640 results
-
Constant time techniques for lattice based cryptography
Speaker : Melissa Rossi - École normale supérieure, CNRS, PSL University, Inria
NIST’s post-quantum cryptography competition has entered in its second phase, the time has come to focus more closely on practical aspects of the candidates. On the lattice-based side, certain schemes chose to implement discrete Gaussian distributions which allow better parameters and security reductions. However, this advantage has also proved to be their Achilles’ heel, as discrete Gaussians[…] -
The Revival of Quadratic Fields Cryptography
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
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
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[…] -
Divisible E-Cash from Constrained Pseudo-Random Functions
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,[…] -
Intrusion Detection Systems over an Encrypted Traffic: Problem and Solutions
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[…]