1,720,957 research outputs found
Définition et conception d'un système optimal de la révocation de certificats
No full textThe Public Key Infrastructure (PKI) is a public key infrastructure whose objective is to meet needs such as public key authentication, access control and authorization functions. The support for these services determines the attributes contained in, as well as auxiliary control information such as policy and certification path constraints. The validation of the certificate goes through the verification of these attributes. A certificate is supposed to be used throughout its validity period. However, various circumstances may interrupt this validity. These circumstances include a name change, an association change, etc. Under such circumstances, the CA must revoke the certificate. Certificate revocation validation and verification services are expected or necessary in several contexts, we can cite some among many others: vehicular communications, (WWW), user authentication, etc. Vehicle communications are at the center of the vehicles of tomorrow and, more generally, of smart cities. Securing these communications is a critical element given the services in perspective. The security of inter-vehicle exchanges is based on the digital signature. This signature requires a key exchange infrastructure (PKI).RFC 5280 defines different revocation methods. Among these, we have a revocation method, which requires the periodic publication by the CA of a signed data structure called CRL (Certificate revocation list). This approach, which is the most widely used, is mature but expensive in terms of time and volume, and vehicular communications bring new constraints. This work relates to the verification of the revocation of X509 certificates and pseudonym certificates used in vehicular communications. Our goal is to reduce latency due to revocation checking of X509 and pseudonyms certificates. In this context, we have proposed a method of revocation, which implies the publication of the revocation lists in a public Blockchain. We then proposed a revocation method able to face the new constraints introduced by the vehicular environment. Our contributions have been validated by an implementation.La Public Key Infrastructure(PKI) est une infrastructure à clés publique dont l’objectif est de répondre à des besoins tel que : l’authentification de clés publiques, le contrôle d'accès et les fonctions d'autorisation, l'identification et l'authentification déterministe et automatisée. La prise en charge de ces services détermine les attributs contenus dans le certificat, ainsi que les informations de contrôle auxiliaires telles que la politique et les contraintes de chemin de certification. La validation du certificat passe par la vérification de ces attributs. Un certificat délivré par une autorité de certification est censé être utilisé pendant toute sa période de validité. Cependant, diverses circonstances peuvent interrompre cette validité. Ces circonstances comprennent le changement de nom, le changement d’association et etc... Sous telles circonstances, l'autorité de certification doit révoquer le certificat. Les services de validation et de vérification de la révocation des certificats sont attendus ou nécessaires dans plusieurs contextes, nous pouvons en citer certains parmi tant d’autres: les communications véhiculaires, le (WWW), l’authentification des utilisateurs et etc. Les communications véhiculaires sont au centre des véhicules de demain et d’une manière plus générale des smart-cities. La sécurisation de ces réseaux est un élément critique au vu des services en perspective. La sécurité des échanges inter-véhicules est basée notamment sur la signature numérique. Cette même signature nécessite d’une infrastructure d’échange de clés (PKI). Le RFC 5280 défini différents méthodes de révocation. Parmi celles-ci nous avons une méthode de révocation qui implique la publication périodique de la part de la CA d’une structure de données signée appelée CRL(Certificate révocation list). Cette approche, qui est la plus utilisée, est mature mais coûteuse en temps et en volume et les communications véhiculaires apportent de nouvelles contraintes. Ces travaux portent sur la vérification de la révocation des certificats X509 et de type pseudonyme utilisés dans les communications véhiculaires. Notre objectif est de réduire la latence due à la vérification de la révocation des certificats X509 et pseudonymes. Nous avons dans ce contexte proposé une méthode de révocation impliquant la publication de la CRL dans une Blockchain de type publique. Nous avons ensuite proposé une méthode de révocation capable de faire face aux nouvelles contraintes introduites par le véhiculaire. Nos contributions ont été validées par une implémentation
Definition and design of an optimal certificate revocation system
No full textLa Public Key Infrastructure(PKI) est une infrastructure à clés publique dont l’objectif est de répondre à des besoins tel que : l’authentification de clés publiques, le contrôle d'accès et les fonctions d'autorisation, l'identification et l'authentification déterministe et automatisée. La prise en charge de ces services détermine les attributs contenus dans le certificat, ainsi que les informations de contrôle auxiliaires telles que la politique et les contraintes de chemin de certification. La validation du certificat passe par la vérification de ces attributs. Un certificat délivré par une autorité de certification est censé être utilisé pendant toute sa période de validité. Cependant, diverses circonstances peuvent interrompre cette validité. Ces circonstances comprennent le changement de nom, le changement d’association et etc... Sous telles circonstances, l'autorité de certification doit révoquer le certificat. Les services de validation et de vérification de la révocation des certificats sont attendus ou nécessaires dans plusieurs contextes, nous pouvons en citer certains parmi tant d’autres: les communications véhiculaires, le (WWW), l’authentification des utilisateurs et etc. Les communications véhiculaires sont au centre des véhicules de demain et d’une manière plus générale des smart-cities. La sécurisation de ces réseaux est un élément critique au vu des services en perspective. La sécurité des échanges inter-véhicules est basée notamment sur la signature numérique. Cette même signature nécessite d’une infrastructure d’échange de clés (PKI). Le RFC 5280 défini différents méthodes de révocation. Parmi celles-ci nous avons une méthode de révocation qui implique la publication périodique de la part de la CA d’une structure de données signée appelée CRL(Certificate révocation list). Cette approche, qui est la plus utilisée, est mature mais coûteuse en temps et en volume et les communications véhiculaires apportent de nouvelles contraintes. Ces travaux portent sur la vérification de la révocation des certificats X509 et de type pseudonyme utilisés dans les communications véhiculaires. Notre objectif est de réduire la latence due à la vérification de la révocation des certificats X509 et pseudonymes. Nous avons dans ce contexte proposé une méthode de révocation impliquant la publication de la CRL dans une Blockchain de type publique. Nous avons ensuite proposé une méthode de révocation capable de faire face aux nouvelles contraintes introduites par le véhiculaire. Nos contributions ont été validées par une implémentation.The Public Key Infrastructure (PKI) is a public key infrastructure whose objective is to meet needs such as public key authentication, access control and authorization functions. The support for these services determines the attributes contained in, as well as auxiliary control information such as policy and certification path constraints. The validation of the certificate goes through the verification of these attributes. A certificate is supposed to be used throughout its validity period. However, various circumstances may interrupt this validity. These circumstances include a name change, an association change, etc. Under such circumstances, the CA must revoke the certificate. Certificate revocation validation and verification services are expected or necessary in several contexts, we can cite some among many others: vehicular communications, (WWW), user authentication, etc. Vehicle communications are at the center of the vehicles of tomorrow and, more generally, of smart cities. Securing these communications is a critical element given the services in perspective. The security of inter-vehicle exchanges is based on the digital signature. This signature requires a key exchange infrastructure (PKI).RFC 5280 defines different revocation methods. Among these, we have a revocation method, which requires the periodic publication by the CA of a signed data structure called CRL (Certificate revocation list). This approach, which is the most widely used, is mature but expensive in terms of time and volume, and vehicular communications bring new constraints. This work relates to the verification of the revocation of X509 certificates and pseudonym certificates used in vehicular communications. Our goal is to reduce latency due to revocation checking of X509 and pseudonyms certificates. In this context, we have proposed a method of revocation, which implies the publication of the revocation lists in a public Blockchain. We then proposed a revocation method able to face the new constraints introduced by the vehicular environment. Our contributions have been validated by an implementation
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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