1,721,026 research outputs found
Soft Constraints for Security
No full textAbstractIntegrity policies and cryptographic protocols have much in common. They allow for a number of participating principals, and consist of sets of rules controlling the actions that principals should or should not perform. They are intended to uphold various security properties, the crucial ones being integrity, confidentiality and authentication.This paper takes a unified view to the analysis of integrity policies and cryptographic protocols: they are artifacts that must be designed to be sufficiently robust to attack given an understood threat model. For example, integrity policy rules provide resilience to the threat of internal fraud, while cryptographic protocols provide resilience to the threat of replay and related attacks. The framework is modelled using (soft) constraints and analysis corresponds to the soft constraint satisfaction problem. Soft constraints facilitate a quantitative approach to analyzing integrity, confidentiality and authentication. Examples will be given: an integrity policy may achieve different levels of integrity under different circumstances; a protocol message may enjoy different levels of confidentiality for different principals; a principal can achieve different levels of authentication with different principals
Retaliation Against Protocol Attacks
No full textSecurity protocols intend to give their parties reasonable assurance that certain security properties will protect their communication session. However, the literature confirms that the protocols may suffer subtle and hidden attacks. Flawed protocols are customarily sent back to the design process, but the costs of reengineering a deployed protocol may be prohibitive. This paper outlines the concept of retaliation: who would steal a sum of money today, should this pose significant risks of having twice as much stolen back tomorrow? When ethics is left behind, attacks are always balanced decisions: if an attack can be retaliated, the economics of security may convince the attacker to refrain from attacking, and us to live with a flawed protocol. This new perspective requires a new threat model where any party may decide to subvert the protocol for his own sake, depending on the risks of retaliation. This threat model, which for example is also suitable to studying non-repudiation protocols, seems more appropriate than the Dolev-Yao model to the present technological/social setting. It is demonstrated that machine-assisted protocol verification can and must be tailored to the new threat model
Soft constraint programming to analysing security protocols
No full textSecurity protocols stipulate how the remote principals of a computer network should interact in order to obtain specific security goals. The crucial goals of confidentiality and authentication may be achieved in various forms, each of different strength. Using soft (rather than crisp) constraints, we develop a uniform formal notion for the two goals. They are no longer formalised as mere yes/no properties as in the existing literature, but gain an extra parameter, the security level. For example, different messages can enjoy different levels of confidentiality, or a principal can achieve different levels of authentication with different principals. The goals are formalised within a general framework for protocol analysis that is amenable to mechanisation by model checking. Following the application of the framework to analysing the asymmetric Needham-Schroeder protocol (Bella and Bistarelli 2001; Bella and Bistarelli 2002), we have recently discovered a new attack on that protocol as a form of retaliation by principals who have been attacked previously. Having commented on that attack, we then demonstrate the framework on a bigger, largely deployed protocol consisting of three phases, Kerberos
Security is Beautiful
No full textIn the movie “Life is Beautiful”, Guido Orefice, the character interpreted by Roberto Benigni, convinces his son Giosuè that they have been interned in a nazi concentration camp not because they are Jews but because they are actually taking part in a long and complex game in which they, and in particular Giosuè, must perform the tasks that the guards give them. A ghastly experience is turned into a livable, at times even almost enjoyable, one. In this position paper, we advocate that, in the same spirit as Guido’s ingenious trick of turning a nazi camp into a sort of playground for his child, security should be beautiful; and if it isn’t so yet, it should then be made beautiful, so that the users experience it in that way. This is, of course, an extremely challenging objective, and we will discuss through further scenarios a few ways in which it could be made possible in the future. It turns out that the Peppa Pig cartoon may also be inspiring
Getmewhere: A Location-Based Privacy-Preserving Information Service
No full textMobile users have got used to getting useful information while they are literally on the move. An implication of this habit is that certain live information, such as that for navigation, for dating and for handling emergencies, should be tailored to the user's current location. While this is technically feasible with the current technology, it raises concerns on the user's location privacy. To address the delicate tradeoff between user's location privacy and appropriateness of the information for that location, this paper discusses three information delivery protocols. One is the widely adopted Android's protocol, the other two are the authors' novel ones, termed AL protocol and LBPP protocol respectively. The former conceals the user's location within a geographical area, the latter employs secure two-party computation. Privacy of all protocols is analysed, motivating the choice to implement the LBPP protocol. It is made available as the 'Getmewhere' service for the reader to download
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
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