646 résultats

  • Candidats NIST basés sur les réseaux: choix de conception et astuces de ninja

    • 25 mars 2020

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

    Orateur : Thomas Prest. - PQShield

    Parmi les 26 schémas post-quantique toujours considérés pour standardisation par le NIST, 12 sont basés sur les réseaux (3 schémas de signature et 9 schémas de chiffrement). Cette présentation leur est consacrée. A haut niveau, tous peuvent être interprétés comme des instanciations directes de paradigmes bien établis. Mais une analyse plus attentive révèle que chacun d'eux fait des choix de[…]
  • Implicit proofs of membership

    • 13 mars 2020

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

    Orateur : Olivier Blazy - Université Limoges

    Smooth hash proof systems have been introduced by Cramer and shoup to build compact efficient cca2 encryption in the standard model. Since then, they found applications in a broad range of protocols from oblivious transfer to authenticated key exchange, passing by witness examples.<br/> In this talk, we will start by a panorama of languages that can be managed by such a primitive and then show how[…]
  • Improved Classical and Quantum Algorithms for Subset-Sum

    • 06 mars 2020

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

    Orateur : André Schrottenloher - INRIA

    We present new classical and quantum algorithms for solving random hard instances of the subset-sum problem, in which we are given n integers on n bits and try to find a subset of them that sums to a given target. This classical NP-complete problem has several applications in cryptography and underlies the security of some proposed post-quantum cryptosystems.<br/> At EUROCRYPT 2010, Howgrave[…]
  • On weak keys in QC-MDPC schemes

    • 21 février 2020

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

    Orateur : Valentin Vasseur - INRIA

    Quasi-cyclic moderate density parity check (QC-MDPC) codes allow the design of McEliece-like public-key encryption schemes with compact keys and a security that provably reduces to hard decoding problems for quasi-cyclic codes. Because of these features, QC-MDPC have attracted a lot of interest from the cryptographic community. In particular, the BIKE suite of key exchange mechanisms has been[…]
  • libecc: a flexible open-source ECC library for embedded devices

    • 14 février 2020

    • ANSSI - Salle Pétri/Turing

    Orateur : Ryad Benadjila et Arnaud Ebalard

    libecc is a software library for elliptic curves based cryptography (ECC), with an API supporting signature algorithms specified in the ISO14888-3 standard.Advanced usages of this library also include the possible implementation of elliptic curve based Diffie-Hellman protocols as well as any algorithm on top of prime fields based elliptic curves (or prime fields, or rings of integers).The[…]
  • Cryptanalysis of code-based cryptosystems using the square-code distinguisher

    • 07 février 2020

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

    Orateur : Mathieu Lequesne - INRIA

    Many code-based cryptosystems have been proposed recently, especially in response to the call for post-quantum cryptography standardization issued by the National Institute of Standards and Technologie. Most code-based cryptosystem rely on the same idea: an error-correcting code with some special structural properties (including good error-correction capacity) serves as the private key. This code[…]