581 research outputs found

    Towards trustworthy computing on untrustworthy hardware

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    Historically, hardware was thought to be inherently secure and trusted due to its obscurity and the isolated nature of its design and manufacturing. In the last two decades, however, hardware trust and security have emerged as pressing issues. Modern day hardware is surrounded by threats manifested mainly in undesired modifications by untrusted parties in its supply chain, unauthorized and pirated selling, injected faults, and system and microarchitectural level attacks. These threats, if realized, are expected to push hardware to abnormal and unexpected behaviour causing real-life damage and significantly undermining our trust in the electronic and computing systems we use in our daily lives and in safety critical applications. A large number of detective and preventive countermeasures have been proposed in literature. It is a fact, however, that our knowledge of potential consequences to real-life threats to hardware trust is lacking given the limited number of real-life reports and the plethora of ways in which hardware trust could be undermined. With this in mind, run-time monitoring of hardware combined with active mitigation of attacks, referred to as trustworthy computing on untrustworthy hardware, is proposed as the last line of defence. This last line of defence allows us to face the issue of live hardware mistrust rather than turning a blind eye to it or being helpless once it occurs. This thesis proposes three different frameworks towards trustworthy computing on untrustworthy hardware. The presented frameworks are adaptable to different applications, independent of the design of the monitored elements, based on autonomous security elements, and are computationally lightweight. The first framework is concerned with explicit violations and breaches of trust at run-time, with an untrustworthy on-chip communication interconnect presented as a potential offender. The framework is based on the guiding principles of component guarding, data tagging, and event verification. The second framework targets hardware elements with inherently variable and unpredictable operational latency and proposes a machine-learning based characterization of these latencies to infer undesired latency extensions or denial of service attacks. The framework is implemented on a DDR3 DRAM after showing its vulnerability to obscured latency extension attacks. The third framework studies the possibility of the deployment of untrustworthy hardware elements in the analog front end, and the consequent integrity issues that might arise at the analog-digital boundary of system on chips. The framework uses machine learning methods and the unique temporal and arithmetic features of signals at this boundary to monitor their integrity and assess their trust level

    VIP-komponentin käyttö SystemVerilog-testipenkissä

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    Tiivistelmä. Digitaalipiirien kasvava kompleksisuus asettaa entistä korkeammat vaatimukset myös mallin varmentavalle testipenkille. Yksi menetelmä vähentää varmennuksen kuormitusta on käyttää eri väyläprotokollille kehitettyjä valmiita varmennuskomponentteja, joita kutsutaan VIP-komponenteiksi (engl. Verification Intellectual Property). Tässä työssä perehdytään Siemens EDA:n I2C Questa VIP-komponentin (QVIP) käyttöön ja varmennetaan tämän avulla äärellisen impulssivasteen (engl. Finite Impulse Response, FIR) suodattimen I2C-väylän toimivuus. Työssä kehitetään testipenkki, jossa VIP-komponentti vastaa I2C-väylän ohjauksesta ja väylän herätteen generoinnista. Joukko testejä luodaan simuloimaan suodattimen eri käyttötilanteita ja väylän virheskenaarioita. Varmennettavat väylän ominaisuudet on kerätty QVIP:iin kuuluvaan varmennussuunnitelmaan, josta seurataan testeissä saavutettua funktionaalista kattavuutta. Suodatinpiiri läpäisee testit, ja valituissa ominaisuuksissa saavutetaan yli 95 prosentin kattavuus. Johtopäätöksenä voidaan todeta, että QVIP:n avulla varmennettiin suodatinpiirin väylän toimivuus. QVIP:n valmiit testipenkkikomponentit ja testisekvenssit säästivät vaivaa testipenkin ja testien kehityksessä, ja sen väyläprotokollan noudattamista seuraavat assertiot paransivat varmennuksen laatua. Lista varmennettavista ominaisuuksista oli myös helppo laatia valmiin varmennussuunnitelman pohjalta. VIP-komponenttien käsittelyn lisäksi työ sisältää lyhyen katsauksen SystemVerilog-varmennuskieleen ja järjestelmäpiirien varmennusteknologioihin kuuluviin assertiopohjaiseen varmennukseen ja universaaliin varmennusmenetelmään.The use of verification ip component in a SystemVerilog testbench. Abstract. The growing complexity of digital integrated circuits sets increasingly higher requirements for the testbenches that verify the design. One method to ease the burden of verification is to use premade verification components developed for various bus protocols. These components are called Verification Intellectual Properties (VIP). In this work, Siemens EDA’s I2C Questa VIP (QVIP) is used to verify the functionality of the I2C bus in a finite impulse response (FIR) filter design. A testbench is developed where QVIP controls the I2C bus and generates test stimulus. A group of test cases are created to simulate different FIR filter use cases and I2C bus error scenarios. The verified features of the I2C bus are collected in a verification plan. The plan is part of QVIP and is used to follow the total functional coverage achieved with the tests. The filter design passes all the tests and over 95 percent functional coverage is reached in the selected features. In conclusion, the functionality of the I2C bus in the filter was successfully verified using QVIP. The premade testbench components and test sequences of QVIP saved effort in testbench and test development, and its protocol assertions improved verification quality. In addition to VIPs, the work includes a brief overview of the verification language SystemVerilog and two system-on-chip (SoC) verification methodologies: Universal Verification Methodology (UVM) and assertion-based verification

    Evaluation of Open-Source EDA Tool “EDA Playground”

