Publicly Verifiable Auctions with Privacy

Online auctions have a steadily growing market size, creating billions of US dollars in sales value every year. To ensure fairness and auditability while preserving the bidder\u27s privacy is the main challenge of an auction scheme. At the same time, utility driven blockchain technology is picking up the pace, offering transparency and data integrity to many applications. In this paper, we present a blockchain-based first price sealed-bid auction scheme. Our scheme offers privacy and public verifiability. It can be built on any public blockchain, which is leveraged to provide transparency, data integrity, and hence auditability. The inability to double spend on a blockchain is used to prevent bid replay attacks. Moreover, our scheme can achieve non-repudiation for both bidders and the auctioneer without revealing the bids and we encapsulate this concept inside the public verification of the auction. We propose to use ElGamal encryption and Bulletproofs to construct an efficient instantiation of our scheme. We also propose to use recursive zkSNARKs to reduce the number of comparison proofs from $N-1$ to $1$, where $N$ is the number of bidders

The ANTENATAL multicentre study to predict postnatal renal outcome in fetuses with posterior urethral valves: objectives and design

Abstract Background Posterior urethral valves (PUV) account for 17% of paediatric end-stage renal disease. A major issue in the management of PUV is prenatal prediction of postnatal renal function. Fetal ultrasound and fetal urine biochemistry are currently employed for this prediction, but clearly lack precision. We previously developed a fetal urine peptide signature that predicted in utero with high precision postnatal renal function in fetuses with PUV. We describe here the objectives and design of the prospective international multicentre ANTENATAL (multicentre validation of a fetal urine peptidome-based classifier to predict postnatal renal function in posterior urethral valves) study, set up to validate this fetal urine peptide signature. Methods Participants will be PUV pregnancies enrolled from 2017 to 2021 and followed up until 2023 in >30 European centres endorsed and supported by European reference networks for rare urological disorders (ERN eUROGEN) and rare kidney diseases (ERN ERKNet). The endpoint will be renal/patient survival at 2 years postnatally. Assuming α = 0.05, 1–β = 0.8 and a mean prevalence of severe renal outcome in PUV individuals of 0.35, 400 patients need to be enrolled to validate the previously reported sensitivity and specificity of the peptide signature. Results In this largest multicentre study of antenatally detected PUV, we anticipate bringing a novel tool to the clinic. Based on urinary peptides and potentially amended in the future with additional omics traits, this tool will be able to precisely quantify postnatal renal survival in PUV pregnancies. The main limitation of the employed approach is the need for specialized equipment. Conclusions Accurate risk assessment in the prenatal period should strongly improve the management of fetuses with PUV

Sublingual immunotherapy for asthma.

