511 résultats

  • Shorter Lattice-Based Fiat-Shamir Signatures

    • 26 janvier 2024

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

    Orateur : Julien Devevey - ANSSI

    We present HAETAE (Hyperball bimodAl modulE rejecTion signAture schemE), a new lattice-based signature scheme, which we submitted to the Korean Post-Quantum Cryptography Competition for standardization. Like the NIST-selected Dilithium signature scheme, HAETAE is based on the Fiat-Shamir with Aborts paradigm, but our design choices target an improved complexity/compactness compromise that is[…]
  • Pseudorandom Correlation Generators from the Quasi-Abelian Decoding Problem

    • 19 janvier 2024

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

    Orateur : Clément Ducros - IRIF

    Secure multi-party computing often enhances efficiency by leveraging correlated randomness. Recently, Boyle et al. showcased the effectiveness of pseudorandom correlation generators (PCGs) in producing substantial correlated (pseudo)randomness, specifically for two-party random oblivious linear evaluations (OLEs). This process involves minimal interactions and subsequent local computations,[…]
  • Evaluation embarquée de l'entropie d'un générateur d'aléa pour la cryptographie

    • 12 janvier 2024

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

    Orateur : David Lubicz - DGA et IRMAR

    Dans cet exposé, nous présentons une méthode de mesure embarquée de la composante thermique du jitter de phase d'un couple d'anneaux d'oscillateurs : cette mesure est nécessaire pour calculer le taux d'entropie d'un générateur d'aléa physique basé sur des anneaux oscillants. La précision de cette mesure dont le principe repose sur un algorithme de type Monte-Carlo dépend de l' équidistribution de[…]
  • Password-Authenticated Key Exchange (PAKE) from Isogenies

    • 08 décembre 2023

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

    Orateur : Sabrina Kunzweiler - Université Bordeaux

    The passwords that we use in our everyday life are often chosen to be easily memorable which makes them vulnerable to attacks. This problem is addressed by password-authenticated key exchange (PAKE). The general idea is to enable two parties who share the same (potentially weak) password to establish a strong session key. Most PAKE protocols used today are based on Diffie-Hellman key exchange in[…]
  • Finding short integer solutions when the modulus is small

    • 24 novembre 2023

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

    Orateur : Eamonn Postlethwaite - King's College London

    We present cryptanalysis of the inhomogenous short integer solution (ISIS) problem for anomalously small moduli by exploiting the geometry of BKZ reduced bases of q-ary lattices. We apply this cryptanalysis to examples from the literature where taking such small moduli has been suggested. A recent work [Espitau–Tibouchi–Wallet–Yu, CRYPTO 2022] suggests small versions of the lattice signature[…]
  • How fast do you heal? A taxonomy for post-compromise security in secure-channel establishment.

    • 10 novembre 2023

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

    Orateur : Léo Robert - Université d'Amiens

    Post-Compromise Security (PCS) is a property of secure-channel establishment schemes, which limits the security breach of an adversary that has compromised one of the endpoint to a certain number of messages, after which the channel heals. An attractive property, especially in view of Snowden's revelation of mass-surveillance, PCS features in prominent messaging protocols such as Signal. In this[…]