429 research outputs found
Podcast No Limit Sécu Episode #332 about the book of Pascal Lafourcade "25 énigmes ludiques pour s’initier à la cryptographie"
No full textL'objectif est de vulgariser la cryptographie et de pouvoir expliquer au plus grand nombre cette discipline au travers d'énigmes ludiques
Podcast No Limit Sécu Episode #332 about the book of Pascal Lafourcade "25 énigmes ludiques pour s’initier à la cryptographie"
No full textL'objectif est de vulgariser la cryptographie et de pouvoir expliquer au plus grand nombre cette discipline au travers d'énigmes ludiques
Podcast No Limit Sécu Episode #332 about the book of Pascal Lafourcade "25 énigmes ludiques pour s’initier à la cryptographie"
No full textL'objectif est de vulgariser la cryptographie et de pouvoir expliquer au plus grand nombre cette discipline au travers d'énigmes ludiques
Proof of Behavior (Short Paper)
No full textOur aim is to change the Proof of Work paradigm. Instead of wasting energy in dummy computations with hash computations, we propose a new approach based on the behavior of the users. Our idea is to design a mechanism that replaces the Proof of Work and that has a positive impact on the world and a social impact on the behaviors of the citizens. For this, we introduce the notion of Proof of Behavior. Based on this notion, we present a new cryptocurrency, called EcoMobiCoin, that encourages the ecological behavior in the mobility of the citizens
Nadie hablaba sino de política, manifestaciones y discursos. Una lectura de Palomita Blanca de Enrique Lafourcade, a propósito de los pormenores narrativos del relato
Get PDFResumen:
Este artículo propone una lectura de Palomita blanca (1971) de Enrique Lafourcade, a partir del estudio de las “catálisis” o pormenores de la narración. Estas unidades mínimas establecen los puntos de anclaje que articulan el relato a nivel político, simbólico e ideológico. En detalles tan ínfimos como los nombres de los protagonistas, los colores que pintan sus ropas o los espacios que habitan, no sólo se hallan estrategias discursivas, sino que, además, indicios de un contexto histórico y social que subyace en los acontecimientos narrados. A partir de este ejercicio crítico establecemos diálogos intertextuales con aquellas otras novelas del autor cuyos argumentos se contextualizan en la década del setenta, vale decir, Salvador Allende (1973), Tres terroristas (1976) y Adiós al Führer (1982).
Palabras clave: Literatura chilena; Enrique Lafourcade; Palomita blanca; catálisis; pormenores narrativos.
Abstract:
This article suggests an interpretation of Palomita Blanca (1971) by Enrique Lafourcade from the study of the “catalyses” or narration details. These minor components establish anchor points that articulate the story at a political, symbolic and ideological level. In this way, in very negligible aspects such as the name of the protagonists, the colours of their clothes or the places where they live, we can not only find narrative strategies, but also hints of the historical and social context hidden in the narrated events. From this critical exercise we establish intertextual dialogues with those other novels written by the author, whose story lines are set in the seventies, that is to say, Salvador Allende (1973), Tres Terroristas (1976) and Adiós al Führer (1982).
Keywords: Chilean Literature; Enrique Lafourcade; Palomita blanca; catalyses; narrative details
Nadie hablaba sino de política, manifestaciones y discursos. Una lectura de Palomita Blanca de Enrique Lafourcade, a propósito de los pormenores narrativos del relato
Get PDFResumen:
Este artículo propone una lectura de Palomita blanca (1971) de Enrique Lafourcade, a partir del estudio de las “catálisis” o pormenores de la narración. Estas unidades mínimas establecen los puntos de anclaje que articulan el relato a nivel político, simbólico e ideológico. En detalles tan ínfimos como los nombres de los protagonistas, los colores que pintan sus ropas o los espacios que habitan, no sólo se hallan estrategias discursivas, sino que, además, indicios de un contexto histórico y social que subyace en los acontecimientos narrados. A partir de este ejercicio crítico establecemos diálogos intertextuales con aquellas otras novelas del autor cuyos argumentos se contextualizan en la década del setenta, vale decir, Salvador Allende (1973), Tres terroristas (1976) y Adiós al Führer (1982).
Palabras clave: Literatura chilena; Enrique Lafourcade; Palomita blanca; catálisis; pormenores narrativos.
Abstract:
This article suggests an interpretation of Palomita Blanca (1971) by Enrique Lafourcade from the study of the “catalyses” or narration details. These minor components establish anchor points that articulate the story at a political, symbolic and ideological level. In this way, in very negligible aspects such as the name of the protagonists, the colours of their clothes or the places where they live, we can not only find narrative strategies, but also hints of the historical and social context hidden in the narrated events. From this critical exercise we establish intertextual dialogues with those other novels written by the author, whose story lines are set in the seventies, that is to say, Salvador Allende (1973), Tres Terroristas (1976) and Adiós al Führer (1982).