BACKGROUND: Asthma is a common long-term respiratory disease affecting approximately 300 million people worldwide. Approximately half of people with asthma have an important allergic component to their disease, which may provide an opportunity for targeted treatment. Sublingual immunotherapy (SLIT) aims to reduce asthma symptoms by delivering increasing doses of an allergen (e.g. house dust mite, pollen extract) under the tongue to induce immune tolerance. However, it is not clear whether the sublingual delivery route is safe and effective in asthma. OBJECTIVES: To assess the efficacy and safety of sublingual immunotherapy compared with placebo or standard care for adults and children with asthma. SEARCH METHODS: We identified trials from the Cochrane Airways Group Specialised Register (CAGR), ClinicalTrials.gov (www.ClinicalTrials.gov), the World Health Organization (WHO) trials portal (www.who.int/ictrp/en/) and reference lists of all primary studies and review articles. The search is up to date as of 25 March 2015. SELECTION CRITERIA: We included parallel randomised controlled trials (RCTs), irrespective of blinding or duration, that evaluated sublingual immunotherapy versus placebo or as an add-on to standard asthma management. We included both adults and children with asthma of any severity and with any allergen-sensitisation pattern. We included studies that recruited participants with asthma, rhinitis, or both, providing at least 80% of trial participants had a diagnosis of asthma. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the search results for included trials, extracted numerical data and assessed risk of bias, all of which were cross-checked for accuracy. We resolved disagreements by discussion.We analysed dichotomous data as odds ratios (ORs) or risk differences (RDs) using study participants as the unit of analysis; we analysed continuous data as mean differences (MDs) or standardised mean differences (SMDs) using random-effects models. We rated all outcomes using GRADE (Grades of Recommendation, Assessment, Development and Evaluation) and presented results in the 'Summary of findings' table. MAIN RESULTS: Fifty-two studies met our inclusion criteria, randomly assigning 5077 participants to comparisons of interest. Most studies were double-blind and placebo-controlled, but studies varied in duration from one day to three years. Most participants had mild or intermittent asthma, often with co-morbid allergic rhinitis. Eighteen studies recruited only adults, 25 recruited only children and several recruited both or did not specify (n = 9).With the exception of adverse events, reporting of outcomes of interest to this review was infrequent, and selective reporting may have had a serious effect on the completeness of the evidence. Allocation procedures generally were not well described, about a quarter of the studies were at high risk of bias for performance or detection bias or both and participant attrition was high or unknown in around half of the studies.One short study reported exacerbations requiring a hospital visit and observed no adverse events. Five studies reported quality of life, but the data were not suitable for meta-analysis. Serious adverse events were infrequent, and analysis using risk differences suggests that no more than 1 in 100 are likely to suffer a serious adverse event as a result of treatment with SLIT (RD 0.0012, 95% confidence interval (CI) -0.0077 to 0.0102; participants = 2560; studies = 22; moderate-quality evidence).Within secondary outcomes, wide but varied reporting of largely unvalidated asthma symptom and medication scores precluded meaningful meta-analysis; a general trend suggested SLIT benefit over placebo, but variation in scales meant that results were difficult to interpret.Changes in inhaled corticosteroid use in micrograms per day (MD 35.10 mcg/d, 95% CI -50.21 to 120.42; low-quality evidence), exacerbations requiring oral steroids (studies = 2; no events) and bronchial provocation (SMD 0.69, 95% CI -0.04 to 1.43; very low-quality evidence) were not often reported. This led to many imprecise estimates with wide confidence intervals that included the possibility of both benefit and harm from SLIT.More people taking SLIT had adverse events of any kind compared with control (OR 1.70, 95% CI 1.21 to 2.38; low-quality evidence; participants = 1755; studies = 19), but events were usually reported to be transient and mild.Lack of data prevented most of the planned subgroup and sensitivity analyses. AUTHORS' CONCLUSIONS: Lack of data for important outcomes such as exacerbations and quality of life and use of different unvalidated symptom and medication scores have limited our ability to draw a clinically useful conclusion. Further research using validated scales and important outcomes for patients and decision makers is needed so that SLIT can be properly assessed as clinical treatment for asthma. Very few serious adverse events have been reported, but most studies have included patients with intermittent or mild asthma, so we cannot comment on the safety of SLIT for those with moderate or severe asthma. SLIT is associated with increased risk of all adverse events

