Temporal Logic (PLTL), Computation Tree Logic (CTL) y Extended Computation Tree Logic (ECTL). Primero se presenta el trabajo realizado sobre Certified Satisfiability. Ahí se muestra una adaptación del ya existente método dual de tableaux y secuentes basados en contexto para satisfactibilidad de fórmulas PLTL en Negation Normal Form. Se ha trabajado la generación de certificados en el caso en el que las fórmulas son insactisfactibles. Por último, se aporta una prueba de soundness del método. Segundo, se ha optimizado con Sat Solvers el método de Certified Satisfiability para el contexto de Certified Model Checking. Se aportan varios ejemplos de sistemas y propiedades. Tercero, se ha creado un nuevo método dual de tableaux y secuentes basados en contexto para realizar Certified Satisfiability para fórmulas CTL yECTL. Se presenta el método y un algoritmo que genera tanto el modelo en el caso de que las fórmulas son satisfactibles como la prueba en el caso en que no lo sean. Por último, se presenta una implementación del método para CTL y una experimentación comparando el método propuesto con otro método de similares características

    Next-Generation Industrial Control System (ICS) Security:Towards ICS Honeypots for Defence-in-Depth Security

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    The advent of Industry 4.0 and smart manufacturing has led to an increased convergence of traditional manufacturing and production technologies with IP communications. Legacy Industrial Control System (ICS) devices are now exposed to a wide range of previously unconsidered threats, which must be considered to ensure the safe operation of industrial processes. Especially as cyberspace is presenting itself as a popular domain for nation-state operations, including against critical infrastructure. Honeypots are a well-known concept within traditional IT security, and they can enable a more proactive approach to security, unlike traditional systems. More work needs to be done to understand their usefulness within OT and critical infrastructure. This thesis advances beyond current honeypot implementations and furthers the current state-of-the-art by delivering novel ways of deploying ICS honeypots and delivering concrete answers to key research questions within the area. This is done by answering the question previously raised from a multitude of perspectives. We discuss relevant legislation, such as the UK Cyber Assessment Framework, the US NIST Framework for Improving Critical Infrastructure Cybersecurity, and associated industry-based standards and guidelines supporting operator compliance. Standards and guidance are used to frame a discussion on our survey of existing ICS honeypot implementations in the literature and their role in supporting regulatory objectives. However, these deployments are not always correctly configured and might differ from a real ICS. Based on these insights, we propose a novel framework towards the classification and implementation of ICS honeypots. This is underpinned by a study into the passive identification of ICS honeypots using Internet scanner data to identify honeypot characteristics. We also present how honeypots can be leveraged to identify when bespoke ICS vulnerabilities are exploited within the organisational network—further strengthening the case for honeypot usage within critical infrastructure environments. Additionally, we demonstrate a fundamentally different approach to the deployment of honeypots. By deploying it as a deterrent, to reduce the likelihood that an adversary interacts with a real system. This is important as skilled attackers are now adept at fingerprinting and avoiding honeypots. The results presented in this thesis demonstrate that honeypots can provide several benefits to the cyber security of and alignment to regulations within the critical infrastructure environment

    Tехнічні засоби діагностування та контролю бортових систем інформаційного обміну на літаку

