86 research outputs found

    Encoding monomorphic and polymorphic types

    Get PDF
    Most automatic theorem provers are restricted to untyped logics, and existing translations from typed logics are bulky or unsound. Recent research proposes monotonicity as a means to remove some clutter. Here we pursue this approach systematically, analysing formally a variety of encodings that further improve on efficiency while retaining soundness and completeness. We extend the approach to rank-1 polymorphism and present alternative schemes that lighten the translation of polymorphic symbols based on the novel notion of “cover”. The new encodings are implemented, and partly proved correct, in Isabelle/HOL. Our evaluation finds them vastly superior to previous schemes

    Polytopic Cryptanalysis

    Get PDF
    Standard differential cryptanalysis uses statistical dependencies between the difference of two plaintexts and the difference of the respective two ciphertexts to attack a cipher. Here we introduce polytopic cryptanalysis which considers interdependencies between larger sets of texts as they traverse through the cipher. We prove that the methodology of standard differential cryptanalysis can unambiguously be extended and transferred to the polytopic case including impossible differentials. We show that impossible polytopic transitions have generic advantages over impossible differentials. To demonstrate the practical relevance of the generalization, we present new low-data attacks on round-reduced DES and AES using impossible polytopic transitions that are able to compete with existing attacks, partially outperforming these

    Bisphenol A-glycidyl methacrylate induces a broad spectrum of DNA damage in human lymphocytes

    Get PDF
    Bisphenol A-glycidyl methacrylate (BisGMA) is monomer of dental filling composites, which can be released from these materials and cause adverse biologic effects in human cells. In the present work, we investigated genotoxic effect of BisGMA on human lymphocytes and human acute lymphoblastic leukemia cell line (CCRF-CEM) cells. Our results indicate that BisGMA is genotoxic for human lymphocytes. The compound induced DNA damage evaluated by the alkaline, neutral, and pH 12.1 version of the comet assay. This damage included oxidative modifications of the DNA bases, as checked by DNA repair enzymes EndoIII and Fpg, alkali-labile sites and DNA double-strand breaks. BisGMA induced DNA-strand breaks in the isolated plasmid. Lymphocytes incubated with BisGMA at 1 mM were able to remove about 50% of DNA damage during 120-min repair incubation. The monomer at 1 mM evoked a delay of the cell cycle in the S phase in CCRF-CEM cells. The experiment with spin trap—DMPO demonstrated that BisGMA induced reactive oxygen species, which were able to damage DNA. BisGMA is able to induce a broad spectrum of DNA damage including severe DNA double-strand breaks, which can be responsible for a delay of the cell cycle in the S phase

    Retour d'expérience sur les bassins d'orage en réseau unitaire: une solution pour limiter les rejets de temps de pluie

    Get PDF
    International audienceLe dĂ©veloppement des systĂšmes d'assainissement s'appuie souvent sur des structures construites il y a plusieurs dĂ©cennies. Ces systĂšmes font face Ă  une augmentation des niveaux d'exigence qui leur sont assignĂ©s. Dans le viseur de l'arrĂȘtĂ© de 2015 notamment, les performances par temps de pluie des systĂšmes de collecte. Un retour d'expĂ©riences sur les bassins d'orage menĂ© par le Cerema fait le point sur les interrogations et les solutions trouvĂ©es par les gestionnaires. CONTEXTE DE L'ETUDE En collaboration avec l'AFB, le GEMCEA, le MinistĂšre de la transition Ă©cologique et solidaire et les Agences de l'eau, le Cerema a rĂ©alisĂ© un vaste retour d'expĂ©riences sur les bassins d'orage implantĂ©s sur les rĂ©seaux d'assainissement unitaires. L'objet de ce retour d'expĂ©riences Ă©tait de voir, sur le terrain, comment les gestionnaires/exploitants avaient eu recours Ă  cette technique pour optimiser le fonctionnement de leur systĂšme, notamment par temps de pluie, et de collecter des informations techniques et financiĂšres quant au fonctionnement, Ă  la conception, au dimensionnement de ce type d'ouvrages. A travers une recherche bibliographique et de nombreux entretiens rĂ©alisĂ©s auprĂšs de 17 maĂźtres d'ouvrage/exploitants, ce travail a aussi permis indirectement de recueillir les tĂ©moignages des personnes interrogĂ©es quant aux enjeux et aux problĂ©matiques auxquelles les services peuvent ĂȘtre confrontĂ©s, aux difficultĂ©s techniques rencontrĂ©es, souvent liĂ©es Ă  leur contexte local, et Ă  la façon dont les collectivitĂ©s ont cherchĂ© Ă  y remĂ©dier notamment par la construction de bassins d'orage. Le projet ayant dĂ©butĂ© au 2nd semestre 2013 et s'Ă©tant terminĂ© en 2018, nous avons ainsi pu ĂȘtre les tĂ©moins, un peu malgrĂ© nous, des interrogations des diffĂ©rents acteurs vis-Ă -vis des Ă©volutions de la rĂ©glementation en matiĂšre d'assainissement : autosurveillance, diagnostic permanent, choix du critĂšre de conformitĂ© du systĂšme de collecte, 
 ainsi que des consĂ©quences des lois NOTRe 5 et MAPTAM 6 sur la rĂ©partition des compĂ©tences Ă  court et moyen termes. Cette communication fait volontairement le choix de se focaliser sur les Ă©lĂ©ments recueillis qui concernent les enjeux et opportunitĂ©s de l'autosurveillance et du diagnostic permanent, les dĂ©marches mises en place par les gestionnaires pour optimiser le fonctionnement de leur systĂšme et rĂ©pondre aux nouveaux critĂšres de conformitĂ© fixĂ©s par l'arrĂȘtĂ© de 2015

    Quantum Algorithms for the k-xor Problem

    Get PDF
    International audienceThe k-xor (or generalized birthday) problem is a widely studied question with many applications in cryptography. It aims at finding k elements of n bits, drawn at random, such that the xor of all of them is 0. The algorithms proposed by Wagner more than fifteen years ago remain the best known classical algorithms for solving them, when disregarding logarithmic factors. In this paper we study these problems in the quantum setting, when considering that the elements are created by querying a random function (or k random functions) H : {0, 1} n → {0, 1} n. We consider two scenarios: in one we are able to use a limited amount of quantum memory (i.e. a number O(n) of qubits, the same as the one needed by Grover's search algorithm), and in the other we consider that the algorithm can use an exponential amount of qubits. Our newly proposed algorithms are of general interest. In both settings, they provide the best known quantum time complexities. In particular, we are able to considerately improve the 3-xor algorithm: with limited qubits, we reach a complexity considerably better than what is currently possible for quantum collision search. Furthermore, when having access to exponential amounts of quantum memory, we can take this complexity below O(2 n/3), the well-known lower bound of quantum collision search, clearly improving the best known quantum time complexity also in this setting. We illustrate the importance of these results with some cryptographic applications
    • 

    corecore