590 results
-
Horizontal isogeny graphs of ordinary abelian varieties and the discrete logarithm problem
Speaker : Benjamin WESOLOWSKI - École Polytechnique Federale de Lausanne
An isogeny graph is a graph whose vertices are abelian varieties (typically elliptic curves, or Jacobians of genus 2 hyperelliptic curves) and whose edges are isogenies between them. Such a graph is "horizontal" if all the abelian varieties have the same endomorphism ring. We study the connectivity and the expander properties of these graphs. We use these results, together with a recent algorithm[…] -
Protocoles de PIR fondés sur des designs transversaux
Speaker : julien lavauzelle - INRIA X
Les protocoles de PIR (Private Information Retrieval) permettent à un utilisateur de récupérer des entrées d'une base de donnée externalisée, sans révéler d'information sur les entrées désirées. Si plusieurs serveurs sont utilisés pour le stockage, et s'ils ne coopèrent pas, une confidentialité inconditionnelle peut être atteinte grâce à des encodages spécifiques de la base de données.<br/> Dans[…] -
Short McEliece key from algebraic geometry codes with automorphism
Speaker : elise barelli - INRIA Saclay
In 1978, McEliece introduced a public key encryption scheme based on linear codes and suggested to use classical Goppa codes, ie: subfield subcodes of algebraic geometric (AG) codes built on a curve of genus 0. This proposition remains secure and in order to have a generalization of classical Goppa codes, in 1996, H. Janwa and O. Moreno suggested to use subfield subcode of AG codes, which we call[…] -
Attaques par invariants : comment choisir les constantes de tour pour s'en protéger
Speaker : Anne Canteaut - Inria
Many lightweight block ciphers apply a very simple key schedule in which the round keys only differ by addition of a round-specific constant. Generally, there is not much theory on how to choose appropriate constants. In fact, several of those schemes were recently broken using invariant attacks, i.e. invariant subspace or nonlinear invariant attacks. This work analyzes the resistance of such[…] -
Soutenance de thèse : Algorithmes de recherche sur bases de données chiffrées
Speaker : Raphaël Bost - Université Rennes 1
La recherche sur les bases de données chiffrées vise à rendre e cace une tâche apparemment simple : déléguer le stockage de données à un serveur qui ne serait pas de con ance, tout en conservant des fonctionnalités de recherche. Avec le développement des services de stockage dans le Cloud, destinés aussi bien aux entreprises qu’aux individus, la mise au point de solutions e caces à ce problème est[…] -
On the Construction of Lightweight S-Boxes
Speaker : Sébastien Duval - INRIA Paris-Rocquencourt
S-Boxes are essential objects in the conception of blockciphers. Typically, an S-Box is simply a permutation (bijective function) on n bits, with n small (usually 4 or 8). Its role in a blockcipher is to bring nonlinearity to the cipher, thus an S-Box must be highly nonlinear. Several parameters of a function are used to measure nonlinearity, among which the most important are differential[…]