511 results
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Algorithms for polynomial selection in the number field sieve
Speaker : Shi Bai - Australian National University
The general number field sieve (GNFS) is the most efficient algorithm known for factoring large integers. It consists of several stages, the first one being polynomial selection. The running-time of the number field sieve depends on the quality of the chosen polynomials. The quality of the chosen polynomials can be modeled in terms of size and root properties. In this talk, we will describe some[…] -
Certification de représentations galoisiennes modulaires
Speaker : Nicolas Mascot - Université de Bordeaux 1
Nous verrons comment certifier algorithmiquement des calculs de représentations galoisiennes associés à des formes modulaires, en nous appuyant notamment sur le théorème de Khare-Wintenberger (ex conjecture de modularité de Serre) et des calculs de cohomologie des groupes afin de déterminer le groupe de Galois de certains polynômes. -
Soutenance de thèse
Speaker : Gwezheneg Robert - Rennes 1
Le codage espace-temps désigne les codes correcteurs mis en place pour les transmissions MIMO. (Ce sont des transmissions sans fil utilisant plusieurs antennes, en émission comme en réception.) Ces codes correcteurs ont la particularité d'avoir des coefficients dans le corps des complexes, et non dans des corps finis. Un des paramètres fondamentaux pour l'évaluation des performances des[…] -
Algebraic Decoding of Folded Gabidulin Codes
Speaker : Hannes Bartz - Technische Universität München
Folded Gabidulin codes were proposed by Mahdavifar and Vardy in 2012. Beside the code construction an interpolation-based decoding scheme that can correct rank errors beyond the unique decoding radius for low code rates was presented.<br/> In this talk we present an efficient interpolation-based decoding algorithm for folded Gabidulin codes that can correct rank errors beyond half the[…] -
Simplified Settings for Discrete Logarithms in Small Characteristic Finite Fields
Speaker : Cécile Pierrot - UPMC LIP6
Public key cryptography is based on hard problems, such as the discrete logarithm problem (DLP). In this talk, I focus on the discrete logarithm problem in finite fields:<br/> Given GF(q^k) and a generator g of GF(q^k)*, we say that we solve the DLP in GF(q^k) if, for any arbitrary element h in GF(q^k)*, we are able to recover an integer x such that: g^x = h. When the characteristic is small[…] -
Computing individual discrete logarithms in non-prime finite fields
Speaker : Aurore Guillevic - Inria Saclay, équipe Grace et Ecole Polytechnique, LIX
This talk is about computing discrete logarithms in non-prime finite fields. These fields arise in pairing-based cryptography. In this setting, the pairing-friendly curve is defined over GF(q) and the pairing takes its values in an extension GF(q^k), where k is the embedding degree.<br/> Fr example, GF(p^2) is the embedding field of supersingular elliptic curves in large characteristic; GF(p[…]