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    Робота публікується згідно наказу ректора від 27.05.2021 р. №311/од "Про розміщення кваліфікаційних робіт вищої освіти в репозиторії НАУ". Керівник дипломної роботи: доцент кафедри авіоніки, Слободян Олександр ПетровичТехнічний прогрес в авіаційній та будь-якій іншій галузі тісно пов'язаний з автоматизацією технологічних процесів. Сьогодні Автоматизація технологічних процесів використовується для підвищення характеристик надійності, довговічності, екологічності, ресурсозбереження і, найголовніше, економічності і простоти експлуатації. Завдяки швидкому розвитку комп'ютерних технологій і мікропроцесорів у нас є можливість використовувати більш досконалі і складні методи моніторингу та управління системами авіаційної промисловості і будь-якими іншими. Мікропроцесорні та електронні обчислювальні пристрої, з'єднані обчислювальними і керуючими мережами з використанням загальних баз даних, мають стандарти, що дозволяють модифікувати і інтегрувати нові пристрої, що, в свою чергу, дозволяє інтегрувати і вдосконалювати виробничі процеси і управляти ними. Проектування системи розподіленої інтегрованої модульної авіоніки (DIMA) з використанням розподіленої інтегрованої технології, змішаного планування критичних завдань, резервний планування в режимі реального часу і механізму зв'язку, який запускається за часом, значно підвищує надійність, безпеку і продуктивність інтегрованої електронної системи в режимі реального часу. DIMA являє собою тенденцію розвитку майбутніх систем авіоніки. У цій статті вивчаються і обговорюються архітектурні характеристики DIMA. Потім він детально вивчає та аналізує розвиток ключових технологій в системі DIMA. Нарешті, в ньому розглядається тенденція розвитку технології DIMA

    Demonstration of a Model-based Approach for Formal Verification of I&C Logics

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    This paper introduces a model-based methodology for conformity assessment of I&C logics using model checking analysis. The presented method extends our previous work of model-based, artefact-driven support for engineering of mission-critical systems. The approach includes an ontology and a data model for constructing a tool-supported data repository for the model checking artefacts. The repository brings to the assessment, among others, the benefits of traceability between requirements, claims and analysis results, and it acts as a sole source for information, avoiding distortion and fragmentation of data. For demonstrating and testing the capabilities of our approach, we performed an exemplary model checking task on an I&C related case study, storing all the created work items to the data repository created with Siemens' Polarion™ tool. Finally, we present a methodology for using the relations between the artefacts to automatically generate assessment reports and explore the capabilities of the selected tool for this task

    Intégration des méthodes formelles dans le développement des RCSFs

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    In this thesis, we have relied on formal techniques in order to first evaluate WSN protocols and then to propose solutions that meet the requirements of these networks. The thesis contributes to the modelling, analysis, design and evaluation of WSN protocols. In this context, the thesis begins with a survey on WSN and formal verification techniques. Focusing on the MAC layer, the thesis reviews proposed MAC protocols for WSN as well as their design challenges. The dissertation then proceeds to outline the contributions of this work. As a first proposal, we develop a stochastic generic model of the 802.11 MAC protocol for an arbitrary network topology and then perform probabilistic evaluation of the protocol using statistical model checking. Considering an alternative power source to operate WSN, energy harvesting, we move to the second proposal where a protocol designed for EH-WSN is modelled and various performance parameters are evaluated. Finally, the thesis explores mobility in WSN and proposes a new MAC protocol, named "Mobility and Energy Harvesting aware Medium Access Control (MEH-MAC)" protocol for dynamic sensor networks powered by ambient energy. The protocol is modelled and verified under several features

    Parameterized Reachability Graph for Software Model Checking Based on PDNet

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    Model checking is a software automation verification technique. However, the complex execution process of concurrent software systems and the exhaustive search of state space make the model-checking technique limited by the state-explosion problem in real applications. Due to the uncertain input information (called system parameterization) in concurrent software systems, the state-explosion problem in model checking is exacerbated. To address the problem that reachability graphs of Petri net are difficult to construct and cannot be explored exhaustively due to system parameterization, this paper introduces parameterized variables into the program dependence net (a concurrent program model). Then, it proposes a parameterized reachability graph generation algorithm, including decision algorithms for verifying the properties. We implement LTL-x verification based on parameterized reachability graphs and solve the problem of difficulty constructing reachability graphs caused by uncertain inputs

