Efficient Enforcement of Security Policies in Distributed Systems

Policy-based management (PBM) is an adaptable security policy mechanism in information systems (IS) that confirm only authorised users can access resources. A few decades ago, the traditional PBM has focused on closed systems, where enforcement mechanisms are trusted by system administrators who define access control policies. Most of current work on the PBM systems focuses on designing a centralised policy decision point (PDP), the component that evaluates an access request against a policy and reports the decision back, which can have performance and resilience drawbacks. Performance and resilience are a major concern for applications in military, health and national security domains where the performance is desirable to increase situational awareness through collaboration and to decrease the length of the decision making cycle. The centralised PDP also represents a single point of failure. In case of the failure of the centralised PDP, all resources in the system may cease to function. The efficient distribution of enforcement mechanisms is therefore key in building large scale policy managed distributed systems. Moving from the traditional PBM systems to dynamic PBM systems supports dynamic adaptability of behaviour by changing policy without recoding or stopping the system. The SANTA history-based dynamic PBM system has a formal underpinning in Interval Temporal Logic (ITL) allowing for formal analysis and verification to take place. The main aim of the research to automatically distribute enforcement mechanisms in the distributed system in order to provide resilience against network failure whilst preserving efficiency of policy decision making. The policy formalisation is based on SANTA policy model to provide a high level of assurance. The contribution of this work addresses the challenge of performance, manageability and security, by designing a Decentralised PBM framework and a corresponding Distributed Enforcements Architecture (DENAR). The ability of enforcing static and dynamic security policies in DENAR is the prime research issue, which balances the desire to distribute systems for flexibility whilst maintaining sufficient security over operations. Our research developed mechanisms to improve the efficiency of the enforcement of security policy mechanisms and their resilience against network failures in distributed information systems

Verification of temporal-epistemic properties of access control systems

Verification of access control systems against vulnerabilities has always been a challenging problem in the world of computer security. The complication of security policies in large- scale multi-agent systems increases the possible existence of vulnerabilities as a result of mistakes in policy definition. This thesis explores automated methods in order to verify temporal and epistemic properties of access control systems. While temporal property verification can reveal a considerable number of security holes, verification of epistemic properties in multi-agent systems enable us to infer about agents' knowledge in the system and hence, to detect unauthorized information flow. This thesis first presents a framework for knowledge-based verification of dynamic access control policies. This framework models a coalition-based system, which evaluates if a property or a goal can be achieved by a coalition of agents restricted by a set of permissions defined in the policy. Knowledge is restricted to the information that agents can acquire by reading system information in order to increase time and memory efficiency. The framework has its own model-checking method and is implemented in Java and released as an open source tool named \char{cmmi10}{0x50}\char{cmmi10}{0x6f}\char{cmmi10}{0x6c}\char{cmmi10}{0x69}\char{cmmi10}{0x56}\char{cmmi10}{0x65}\char{cmmi10}{0x72}. In order to detect information leakage as a result of reasoning, the second part of this thesis presents a complimentary technique that evaluates access control policies over temporal-epistemic properties where the knowledge is gained by reasoning. We will demonstrate several case studies for a subset of properties that deal with reasoning about knowledge. To increase the efficiency, we develop an automated abstraction refinement technique for evaluating temporal-epistemic properties. For the last part of the thesis, we develop a sound and complete algorithm in order to identify information leakage in Datalog-based trust management systems

Towards Sustainable Blockchains:Cryptocurrency Treasury and General Decision-making Systems with Provably Secure Delegable Blockchain-based Voting

The blockchain technology and cryptocurrencies, its most prevalent application, continue to gain acceptance and wide traction in research and practice within academia and the industry because of its promise in decentralised and distributed computing. Notably, the meteoric rise in the value and number of cryptocurrencies since the creation of Bitcoin in 2009 have ushered in newer innovations and interventions that addressed some of the prominent issues that affect these platforms. Despite the increased privacy, security, scalability, and energy-saving capabilities of new consensus protocols in newer systems, the development and management of blockchains, mostly, do not reflect the decentralisation principle despite blockchains being decentralised and distributed in their architecture. The concept of treasury has been identified as a tool to address this problem. We explore the idea of blockchain treasury systems within literature and practice, especially with relation to funding and decision-making power towards blockchain development and maintenance. Consequently, we propose a taxonomy for treasury models within cryptocurrencies. Thereafter, we propose an efficient community-controlled and decentralised collaborative decision-making mechanism to support the development and management of blockchains. Our proposed system incentivises participants and is proven secure under the universally composable (UC) framework while also addressing gaps identified from our investigation of prior systems e.g. non-private ballots and insecure voting. Furthermore, we adapt our system and propose a privacy-preserving general decision making system for blockchain governance that supports privacy-centric cryptocurrencies. Besides, using a set of metrics, we introduce a consensus analysis mechanism to enhance the utility of decision-making of the systems by evaluating individual choices against collective (system-wide) decisions. Finally, we provide pilot system implementations with benchmark results confirming the efficiency and practicality of our constructions