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    With the advancement of Information Technology, the design, verification, and manufacturing of Integrated circuits have been challenging and time consuming. Unlike the software domain, Electronic Design Automation (EDA) tools are mostly commercially available, and access is limited to the students. An open-source EDA tool might help the students to initialize the learning process. This thesis showcases an open-source EDA platform, EDA Playground, where users can practice their hardware description language (HDL) codes, create a testbench to simulate their designs and synthesize their code. The thesis shows how EDA Playground provides its users with the ability to write code in various HDLs, enabling them to evaluate their designs using a range of both commercial and freely available simulators. Additionally, it also shows how the platform helps in identifying and resolving design failures through the utilization of waveform viewing tool, EPwave, developed my EDA Playground and logs. It is also highlighted how users have the ability to employ commercial synthesizers in order to combine their codes, thereby facilitating the assessment of device utilization and circuit diagram. Another notable objective of the thesis is to highlight the application of EDA Playground to the incorporate of UVM 1.2. A step-by-step UVM testbench of a simple SystemVerilog adder was developed and simulated as a part of the thesis. Prospective users have the opportunity to gain knowledge about this methodology by accessing educational resources, which encompass various tools and examples provided for their advantage. The thesis provides an extensive array of use cases that showcase the varied functionalities provided by EDA Playground. This thesis extensively employs and evaluates the diverse resources offered on EDA Playground to determine their usefulness

    LIPIcs, Volume 277, GIScience 2023, Complete Volume

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    LIPIcs, Volume 277, GIScience 2023, Complete Volum

    12th International Conference on Geographic Information Science: GIScience 2023, September 12–15, 2023, Leeds, UK

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    Uranium in natural waters and the environment: distribution, speciation and impact

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    The concentrations of U in natural waters are usually low, being typically less than 4 μg/L in river water, around 3.3 μg/L in open seawater, and usually less than 5 μg/L in groundwater. Higher concentrations can occur in both surface water and groundwater and the range spans some six orders of magnitude, with extremes in the mg/L range. However, such extremes in surface water are rare and linked to localized mineralization or evaporation in alkaline lakes. High concentrations in groundwater, substantially above the WHO provisional guideline value for U in drinking water of 30 μg/L, are associated most strongly with (i) granitic and felsic volcanic aquifers, (ii) continental sandstone aquifers especially in alluvial plains and (iii) areas of U mineralization. High-U groundwater provinces are more common in arid and semi-arid terrains where evaporation is an additional factor involved in concentrating U and other solutes. Examples of granitic and felsic volcanic terrains with documented high U concentrations include several parts of peninsular India, eastern USA, Canada, South Korea, southern Finland, Norway, Switzerland and Burundi. Examples of continental sandstone aquifers include the alluvial plains of the Indo-Gangetic Basin of India and Pakistan, the Central Valley, High Plains, Carson Desert, Española Basin and Edwards-Trinity aquifers of the USA, Datong Basin, China, parts of Iraq and the loess of the Chaco-Pampean Plain, Argentina. Many of these plains host eroded deposits of granitic and felsic volcanic precursors which likely act as primary sources of U. Numerous examples exist of groundwater impacted by U mineralization, often accompanied by mining, including locations in USA, Australia, Brazil, Canada, Portugal, China, Egypt and Germany. These may host high to extreme concentrations of U but are typically of localized extent. The overarching mechanisms of U mobilization in water are now well-established and depend broadly on redox conditions, pH and solute chemistry, which are shaped by the geological conditions outlined above. Uranium is recognized to be mobile in its oxic, U(VI) state, at neutral to alkaline pH (7–9) and is aided by the formation of stable U–CO3(±Ca, Mg) complexes. In such oxic and alkaline conditions, U commonly covaries with other similarly controlled anions and oxyanions such as F, As, V and Mo. Uranium is also mobile at acidic pH (2–4), principally as the uranyl cation UO22+. Mobility in U mineralized areas may therefore occur in neutral to alkaline conditions or in conditions with acid drainage, depending on the local occurrence and capacity for pH buffering by carbonate minerals. In groundwater, mobilization has also been observed in mildly (Mn-) reducing conditions. Uranium is immobile in more strongly (Fe-, SO4-) reducing conditions as it is reduced to U(IV) and is either precipitated as a crystalline or ‘non-crystalline’ form of UO2 or is sorbed to mineral surfaces. A more detailed understanding of U chemistry in the natural environment is challenging because of the large number of complexes formed, the strong binding to oxides and humic substances and their interactions, including ternary oxide-humic-U interactions. Improved quantification of these interactions will require updating of the commonly-used speciation software and databases to include the most recent developments in surface complexation models. Also, given their important role in maintaining low U concentrations in many natural waters, the nature and solubility of the amorphous or non-crystalline forms of UO2 that result from microbial reduction of U(VI) need improved quantification. Even where high-U groundwater exists, percentage exceedances of the WHO guideline value are variable and often small. More rigorous testing programmes to establish usable sources are therefore warranted in such vulnerable aquifers. As drinking-water regulation for U is a relatively recent introduction in many countries (e.g. the European Union), testing is not yet routine or established and data are still relatively limited. Acquisition of more data will establish whether analogous aquifers elsewhere in the world have similar patterns of aqueous U distribution. In the high-U groundwater regions that have been recognized so far, the general absence of evidence for clinical health symptoms is a positive finding and tempers the scale of public health concern, though it also highlights a need for continued investigation

    Labour problems in the sugar industry of Ile de France or Mauritius, 1790 - 1842

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    The island of Mauritius is situated in the south-western Indian Ocean between 19°591, 20°321 south latitude and 57°18 1 , 57° 49 1 east longitude. The nearest landmass of any considerable extent is Madagascar which Iies some 900 km due west of Mauritius; but there are a number of islands and islets in the vicinity, notably Reunion, Rodrigues and the Cargados Carajos, which together with Mauritius constitute the archipelago of the Mascarenes
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