3,041 research outputs found

    ENHANCING CLOUD SYSTEM RUNTIME TO ADDRESS COMPLEX FAILURES

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    As the reliance on cloud systems intensifies in our progressively digital world, understanding and reinforcing their reliability becomes more crucial than ever. Despite impressive advancements in augmenting the resilience of cloud systems, the growing incidence of complex failures now poses a substantial challenge to the availability of these systems. With cloud systems continuing to scale and increase in complexity, failures not only become more elusive to detect but can also lead to more catastrophic consequences. Such failures question the foundational premises of conventional fault-tolerance designs, necessitating the creation of novel system designs to counteract them. This dissertation aims to enhance distributed systems’ capabilities to detect, localize, and react to complex failures at runtime. To this end, this dissertation makes contributions to address three emerging categories of failures in cloud systems. The first part delves into the investigation of partial failures, introducing OmegaGen, a tool adept at generating tailored checkers for detecting and localizing such failures. The second part grapples with silent semantic failures prevalent in cloud systems, showcasing our study findings, and introducing Oathkeeper, a tool that leverages past failures to infer rules and expose these silent issues. The third part explores solutions to slow failures via RESIN, a framework specifically designed to detect, diagnose, and mitigate memory leaks in cloud-scale infrastructures, developed in collaboration with Microsoft Azure. The dissertation concludes by offering insights into future directions for the construction of reliable cloud systems

    Taser and Social, Ethnic and Racial Disparities research programme

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    Report from the 'Taser use and its association with social, ethnic and racial disparities in policing (TASERD)' research project. The research project was initiated by the National Police Chiefs’ Council and commissioned by the College of Policing, after their Officer and Staff Safety Review (OSSR) in 2019 found there was growing evidence to suggest that Tasers were being used disproportionately in society. It was carried out by researchers from Keele University, UCL, The University of Exeter and Staffordshire University.National Police Chiefs’ CouncilLondon’s Mayor's Office for Policing and Crime (MOPAC

    Risk and threat mitigation techniques in internet of things (IoT) environments: a survey

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    Security in the Internet of Things (IoT) remains a predominant area of concern. Although several other surveys have been published on this topic in recent years, the broad spectrum that this area aims to cover, the rapid developments and the variety of concerns make it impossible to cover the topic adequately. This survey updates the state of the art covered in previous surveys and focuses on defences and mitigations against threats rather than on the threats alone, an area that is less extensively covered by other surveys. This survey has collated current research considering the dynamicity of the IoT environment, a topic missed in other surveys and warrants particular attention. To consider the IoT mobility, a life-cycle approach is adopted to the study of dynamic and mobile IoT environments and means of deploying defences against malicious actors aiming to compromise an IoT network and to evolve their attack laterally within it and from it. This survey takes a more comprehensive and detailed step by analysing a broad variety of methods for accomplishing each of the mitigation steps, presenting these uniquely by introducing a “defence-in-depth” approach that could significantly slow down the progress of an attack in the dynamic IoT environment. This survey sheds a light on leveraging redundancy as an inherent nature of multi-sensor IoT applications, to improve integrity and recovery. This study highlights the challenges of each mitigation step, emphasises novel perspectives, and reconnects the discussed mitigation steps to the ground principles they seek to implement

    La traduzione specializzata all’opera per una piccola impresa in espansione: la mia esperienza di internazionalizzazione in cinese di Bioretics© S.r.l.

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    Global markets are currently immersed in two all-encompassing and unstoppable processes: internationalization and globalization. While the former pushes companies to look beyond the borders of their country of origin to forge relationships with foreign trading partners, the latter fosters the standardization in all countries, by reducing spatiotemporal distances and breaking down geographical, political, economic and socio-cultural barriers. In recent decades, another domain has appeared to propel these unifying drives: Artificial Intelligence, together with its high technologies aiming to implement human cognitive abilities in machinery. The “Language Toolkit – Le lingue straniere al servizio dell’internazionalizzazione dell’impresa” project, promoted by the Department of Interpreting and Translation (Forlì Campus) in collaboration with the Romagna Chamber of Commerce (Forlì-Cesena and Rimini), seeks to help Italian SMEs make their way into the global market. It is precisely within this project that this dissertation has been conceived. Indeed, its purpose is to present the translation and localization project from English into Chinese of a series of texts produced by Bioretics© S.r.l.: an investor deck, the company website and part of the installation and use manual of the Aliquis© framework software, its flagship product. This dissertation is structured as follows: Chapter 1 presents the project and the company in detail; Chapter 2 outlines the internationalization and globalization processes and the Artificial Intelligence market both in Italy and in China; Chapter 3 provides the theoretical foundations for every aspect related to Specialized Translation, including website localization; Chapter 4 describes the resources and tools used to perform the translations; Chapter 5 proposes an analysis of the source texts; Chapter 6 is a commentary on translation strategies and choices

