177 research outputs found

    TaLoS: secure and transparent TLS termination inside SGX enclaves

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    We introduce TaLoS1, a drop-in replacement for existing transport layer security (TLS) libraries that protects itself from a malicious environment by running inside an Intel SGX trusted execution environment. By minimising the amount of enclave transitions and reducing the overhead of the remaining enclave transitions, TaLoS imposes an overhead of no more than 31% in our evaluation with the Apache web server and the Squid proxy

    Glamdring: automatic application partitioning for Intel SGX

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    Trusted execution support in modern CPUs, as offered by Intel SGX enclaves , can protect applications in untrusted environments. While prior work has shown that legacy applications can run in their entirety inside enclaves, this results in a large trusted computing base (TCB). Instead, we explore an approach in which we partition an applica- tion and use an enclave to protect only security-sensitive data and functions, thus obtaining a smaller TCB. We describe Glamdring , the first source-level parti- tioning framework that secures applications written in C using Intel SGX. A developer first annotates security- sensitive application data. Glamdring then automatically partitions the application into untrusted and enclave parts: (i) to preserve data confidentiality, Glamdring uses dataflow analysis to identify functions that may be ex- posed to sensitive data; (ii) for data integrity, it uses back- ward slicing to identify functions that may affect sensitive data. Glamdring then places security-sensitive functions inside the enclave, and adds runtime checks and crypto- graphic operations at the enclave boundary to protect it from attack. Our evaluation of Glamdring with the Mem- cached store, the LibreSSL library, and the Digital Bitbox bitcoin wallet shows that it achieves small TCB sizes and has acceptable performance overheads

    Informing additive manufacturing technology adoption: total cost and the impact of capacity utilisation

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    Informing Additive Manufacturing (AM) technology adoption decisions, this paper investigates the relationship between build volume capacity utilisation and efficient technology operation in an inter-process comparison of the costs of manufacturing a complex component used in the packaging industry. Confronting the reported costs of a conventional machining and welding pathway with an estimator of the costs incurred through an AM route utilising Direct Metal Laser Sintering (DMLS), we weave together four aspects: optimised capacity utilisation, ancillary process steps, the effect of build failure and design adaptation. Recognising that AM users can fill unused machine capacity with other, potentially unrelated, geometries, we posit a characteristic of ‘fungible’ build capacity. This aspect is integrated in the cost estimation framework through computational build volume packing, drawing on a basket of sample geometries. We show that the unit cost in mixed builds at full capacity is lower than in builds limited to a single type of geometry; in our study, this results in a mean unit cost overstatement of 157%. The estimated manufacturing cost savings from AM adoption range from 36 to 46%. Additionally, we indicate that operating cost savings resulting from design adaptation are likely to far outweigh the manufacturing cost advantage

    Liver Graft Revascularization by Donor Portal Vein Arterialization Following “No Touch” Donor Hepatectomy

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    Unsatisfactory immediate function of the transplanted liver together with technical complications contribute to a persisting early mortality for hepatic transplantation in the 20% range. We report our initial clinical experience with methods, one not previously used clinically, that resulted in uniformly well-functioning liver grafts in 11 patients and contributed to a satisfactory success rate for the procedure. Donors were heart-beating. During the donor operation all manipulations of the liver were avoided until after cold preservation, achieved by external cooling at the same time as circulatory interruption, donor exsanguination and perfusion of the liver with cold oxygenated fluid of “extracellular̵ type. The organs were then gently dissected. At transplantation the livers were revascularized with arterial blood shunted from the recipient iliac artery to the graft portal vein after completion of the suprahepatic IVC anastomosis. The infrahepatic IVCs and hepatic arteries were then joined, the iliac artery shunts discontinued and the portal veins joined. Total ischaemic intervals for the allografts were 3½–8 (average 5). Anhepatic intervals were 1–2¼ (average 2). The arterio-portal shunts were operating for 18–85 (mean 46) min. Blood loss and haemodynamic, acid-base and electrolyte abnormalities at revascularization were minimal. All grafts secreted bile immediately and all parameters reflected continuing improvement of liver function thereafter. Nine patients (82%) are alive between 4 and 18 (mean 11) months after transplantation. We conclude that these methods offer effective avoidance of serious organ damage during donor hepatectomy and preservation, reduced allograft ischaemic interval and reduced recipient anhepatic time. They result in avoidance of blood loss at the time of revascularization, together with minimal haemodynamic, acid-base or biochemical changes. In addition, they allow the surgeon to perform and test all anastomoses without time constraints, provide the capability to deal with unexpected complications, and assure good early graft function

