627 results

  • The Revival of Quadratic Fields Cryptography

    • January 17, 2020

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

    Speaker : Guilhem Castagnos - Université Bordeaux 1

    More than 30 years ago, Buchmann and Williams proposed using ideal class groups of imaginary quadratic fields in cryptography with a Diffie-Hellman style key exchange protocol. After several twists, there has been in recent years a new interest in this area. This rebirth is mainly due to two features. First, class groups of imaginary quadratic fields allow the design of cryptographic protocols[…]
  • Computing isogenies from modular equations in genus 2

    • January 10, 2020

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

    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:[…]
  • Vers une meilleure compréhension de l’apprentissage profond appliqué aux attaques par observation

    • January 10, 2020

    • CEA - Salle Métivier

    Speaker : Loïc Masure

    Les attaques par observation (SCA) exploitent les failles d’une primitive cryptographique embarquée sur un composant (type carte à puce, IoT, …), en mesurant des grandeurs physiques qui dépendent indirectement de la valeur de la clé secrète. C’est pourquoi il est primordial pour les développeurs de proposer des contre-mesures adaptées et d’évaluer leur efficacité face à un attaquant potentiel.Au[…]
  • Intrusion Detection Systems over an Encrypted Traffic: Problem and Solutions

    • December 06, 2019

    • Inria Center of the University of Rennes - - Petri/Turing room

    Speaker : Sébastien Canard (Orange)

    Privacy and data confidentiality are today at the heart of many discussions. But such data protection should not be done at the detriment of other security aspects. In the context of network traffic, intrusion detection system becomes in particular totally blind when the traffic is encrypted, making clients again vulnerable to known threats and attacks. Reconciling security and privacy is then one[…]
  • Divisible E-Cash from Constrained Pseudo-Random Functions

    • December 06, 2019

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

    Speaker : Olivier Sanders - Orange

    Electronic cash (e-cash) is the digital analogue of regular cash which aims at preserving users' privacy. Following Chaum's seminal work, several new features were proposed for e-cash to address the practical issues of the original primitive. Among them, divisibility has proved very useful to enable efficient storage and spendings. Unfortunately, it is also very difficult to achieve and, to date,[…]
  • Présentation des fondamentaux du management du risque et d’EBIOS Risk Manager

    • November 29, 2019

    • Inria Center of the University of Rennes - - Petri/Turing room

    Speaker : Vincent Loriot (ANSSI)

    Résumé :a. Présentation ANSSIb. Tendances de la menace cyber et démarche pour s’en protégerc. Fondamentaux de la méthode EBIOS Risk ManagerLa présentation théorique sera complétée avec un atelier pratique couvrant les sujets suivants :a. Les besoins et enjeux de sécuritéb. Les couples Source de Risque / Objectif Viséc. La cartographie de menace de l’écosystème