522 résultats
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Zero-Knowledge Argument for Matrix-Vector Relations and Lattice-Based Group Encryption
Orateur : Fabrice Mouhartem - ENS Lyon
Group encryption (GE) is the natural encryption analogue of group signatures in that it allows verifiably encrypting messages for some anonymous member of a group while providing evidence that the receiver is a properly certified group member. Should the need arise, an opening authority is capable of identifying the receiver of any ciphertext. As intro- duced by Kiayias, Tsiounis and Yung […] -
Key Reinstallation Attacks: Forcing Nonce Reuse in WPA2
Orateur : Mathy Vanhoef - KU-Leuven
We introduce key reinstallation attacks (KRACKs). These attacks abuse features of a protocol to reinstall an already in-use key, thereby resetting nonces and/or replay counters associated to this key. We show that our novel attack technique breaks several handshakes that are used in a WPA2-protected network.<br/> All protected Wi-Fi networks use the 4-way handshake to generate fresh session keys.[…] -
Grost Distinguishing Attack: A new rebound attack of an AES-like permutation
Orateur : Victor Cauchois - DGA et IRMAR
Grostl est une fonction de hachage finaliste de la compétition SHA-3. Elle est dotée d'une preuve de sécurité qui assure sa résistance aux attaques en collision, pré-image et seconde pré-image sous l'hypothèse que deux permutations internes sont idéales. Ces permutations, 14 tours d'un SPN, calques de l'AES, présentent une structure sensible aux attaques rebond. Ces attaques sont des attaques[…] -
Learning With Errors and Extrapolated Dihedral Cosets Problem
Orateur : Weiqiang Wen - ENS de Lyon
The hardness of the learning with errors (LWE) problem is one of the most fruitful resources of modern cryptography. In particular, it is one of the most prominent candidates for secure post-quantum cryptography. Understanding its quantum complexity is therefore an important goal. We show that under quantum polynomial time reductions, LWE is equivalent to a relaxed version of the dihedral coset[…] -
Horizontal isogeny graphs of ordinary abelian varieties and the discrete logarithm problem
Orateur : 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
Orateur : 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[…]