Towards Achieving Provable Side-Channel Security in Practice

Physical side-channel attacks are powerful attacks that exploit a device\u27s physical emanations to break the security of cryptographic implementations. Many countermeasures have been proposed against these attacks, especially the widely-used and efficient masking countermeasure. Nevertheless, proving the security of masked implementations is challenging. Current techniques rely on empirical approaches to validate the security of such implementations. On the other hand, the theoretical community introduced leakage models to provide formal proofs of the security of masked implementations. Meanwhile, these leakage models rely on physical assumptions that are difficult to satisfy in practice, and the literature lacks a clear framework to implement proven secure constructions on a physical device while preserving the proven security. In this paper, we present a complete methodology describing the steps to turn an abstract masking scheme proven secure in a theoretical leakage model into a physical implementation satisfying provable security against side-channel attacks in practice. We propose new tools to enforce or relax the physical assumptions the indeal noisy leakage model rely on and provide novel ways of including them in a physical implementation. We also highlight the design goals for an embedded device to reach high levels of proven security, discussing the limitations and open problems of the practical usability of the leakage models. Our goal is to show that it is possible to bridge theory and practice and to motivate further research to fully close the gap and get practical implementations proven secure against side-channel attacks on a physical device without any ideal assumption about the leakage

A Side Journey To Titan: Revealing and Breaking NXP's P5x ECDSA Implementation on the Way

International audienceThe Google Titan Security Key is a FIDO U2F hardware device proposed by Google (available since July 2018) as a two-factor authentication token to sign in to applications such as your Google account. In this paper, we present a sidechannel attack that targets the Google Titan Security Key 's secure element (the NXP A700x chip) by the observation of its local electromagnetic radiations during ECDSA signatures. This work shows that an attacker can clone a legitimate Google Titan Security Key. As a side observation, we identified a novel correlation between the elliptic curve group order and the lattice-based attack success rate

Does laughing have a stress-buffering effect in daily life? An intensive longitudinal study.

Positive affect is associated with alleviating mental and physiological stress responses. As laughter is a common physiological operationalization of positive affect, we investigated whether the effects of experiencing a stressful event on stress symptoms is lessened by frequency and intensity of daily laughter. Using an intensive longitudinal design, we ambulatory assessed the self-reported experience of stressful events, stress symptoms and the frequency as well as the intensity of laughter in university students' daily lives. Our hierarchical ecological momentary assessment data were analyzed with multilevel models. The results support the stress-buffering model of positive affect: We found that the frequency of laughter attenuated the association between stressful events and subsequent stress symptoms. The level of intensity of laughter, however, was found to have no significant effect. Future studies should use additional psychophysiological indicators of stress and straighten out the differential contributions of frequency and intensity of daily laughter

Establishing contact between cell-laden hydrogels and metallic implants with a biomimetic adhesive for cell therapy supported implants

International audienc

Unexpected Bactericidal Activity of Poly(arginine)/Hyaluronan Nanolayered Coatings

The number of nosocomial infections related to implants and medical devices increase alarmingly worldwide. New strategies based on the design of antimicrobial coatings are required to prevent such infections. Polyelectrolyte “multilayer” films constitute a powerful tool for nanoscale surface functionalization which allows addressing this issue. By investigating films built up with poly(arginine) (PAR) of various chain lengths (10, 30, 100, and 200 residues) and hyaluronic acid (HA), we demonstrate that exclusively films constructed with poly(arginine) composed of 30 residues (PAR30) acquire a strong antimicrobial activity against Gram-positive and Gram-negative pathogenic bacteria associated with infections of medical devices. This chain-size effect is extremely striking and is the first example reported where the length of the polyelectrolytes played a key-role in the functionality of the films. Moreover, this unexpected functionality of nanolayered polypeptide/polysaccharide PAR30/HA films occurs without adding any specific antimicrobial agent, such as antibiotics or antimicrobial peptides. PAR30/HA film inhibits bacteria through a contact-killing mechanism due to the presence of mobile PAR30 chains. These chains are assumed to diffuse toward the interface, where they interact with the bacteria with the consequence of killing them. This new coating with unique properties based on the association of a homopolypeptide of 30 residues with a polysaccharide constitutes a simple system to prevent implant-related infections with a reasonable production cost

Unexpected Bactericidal Activity of Poly(arginine)/Hyaluronan Nanolayered Coatings

The number of nosocomial infections related to implants and medical devices increase alarmingly worldwide. New strategies based on the design of antimicrobial coatings are required to prevent such infections. Polyelectrolyte “multilayer” films constitute a powerful tool for nanoscale surface functionalization which allows addressing this issue. By investigating films built up with poly­(arginine) (PAR) of various chain lengths (10, 30, 100, and 200 residues) and hyaluronic acid (HA), we demonstrate that exclusively films constructed with poly­(arginine) composed of 30 residues (PAR30) acquire a strong antimicrobial activity against Gram-positive and Gram-negative pathogenic bacteria associated with infections of medical devices. This chain-size effect is extremely striking and is the first example reported where the length of the polyelectrolytes played a key-role in the functionality of the films. Moreover, this unexpected functionality of nanolayered polypeptide/polysaccharide PAR30/HA films occurs without adding any specific antimicrobial agent, such as antibiotics or antimicrobial peptides. PAR30/HA film inhibits bacteria through a contact-killing mechanism due to the presence of mobile PAR30 chains. These chains are assumed to diffuse toward the interface, where they interact with the bacteria with the consequence of killing them. This new coating with unique properties based on the association of a homopolypeptide of 30 residues with a polysaccharide constitutes a simple system to prevent implant-related infections with a reasonable production cost