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655 results
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Seminar
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Cryptography
Standard models for finite fields
Speaker : Bart de Smit - University of Leiden
We give a deterministic polynomial time algorithm that on input two finite fields of the same cardinality produces an isomorphism between the two. Moreover, if for three finite fields of the same cardinality one applies the algorithm to the three pairs of fields then one obtains a commutative triangle. The algorithm depends on the definition of F_q as an actual field rather than a field up to[…] -
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Seminar
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Cryptography
Quelques aspects algorithmiques de la cryptographie
Speaker : David Lubicz - DGA et Université Rennes I
La cryptographie à clef publique, qui fut inventée dans les années soixante-dix par W. Diffie et M. Hellman, apporte par rapport à la cryptographie symétrique un certain nombre de fonctionnalités particulièrement intéressantes pour les applications pratiques. Sa mise en oeuvre repose le plus souvent sur la difficulté calculatoire de certains problèmes issus de la théorie des nombres. De là, on[…] -
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Seminar
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Cryptography
An infinite class of balanced functions with optimal algebraic
Speaker : 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 high[…] -
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Seminar
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Cryptography
Breaking the F-FCSR-H stream cipher in real time
Speaker : Thomas Johanson - Lund University
The F-FCSR stream cipher family has been presented a few years ago. Apart from some flaws in the initial propositions, corrected in a later stage, there are no known weaknesses of the core of these algorithms. The hardware oriented version, called FCSR-H, is one of the ciphers selected for the eSTREAM portfolio. In this paper we present a new and severe cryptanalytic attack on the F-FCSR stream[…] -
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Seminar
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Cryptography
Key Recovery Attacks of Practical Complexity on AES Variants With Up To 10 Rounds
Speaker : Orr Dunkelman - ENS
AES is the best known and most widely used block cipher. Its three versions (AES-128, AES-192, and AES-256) differ in their key sizes (128 bits, 192 bits and 256 bits) and in their number of rounds (10, 12, and 14, respectively). In the case of AES-128, there is no known attack which is faster than the 2^{128} complexity of exhaustive search. However, AES-192 and AES-256 were recently shown to be[…] -
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Seminar
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Cryptography
Hardware Operators for Pairing-Based Cryptography
Speaker : Jean-Luc Beuchat - University of Tsukuba
This talk is devoted to the design of fast parallel accelerators for the cryptographic Tate pairing. We propose here a novel hardware implementation of Miller's loop based on a pipelined Karatsuba-Ofman multiplier. Thanks to a careful choice of the mean of computing the Tate pairing and algorithms for tower field arithmetic, we manage to keep the pipeline busy. We also describe the strategies we[…] -