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657 results
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Seminar
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Cryptography
Implicit proofs of membership
Speaker : Olivier Blazy - Université Limoges
Smooth hash proof systems have been introduced by Cramer and shoup to build compact efficient cca2 encryption in the standard model. Since then, they found applications in a broad range of protocols from oblivious transfer to authenticated key exchange, passing by witness examples.<br/> In this talk, we will start by a panorama of languages that can be managed by such a primitive and then show how[…] -
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Seminar
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Cryptography
Soutenance de thèse: Conception de courbes elliptiques et applications
Speaker : Rémi Clarisse - Rennes
Le thème de la sécurité de l’information est prédominant dans nos vies actuelles. En particulier, les utilisateurs de service, plus précisément en ligne, s’attendent de plus en plus à ce que leurs données à caractère personnel soient traitées dignement et avec leur consentement. Cela incite donc à concevoir des systèmes se pliant à de telles exigences. Le recours à la cryptographie permet de[…] -
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Seminar
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Cryptography
Middle-Product Learning with Rounding Problem and its Applications
Speaker : Katharina Boudgoust - Univ Rennes, CNRS, IRISA
This talk focuses on a new variant of the Learning With Errors (LWE) problem, a fundamental computational problem used in lattice-based cryptography.<br/> At Crypto17, Roşca et al. introduced the Middle-Product LWE problem (MP-LWE), whose hardness is based on the hardness of the Polynomial LWE (P-LWE) problem parameterized by a large set of polynomials, making it more secure against the possible[…] -
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Seminar
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Cryptography
Traceable Constant-Size Multi-Authority Credentials
Speaker : Chloé Hébant - ENS
Many attribute-based anonymous credential (ABC) schemes have been proposed allowing a user to prove the possession of some attributes, anonymously. They became more and more practical with, for the most recent papers, a constant-size credential to show a subset of attributes issued by a unique credential issuer. However, proving possession of attributes coming from K different credential issuers[…] -
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Seminar
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Cryptography
Computing isogenies from modular equations in genus 2
Speaker : Jean Kieffer - Université Bordeaux 1
Given two l-isogenous elliptic curves, a well-known algorithm of Elkies uses modular polynomials to compute this isogeny explicitly. In this work, we generalize his ideas to Jacobians of genus 2 curves. Our algorithms works for both l-isogenies and (in the RM case) cyclic isogenies, and uses Siegel or Hilbert type modular equations respectively. This has applications for point counting in genus 2:[…] -
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Seminar
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Cryptography
Key recovery from partial information
Speaker : Gabrielle De Michelli - UC San Diego
The security of deployed protocols not only relies on the hardness of the underlying mathematical problem but also on the implementation of the algorithms involved. Many fast modular exponentiation algorithms have piled up over the years and some implementations have brought vulnerabilities that are exploitable by side-channel attacks, in particular cache attacks.<br/> In this talk, we consider[…] -