1,721,037 research outputs found
A survey of microarchitectural timing attacks and countermeasures on contemporary hardware
Full text linkPublished online: 26 December 2016Microarchitectural timing channels expose hidden hardware states though timing. We survey recent attacks that exploit microarchitectural features in shared hardware, especially as they are relevant for cloud computing. We classify types of attacks according to a taxonomy of the shared resources leveraged for such attacks. Moreover, we take a detailed look at attacks used against shared caches. We survey existing countermeasures. We finally discuss trends in attacks, challenges to combating them, and future directions, especially with respect to hardware support.Qian Ge, Yuval Yarom, David Cock, Gernot Heise
Last-level cache side-channel attacks are practical
No full textWe present an effective implementation of the PRIME+PROBE side-channel attack against the lastlevel cache. We measure the capacity of the covert channel the attack creates and demonstrate a cross-core, cross-VM attack on multiple versions of GnuPG. Our technique achieves a high attack resolution without relying on weaknesses in the OS or virtual machine monitor or on sharing memory between attacker and victim.Fangfei Liu, Yuval Yarom, Qian Ge, Gernot Heiser, Ruby B. Le
Side-Channeling the Kalyna Key Expansion
No full textIn 2015, the block cipher Kalyna has been approved as the new encryption standard of Ukraine. The cipher is a substitution-permutation network, whose design is based on AES, but includes several different features. Most notably, the key expansion in Kalyna is designed to resist recovering the master key from the round keys. In this paper we present a cache attack on the Kalyna key expansion algorithm. Our attack observes the cache access pattern during key expansion, and uses the obtained information together with one round key to completely recover the master key. We analyze all five parameter sets of Kalyna. Our attack significantly reduces the attack cost and is practical for the Kalyna-128/128 variant, where it is successful for over 97% of the keys and has a complexity of only 243.58 . To the best of our knowledge, this is the first attack on the Kalyna key expansion algorithm. To show that the attack is feasible, we run the cache attack on the reference implementation of Kalyna-128/128, demonstrating that we can obtain the required side-channel information. We further perform the key-recovery step on our university’s high-performance compute cluster. We find the correct key within 37 hours and note that the attack requires 50K CPU hours for enumerating all key candidates. As a secondary contribution we observe that the additive key whitening used in Kalyna facilitates first round cache attacks. Specifically, we design an attack that can recover the full first round key with only seven adaptively chosen plaintexts.Chitchanok Chuengsatiansup, Daniel Genkin, Yuval Yarom, and Zhiyuan Zhan
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
More on sliding right
Full text linkThis text can be thought of an “external appendix” to the paper Sliding right into disaster: Left-to-right sliding windows leak by Daniel J. Bernstein, Joachim Breitner, Daniel Genkin, Leon Groot Bruinderink, Nadia Heninger, Tanja Lange, Christine van Vredendaal and Yuval Yarom [1, 2], and goes into the details of an alternative way to find the knowable bits of the secret exponent, which is complete and can (in rare corner cases) find more bits than the rewrite rules in Section 3.1 of [1], an algorithm to calculate the collision entropy H that is used in Theorem 3 of [1], and a proof of Theorem 3
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