Identity-based cryptography

During this Thesis we investigated the possibilities that Identity-based Encryption offers when used out of their original purpose. We managed to generalize a whole class of different identity-based encryption schemes into Downgradable Identity-based Encryptions. We found a generic way to construct Blind Identity-based Encryptions. These two works leads both to applications that are not a priori linked with IBE: Attribute-based Encryption from Downgradable IBE and Oblivious Transfer for Blind IBE, in the case of Affine IBE we manage to reduce the communication cost from a linear to logarithmic. As application we also find a way to use Hierarchical IBE to construct a special type of signature called Identity-based Designated Verifier Signature. We continue the research out of the context of IBE's application with Oblivious Transfer. We manage to generalize the concept of Oblivious Transfer into a new protocol called Oblivious Language-based Envelope encompassing many kind of protocols. Finally, in the image of the whole Thesis we construct Oblivious Transfer with a very different primitive called Password Authenticated Key Exchange. Surprisingly, with some optimizations this last transformation leads to a very efficient Oblivious Transfer Protocol. The Identity-based Encryption is our main basis of work, thus efficient instantiations of this primitive were the key of our own efficiency, thus we used the instanciation from the paper of Blazy et als at crypto 2014 which is efficient, tight secure and affine.Dans cette thèse nous étudions les possibilités que les chiffrements basés sur l’identité offrent quand ils sont utilisés dans un but différent qu’un simple chiffrement. Nous avons pu généraliser différents types de chiffrement basés sur l’identité en une nouvelle primitive nommé Downgradable Identity-based Encryption (DIBE). Nous avons trouvé un moyen générique de transformer de simple IBE en des IBE en blanc, dans le cas où l’IBE est affine nous rendons le coût de communication très faible (de linéaire à logarithmique). Ces deux primitives ont donné lieux à différentes applications : les chiffrements basés sur les attributs pour la première et le transfère inconscient pour la deuxième. Une autre application est l’utilisation d’IBE hiérarchiques pour créer des signatures à vérifieur désigné basées sur l’identité. Ensuite nous avons regardé le transfère inconscient seul et avons réussi à le généraliser en un nouveau protocole nommé Oblivious Language-based Envelope. Finalement, nous avons construit une transformation d’un protocole à un autre, d’un échange authentifié de clés par mot de passe nous avons construit un transfère inconscient. En prenant une instanciation particulière nous obtenons un protocole plus efficace que tous les précédents pour le même niveau de sécurité. La primitive chiffrement basé sur l’identité est notre outil principal pour réaliser nos constructions. Nous avons donc besoin d’une instanciation efficace de cette primitive. Nous avons utilisé celle de Blazy Kiltz et Pan à CRYPTO’14 qui est très efficace mais possède aussi une structure particulière dite affine

Cryptographie de l'identité

Dans cette thèse nous étudions les possibilités que les chiffrements basés sur l’identité offrent quand ils sont utilisés dans un but différent qu’un simple chiffrement. Nous avons pu généraliser différents types de chiffrement basés sur l’identité en une nouvelle primitive nommé Downgradable Identity-based Encryption (DIBE). Nous avons trouvé un moyen générique de transformer de simple IBE en des IBE en blanc, dans le cas où l’IBE est affine nous rendons le coût de communication très faible (de linéaire à logarithmique). Ces deux primitives ont donné lieux à différentes applications : les chiffrements basés sur les attributs pour la première et le transfère inconscient pour la deuxième. Une autre application est l’utilisation d’IBE hiérarchiques pour créer des signatures à vérifieur désigné basées sur l’identité. Ensuite nous avons regardé le transfère inconscient seul et avons réussi à le généraliser en un nouveau protocole nommé Oblivious Language-based Envelope. Finalement, nous avons construit une transformation d’un protocole à un autre, d’un échange authentifié de clés par mot de passe nous avons construit un transfère inconscient. En prenant une instanciation particulière nous obtenons un protocole plus efficace que tous les précédents pour le même niveau de sécurité. La primitive chiffrement basé sur l’identité est notre outil principal pour réaliser nos constructions. Nous avons donc besoin d’une instanciation efficace de cette primitive. Nous avons utilisé celle de Blazy Kiltz et Pan à CRYPTO’14 qui est très efficace mais possède aussi une structure particulière dite affine.During this Thesis we investigated the possibilities that Identity-based Encryption offers when used out of their original purpose. We managed to generalize a whole class of different identity-based encryption schemes into Downgradable Identity-based Encryptions. We found a generic way to construct Blind Identity-based Encryptions. These two works leads both to applications that are not a priori linked with IBE: Attribute-based Encryption from Downgradable IBE and Oblivious Transfer for Blind IBE, in the case of Affine IBE we manage to reduce the communication cost from a linear to logarithmic. As application we also find a way to use Hierarchical IBE to construct a special type of signature called Identity-based Designated Verifier Signature. We continue the research out of the context of IBE's application with Oblivious Transfer. We manage to generalize the concept of Oblivious Transfer into a new protocol called Oblivious Language-based Envelope encompassing many kind of protocols. Finally, in the image of the whole Thesis we construct Oblivious Transfer with a very different primitive called Password Authenticated Key Exchange. Surprisingly, with some optimizations this last transformation leads to a very efficient Oblivious Transfer Protocol. The Identity-based Encryption is our main basis of work, thus efficient instantiations of this primitive were the key of our own efficiency, thus we used the instanciation from the paper of Blazy et als at crypto 2014 which is efficient, tight secure and affine

