599 résultats
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Une famille d'algorithmes efficaces de réduction de réseau,
Orateur : Nicolas Gama - ENS
Alors que les cryptosystèmes à clé publique les plus utilisés reposent sur la difficulté de la factorisation ou du logarithme discret, il est intéressant d'étudier d'autres alternatives reposant sur des problèmes plus difficiles, et potentiellement résistants aux ordinateurs quantiques. La sécurité de certains cryptosystèmes, comme NTRU, LWE ou GPV reposent sur des problèmes issus de la[…] -
An infinite class of balanced functions with optimal algebraic
Orateur : Claude Carlet - Université Paris 8
Travail en commun avec Keqin Feng, Tsinghua University, Pékin.<br/> After the improvement by Courtois and Meier of the algebraic attacks on stream ciphers and the introduction of the related notion of algebraic immunity, several constructions of infinite classes of Boolean functions with optimum algebraic immunity have been proposed. All of them gave functions whose algebraic degrees are[…] -
Computing isogenies of small degrees on Abelian Varieties
Orateur : Damien Robert - LORIA
Isogenies are an essential tool in Elliptic Curves cryptography, where they are used in a wide variety of area: fast point counting, complex multiplication methods... Velu's formulas give an efficient method for computing such isogenies, but there are no formula known for curves of higher genera or general abelian varieties (except some special case for isogenies of degree 2). In this talk we[…] -
Lifting techniques for polynomial system solving.
Orateur : Eric Schost - University of Western Ontario
Through examples taken from point-counting problems or invariant theory, I will give an overview of how lifting techniques (that is, symbolic versions of Newton's iteration) can help us solve polynomial systems.<br/> I will review the key ingredients needed to put this kind of approach to practice, such as degree bounds or efficient arithmetic for polynomials and power series, and hint[…] -
A Residue Approach of the Finite Fields Arithmetics
Orateur : Jean-Claude Bajard - Université de Montpellier
Finite fields arithmetic is one of the challenges in current computer arithmetic. It occurs, in particular, in cryptography where the needs increase with the evolution of the technologies and also of the attacks. Through our research, we have proposed different systems based on residues representations. Different kinds of finite fields are concerned with. For each of them, some specificities of[…] -
Advances in cryptographic coprocessor design on FPGAs
Orateur : Nele Mentens - Katholieke Universiteit Leuven
Security in embedded systems requires the choice of a suitable implementation platform. For some systems, a general purpose microprocessor satisfies the requirements, but when high performance is the main criterium, cryptographic coprocessors in hardware are indispensable. When very high performance is required or when a high volume of coprocessors is needed, ASICs (Application Specific Integrated[…]