    Validation and Verification of Safety-Critical Systems in Avionics

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    This research addresses the issues of safety-critical systems verification and validation. Safety-critical systems such as avionics systems are complex embedded systems. They are composed of several hardware and software components whose integration requires verification and testing in compliance with the Radio Technical Commission for Aeronautics standards and their supplements (RTCA DO-178C). Avionics software requires certification before its deployment into an aircraft system, and testing is mandatory for certification. Until now, the avionics industry has relied on expensive manual testing. The industry is searching for better (quicker and less costly) solutions. This research investigates formal verification and automatic test case generation approaches to enhance the quality of avionics software systems, ensure their conformity to the standard, and to provide artifacts that support their certification. The contributions of this thesis are in model-based automatic test case generations approaches that satisfy MC/DC criterion, and bidirectional requirement traceability between low-level requirements (LLRs) and test cases. In the first contribution, we integrate model-based verification of properties and automatic test case generation in a single framework. The system is modeled as an extended finite state machine model (EFSM) that supports both the verification of properties and automatic test case generation. The EFSM models the control and dataflow aspects of the system. For verification, we model the system and some properties and ensure that properties are correctly propagated to the implementation via mandatory testing. For testing, we extended an existing test case generation approach with MC/DC criterion to satisfy RTCA DO-178C requirements. Both local test cases for each component and global test cases for their integration are generated. The second contribution is a model checking-based approach for automatic test case generation. In the third contribution, we developed an EFSM-based approach that uses constraints solving to handle test case feasibility and addresses bidirectional requirements traceability between LLRs and test cases. Traceability elements are determined at a low-level of granularity, and then identified, linked to their source artifact, created, stored, and retrieved for several purposes. Requirements’ traceability has been extensively studied but not at the proposed low-level of granularity

    Dash: declarative behavioural modelling in Alloy with control state hierarchy

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    This is a post-peer-review, pre-copyedit version of an article published in Software and Systems Modeling. The final authenticated version is available online at: https://doi.org/10.1007/s10270-022-01012-1We present Dash, an extension to the Alloy language to model dynamic behaviour using the labelled control state hierarchy of Statecharts. From Statecharts, Dash borrows the concepts to specify hierarchy, concurrency, and communication for describing behaviour in a compositional manner. From Alloy, Dash uses the expressiveness of relational logic and set theory to abstractly and declaratively describe structures, data, and operations. We justify our semantic design decisions for Dash, which carefully mix the usual semantic understanding of control state hierarchy with the declarative perspective. We describe and implement the semantics of a Dash model by translating it to Alloy, taking advantage of Alloy language features. We evaluate our Dash translation and perform model checking analysis, enabled by our translation, in the Alloy Analyzer using several case studies. Dash provides modellers with a language that seamlessly combines the semantics of control-modelling paradigms with Alloy’s existing strengths in modelling data and operations abstractly

    A User Study for Evaluation of Formal Verification Results and their Explanation at Bosch

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    Context: Ensuring safety for any sophisticated system is getting more complex due to the rising number of features and functionalities. This calls for formal methods to entrust confidence in such systems. Nevertheless, using formal methods in industry is demanding because of their lack of usability and the difficulty of understanding verification results. Objective: We evaluate the acceptance of formal methods by Bosch automotive engineers, particularly whether the difficulty of understanding verification results can be reduced. Method: We perform two different exploratory studies. First, we conduct a user survey to explore challenges in identifying inconsistent specifications and using formal methods by Bosch automotive engineers. Second, we perform a one-group pretest-posttest experiment to collect impressions from Bosch engineers familiar with formal methods to evaluate whether understanding verification results is simplified by our counterexample explanation approach. Results: The results from the user survey indicate that identifying refinement inconsistencies, understanding formal notations, and interpreting verification results are challenging. Nevertheless, engineers are still interested in using formal methods in real-world development processes because it could reduce the manual effort for verification. Additionally, they also believe formal methods could make the system safer. Furthermore, the one-group pretest-posttest experiment results indicate that engineers are more comfortable understanding the counterexample explanation than the raw model checker output. Limitations: The main limitation of this study is the generalizability beyond the target group of Bosch automotive engineers.Comment: This manuscript is under review with the Empirical Software Engineering journa
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