Towards Security Limits in Side-Channel Attacks

This paper considers a recently introduced framework for the analysis of physically observable cryptographic devices. It exploits a model of computation that allows quantifying the effect of practically relevant leakage functions with a combination of security and information theoretic metrics. As a result of these metrics, a unified evaluation methodology for side-channel attacks was derived that we illustrate by applying it to an exemplary block cipher implementation. We first consider a Hamming weight leakage function and evaluate the efficiency of two commonly investigated countermeasures, namely noise addition and masking. Then, we show that the proposed methodology allows capturing certain non-trivial intuitions about the respective effectiveness of these countermeasures Finally, we justify the need of combined metrics for the evaluation, comparison and understanding of side-channel attacks

Unifying view of mechanical and functional hotspots across class A GPCRs

G protein-coupled receptors (GPCRs) are the largest superfamily of signaling proteins. Their activation process is accompanied by conformational changes that have not yet been fully uncovered. Here, we carry out a novel comparative analysis of internal structural fluctuations across a variety of receptors from class A GPCRs, which currently has the richest structural coverage. We infer the local mechanical couplings underpinning the receptors' functional dynamics and finally identify those amino acids whose virtual deletion causes a significant softening of the mechanical network. The relevance of these amino acids is demonstrated by their overlap with those known to be crucial for GPCR function, based on static structural criteria. The differences with the latter set allow us to identify those sites whose functional role is more clearly detected by considering dynamical and mechanical properties. Of these sites with a genuine mechanical/dynamical character, the top ranking is amino acid 7x52, a previously unexplored, and experimentally verifiable key site for GPCR conformational response to ligand binding. \ua9 2017 Ponzoni et al

Increased Skeletal Muscle 11βHSD1 mRNA Is Associated with Lower Muscle Strength in Ageing

Background: Sarcopenia, the loss of muscle mass and function with age, is associated with increased morbidity and mortality. Current understanding of the underlying mechanisms is limited. Glucocorticoids (GC) in excess cause muscle weakness and atrophy. We hypothesized that GC may contribute to sarcopenia through elevated circulating levels or increased glucocorticoid receptor (GR) signaling by increased expression of either GR or the GC-amplifying enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11βHSD1) in muscle. Methods: There were 82 participants; group 1 comprised 33 older men (mean age 70.2years, SD 4.4) and 19 younger men (22.2years, 1.7) and group 2 comprised 16 older men (79.1years, 3.4) and 14 older women (80.1years, 3.7). We measured muscle strength, mid-thigh cross-sectional area, fasting morning plasma cortisol, quadriceps muscle GR and 11βHSD1 mRNA, and urinary glucocorticoid metabolites. Data were analysed using multiple linear regression adjusting for age, gender and body size. Results: Muscle strength and size were not associated with plasma cortisol, total urinary glucocorticoids or the ratio of urinary 5β-tetrahydrocortisol +5α-tetrahydrocortisol to tetrahydrocortisone (an index of systemic 11βHSD activity). Muscle strength was associated with 11βHSD1 mRNA levels (β -0.35, p = 0.04), but GR mRNA levels were not significantly associated with muscle strength or size. Conclusion: Although circulating levels of GC are not associated with muscle strength or size in either gender, increased cortisol generation within muscle by 11βHSD1 may contribute to loss of muscle strength with age, a key component of sarcopenia. Inhibition of 11βHSD1 may have therapeutic potential in sarcopenia

Anthropometric and physical characteristics in U16, U18 and U20 elite French youth rugby union players

International audienceThe aims of this study in elite youth French players were to 1) describe the anthropometric and physical characteristics of international and non-international players from U16 to U20, and 2) compare these characteristics across age categories and playing standard (international or non-international). Altogether, 1423 players from the French Rugby Federation's academies participated in a physical testing battery, part of its national young player development pathway. From seasons 2010 to 2020, players were assessed for anthropometric (body mass and height), off-field (bench press; isometric squat, vertical jump) and on-field physical characteristics (aerobic capacity: maximal aerobic speed [MAS]; speed: 10-m, 50m sprint). A 2-way mixed model analysis of variance (ANOVA) was used to compare physical characteristics across age categories and playing standards. Two separate models were used for forwards and backs. A main statistical effect was observed for age category and playing standard (range p < 0.05-p < 0.001). Pair-wise category comparisons showed that older players were generally taller, heavier, stronger, faster and demonstrated better aerobic qualities than younger peers. The same results were observed for INT compared with NI players while INT forwards were also taller and heavier than NI peers (range p < 0.01-p < 0.001). Findings revealed a clear progression in anthropometric characteristics and physical qualities throughout the age development pathway in elite young French rugby players. Findings also identified certain physical qualities (strength, power and speed) necessary at younger levels to achieve international standard