Table of contents

  • This session has been presented May 17, 2024.

Description

  • Speaker

    Damien Stehlé - Cryptolab

Fully homomorphic encryption (FHE) is a form of encryption that allows arbitrary computations on data without requiring to decrypt the ciphertexts. Among the diverse FHE schemes, CKKS is designed to efficiently perform computations on real numbers in an encrypted state. Interestingly, Drucker et al [J. Cryptol.] recently proposed an efficient strategy to use CKKS in a black-box manner to perform computations on binary data. In this talk, after an introduction on fully homomorphic encryption, I will explain how to modify CKKS to gain efficiency when handling binary data. As we will see, the obtained performance compares very favourably with that of the other FHE schemes. Based on joint work with Youngjin Bae, Jung Hee Cheon and Jaehyung Kim.

Next sessions

  • Oblivious Transfer from Zero-Knowledge Proofs (or how to achieve round-optimal quantum Oblivious Transfer without structure)

    • June 06, 2025 (13:45 - 14:45)

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

    Speaker : Léo Colisson - Université Grenoble Alpes

    We provide a generic construction to turn any classical Zero-Knowledge (ZK) protocol into a composable oblivious transfer (OT) protocol (the protocol itself involving quantum interactions), mostly lifting the round-complexity properties and security guarantees (plain-model/statistical security/unstructured functions…) of the ZK protocol to the resulting OT protocol. Such a construction is unlikely[…]
    • Cryptography

  • La crypto-graphie et les crypto-monnaies

    • June 13, 2025 (13:45 - 14:45)

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

    Speaker : Daniel Augot - INRIA Saclay—Île-de-France

    De nos jours, la requête «crypto» dans un moteur de recherche renvoieaux cryptomonnaies. Mais «crypto means crypto», et on peut se poser laquestion des liens pertinents entre les deux domaines.   D'un coté, le monde des cryptomonnaies et de la technologiesous-jacente s'est développé et évolue encore en dehors du mondeacadémique. Il faut suivre d'un coté des posts de blog, des fils dediscussion X[…]
  • SoK: Security of the Ascon Modes

    • June 20, 2025 (13:45 - 14:45)

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

    Speaker : Charlotte Lefevre - Radboud University

    The Ascon authenticated encryption scheme and hash function of Dobraunig et al (Journal of Cryptology 2021) were recently selected as winner of the NIST lightweight cryptography competition. The mode underlying Ascon authenticated encryption (Ascon-AE) resembles ideas of SpongeWrap, but not quite, and various works have investigated the generic security of Ascon-AE, all covering different attack[…]
  • Comprehensive Modelling of Power Noise via Gaussian Processes with Applications to True Random Number Generators

    • June 27, 2025 (13:45 - 14:45)

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

    Speaker : Maciej Skorski - Laboratoire Hubert Curien

    The talk examines power noise modelling through Gaussian Processes for secure True Random Number Generators.   While revisiting one-sided fractional Brownian motion, we obtain novel contributions by quantifying posterior uncertainty in exact analytical form, establishing quasi-stationary properties, and developing rigorous time-frequency analysis. These results are applied to model oscillator[…]
    • Cryptography

    • TRNG

  • CryptoVerif: a computationally-sound security protocol verifier

    • September 05, 2025 (13:45 - 14:45)

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

    Speaker : Bruno Blanchet - Inria

    CryptoVerif is a security protocol verifier sound in the computational model of cryptography. It produces proofs by sequences of games, like those done manually by cryptographers. It has an automatic proof strategy and can also be guided by the user. It provides a generic method for specifying security assumptions on many cryptographic primitives, and can prove secrecy, authentication, and[…]
    • Cryptography

Show previous sessions