1,720,962 research outputs found
Analysis of a two-factor graphical password scheme
No full textGraphical passwords are a promising research branch, but implementation of many proposed schemes often requires considerable resources (e.g., data storage, high quality displays) making difficult their usage on small devices, such as old-fashioned ATM terminals. Furthermore, most of the time, such schemes lack a careful security analysis. In this paper, we analyze the security and usability for an authentication mechanism that can be instantiated as a graphical password scheme. We model the information an adversary might extract by analyzing the transcripts of authentication sessions as a boolean formula. Our experiments show that the time needed by a passive adversary to extract the user secret in the last presented protocol grows exponentially in the system parameter, giving evidence of the security of the proposed scheme
On user authentication by means of video events recognition
No full textGraphical password schemes have been widely analyzed in the last couple of decades. Typically such schemes are not resilient to adversaries who are able to collect a considerable amount of session transcripts, and can process them automatically in order to extract the secret. In this paper we discuss a possible enhancement to graphical passwords aiming at making infeasible to the attacker to automatically process the collected transcripts. In particular, we investigate the possibility of replacing static graphical challenges with on-the-fly edited videos. In our approach, the system challenges the user by showing her a short film containing a number of pre-defined pass-events and the user replies with the proof that she recognized such events. We present a proof-of-concept prototype, FilmPW, and discuss some issues related to event life-cycle management. Our preliminary experiments show that such an authentication mechanism is well accepted by users and achieves low error rates
Interoperability Between Federated Authentication Systems.
No full textFederated authentication allows users to use their home authentication credentials for gaining access to other institutions services while moving among different institutions. Different federated authentication systems have been designed and implemented. Despite simplified users mobility, one key problem in this area is that different authentication systems do not cooperate. In this paper we propose a protocol for allowing full communication between two federated authentication systems, Shibboleth a de facto standard in this context, and PAPI
A Graphical PIN Authentication Mechanism for Smart Cards and Low-Cost Devices
Full text linkPasswords and PINs are still the most deployed authentication mechanisms and their protection is a classical branch of research in computer security. Several password schemes, as well as more sophisticated tokens, algorithms, and protocols, have been proposed during the last years. Some proposals require dedicated devices, such as biometric sensors, whereas, others of them have high computational requirements. Graphical passwords are a promising research branch, but implementation of many proposed schemes often requires considerable resources (e.g., data storage, high quality displays) making difficult their usage on small devices, like old fashioned ATM terminals, smart cards and many low-price cellular phones. In this paper we present a graphical mechanism that handles authentication by means of a numerical PIN, that users have to type on the basis of a secret sequence of objects and a graphical challenge. The proposed scheme can be instantiated in a way to require low computation capabilities, making it also suitable for small devices with limited resources. We prove that our scheme is effective against "shoulder surfing" attacks. © 2008 Springer-Verlag Berlin Heidelberg
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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