Filter by content type

Select one or more filters. This choice will reload the page to display the filtered results.

Remove all filters

652 results

    • Seminar

    • Cryptography

    Un algorithme pour trouver toutes les formules calculant une application bilinéaire.

    • April 18, 2014

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

    Speaker : Nicolas Estibal - IRISA

    La multiplication est une opération arithmétique coûteuse comparativement à l'addition. Aussi il est intéressant, étant donné une application, de minimiser le nombre de produits à effectuer pour la calculer. Dans cette étude, nous nous restreignons au cas des applications bilinéaires.<br/> En effet, parmi les applications bilinéaires, nous étions intéressés en premier lieu par la multiplication[…]
    • Seminar

    • Cryptography

    Power decoding of Hermitian codes in sub-quadratic time

    • January 09, 2015

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

    Speaker : Johan Nielsen - INRIA Saclay Ile de France

    Reed-Solomon codes have optimal minimum distance and we know efficient encoding and decoding algorithms of quasi-linear complexity in the length. Their main drawback is that their lengths are bounded by the size of the alphabet, i.e. the field over which they are defined. Algebraic geometry codes are a generalisation allowing longer codes on the same alphabet, and one of the most interesting sub[…]
    • Seminar

    • Cryptography

    How to find low-weight polynomial multiples.

    • June 13, 2014

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

    Speaker : Carl Löndahl - Université de Lund

    We present an improved algorithm for finding low-weight multiples of polynomials over the binary field using coding heoretic methods. The associated code defined by the given olynomial has a cyclic structure, allowing an algorithm to earch for shifts of the sought minimum-weight odeword. Therefore, a code with higher dimension is onstructed, having a larger number of low-weight codewords nd[…]
    • Seminar

    • Cryptography

    A heuristic quasi-polynomial algorithm for discrete logarithm

    • October 03, 2014

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

    Speaker : Razvan Basbulescu - LORIA

    in finite fields of small characteristic The difficulty of discrete logarithm computations in fields GF(q^k) depends on the relative sizes of k and q. Until recently all the cases had a sub-exponential complexity of type L(1/3), similar to the complexity of factoring. If n is the bit-size of q^k, then L(1/3) can be approximated by 2^(n^(1/3)). In 2013, Joux designed a new algorithm for constant[…]
    • Seminar

    • Cryptography

    Points rationnels sur une surface cubique

    • January 24, 2014

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

    Speaker : Jenny Cooley - University of Warwick

    Soit F_q un corps fini à au moins 13 éléments. Soit S une surface cubique non singulière sur laquelle il y a au moins une droite rationnelle incluse. Il existe une façon de générer les points rationnels en utilisant des opérations tangentes et sécantes qui est similaire à la loi de composition du groupe de points d'une courbe elliptique. Dans cet exposé, nous utilisons le principe des tiroirs pour[…]
    • Seminar

    • Cryptography

    Cryptanalysis of Round-Reduced PRINCE and TWINE

    • March 27, 2015

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

    Speaker : Patrick Derbez - Luxembourg

    NXP Semiconductors and its academic partners challenged the cryptographic community with finding practical attacks on the block cipher they designed, PRINCE. In the first part of this talk we present new attacks on round-reduced PRINCE including the ones which won the challenge in the 6 and 8-round categories --- the highest for which winners were identified. Our first attacks rely on a meet-in[…]