QUAD: Overview and Recent Developments

We give an outline of the specification and provable security features of the QUAD stream cipher proposed at Eurocrypt 2006. The cipher relies on the iteration of a multivariate system of quadratic equations over a finite field, typically GF(2) or a small extension. In the binary case, the security of the keystream generation can be related, in the concrete security model, to the conjectured intractability of the MQ problem of solving a random system of m equations in n unknowns. We show that this security reduction can be extended to incorporate the key and IV setup and provide a security argument related to the whole stream cipher.We also briefly address software and hardware performance issues and show that if one is willing to pseudorandomly generate the systems of quadratic polynomials underlying the cipher, this leads to suprisingly inexpensive hardware implementations of QUAD

Analysis of Intermediate Field Systems

We study a new generic trapdoor for public key multivariate cryptosystems, called IFS for Intermediate Field Systems, which can be seen as dual to HFE. This new trapdoor relies on the possibility to invert a system of quadratic multivariate equations with few (logarithmic with respect to the security parameter) unknowns on an intermediate field thanks to Groebner bases algorithms. We provide a comprehensive study of the security of this trapdoor and show that it is equivalent to the security provided by HFE. Therefore, while insecure in its basic form, this trapdoor may reveal quite attractive when used with, e.g., the minus modifier

Decim v2

The original publication is available at www.springerlink.comIn this paper, we present Decimv2, a stream cipher hardware- oriented selected for the phase 3 of the ECRYPT stream cipher project eSTREAM. As required by the initial call for hardware-oriented stream cipher contribution, Decimv2 manages 80-bit secret keys and 64-bit public initialization vectors. The design of Decimv2 combines two filtering mechanisms: a nonlinear Boolean filter over a LFSR, followed by an irregular decimation mechanism called the ABSG. Since designers have been invited to demonstrate flexibility of their design by proposing vari-ants that take 128-bit keys, we also present a 128-bit security version of Decim called Decim-128

Code Renewability for Native Software Protection

Software protection aims at safeguarding assets embedded in software by preventing and delaying reverse engineering and tampering attacks. This paper presents an architecture and supporting tool flow to renew parts of native applications dynamically. Renewed and diversified code and data belonging to either the original application or to linked-in protections are delivered from a secure server to a client on demand. This results in frequent changes to the software components when they are under attack, thus making attacks harder. By supporting various forms of diversification and renewability, novel protection combinations become available, and existing combinations become stronger. The prototype implementation is evaluated on a number of industrial use cases

A 60-million-year Cenozoic history of western Amazonian ecosystems in Contamana, eastern Peru

Weprovide a synopsis of ~60million years of life history in Neotropical lowlands, based on a comprehensive survey of the Cenozoic deposits along the Quebrada Cachiyacu near Contamana in PeruvianAmazonia. The 34 fossilbearing localities identified have yielded a diversity of fossil remains, including vertebrates,mollusks, arthropods, plant fossils, and microorganisms, ranging from the early Paleocene to the lateMiocene–?Pliocene (N20 successive levels). This Cenozoic series includes the base of the Huchpayacu Formation (Fm.; early Paleocene; lacustrine/ fluvial environments; charophyte-dominated assemblage), the Pozo Fm. (middle + ?late Eocene; marine then freshwater environments; most diversified biomes), and complete sections for the Chambira Fm. (late Oligocene–late early Miocene; freshwater environments; vertebrate-dominated faunas), the Pebas Fm. (late early to early late Miocene; freshwater environments with an increasing marine influence; excellent fossil record), and Ipururo Fm. (late Miocene–?Pliocene; fully fluvial environments; virtually no fossils preserved). At least 485 fossil species are recognized in the Contamana area (~250 ‘plants’, ~212 animals, and 23 foraminifera). Based on taxonomic lists from each stratigraphic interval, high-level taxonomic diversity remained fairly constant throughout themiddle Eocene–Miocene interval (8-12 classes), ordinal diversity fluctuated to a greater degree, and family/species diversity generally declined, with a drastic drop in the early Miocene. The Paleocene–?Pliocene fossil assemblages from Contamana attest at least to four biogeographic histories inherited from (i) Mesozoic Gondwanan times, (ii) the Panamerican realm prior to (iii) the time of South America’s Cenozoic “splendid isolation”, and (iv) Neotropical ecosystems in the Americas. No direct evidence of any North American terrestrial immigrant has yet been recognized in the Miocene record at Contamana.Facultad de Ciencias Naturales y Muse

Benzo[a]pyrene, Aflatoxine B1 and Acetaldehyde Mutational Patterns in TP53 Gene Using a Functional Assay: Relevance to Human Cancer Aetiology