Keywords: Chilean Literature; Enrique Lafourcade; Palomita blanca; catalyses; narrative details
Secure Outsourcing of Multi-Armed Bandits
No full textInternational audienceWe consider the problem of cumulative reward maximization in multi-armed bandits. We address the security concerns that occur when data and computations are outsourced to an honest-but-curious cloud i.e., that executes tasks dutifully, but tries to gain as much information as possible. We consider situations where data used in bandit algorithms is sensitive and has to be protected e.g., commercial or personal data. We rely on cryptographic schemes and propose UCB-DS, a distributed and secure protocol based on the UCB algorithm. We prove that UCB-DS computes the same cumulative reward as UCB while satisfying desirable security properties. In particular, cloud nodes cannot learn the cumulative reward or the sum of rewards for more than one arm. Moreover, by analyzing messages exchanged among cloud nodes, an external observer cannot learn the cumulative reward or the sum of rewards produced by some arm. We show that the overhead due to cryptographic primitives is linear in the size of the input. Our implementation confirms the linear-time behavior and the practical feasibility of our protocol, on both synthetic and real-world data.TR at https://sancy.iut-clermont.uca.fr/~lafourcade/PAPERS/PDF/CLLS2020.pd
Appel à communication pour la Journée d’étude "Les élèves d’Eugène Viollet-le-Duc" (date limite : 29 avril 2019)
No full textAppel_JED_ fev_2020_Les élèves de VLDDownload Comité d’organisation : Florence Lafourcade, architecte DE, doctorante en histoire de l'architecture (ARCHE, Université de Strasbourg), Mohammed Hadjiat, architecte DE, doctorant en histoire de l’architecture (ARCHE, Université de Strasbourg / InVisu), Bérénice Gaussuin, architecte DESA, du patrimoine, doctorante en architecture (LIAT, ENSA Paris-Malaquais / Université Paris-Est) Contact : [email protected] Journée d’étude organisée ..
Efficient Card-Based ZKP for Single Loop Condition and Its Application to Moon-or-Sun
No full textInternational audienceA zero-knowledge proof (ZKP) allows a prover to prove to a verifier that it knows some secret, such as a solution to a difficult puzzle, without revealing any information about it. In recent years, ZKP protocols using only a deck of playing cards for solutions to various pencil puzzles have been proposed. The previous work of Lafourcade et al. deals with a famous puzzle called Slitherlink. Their proposed protocol can verify that a solution forms a single loop without revealing anything about the solution, except this fact. Their protocol guarantees that the solution satisfies the single-loop condition, by interactively constructing a solution starting from a state that holds a simple single loop, and proceeding via steps that preserve the invariant of encoding a single loop, until the proper solution is reached. A drawback of their protocol is that it requires additional verifications to guarantee a single loop. In this study, we propose a more efficient ZKP protocol for such a puzzle with fewer additional verifications. For this, we employ the previous work of Robert et al., which addressed the connectivity property in a puzzle. That is, we verify that a solution is connected but not split, to be a single loop. Applying our proposal, we construct a card-based ZKP protocol for Moon-or-Sun, which has its specific rule of alternating pattern in addition to the single-loop condition
Unlinkable and Strongly Accountable Sanitizable Signatures from Verifiable Ring Signatures
Get PDFInternational audienceAn Unlinkable Sanitizable Signature scheme (USS) allows a sanitizer to modify some parts of a signed message in such away that nobody can link the modified signature to the original one. A Verifiable Ring Signature scheme (VRS) allows the users to sign messages anonymously within a group where a user can prove a posteriori to a verifier that it is the author of a given signature. In this paper, we first revisit the notion of VRS: we improve the proof capabilities of the users, we give a complete security model for VRS and we give an efficient and secure scheme called EVeR. Our main contribution is GUSS, a Generic USS based on a VRS scheme and an unforgeable signature scheme. We show that GUSS instantiated with EVeR and Schnorr's signature is twice as efficient as the best USS scheme of the literature. Moreover, we propose a stronger definition of accountability: an USS is accountable when the signer can prove whether a signature is sanitized. We formally define the notion of strong accountability where the sanitizer can also prove the origin of a signature. We show that the notion of strong accountability is important in practice. Finally, we prove the security properties of GUSS (including strong accountability) and EVeR under the Decisional Diffie-Hellman (DDH) assumption in the random oracle model
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