599 résultats
-
Couplages et applications industrielles
Orateur : Renaud Dubois - Thales
Les couplages permettent de réaliser de nouveaux protocoles cryptographiques ou d'en améliorer les complexités : chiffrement broadcast, IBE... On trouve peu d'exemples de développements concrets de tels sytèmes. Nous exposons les contraintes industrielles qui se posent lors du développement de ces outils. Nous présentons les choix de développement et les performances atteintes par la[…] -
Implémentation d'un système cryptographique à base de
Orateur : Sébastien Canard - Orange Labs
Dans cet exposé, nous considérons un protocole cryptographique faisant appel au calcul de couplages. Notre objectif est de regarder toutes les techniques qui existent lorsque ce protocole doit être implémenté dans un environnement restreint tel qu'une carte à puce ou un téléphone mobile.<br/> Nous verrons dans un premier temps les benchmarks actuels pour une implémentation d'un[…] -
Multiplication by n on elliptic curves over rings
Orateur : Jinbi Jin - Leiden university
Division polynomials express multiples of *affine* points on Weierstrass elliptic curves over fields. The restriction to affine points becomes an issue with elliptic curves over arbitrary rings, where it may happen that there are multiple 'points at infinity'. We will explain how a modification of the classical division polynomials describes multiplication on all points of Weierstrass[…] -
An explicit description of (log) de Rham cohomology over the Witt vector
Orateur : Moritz Minzlaff - Technische Universität Berlin
Motivated by applications to computing zeta functions, we will discuss the log de Rham and de Rham cohomologies of smooth schemes (together with 'nice' divisors) over the Witt vectors. For the former, we will give an explicit description that eventually might lead to improvements to point counting algorithms. Regarding the latter, we will measure "how far" the de Rham[…] -
On the (In)Security of IPsec in MAC-then-Encrypt Configurations.
Orateur : Jean Paul Degabriele - Royal Holloway, University of London
IPsec allows a huge amount of flexibility in the ways in which its component cryptographic mechanisms can be combined to build a secure communications service. This may be good for supporting different security requirements but is potentially bad for security. We demonstrate the reality of this by describing efficient, plaintext-recovering attacks against all configurations of IPsec in which[…] -
Towards Automatic Verification of Security Proofs for
Orateur : Marion Daubrignard - Verimag
Providing security proofs instead of arguing lack of existing relevant attacks is a quite new approach when it comes to cryptography. In the last thirty years, a lot of work has been done to formalize security of systems and prove of the achievement of security criteria. It has resulted in the design of a great number of proofs under various hypotheses. Though a step in the right direction, these[…]