Preuve de localisation : calculs multi-parties sécurisés

Aujourd’hui, la grande majorité des gens possède en permanence un téléphone qui leur permet à la fois de se géolocaliser (GPS), mais aussi de rester connectés entre eux (GSM - WIFI). Grâce à ces nouvelles technologies, on pourrait permettre aux individus d’obtenir des preuves de leur localisation, authentifiées par les utilisateurs environnants. Ainsi, un prouveur pourrait affirmer devant un juge qu’il ne se situait pas sur les lieux d’un crime à une date et une heure précise, et que plusieurs témoins ont certifié que cette preuve était correcte. Cependant, cette approche pose un certain nombre de problèmes concernant la vie privée et l’anonymat des divers intervenants. En effet, le prouveur ne souhaite sans doute pas diffuser sa position publiquement à chaque fois qu’il demande d’obtenir une preuve de sa localisation. De même, les témoins préféreraient garder leur identité et leur position secrètes. Par ailleurs, il est important que le juge puisse tout de même récupérer ces informations confidentielles, le juge devant être en mesure de déceler des complicités parmi les témoins. En effet, le juge doit pouvoir détecter si le prouveur essaie de forger de fausses preuves avec l’aide de certains témoins. L’objectif de ce mémoire est donc de concevoir des protocoles de calcul multi-parties permettant à un prouveur d’obtenir des preuves de localisation signées par des témoins, tout en respectant la vie privée des participants et en offrant au seul juge la possibilité de connaître ce qui lui est nécessaire

Characterizing the qIND-qCPA (in)security of the CBC, CFB, OFB and CTR modes of operation

We fully characterize the post-quantum security of the $\mathsf{CBC}$, $\mathsf{CFB}$, $\mathsf{OFB}$ and $\mathsf{CTR}$ modes of operation by considering all possible notions of $\textsf{qIND-qCPA}$ security defined by Carstens, Ebrahimi, Tabia and Unruh (TCC 2021), thus extending the work performed by Anand, Targhi, Tabia and Unruh (PQCrypto 2016). We show that the results obtained by Anand et al. for the $\textsf{qIND-qCPA-P6}$ security of these modes carry on to the other $\textsf{IND-qCPA}$ notions, namely the $\textsf{qIND-qCPA-P10}$ and $\textsf{qIND-qCPA-P11}$ ones. We also show that all of these modes are insecure according to all of the other notions, regardless of the block cipher they are used with. We also provide two general results concerning the insecurity of commonly used properties of block ciphers, namely those preserving the length of their input and those using the $\texttt{XOR}$ operation as a way to randomize the encryption. Finally, we use these results to highlight the need for new quantum semantic security notions

On the Concrete Security of Goldreich's Pseudorandom Generator

Local pseudorandom generators allow to expand a short random string into a long pseudorandom string, such that each output bit depends on a constant number d of input bits. Due to its extreme efficiency features, this intriguing primitive enjoys a wide variety of applications in cryptography and complexity. In the polynomial regime, where the seed is of size n and the output of size ns for s > 1, the only known solution, commonly known as Goldreich's PRG, proceeds by applying a simple d-ary predicate to public random size-d subsets of the bits of the seed. While the security of Goldreich's PRG has been thoroughly investigated, with a variety of results deriving provable security guarantees against class of attacks in some parameter regimes and necessary criteria to be satisfied by the underlying predicate, little is known about its concrete security and efficiency. Motivated by its numerous theoretical applications and the hope of getting practical instantiations for some of them, we initiate a study of the concrete security of Goldreich's PRG, and evaluate its resistance to cryptanalytic attacks. Along the way, we develop a new guess-and-determine-style attack, and identify new criteria which refine existing criteria and capture the security guarantees of candidate local PRGs in a more fine-grained way

Les encyclopédismes en France à l'ère des révolutions (1789-1850)

Après la Révolution française, l’idée d’encyclopédie prend une extension considérable. Jusqu’au Printemps des peuples de 1848, elle est indissociable de l’idée de république universelle, et se trouve au cœur d’une multiplicité d’enjeux pour la reconstruction institutionnelle, intellectuelle et politique de la société postrévolutionnaire. C’est à la singularité de ce moment (1789-1848) dans l’histoire longue de l’encyclopédisme que sont consacrées les différentes contributions de ce volume. Loin de se limiter à un moment de l’histoire des sciences, l’encyclopédisme nous révèle la manière dont les sociétés modernes se représentent elles-mêmes et s’instituent politiquement.After the French Revolution, the idea of an encyclopedia took on a considerable scope. Until the Spring of the Peoples in 1848, it was inseparable from the idea of a universal republic, and was at the heart of a multiplicity of challenges for the institutional, intellectual and political reconstruction of post-revolutionary society. It is to the singularity of this moment (1789-1848) in the long history of encyclopedism that the various contributions in this volume are dedicated. Far from being limited to a moment in the history of science, encyclopedism reveals to us the way in which modern societies represent themselves and establish themselves politically

