Signature

Résumé

thumb|La signature de John Hancock est l'une des plus remarquables de la Déclaration d'indépendance des États-Unis. thumb|Signature de Benjamin Franklin. thumb|Signature du Mahatma Gandhi. thumb|Signature de Chahbanou Farah Pahlavi d’Iran en écriture persane. thumb|Signature de Johannes Vermeer. thumb|Marques valant signatures dans des actes paroissiaux de Penmarc'h. Une signature est une marque autographe permettant d'identifier son auteur et témoigner du caractere authentique (lettre) ou valider le contenu (contrat, traité de paix) ou l'oeuvre (tableau) auquel elle se rapporte. Par extension, le terme est employé pour désigner la cause d'un phénomène physique. Le paraphe, quant à lui, est la marque visuelle abrégée de la signature complète tandis que le parapheur est un registre cartonné destiné à présenter page à page et l'un après l'autre chaque document sur lequel chaque personne concernée doit apposer sa signature (gouvernement, administration, entreprise). A l'ère de la numéri

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https://fr.wikipedia.org/wiki/Signature

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Publications associées (16)

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Unités associées (3)

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Concepts associés (3)

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Cours associés (11)

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Séances de cours associées (19)

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, , , , , , ,

BCL9/9L proteins enhance the transcriptional output of the beta-catenin/TCF transcriptional complex and contribute critically to upholding the high WNT signaling level required for stemness maintenance in the intestinal epithelium. Here we show that a BCL9/9L-dependent gene signature derived from independent mouse colorectal cancer (CRC) models unprecedentedly separates patient subgroups with regard to progression free and overall survival. We found that this effect was by and large attributable to stemness related gene sets. Remarkably, this signature proved associated with recently described poor prognosis CRC subtypes exhibiting high stemness and/or epithelial-to-mesenchymal transition (EMT) traits. Consistentwith the notion that high WNT signaling is required for stemnessmaintenance, ablating Bcl9/9l-beta-catenin inmurine oncogenic intestinal organoids provoked their differentiation and completely abrogated their tumorigenicity, while not affecting their proliferation. Therapeutic strategies aimed at targetingWNT responses may be limited by intestinal toxicity. Our findings suggest that attenuating WNT signaling to an extent that affects stemness maintenance without disturbing intestinal renewal might be well tolerated and prove sufficient to reduce CRC recurrence and dramatically improve disease outcome. (C) 2015 The Authors. Published by Elsevier B.V.

Elsevier Science Bv2015

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Hardware Attacks against Hash-based Cryptographic Algorithms

Aymeric Genet

This thesis surveys the current state of the art of hash-based cryptography with a view to finding vulnerabilities related to side-channel attacks and fault attacks. For side-channel investigation, we analyzed the power consumption of an Arduino Due microcontroller running a custom ARM implementation of SPHINCS-256---the most advanced digital signature scheme based on hash functions. Simple power analysis (SPA) was applied on a single trace to obtain a first insight into the implementation, and then on multiple traces to identify an initial data dependence of the power consumption on the hash functions involved in the instance. Based on this result, differential power analysis (DPA), with difference of means, V-test, and Pearson correlation, was applied to further investigate the leakage relating to BLAKE-256, as this function is used within SPHINCS-256 several times with the same secret key but applied on different known addresses. Concerning fault attacks, using instances of one-time signature (OTS) or few-times signatures (FTS) to sign a same message has been shown to theoretically make many schemes, such as LD-OTS, W-OTS, and HORS, existentially forgeable with non-invasive attacks. These vulnerabilities are fatal for the Merkle signature schemes which implement the tree chaining method (CMSS). When the schemes provide n/2 = 128 bits of quantum security, a universal forgery can be created with around q = 20 different faulty signatures. This thesis demonstrates a practical application of fault attacks to create this universal forgery using voltage glitching on the previously mentioned ARM implementation of SPHINCS-256. An invasive attack performing key recovery against W-OTS by forcing bits of two quantities to be zero is also described. Countermeasures to thwart all the described attacks are discussed.

2017

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A stroma-related gene signature predicts resistance to neoadjuvant chemotherapy in breast cancer

Michel Aguet, Pascale Anderle Pedone, Sylvie André Baflast, Mauro Delorenzi

To better understand the relationship between tumor-host interactions and the efficacy of chemotherapy, we have developed an analytical approach to quantify several biological processes observed in gene expression data sets. We tested the approach on tumor biopsies from individuals with estrogen receptor-negative breast cancer treated with chemotherapy. We report that increased stromal gene expression predicts resistance to preoperative chemotherapy with 5-fluorouracil, epirubicin and cyclophosphamide (FEC) in subjects in the EORTC 10994/BIG 00-01 trial. The predictive value of the stromal signature was successfully validated in two independent cohorts of subjects who received chemotherapy but not in an untreated control group, indicating that the signature is predictive rather than prognostic. The genes in the signature are expressed in reactive stroma, according to reanalysis of data from microdissected breast tumor samples. These findings identify a previously undescribed resistance mechanism to FEC treatment and suggest that antistromal agents may offer new ways to overcome resistance to chemotherapy.

Nature Publishing Group2009

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