Identity-based cryptography

During this Thesis we investigated the possibilities that Identity-based Encryption offers when used out of their original purpose. We managed to generalize a whole class of different identity-based encryption schemes into Downgradable Identity-based Encryptions. We found a generic way to construct Blind Identity-based Encryptions. These two works leads both to applications that are not a priori linked with IBE: Attribute-based Encryption from Downgradable IBE and Oblivious Transfer for Blind IBE, in the case of Affine IBE we manage to reduce the communication cost from a linear to logarithmic. As application we also find a way to use Hierarchical IBE to construct a special type of signature called Identity-based Designated Verifier Signature. We continue the research out of the context of IBE's application with Oblivious Transfer. We manage to generalize the concept of Oblivious Transfer into a new protocol called Oblivious Language-based Envelope encompassing many kind of protocols. Finally, in the image of the whole Thesis we construct Oblivious Transfer with a very different primitive called Password Authenticated Key Exchange. Surprisingly, with some optimizations this last transformation leads to a very efficient Oblivious Transfer Protocol. The Identity-based Encryption is our main basis of work, thus efficient instantiations of this primitive were the key of our own efficiency, thus we used the instanciation from the paper of Blazy et als at crypto 2014 which is efficient, tight secure and affine.Dans cette thèse nous étudions les possibilités que les chiffrements basés sur l’identité offrent quand ils sont utilisés dans un but différent qu’un simple chiffrement. Nous avons pu généraliser différents types de chiffrement basés sur l’identité en une nouvelle primitive nommé Downgradable Identity-based Encryption (DIBE). Nous avons trouvé un moyen générique de transformer de simple IBE en des IBE en blanc, dans le cas où l’IBE est affine nous rendons le coût de communication très faible (de linéaire à logarithmique). Ces deux primitives ont donné lieux à différentes applications : les chiffrements basés sur les attributs pour la première et le transfère inconscient pour la deuxième. Une autre application est l’utilisation d’IBE hiérarchiques pour créer des signatures à vérifieur désigné basées sur l’identité. Ensuite nous avons regardé le transfère inconscient seul et avons réussi à le généraliser en un nouveau protocole nommé Oblivious Language-based Envelope. Finalement, nous avons construit une transformation d’un protocole à un autre, d’un échange authentifié de clés par mot de passe nous avons construit un transfère inconscient. En prenant une instanciation particulière nous obtenons un protocole plus efficace que tous les précédents pour le même niveau de sécurité. La primitive chiffrement basé sur l’identité est notre outil principal pour réaliser nos constructions. Nous avons donc besoin d’une instanciation efficace de cette primitive. Nous avons utilisé celle de Blazy Kiltz et Pan à CRYPTO’14 qui est très efficace mais possède aussi une structure particulière dite affine

Contribution à la prise en charge du laparoschisis de diagnostic anténatal (à propos de 18 cas ; revue de la littérature)

BREST-BU Médecine-Odontologie (290192102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Efficient ID-based Designated Verifier Signature

International audienceno abstrac

Effect of liquids on the metal to insulator transition of vanadium dioxide thin films

International audienc

VO2 PLD thin films under water environment: influence on Metal to Insulator Transition properties

International audienc