78 research outputs found
Using the Trace Operator to Repair the Polynomial Reconstruction Based Cryptosystem Presented at Eurocrypt 2003
No full textIn this paper, we present a modication of the Augot-Finiasz cryptosystem presented at EUROCRYPT 2003. Coron managed to design an attack against the original cryptosystem enabling an attacker to decrypt any intercepted ciphertext eciently. We introduce here a modication of the scheme which appears to resist to this attack. We furthermore propose parameters thwarting the state of the art attacks
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A variant of the McEliece cryptosystem with increased public key security
No full textWe propose a new variant of the McEliece cryptosystem which ensures that the code used as the public key is not permutation-equivalent to the secret code. This allows to increase the security of the public key, and to reconsider possible adoption of classical families of codes, like Reed-Solomon codes. A reduction in the key size or, equivalently, an increased level of security against information set decoding are the main advantages of the modified cryptosystem. As a drawback, the domain of intentional error vectors must be restricted, but we show that this has no significant impact on the security level
A complete characterization of irreducible cyclic orbit codes
No full textConstant dimension codes are subsets of the nite Grassmann variety. The study of constant dimension codes with good distances have been central in random linear network coding theory. Orbit codes represent a subclass of constant dimension codes. They are characterized that the elements of the code can be viewed as the orbit under a group action. The paper gives a complete characterization of orbit codes that are generated by an irreducible cyclic group, i.e. an irreducible group having one generator. We show how some of the basic properties of these codes, the cardinality and the minimum distance, can be derived using the isomorphism of the vector space and the extension field
Echinococcus multilocularis: identification of the parasite and echinococcosis diagnosis in animals
No full textAfter a brief description of the parasite’s taxonomic status, the author reviews the diagnosis techniques
of Echinococcosis in definitive (foxes, dogs, cats), intermediate (rodents) and aberrant hosts.
Species identification is an essential prerequisite to the establishment of local control programmes
(particularly in rodents).
Current reliable methods, recognised by WHO, to diagnose the parasitosis at necropsy in definitive
hosts include: i) the intestinal smear technique (IST) with a sensitivity and specificity of 100%; ii) the
sedimentation and counting technique (SCT) with a sensitivity of 100% and a specificity of 78%.
ELISA coproantigen detection in dog, cat and fox faecal samples is possible with a sensitivity of 80-
87% and a specificity of 70-99%. Furthermore, molecular biology techniques based on PCR
(Polymerase Chain Reaction) are now available in specialized laboratories for the detection of E.
multilocularis eggs or DNA, directly from faecal samples of carnivores.
Special safety precautions must be implemented when handling definitive hosts infected with E.
multilocularis and when using materials potentially contaminated with Echinococcus eggs.
Two molecules (praziquantel and epsiprantel) are available for prophylaxis.Après un rappel sur la
diagnose d'Echinococcus multilocularis, l'auteur rapporte les techniques de diagnostic de
l'échinococcose chez les hôtes définitifs (renard, chien, chat), les intermédiaires
(rongeurs), ainsi que chez les hôtes inhabituels. L'identification d'espèce est essentielle
à l'établissement d'un programme local de contrôle (en particulier chez les rongeurs). Les
méthodes actuelles, fiables pour le diagnostic chez les hôtes définitifs, réalisées à
l'autopsie de l'animal, sont la technique de sédimentation (SCT), avec une spécificité et
une sensibilité de 100 %, et celle du « grattage intestinal » (IST), avec une spécificité de
100 % et une sensibilité de 78 %. La détection de coproantigène par ELISA dans les fèces de
chiens, de chats et de renards est possible avec une sensibilité de 80 à 87 % et une
spécificité comprise entre 70 et 99 %. Des techniques de biologie moléculaire utilisant la
PCR (Polymerase Chain Reaction) sont appliquées dans des laboratoires spécialisés, pour la
détection d'oeufs d'E. multilocularis ou de l'ADN, directement à partir des échantillons
fécaux de carnivores. La manipulation des hôtes définitifs infectés par E. multilocularis et
l'utilisation du matériel potentiellement contaminé par les oeufs d'Echinococcus requièrent
des précautions spéciales de sécurité. Deux molécules (praziquantel et epsiprantel) sont
disponibles pour la prophylaxie
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