    Phylogenetic and Molecular Characterization of a 23S Ribosomal-Rna Gene Positions the Genus Campylobacter in the Epsilon-Subdivision of the Proteobacteria and Shows That the Presence of Transcribed Spacers Is Common in Campylobacter Spp

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    The nucleotide sequence of a 23S rRNA gene of Campylobacter coli VC167 was determined. The primary sequence of the C. coli 23S rRNA was deduced, and a secondary-structure model was constructed. Comparison with Escherichia coli 23S rRNA showed a major difference in the C. coli rRNA at approximately position 1170 (E. coli numbering) in the form of an extra sequence block approximately 147 bp long. PCR analysis of 31 other strains of C. coli and C. jejuni showed that 69% carried a transcribed spacer of either ca, 147 or ca. 37 bp. Comparison of all sequenced Campylobacter transcribed spacers showed that the Campylobacter inserts were related in sequence and percent G+C content. All Campylobacter strains carrying transcribed spacers in their 23S rRNA genes produced fragmented 23S rRNAs. Other strains which produced unfragmented 23S rRNAs did not appear to carry transcribed spacers at this position in their 23S rRNA genes. At the 1850 region (E. coli numbering), Campylobacter 23S rRNA displayed a base pairing signature most like that of the beta and gamma subdivisions of the class Proteobacteria, but in the 270 region, Campylobacter 23S rRNA displayed a helix signature which distinguished it from the alpha, beta, and gamma subdivisions. Phylogenetic analysis comparing C. coli VC167 23S rRNA and a C. jejuni TGH9011 (ATCC 43431) 23S rRNA with 53 other completely sequenced (eu)bacterial 23S rRNAs showed that the two campylobacters form a sister group to the alpha, beta, and gamma proteobacterial 23S rRNAs, a positioning consistent with the idea that the genus Campylobacter belongs to the epsilon subdivision of the class Proteobacteria

    "A convenient truth": air travel passengers' willingness to pay to offset their CO2 emissions

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    Several economic reviews demonstrate the substantial costs related to climate change and consequently call for early action. These reviews, however, have been limited to measuring ‘objective’ risks and expected material damage related to climate change. The ‘subjective’ perceived risk of climate change and society’s willingness to pay (WTP) to avoid these risks are expected to provide an important additional motivation for direct action. We investigate whether and why air travel passengers—an increasingly important source of greenhouse gas emissions—are supportive of measures that increase the cost of their travel based on the polluter pays principle and compensate the damage caused by their flight. Compared to the results of the few previous studies that have elicited WTP estimates for climate policy more generally, our results appear to be at the lower end of the scale, while a comparison to estimates of the social cost of carbon shows that the average WTP estimate in this study is close to the estimated marginal damage cost. Although significant differences are found between travellers from Europe, North America, Asia and the rest of the world, we show that there exists a substantial demand for climate change mitigation action. The positive risk premium over and above the expected property damage cost assessments should be accounted for more explicitly in economic reviews as it will add to the burden of proof of direct action. Measurements of passenger WTP will help policy makers to design effective financial instruments aimed at discouraging climate-unfriendly travel activities as well as to generate funds for the measures directed at climate change mitigation and adaptation. Based on stated WTP by travellers to offset their greenhouse gas emissions, funds in the order of magnitude of €23 billion could be generated annually to finance climate change mitigation activities

    Interacting with the public as a risk factor for employee psychological distress

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    Background: The 1-month prevalence of any mental disorder in employees ranges from 10.5% to 18.5%. Mental disorders are responsible for substantial losses in employee productivity in both absenteeism and presenteeism. Potential work related factors contributing to mental difficulties are of increasing interest to employers. Some data suggests that being sales staff, call centre operator, nurse or teacher increases psychological distress. One aspect of these occupations is that there is an interaction with the public. The aim of this study is to evaluate whether employees who interact with the public are at greater risk of psychological distress
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