Corps saccagés

Le corps malmené, violenté, brutalisé a fait l’objet, pour la période moderne et contemporaine, d’un certain nombre de travaux remarquables, mais souvent épars. L’étude des « corps saccagés », vivants ou morts, pose la question d’une « cruauté résiduelle » et celle du transfert de la violence concrète vers l’imaginaire. Mais faire l’inventaire des corps dégradés, lacérés ou encore démembrés s’avère sans doute une entreprise démesurée. Il reste toutefois possible de multiplier les approches et de s’attacher aussi bien à décrire les corps brutalisés, qu’à s’interroger sur les logiques du passage à l’acte ou à analyser la « réception » des violences corporelles. Dans le même temps s’élabore une science des « indices », étudiant les plaies et les traces sanguinolentes, tentant d’expliquer les crimes particulièrement horribles. À leur tour, des artistes se mettent à la recherche de la matérialité du corps, quitte à s’attacher plus particulièrement « à cette charogne des corps morcelés enfouie en chacun de nous ». Le crime individuel comme le massacre, les violences sexuelles à l’intérieur de la famille ou l’instrumentalisation des violences corporelles donnent au « corps saccagé » une actualité sans cesse renouvelée. Du corps des enfants violentés aux corps malmenés des soldats, il s’agit de varier les échelles d’analyse et d’examiner aussi bien les brutalités individuelles que les drames collectifs. Les usages du corps renseignent sur la volonté de savoir ce qui s’est passé ; ils informent sur les pratiques inavouables à l’encontre des corps vivants ou morts ; ils fixent, selon les époques, les formes de violences corporelles jugées inacceptables

Psychosocial Impact of Predictive Genetic Testing in Hereditary Heart Diseases: The PREDICT Study

International audiencePredictive genetic testing (PGT) is offered to asymptomatic relatives at risk of hereditary heart disease, but the impact of result disclosure has been little studied. We evaluated the psychosocial impacts of PGT in hereditary heart disease, using self-report questionnaires (including the State-Trait Anxiety Inventory) in 517 adults, administered three times to the prospective cohort (PCo: n = 264) and once to the retrospective cohort (RCo: n = 253). The main motivations for undergoing PGT were "to remove doubt" and "for their children". The level of anxiety increased between pre-test and result appointments (p <0.0001), returned to baseline after the result (PCo), and was moderately elevated at 4.4 years (RCo). Subjects with a history of depression or with high baseline anxiety were more likely to develop anxiety after PGT result (p = 0.004 and p <0.0001, respectively), whatever it was. Unfavourable changes in professional and/or family life were observed in 12.4% (PCo) and 18.7% (RCo) of subjects. Few regrets about PGT were expressed (0.8% RCo, 2.3% PCo). Medical benefit was not the main motivation, which emphasises the role of pre/post-test counselling. When PGT was performed by expert teams, the negative impact was modest, but careful management is required in specific categories of subjects, whatever the genetic test result

NEXN gene in cardiomyopathies and sudden cardiac deaths: prevalence, phenotypic expression, and prognosis

