Les mille traces de la conscience littéraire dans les Métamorphoses d’Ovide

Le but de cet article est de montrer comment Ovide marque le texte des Métamorphoses comme texte, en suivant la trace des éléments qui mettent en perspective l’élaboration de la narration (jeux de genres et mise en abyme des récits, puis autonomisation de la description comme « morceau esthétique ») et la conception du signifiant dans l’œuvre et sa représentation dans le corps même du texte

Higher order differential attacks on iterated block ciphers using almost bent round functions

International audienceWe show that the use of a round function whose Walsh coefficients are divisible by a high power of 2 may lead to a higher order differential attack

Weakness of Block Ciphers Using Highly Nonlinear Confusion Functions

The level of security of an iterated block cipher is mainly quantified in terms of resistance against known attacks. In particular the resistance against the two main generic attacks, the linear and the differential ones has been formalized in terms of «provable security» which lies on some properties of the confusion functions used in the system. It demands especiall- y that these functions have a high nonlinearity. However such a property implies in the case of almost bent functions, that the Walsh spectrum is divisible by a high power of 2. We show how this provides a new upper bound for the degree of the product of Boolean components of an almost bent function. This result leads to a higher order differential attack on any 5-round Feistel cipher using an almost bent function as a round function. We also show that it is precisely the origin of the weakness of MISTY1 allowing a 7-th order differential attack

Cryptanalysis of block ciphers and weight divisibility of some binary codes

International audienceThe resistance of an iterated block cipher to most classical attacks can be quantified by some properties of its round function. The involved parameters (nonlinearity, degrees of the derivatives...) for a function F from GF(2^m) into GF(2^m) are related to the weight distribution of a binary linear code C_F of length (2^m − 1) and dimension 2m. In particular, the weight divisibility of C_F appears as an important criterion in the context of linear cryptanalysis and of higher-order differential attacks. When the round function F is a power permutation over GF(2^m), the associated code C_F is the dual of a primitive cyclic code with two zeroes. Therefore, McEliece's theorem provides a powerful tool for evaluating the resistance of some block ciphers to linear and higherorder differential attacks

A Unified Indifferentiability Proof for Permutation- or Block Cipher-Based Hash Functions

In the recent years, several hash constructions have been introduced that aim at achieving enhanced security margins by strengthening the Merkle-Damgård mode. However, their security analysis have been conducted independently and using a variety of proof methodologies. This paper unifies these results by proposing a unique indifferentiability proof that considers a broadened form of the general compression function introduced by Stam at FSE09. This general definition enables us to capture in a realistic model most of the features of the mode of operation ({\em e.g.}, message encoding, blank rounds, message insertion,...) within the pre-processing and post-processing functions. Furthermore, it relies on an inner primitive which can be instantiated either by an ideal block cipher, or by an ideal permutation. Then, most existing hash functions can be seen as the Chop-MD construction applied to some compression function which fits the broadened Stam model. Our result then gives the tightest known indifferentiability bounds for several general modes of operations, including Chop-MD, Haifa or sponges. Moreover, we show that it applies in a quite automatic way, by providing the security bounds for 7 out of the 14 second round SHA-3 candidates, which are in some cases improved over previously known ones

L’enlèvement de Ganymède dans les Métamorphoses d’Ovide : mythe érotique, mythe politique

Dans la trame de leurs récits, les Métamorphoses d’Ovide accordent à l’enlèvement de Ganymède une place minime par son nombre de vers : six, mais remarquable par sa signification : Rex superum Phrygii quondam Ganymedis amorearsit et inuentum est aliquid quod Iuppiter essequam quod erat mallet Nulla tamen alite uertidignatur nisi quae posset sua fulmina ferreNec mora Percusso mendacibus aere pennisabripit Iliaden Qui nunc quoque pocula misce inuitaque Ioui nectar Iunone ministrat. Pour situer ..

Écho et Narcisse, voix et figures d’impossible éros

Videau Anne. Écho et Narcisse, voix et figures d’impossible éros. In: Φιλολογία. Mélanges offerts à Michel Casevitz. Lyon : Maison de l'Orient et de la Méditerranée Jean Pouilloux, 2006. pp. 223-235. (Collection de la Maison de l'Orient méditerranéen ancien. Série littéraire et philosophique, 35

L’épopée des Métamorphoses d’Ovide, une « forgerie » philologique et politique

Les Métamorphoses, commencées sans doute en l’an 2 de notre ère, témoignent de la passion « mythologique », collectionneuse de récits du passé, qui marque le tournant de la République romaine au début du Principat : on songe, en langue grecque, aux Erôtika pathèmata de Parthénios, qui les dédie à l’homme politique et poète Gallus, suicidé en 26 avant J.-C., à la Bibliothèque historique de Diodore de Sicile, à l’œuvre contemporaine de Conon, aux Antiquités romaines de Denys d’Halicarnasse; et,..

Écho et Narcisse, voix et figures d’impossible éros

Videau Anne. Écho et Narcisse, voix et figures d’impossible éros. In: Φιλολογία. Mélanges offerts à Michel Casevitz. Lyon : Maison de l'Orient et de la Méditerranée Jean Pouilloux, 2006. pp. 223-235. (Collection de la Maison de l'Orient méditerranéen ancien. Série littéraire et philosophique, 35