Description
At the Asiacrypt 2003 conference, Billet and Gilbert introduce a block cipher, which, to quote them, has the following paradoxical property: it is computationally easy to derive many equivalent distinct descriptions of the same instance of the block cipher; but it is computationally difficult, given one or even up to k of them, to recover the socalled meta-key from which they were derived, or to find any additional equivalent description, or more generally to forge any new untraceable description of the same instance of the block cipher. They exploit this property to introduce the first traceable block cipher. Their construction relies on the Isomorphism of Polynomials (IP) problem. At Eurocrypt 2006, Faugere and Perret show how to break this scheme by algebraic attack. We here strengthen the original traceable block cipher against this attack by concealing the underlying IP problems. Our modifications are such that our description of the block cipher now does not give the expected results all the time and parallel executions are used to obtain the correct value.<br/> (this work was done with Julien Bringer and Emmanuelle Dottax and will be presented - in part - at CMS'2006)
Prochains exposés
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!!! Reporté !!! 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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MIKE: An efficient and compact NIKE Based on a Commutative Monoidal Action
Orateur : Jonathan Komada Eriksen - COSIC, KU Leuven
Robert recently described a powerful correspondence between certain (Hermitian) modules and (polarized) abelian varieties, which simultaneously generalizes both the class-group action underlying protocols such as CSIDH, and the Deuring correspondence, underlying protocols such as SQIsign. Using this correspondence, he also proposed how to construct a post-quantum NIKE, called MIKE, which, at a[…]-
Cryptography
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TBA
Orateur : Anmoal Porwal - Technical University of Munich
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Cryptography
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Asymmetric primitive
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