Description
I will describe an algorithm for computing the zeta function of an arbitrary hyperelliptic curve in characteristic 2. This is a generalisation of an earlier method of myself and Wan, which tackled a restricted class of curves. The algorithm reduces the problem to that of computing the L-function of an additive character sum over an open subset of the projective line. This latter task can be achieved using the Dwork-Reich trace formula, Dwork's analytic construction of an additive character, and a method for `cohomological reduction' similar to the `Hermite reduction' algorithm used in the symbolic integration of rational functions. The talk is based upon joint work with Daqing Wan. See http://web.comlab.ox.ac.uk/oucl/work/alan.lauder/ for a version of the earlier paper, which has now appeared in LMS JCM, and also two other related papers.
Prochains exposés
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Encryption homomorphe sans bruit à l'aide de groupes
Orateur : Pierre Guillot - Ravel Technologies (dispo Université de Strasbourg, IRMA)
Je vais rappeler les travaux de Nuida et Ostrovski sur l'utilisation des groupes pour l'élaboration de schémas cryptographiques homomorphes. Je vais présenter nos travaux qui fournissent des encodages à la fois plus efficaces et plus généraux, et qui déterminent exactement quels groupes peuvent être utilisés. Puis je vais discuter GRAFHEN, un protocole qui utilise ces idées. Je dirai juste[…]-
Cryptography
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