Robust Encryption, Extended

Robustness is a notion often tacitly assumed while working with encrypted data. Roughly speaking, it states that a ciphertext cannot be decrypted under different keys. Initially formalized in a public-key context, it has been further extended to key-encapsulation mechanisms, and more recently to pseudorandom functions, message authentication codes and authenticated encryption. In this work, we motivate the importance of establishing similar guarantees for functional encryption schemes, even under adversarially generated keys. Our main security notion is intended to capture the scenario where a ciphertext obtained under a master key (corresponding to Authority 1) is decrypted by functional keys issued under a different master key (Authority 2). Furthermore, we show there exist simple functional encryption schemes where robustness under adversarial key-generation is not achieved. As a secondary and independent result, we formalize robustness for digital signatures – a signature should not verify under multiple keys – and point out that certain signature schemes are not robust when the keys are adversarially generated. We present simple, generic transforms that turn a scheme into a robust one, while maintaining the original scheme’s security. For the case of public-key functional encryption, we look into ciphertext anonymity and provide a transform achieving it

New Public-Key Cryptosystem Blueprints Using Matrix Products in Fp\mathbb F_p

Given a set of matrices $\mathbf{A} := \{A_0, \dotsc, A_{k-1}\}$, and a matrix $M$ guaranteed to be the product of some ordered subset of $\mathbf{L}\subset\mathbf{A}$, can $\mathbf{L}$ be efficiently recovered? We begin by observing that the answer is positive under some assumptions on $\mathbf{A}$. Noting that appropriate transformations seem to make $\mathbf{L}$\u27s recovery difficult we provide the blueprint of two new public-key cryptosystems based upon this problem. We term those constructions blueprints because, given their novelty, we are still uncertain of their exact security. Yet, we daringly conjecture that even if attacks are found on the proposed constructions, these attacks could be thwarted by adjustments in the key generation, key size or the encryption mechanism, thereby resulting on the long run in fully-fledged public-key cryptosystems that do not seem to belong to any of the mainstream public-key encryption paradigms known to date

Large Mode Area Solid-Core Photonic Bandgap Yb-doped Fiber with Hetero-Structured Cladding for Compact High-Power Laser Systems

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Temperature Effect on the Radioluminescence of Cu-, Ce-, and CuCe-Doped Silica-Based Fiber Materials

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TAVR Patients Requiring Anticoagulation: Direct Oral Anticoagulant or Vitamin K Antagonist?

International audienceOBJECTIVES: Using French transcatheter aortic valve replacement (TAVR) registries linked with the nationwide administrative databases, the study compared the rates of long-term mortality, bleeding, and ischemic events after TAVR in patients requiring oral anticoagulation with direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs). BACKGROUND: The choice of optimal drug for anticoagulation after TAVR remains debated. METHODS: Data from the France-TAVI and FRANCE-2 registries were linked to the French national health single-payer claims database, from 2010 to 2017. Propensity score matching was used to reduce treatment-selection bias. Two primary endpoints were death from any cause (efficacy) and major bleeding (safety). RESULTS: A total of 24,581 patients who underwent TAVR were included and 8,962 (36.4%) were treated with OAC. Among anticoagulated patients, 2,180 (24.3%) were on DOACs. After propensity matching, at 3 years, mortality (hazard ratio [HR]: 1.37; 95% confidence interval [CI]: 1.12-1.67; P \textless 0.005) and major bleeding including hemorrhagic stroke (HR: 1.64; 95% CI: 1.17-2.29; P \textless 0.005) were lower in patients on DOACs compared with those on VKAs. The rates of ischemic stroke (HR: 1.32; 95% CI: 0.81-2.15; P = 0.27) and acute coronary syndrome (HR: 1.17; 95% CI: 0.68-1.99; P = 0.57) did not differ among groups. CONCLUSIONS: In these large multicenter French TAVR registries with an exhaustive clinical follow-up, the long-term mortality and major bleeding were lower with DOACs than VKAs at discharge. The present study supports preferential use of DOACs rather than VKAs in patients requiring oral anticoagulation therapy after TAVR

Late Outcomes of Transcatheter Aortic Valve Replacement in High-Risk Patients The FRANCE-2 Registry

International audienceBACKGROUND Transcatheter aortic valve replacement (TAVR) has revolutionized management of high-risk patients with severe aortic stenosis. However, survival and the incidence of severe complications have been assessed in relatively small populations and/or with limited follow-up. OBJECTIVES This report details late clinical outcome and its determinants in the FRANCE-2 (FRench Aortic National CoreValve and Edwards) registry. METHODS The FRANCE-2 registry prospectively included all TAVRs performed in France. Follow-up was scheduled at 30 days, at 6 months, and annually from 1 to 5 years. Standardized VARC (Valve Academic Research Consortium) outcome definitions were used. RESULTS A total of 4,201 patients were enrolled between January 2010 and January 2012 in 34 centers. Approaches were transarterial (transfemoral 73%, transapical 18%, subclavian 6%, and transaortic or transcarotid 3%) or, in 18% of patients, transapical. Median follow-up was 3.8 years. Vital status was available for 97.2% of patients at 3 years. The 3-year all-cause mortality was 42.0% and cardiovascular mortality was 17.5%. In a multivariate model, predictors of 3-year all-cause mortality were male sex (p = 2 of 4 (p < 0.001). Severe events according to VARC criteria occurred mainly during the first month and subsequently in < 2% of patients/year. Mean gradient, valve area, and residual aortic regurgitation were stable during follow-up. CONCLUSIONS The FRANCE-2 registry represents the largest database available on late results of TAVR. Late mortality is largely related to noncardiac causes. Incidence rates of severe events are low after the first month. Valve performance remains stable over time. (J Am Coll Cardiol 2016; 68: 1637-47) (C) 2016 by the American College of Cardiology Foundation

Registry of transcatheter aortic-valve implantation in high-risk patients.

International audienceBACKGROUND: Transcatheter aortic-valve implantation (TAVI) is an emerging intervention for the treatment of high-risk patients with severe aortic stenosis and coexisting illnesses. We report the results of a prospective multicenter study of the French national transcatheter aortic-valve implantation registry, FRANCE 2. METHODS: All TAVIs performed in France, as listed in the FRANCE 2 registry, were prospectively included in the study. The primary end point was death from any cause. RESULTS: A total of 3195 patients were enrolled between January 2010 and October 2011 at 34 centers. The mean (±SD) age was 82.7±7.2 years; 49% of the patients were women. All patients were highly symptomatic and were at high surgical risk for aortic-valve replacement. Edwards SAPIEN and Medtronic CoreValve devices were implanted in 66.9% and 33.1% of patients, respectively. Approaches were either transarterial (transfemoral, 74.6%; subclavian, 5.8%; and other, 1.8%) or transapical (17.8%). The procedural success rate was 96.9%. Rates of death at 30 days and 1 year were 9.7% and 24.0%, respectively. At 1 year, the incidence of stroke was 4.1%, and the incidence of periprosthetic aortic regurgitation was 64.5%. In a multivariate model, a higher logistic risk score on the European System for Cardiac Operative Risk Evaluation (EuroSCORE), New York Heart Association functional class III or IV symptoms, the use of a transapical TAVI approach, and a higher amount of periprosthetic regurgitation were significantly associated with reduced survival. CONCLUSIONS: This prospective registry study reflected real-life TAVI experience in high-risk elderly patients with aortic stenosis, in whom TAVI appeared to be a reasonable option. (Funded by Edwards Lifesciences and Medtronic.)