Fragmentation and Coherence : A Study into the Law of the World Trade Organization

Tämä työ käsittelee kansainvälisen oikeuden ja Maailman kauppajärjestön (WTO) oikeuden suhdetta. Suhdetta tarkastellaan yleisesti kansainvälisen oikeuden fragmentaation ja koherenssin käsitteiden avulla. WTO:n oikeus on luonteeltaan julkista kansainvälistä oikeutta. WTO:n oikeus on kuitenkin eriytynyt muusta julkisesta kansainvälisestä oikeudesta valtioiden vastuuta koskevien sääntöjen osalta. Näiden sääntöjen osalta WTO:n oikeus on fragmentoitunut erityiseksi kansainvälisen oikeuden osa-alueeksi. WTO:n riidanratkaisuelin on soveltanut järjestelmällisesti WTO:n ulkoista kansainvälistä oikeutta kuten tapaoikeudellisia sääntöjä kansainvälisten sopimusten tulkinnasta. Riidanratkaisuelin on tuonut WTO:n oikeuteen myös yleisiä aineellisia ja menettelyllisiä oikeusperiaatteita. Riidanratkaisuelimen käytäntö on todiste WTO:n oikeuden koherenssista. Työssä WTO:n ulkoisen oikeuden soveltamisen esittely aloitetaan oikeuslähteiden määrittelyllä. Tämän jälkeen työ esittää yksityiskohtaisesti WTO:n riidanratkaisuelimen toimivallan ja sovellettavan lain. Kuvaus perustuu WTO:n sitoviin oikeuslähteisiin sekä riidanratkaisuelimen tapauskäytäntöön. Vaikka riidanratkaisuelimen käytäntö osoittaa pyrkimystä koherenssiin yleisen kansainvälisen oikeuden ja WTO:n oikeuden välillä, suurin haaste koherenssille ovat kansainvälisen oikeuden erityisten osa-alueiden kuten ympäristöoikeuden, ihmisoikeuksien ja WTO:n oikeuden väliset aineelliset ristiriidat. Lopulta työ paljastaa esimerkinomaisesti näitä ristiriitoja sekä arvioi onko niiden ratkaisu mahdollista WTO:n oikeudessa.This study analyzes the relationship between public international law and the legal system of the World Trade Organization from the perspective of fragmentation of international law specializing in the application of external public international law in the Dispute Settlement Body of the WTO. Fragmentation of international law was found to result from historical, functional and regional grouping of law-making treaties. In contrast, coherence in WTO law was found to result from, inter alia, the nature of the WTO as an international organization and from the subscription of general international law by the WTO panels and the Appellate Body. An irresolvable rule conflict of international law reveals the lack of coherence therein. In terms of WTO Law, conflicting rules have been found at least in environmental law, in human rights law and in international labour law. Review of relevant panel and Appellate Body reports did not provide evidence of current existence of such conflicts on a normative or functional level. Harmonious interpretation removed the conditions for conflict. It is questionable if harmonious interpretation ultimately increases coherence between WTO law and other subsystems of international law. Perhaps it is the best the WTO can do at the moment – but by no means it is enough for the protection of social goods such as human rights, the environment or the global workforce

A patient agent controlled customized blockchain based framework for internet of things

