logo EDITE Sebastien DUVAL
Sebastien DUVAL
État académique
Thèse en cours...
Sujet: Constructions pour la cryptographie à bas coût
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Ellipse bleue: doctorant, ellipse jaune: docteur, rectangle vert: permanent, rectangle jaune: HDR. Trait vert: encadrant de thèse, trait bleu: directeur de thèse, pointillé: jury d'évaluation à mi-parcours ou jury de thèse.
Productions scientifiques
Construction of Lightweight S-Boxes using Feistel and MISTY structures
International audience
Selected Areas in Cryptography - SAC 2015 https://hal.inria.fr/hal-01205187 Selected Areas in Cryptography - SAC 2015, Aug 2015, Sackville, Canada. SpringerARRAY(0x7fe6a72e84f8) 2015-08-12
Cryptanalysis of the FLIP Family of Stream Ciphers
International audience
At Eurocrypt 2016, Méaux et al. proposed FLIP, a new family of stream ciphers intended for use in Fully Homomorphic Encryption systems. Unlike its competitors which either have a low initial noise that grows at each successive encryption, or a high constant noise, the FLIP family of ciphers achieves a low constant noise thanks to a new construction called filter permutator. In this paper, we present an attack on the early version of FLIP that exploits the structure of the filter function and the constant internal state of the cipher. Applying this attack to the two instantiations proposed by Méaux et al. allows for a key recovery in 2 54 basic operations (resp. 2 68), compared to the claimed security of 2 80 (resp. 2 128).
Crypto 2016 - 36th Annual International Cryptology Conference https://hal.inria.fr/hal-01404145 Matthew Robshaw; Jonathan Katz. Crypto 2016 - 36th Annual International Cryptology Conference, Aug 2016, Santa Barbara, United States. Springer, 9814, pp.457 - 475, 2016, LNCS - Lecture Notes in Computer Science. <10.1007/978-3-662-53018-4_17>ARRAY(0x7fe6a72df218) 2016-08-14
A generalisation of Dillon's APN permutation with the best known differential and nonlinear properties for all fields of size 24k+2
International audience
The existence of Almost Perfect Nonlinear (APN) permutations operating on an even number of variables was a long-standing open problem, until an example with six variables was exhibited by Dillon et al. in 2009. However it is still unknown whether this example can be generalised to any even number of inputs. In a recent work, Perrin et al. described an infinite family of permutations, named butterflies, operating on (4k + 2) variables and with differential uniformity at most 4, which contains the Dillon APN permutation. In this paper, we generalise this family, and we completely solve the two open problems raised by Perrin et al. Indeed we prove that all functions in this larger family have the best known nonlinearity. We also show that this family does not contain any APN permutation besides the Dillon permutation, implying that all other functions have differential uniformity exactly four.
ISSN: 0018-9448 IEEE Transactions on Information Theory https://hal.inria.fr/hal-01589131 IEEE Transactions on Information Theory, Institute of Electrical and Electronics Engineers, 2017, 17 p. <10.1109/TIT.2017.2676807>ARRAY(0x7fe6a72dbc08) 2017