Mutations in the TP53 gene are the most common alterations in human tumours. TP53 mutational patterns have sometimes been linked to carcinogen exposure. In hepatocellular carcinoma, a specific G>T transversion on codon 249 is classically described as a fingerprint of aflatoxin B1 exposure. Likewise G>T transversions in codons 157 and 158 have been related to tobacco exposure in human lung cancers. However, controversies remain about the interpretation of TP53 mutational pattern in tumours as the fingerprint of genotoxin exposure. By using a functional assay, the Functional Analysis of Separated Alleles in Yeast (FASAY), the present study depicts the mutational pattern of TP53 in normal human fibroblasts after in vitro exposure to well-known carcinogens: benzo[a]pyrene, aflatoxin B1 and acetaldehyde. These in vitro patterns of mutations were then compared to those found in human tumours by using the IARC database of TP53 mutations. The results show that the TP53 mutational patterns found in human tumours can be only partly ascribed to genotoxin exposure. A complex interplay between the functional impact of the mutations on p53 phenotype and the cancer natural history may affect these patterns. However, our results strongly support that genotoxins exposure plays a major role in the aetiology of the considered cancers

The Cell Adhesion Molecule “CAR” and Sialic Acid on Human Erythrocytes Influence Adenovirus In Vivo Biodistribution

Although it has been known for 50 years that adenoviruses (Ads) interact with erythrocytes ex vivo, the molecular and structural basis for this interaction, which has been serendipitously exploited for diagnostic tests, is unknown. In this study, we characterized the interaction between erythrocytes and unrelated Ad serotypes, human 5 (HAd5) and 37 (HAd37), and canine 2 (CAV-2). While these serotypes agglutinate human erythrocytes, they use different receptors, have different tropisms and/or infect different species. Using molecular, biochemical, structural and transgenic animal-based analyses, we found that the primary erythrocyte interaction domain for HAd37 is its sialic acid binding site, while CAV-2 binding depends on at least three factors: electrostatic interactions, sialic acid binding and, unexpectedly, binding to the coxsackievirus and adenovirus receptor (CAR) on human erythrocytes. We show that the presence of CAR on erythrocytes leads to prolonged in vivo blood half-life and significantly reduced liver infection when a CAR-tropic Ad is injected intravenously. This study provides i) a molecular and structural rationale for Ad–erythrocyte interactions, ii) a basis to improve vector-mediated gene transfer and iii) a mechanism that may explain the biodistribution and pathogenic inconsistencies found between human and animal models

Décharge d'ordures ménagères. / Obligation pour les installations d'élimination des déchets par stockage de n'accueillir que des déchets ultimes. / Qualification du déchet ultime. / Non-respect par l'exploitant des obligations de contrôle sur l'origine des déchets qu'il réceptionne. / Prononcé d'une astreinte. Cour de cassation, 3e Chambre civile, 5 décembre 2007, Société Coved c/ SA Clinique Ker Yonnec, n° de pourvoi 06-19179. Avec avis et note

Guérin Olivier, Billet Philippe. Décharge d'ordures ménagères. / Obligation pour les installations d'élimination des déchets par stockage de n'accueillir que des déchets ultimes. / Qualification du déchet ultime. / Non-respect par l'exploitant des obligations de contrôle sur l'origine des déchets qu'il réceptionne. / Prononcé d'une astreinte. Cour de cassation, 3e Chambre civile, 5 décembre 2007, Société Coved c/ SA Clinique Ker Yonnec, n° de pourvoi 06-19179. Avec avis et note. In: Revue Juridique de l'Environnement, n°3, 2008. pp. 313-332

Lésions traumatiques du rachis spondylarthritique (à propos de 36 cas)

La spondylarthrite ankylosante est une pathologie inflammatoire chronique prédominant au niveau du squelette axial aboutissant à la constitution d'une colonne bambou . Lors d'un traumatisme, elle adopte un comportement biomécanique comparable à celui d'un os long. Cet élément induit des lésions traumatiques propres dont la prise en charge se doit d'être spécifique. Dans cette étude, 36 cas de lésions traumatiques sur spondylarthrite ankylosante ont été analysés sur une période de 10 ans. Ces lésions font suite à un traumatisme à faible énergie. Les fractures constatées sont des fractures-dislocations, prédominant au niveau du rachis cervical bas, hautement instable, expliquant un taux de 50% de blessés médullaires. Le caractère peu symptomatique de ces lésions associé à une sensibilité médiocre des radiographies standards justifient une exploration tomodensitométrique rachidienne complète. La prise en charge est dans 8 cas sur 10 chirurgicale. La fixation postérieure longue et circonférentielle sont les seules techniques chirurgicales garantissant une bonne stabilité. De plus, en cas de lésion médullaire, la prise en charge chirurgicale démontre sa supériorité en terme de récupération fonctionnelle. La survenue d'une fracture cervicale basse (sous-jacente à C6) constitue une opportunité pour la correction d'une cyphose si celle-ci le justifie.NANTES-BU Médecine pharmacie (441092101) / SudocSudocFranceF