Although Blockchain implementations have emerged as revolutionary technologies for various industrial applications including cryptocurrencies, they have not been widely deployed to store data streaming from sensors to remote servers in architectures known as Internet of Things. New Blockchain for the Internet of Things models promise secure solutions for eHealth, smart cities, and other applications. These models pave the way for continuous monitoring of patient’s physiological signs with wearable sensors to augment traditional medical practice without recourse to storing data with a trusted authority. However, existing Blockchain algorithms cannot accommodate the huge volumes, security, and privacy requirements of health data. In this thesis, our first contribution is an End-to-End secure eHealth architecture that introduces an intelligent Patient Centric Agent. The Patient Centric Agent executing on dedicated hardware manages the storage and access of streams of sensors generated health data, into a customized Blockchain and other less secure repositories. As IoT devices cannot host Blockchain technology due to their limited memory, power, and computational resources, the Patient Centric Agent coordinates and communicates with a private customized Blockchain on behalf of the wearable devices. While the adoption of a Patient Centric Agent offers solutions for addressing continuous monitoring of patients’ health, dealing with storage, data privacy and network security issues, the architecture is vulnerable to Denial of Services(DoS) and single point of failure attacks. To address this issue, we advance a second contribution; a decentralised eHealth system in which the Patient Centric Agent is replicated at three levels: Sensing Layer, NEAR Processing Layer and FAR Processing Layer. The functionalities of the Patient Centric Agent are customized to manage the tasks of the three levels. Simulations confirm protection of the architecture against DoS attacks. Few patients require all their health data to be stored in Blockchain repositories but instead need to select an appropriate storage medium for each chunk of data by matching their personal needs and preferences with features of candidate storage mediums. Motivated by this context, we advance third contribution; a recommendation model for health data storage that can accommodate patient preferences and make storage decisions rapidly, in real-time, even with streamed data. The mapping between health data features and characteristics of each repository is learned using machine learning. The Blockchain’s capacity to make transactions and store records without central oversight enables its application for IoT networks outside health such as underwater IoT networks where the unattended nature of the nodes threatens their security and privacy. However, underwater IoT differs from ground IoT as acoustics signals are the communication media leading to high propagation delays, high error rates exacerbated by turbulent water currents. Our fourth contribution is a customized Blockchain leveraged framework with the model of Patient-Centric Agent renamed as Smart Agent for securely monitoring underwater IoT. Finally, the smart Agent has been investigated in developing an IoT smart home or cities monitoring framework. The key algorithms underpinning to each contribution have been implemented and analysed using simulators.Doctor of Philosoph

Proceedings of the 3rd International Workshop on Formal Aspects in Security and Trust (FAST2005)

The present report contains the pre-proceedings of the third international Workshop on Formal Aspects in Security and Trust (FAST2005), held in Newcastle upon Tyne, 18-19 July 2005. FAST is an event affliated with the Formal Methods 2005 Congress (FM05). The third international Workshop on Formal Aspects in Security and Trust (FAST2005) aims at continuing the successful effort of the previous two FAST workshop editions for fostering the cooperation among researchers in the areas of security and trust. The new challenges offered by the so-called ambient intelligence space, as a future paradigm in the information society, demand for a coherent and rigorous framework of concepts, tools and methodologies to provide user\u27s trust&confidence on the underlying communication/interaction infrastructure. It is necessary to address issues relating to both guaranteeing security of the infrastructure and the perception of the infrastructure being secure. In addition, user confidence on what is happening must be enhanced by developing trust models effective but also easily comprehensible and manageable by users

Cyber Law and Espionage Law as Communicating Vessels

Professor Lubin\u27s contribution is Cyber Law and Espionage Law as Communicating Vessels, pp. 203-225. Existing legal literature would have us assume that espionage operations and “below-the-threshold” cyber operations are doctrinally distinct. Whereas one is subject to the scant, amorphous, and under-developed legal framework of espionage law, the other is subject to an emerging, ever-evolving body of legal rules, known cumulatively as cyber law. This dichotomy, however, is erroneous and misleading. In practice, espionage and cyber law function as communicating vessels, and so are better conceived as two elements of a complex system, Information Warfare (IW). This paper therefore first draws attention to the similarities between the practices – the fact that the actors, technologies, and targets are interchangeable, as are the knee-jerk legal reactions of the international community. In light of the convergence between peacetime Low-Intensity Cyber Operations (LICOs) and peacetime Espionage Operations (EOs) the two should be subjected to a single regulatory framework, one which recognizes the role intelligence plays in our public world order and which adopts a contextual and consequential method of inquiry. The paper proceeds in the following order: Part 2 provides a descriptive account of the unique symbiotic relationship between espionage and cyber law, and further explains the reasons for this dynamic. Part 3 places the discussion surrounding this relationship within the broader discourse on IW, making the claim that the convergence between EOs and LICOs, as described in Part 2, could further be explained by an even larger convergence across all the various elements of the informational environment. Parts 2 and 3 then serve as the backdrop for Part 4, which details the attempt of the drafters of the Tallinn Manual 2.0 to compartmentalize espionage law and cyber law, and the deficits of their approach. The paper concludes by proposing an alternative holistic understanding of espionage law, grounded in general principles of law, which is more practically transferable to the cyber realmhttps://www.repository.law.indiana.edu/facbooks/1220/thumbnail.jp