A Distinguisher-Based Attack of a Homomorphic Encryption Scheme Relying on Reed-Solomon Codes

Bogdanov and Lee suggested a homomorphic public-key encryption scheme based on error correcting codes. The underlying public code is a modified Reed-Solomon code obtained from inserting a zero submatrix in the Vandermonde generating matrix defining it. The columns that define this submatrix are kept secret and form a set $L$. We give here a distinguisher that detects if one or several columns belong to $L$ or not. This distinguisher is obtained by considering the code generated by component-wise products of codewords of the public code (the so called "square code"). This operation is applied to punctured versions of this square code obtained by picking a subset $I$ of the whole set of columns. It turns out that the dimension of the punctured square code is directly related to the cardinality of the intersection of $I$ with $L$. This allows an attack which recovers the full set $L$ and which can then decrypt any ciphertext.Comment: 11 page

A Distinguisher-Based Attack on a Variant of McEliece's Cryptosystem Based on Reed-Solomon Codes

Baldi et \textit{al.} proposed a variant of McEliece's cryptosystem. The main idea is to replace its permutation matrix by adding to it a rank 1 matrix. The motivation for this change is twofold: it would allow the use of codes that were shown to be insecure in the original McEliece's cryptosystem, and it would reduce the key size while keeping the same security against generic decoding attacks. The authors suggest to use generalized Reed-Solomon codes instead of Goppa codes. The public code built with this method is not anymore a generalized Reed-Solomon code. On the other hand, it contains a very large secret generalized Reed-Solomon code. In this paper we present an attack that is built upon a distinguisher which is able to identify elements of this secret code. The distinguisher is constructed by considering the code generated by component-wise products of codewords of the public code (the so-called "square code"). By using square-code dimension considerations, the initial generalized Reed-Solomon code can be recovered which permits to decode any ciphertext. A similar technique has already been successful for mounting an attack against a homomorphic encryption scheme suggested by Bogdanoc et \textit{al.}. This work can be viewed as another illustration of how a distinguisher of Reed-Solomon codes can be used to devise an attack on cryptosystems based on them.Comment: arXiv admin note: substantial text overlap with arXiv:1203.668

Les variations linguistiques à l’intérieur des locutions contenant le mot « tête »

Introduction : les locuteurs sont susceptibles d’utiliser des locutions qui peuvent nuire à la transmission d’un message. Objectifs : répertorier des locutions dans lesquelles apparait le mot « tête » et de distinguer les variations (diatopique, diachronique, diaphasique, diastratique, diagénique et chronolectale) auxquelles ces locutions sont soumises au Canada (en Ontario, au Québec et dans les provinces de l’Atlantique), en France et au Burkina Faso. Méthodologie : un questionnaire, accessible électroniquement et disponible en format papier, a permis de recueillir les données nécessaires à notre étude et d’évaluer la connaissance et l’usage des locutions chez les locuteurs de notre échantillon. Résultats et conclusions : nos conclusions, qui découlent de 15 hypothèses, contribuent au domaine de la variation linguistique des locutions qui est peu exploré, selon nos recherches bibliographiques, et vérifient plusieurs théories qui ne sont pas dotées de preuves empiriques ou qui sont contradictoires.Maîtrise ès arts en Sociologie (M.A.

Mechanical de-tethering technique for Silicon MEMS etched with DRIE process.

International audienceGetting Micro-Electro-Mechanical Systems (MEMS) out of a wafer after fabrication processes is of great interest in testing, packaging or simply using these devices. Actual solutions require special machines like wafer dicing machines, increasing time and cost of de-tethering MEMS. This article deals with a new solution for manufacturing mechanical de-tetherable silicon MEMS. The presented solution could be done with DRIE process, already used in silicon MEMS fabrication, without additional time or cost. We are proposing a new way to create a notch on tethers linking both wafer and millimetric MEMS, especially designed to break with a specified mechanical force. A theoretical silicon fracture study, the experimental results and dimensional rules to design the tethers are presented in this article. This new technique is particularly useful for microscopic MEMS parts, and will find applications in the field of the MEMS components micro-assembly

Silicon end-effectors for microgripping tasks.

International audienceMicromanipulation is a key task to perform serial assembly of MEMS. The two-fingered microgrippers are usable but require specific studies to be able to work in the microworld. In this paper, we propose a new microgripping system where actuators and the end-effectors of the gripper are fabricated separately. End-effectors can thus be adapted to the manipulated micro-objects without new design and/or fabrication of the actuator. The assembly of the end-effectors on our piezoelectric actuators guarantee a great modularity for the system. This paper focuses on the original design, development and experimentation of new silicon end-effectors, compatible with our piezoelectric actuator. These innovative end-effectors are realized with the well known DRIE process and are able to perform micromanipulation tasks of objects whose typical size is between 5 μm and 1 mm

Parcours de lecture pluriels dans Bruges-la-Morte.

This thesis is about Georges Rodenbach's photographic novel Bruges-la-Morte. Examining the type of use that the novel makes of textual and iconic media, it proposes an analysis of the effects of its hybrid form using an approach based on the theories of reading. The first chapter deals with the elements of the work that distance it from the standard novel of the late nineteenth century with respect to the generic positioning, typography and use of photography in a literary work. The second chapter leads a double analysis of the textual and iconic reading effects in the novel and shows how its fragmentary form makes the reader interact actively with text and images and renews all conventional reading pragmatics

The architect’s office: practice and organization of work (18th-21st century)

An emerging research topic? To propose the architect’s office as the central theme of this issue of the Cahiers de la recherche architecturale, urbaine et paysagère was somewhat of a gamble. We hypothesized that it would allow to exceed traditional “heroic” narratives, which concentrate on the charismatic figure of the architect, thus omitting the complexity and variety of architectural’s production, along with an understanding of more recent evolutions. One year having passed since the call..