    From Black-box to Glass-box

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    Investigation into Photon Emissions as a Side-Channel Leakage in Two Microcontrollers: A Focus on SRAM Blocks

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    Microcontrollers are extensively utilized across a diverse range of applications. However, with the escalating usage of these devices, the risk to their security and the valuable data they process correspondingly intensifies. These devices could potentially be susceptible to various security threats, with side channel leakage standing out as a notable concern. Among the numerous types of side-channel leakages, photon emissions from active devices emerge as a potentially significant concern. These emissions, a characteristic of all semiconductor devices including microcontrollers, occur during their operation. Depending on the operating point and the internal state of the chip, these emissions can reflect the device’s internal operations. Therefore, a malicious individual could potentially exploit these emissions to gain insights into the computations being performed within the device. This dissertation delves into the investigation of photon emissions from the SRAM blocks of two distinct microcontrollers, utilizing a cost-effective setup. The aim is to extract information from these emissions, analyzing them as potential side-channel leakage points. In the first segment of the study, a PIC microcontroller variant is investigated. The quiescent photon emissions from the SRAM are examined. A correlation attack was successfully executed on these emissions, which led to the recovery of the AES encryption key. Furthermore, differential analysis was used to examine the location of SRAM bits. The combination of this information with the application of an image processing method, namely the Structural Similarity Index (SSIM), assisted in revealing the content of SRAM cells from photon emission images. The second segment of this study, for the first time, emphasizes on a RISC-V chip, examining the photon emissions of the SRAM during continuous reading. Probing the photon emissions from the row and column detectors led to the identification of a target word location, which is capable of revealing the AES key. Also, the content of target row was retrieved through the photon emissions originating from the drivers and the SRAM cells themselves. Additionally, the SSIM technique was utilized to determine the address of a targeted word in RISC-V photon emissions which cannot be analyzed through visual inspection. The insights gained from this research contribute to a deeper understanding of side-channel leakage via photon emissions and demonstrate its potential potency in extracting critical information from digital devices. Moreover, this information significantly contributes to the development of innovative security measures, an aspect becoming increasingly crucial in our progressively digitized world

    20th SC@RUG 2023 proceedings 2022-2023

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    Breaking the t<n/3t< n/3 Consensus Bound: Asynchronous Dynamic Proactive Secret Sharing under Honest Majority

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    A proactive secret sharing scheme (PSS), expressed in the dynamic-membership setting, enables a committee of n holders of secret-shares, dubbed as players, to securely hand-over new shares of the same secret to a new committee. We dub such a sub-protocol as a Refresh. All existing PSS under an honest majority, require the use of a broadcast (BC) in each refresh. BC is costly to implement, and its security relies on timing assumptions on the network. So the privacy of the secret and/or its guaranteed delivery, either depend on network assumptions, or, on the reliability of a public ledger. By contrast, PSS over asynchronous channels do not have these constraints. However, all of them (but one, with exponential complexity) use asynchronous verifiable secret sharing (AVSS) and consensus (MVBA and/or ACS), which are impossible under asynchrony beyond t<n/3 corruptions, whatever the setup. We present a PSS, named asynchronous-proactive secret sharing (APSS), which is the first PSS under honest majority with guaranteed output delivery in a completely asynchronous network. More generally, APSS allows any flexible threshold t<nt<n, such that privacy and correctness are guaranteed up to t corruptions, and liveness as soon as t+1t+1 players behave honestly. Correctness can be lifted to any number of corruptions, provided a linearly homomorphic commitment scheme. Moreover, each refresh completes at the record speed of 2δ2\delta, where δ\delta is the actual message delivery delay. APSS demonstrates that proactive refreshes are possible as long as players of the initial committee only, have a common view on a set of (publicly committed or encrypted) shares. Despite not providing consensus on a unique set of shares, APSS surprisingly enables the opening of any linear map over secrets { non-interactively, without consensus }. This, in turn, applies to threshold signing, decryption and randomness generation. APSS can also be directly integrated into the asynchronous Schnorr threshold signing scheme Roast [CCS\u2722]. Of independent interest, we: - provide the first UC formalization (and proof) of proactive AVSS, furthermore for arbitrary thresholds; - provide additional mechanisms enabling players of a committee to start a refresh then erase their old shares, synchronously up to δ\delta from each other; - improve by 50x the verification speed of the NIZKs of encrypted re-sharing of [Cascudo et al, Asiacrypt\u2722], by using novel optimizations of batch Schnorr proofs of knowledge. We demonstrate efficiency of APSS with an implementation which uses this optimization as baseline

    20th SC@RUG 2023 proceedings 2022-2023

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