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716 résultats

• • Séminaire

  • Cryptographie

  Middle-Product Learning with Rounding Problem and its Applications

  • 17 avril 2020

  • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

  Orateur : 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[…]

• • Séminaire

  • Cryptographie

  Traceable Constant-Size Multi-Authority Credentials

  • 29 avril 2022

  • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

  Orateur : 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[…]

• • Séminaire

  • Cryptographie

  Computing isogenies from modular equations in genus 2

  • 10 janvier 2020

  • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

  Orateur : 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:[…]

• • Séminaire

  • Cryptographie

  Key recovery from partial information

  • 01 octobre 2021

  • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

  Orateur : 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[…]

• • Séminaire

  • Cryptographie

  Improved Classical and Quantum Algorithms for Subset-Sum

  • 06 mars 2020

  • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

  Orateur : André Schrottenloher - INRIA

  We present new classical and quantum algorithms for solving random hard instances of the subset-sum problem, in which we are given n integers on n bits and try to find a subset of them that sums to a given target. This classical NP-complete problem has several applications in cryptography and underlies the security of some proposed post-quantum cryptosystems.<br/> At EUROCRYPT 2010, Howgrave[…]

• • Séminaire

  • Cryptographie

  Workshop mise en oeuvre de la cryptographie post-quantique

  • 17 novembre 2021

  • IRMAR - Université de Rennes - Campus Beaulieu Bat. 22, RDC, Rennes - Amphi Lebesgue

  Orateur : European CyberWeek - Rennes

  L'inscription est gratuite mais obligatoire, en particulier pour des raisons de jauges. Le nombre de places est limité. Le programme est disponible à l'adresse <a href="https://www.european-cyber-week.eu/cryptographie-post-quantique">https://www.european-cyber-week.eu/cryptographie-post-quantique</a><br/&gt;