International audienceBACKGROUND: Few clinical data are available on NEXN mutation carriers, and the gene’s involvement in cardiomyopathies or sudden death has not been fully established. Our objectives were to assess the prevalence of putative pathogenic variants in NEXN and to describe the phenotype and prognosis of patients carrying the variants. METHODS: DNA samples from consecutive patients with cardiomyopathy or sudden cardiac death/sudden infant death syndrome/idiopathic ventricular fibrillation were sequenced with a custom panel of genes. Index cases carrying at least one putative pathogenic variant in the NEXN gene were selected. RESULTS: Of the 9516 index patients sequenced, 31 were carriers of a putative pathogenic variant in NEXN only, including 2 with double variants and 29 with a single variant. Of the 29 unrelated probands with a single variant (16 males; median age at diagnosis, 32.0 [26.0–49.0] years), 21 presented with dilated cardiomyopathy (prevalence, 0.33%), and 3 presented with hypertrophic cardiomyopathy (prevalence, 0.14%). Three patients had idiopathic ventricular fibrillation, and there were 2 cases of sudden infant death syndrome (prevalence, 0.46%). For patients with dilated cardiomyopathy, the median left ventricle ejection fraction was 37.5% (26.25–50.0) at diagnosis and improved with treatment in 13 (61.9%). Over a median follow-up period of 6.0 years, we recorded 3 severe arrhythmic events and 2 severe hemodynamic events. CONCLUSIONS: Putative pathogenic NEXN variants were mainly associated with dilated cardiomyopathy; in these individuals, the prognosis appeared to be relatively good. However, severe and early onset phenotypes were also observed—especially in patients with double NEXN variants. We also detected NEXN variants in patients with hypertrophic cardiomyopathy and sudden infant death syndrome/idiopathic ventricular fibrillation, although a causal link could not be established

Effect of anakinra versus usual care in adults in hospital with COVID-19 and mild-to-moderate pneumonia (CORIMUNO-ANA-1): a randomised controlled trial

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Effect of Tocilizumab vs Usual Care in Adults Hospitalized With COVID-19 and Moderate or Severe Pneumonia

International audienceImportance Severe pneumonia with hyperinflammation and elevated interleukin-6 is a common presentation of coronavirus disease 2019 (COVID-19).Objective To determine whether tocilizumab (TCZ) improves outcomes of patients hospitalized with moderate-to-severe COVID-19 pneumonia.Design, Setting, and Particpants This cohort-embedded, investigator-initiated, multicenter, open-label, bayesian randomized clinical trial investigating patients with COVID-19 and moderate or severe pneumonia requiring at least 3 L/min of oxygen but without ventilation or admission to the intensive care unit was conducted between March 31, 2020, to April 18, 2020, with follow-up through 28 days. Patients were recruited from 9 university hospitals in France. Analyses were performed on an intention-to-treat basis with no correction for multiplicity for secondary outcomes.Interventions Patients were randomly assigned to receive TCZ, 8 mg/kg, intravenously plus usual care on day 1 and on day 3 if clinically indicated (TCZ group) or to receive usual care alone (UC group). Usual care included antibiotic agents, antiviral agents, corticosteroids, vasopressor support, and anticoagulants.Main Outcomes and Measures Primary outcomes were scores higher than 5 on the World Health Organization 10-point Clinical Progression Scale (WHO-CPS) on day 4 and survival without need of ventilation (including noninvasive ventilation) at day 14. Secondary outcomes were clinical status assessed with the WHO-CPS scores at day 7 and day 14, overall survival, time to discharge, time to oxygen supply independency, biological factors such as C-reactive protein level, and adverse events.Results Of 131 patients, 64 patients were randomly assigned to the TCZ group and 67 to UC group; 1 patient in the TCZ group withdrew consent and was not included in the analysis. Of the 130 patients, 42 were women (32%), and median (interquartile range) age was 64 (57.1-74.3) years. In the TCZ group, 12 patients had a WHO-CPS score greater than 5 at day 4 vs 19 in the UC group (median posterior absolute risk difference [ARD] −9.0%; 90% credible interval [CrI], −21.0 to 3.1), with a posterior probability of negative ARD of 89.0% not achieving the 95% predefined efficacy threshold. At day 14, 12% (95% CI −28% to 4%) fewer patients needed noninvasive ventilation (NIV) or mechanical ventilation (MV) or died in the TCZ group than in the UC group (24% vs 36%, median posterior hazard ratio [HR] 0.58; 90% CrI, 0.33-1.00), with a posterior probability of HR less than 1 of 95.0%, achieving the predefined efficacy threshold. The HR for MV or death was 0.58 (90% CrI, 0.30 to 1.09). At day 28, 7 patients had died in the TCZ group and 8 in the UC group (adjusted HR, 0.92; 95% CI 0.33-2.53). Serious adverse events occurred in 20 (32%) patients in the TCZ group and 29 (43%) in the UC group (P = .21).Conclusions and Relevance In this randomized clinical trial of patients with COVID-19 and pneumonia requiring oxygen support but not admitted to the intensive care unit, TCZ did not reduce WHO-CPS scores lower than 5 at day 4 but might have reduced the risk of NIV, MV, or death by day 14. No difference on day 28 mortality was found. Further studies are necessary for confirming these preliminary results.Trial Registration ClinicalTrials.gov Identifier: NCT0433180