1,721,060 research outputs found
AutoCC: Automatic Discovery of Covert Channels in Time-Shared Hardware
Full text linkCovert channels enable information leakage between security domains that should be isolated by observing execution differences in shared hardware. These channels can appear in any stateful shared resource, including caches, predictors, and accelerators. Previous works have identified many vulnerable components, demonstrating and defending against attacks via reverse engineering. However, this approach requires much human effort and reasoning. With the Cambrian explosion of specialized hardware, it is becoming increasingly difficult to identify all vulnerabilities manually.To tackle this challenge, we propose AutoCC, a methodology that leverages formal property verification (FPV) to automatically discover covert channels in hardware that is shared between processes. AutoCC operates at the register-transfer level (RTL) to exhaustively examine any machine state left by a process after a context switch that creates an execution difference. Upon finding such a difference, AutoCC provides a precise execution trace showing how the information was encoded into the machine state and recovered.Leveraging AutoCC’s flow to generate FPV testbenches that apply our methodology, we evaluated it on four open-source hardware projects, including two RISC-V cores and two accelerators. Without hand-written code or directed tests, AutoCC uncovered known covert channels (within minutes instead of many hours of test-driven emulations) and unknown ones. Although AutoCC is primarily intended to find covert channels, our evaluation has also found RTL bugs, demonstrating that AutoCC is an effective tool to test both the security and reliability of hardware designs.CCS CONCEPTS• Security and privacy → Side-channel analysis and countermeasures; Tamper-proof and tamper-resistant designs; Information flow control; • Hardware → Best practices for EDA
Systematic Prevention of On-Core Timing Channels by Full Temporal Partitioning
No full textMicroarchitectural timing channels enable unwanted information flow across security boundaries, violating fundamental security assumptions. They leverage timing variations of several state-holding microarchitectural components and have been demonstrated across instruction set architectures and hardware implementations. Analogously to memory protection, (Ge et al. 2019) have proposed time protection for preventing information leakage via timing channels. They also showed that time protection calls for hardware support. This work leverages the open and extensible RISC-V instruction set architecture (ISA) to introduce the temporal fence instruction fence.t , which provides the required mechanisms by clearing vulnerable microarchitectural state and guaranteeing a history-independent context-switch latency. We propose and discuss three different implementations of fence.t and implement them on an experimental version of the seL4 microkernel (Klein et al. 2014) and CVA6, an open-source, in-order, application class, 64-bit RISC-V core (Zaruba and Benini 2019). We find that a complete, systematic, ISA-supported erasure of all non-architectural core components is the most effective implementation while featuring a low implementation effort, a minimal performance overhead of less than 1%, and negligible hardware costs
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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