Posts classified under: Séminaire Cryptologie et sécurité

NIST recently released a publication related to the transition to Post-Quantum Cryptography which specifies that most of the public key classical cryptosystems, especially RSA will be officially deprecated by 2030 and banned after 2035. In this talk, I will review the limits of the main cryptanalytical attacks on RSA, and present two new variants of … Continue reading Abderrahmane Nitaj – The last decade of the RSA cryptosystem

On se situera à l’intersection des sciences de données et des sciences cognitives pour qualifier formellement les rhétoriques et représentations mobilisées dans les commentaires en ligne sur la vaccination. Le corpus (135 620 textes, 5 481 450 occurrences et 53 835 formes lexicales) fait d'abord l’objet d’une classification hiérarchique descendante (CDH). Pour l’interpréter, on mobilise … Continue reading Pascal Marchand – A la recherche des signes complotistes en ligne: exploration et expérimentation par la textométrie.

Physical layer security aims to exploit the randomness of noisy channels in order to enhance security through coding and signal processing techniques. Unlike cryptography, it does not place any limitations on the adversary's computational power, but relies on an asymmetry in the channel quality between the legitimate users and the adversary. In this talk, we … Continue reading Laura Luzzi – Finite blocklength secrecy analysis of polar and Reed-Muller codes in binary erasure wiretap channels

The decoding problem is fundamental in post-quantum cryptography. It can be broadly described as essentially solving a linear system with a non-linear constraint on the solution. Phrased this way, the problem applies to both code-based and lattice-based cryptography. For example, the linear system may be defined over FF_q, with the non-linear constraint being a condition … Continue reading Kévin Carrier – Combinatorial Attacks On The Decoding Problem

La compréhension du code binaire est cruciale en rétro-ingénierie. Usuellement, des bases de fonctions servent à identifier dans un binaire les fonctions proches de références connues. Cependant, souvent les projections sous-jacentes traitent chaque code source séparément. En revanche, les modèles de langage récents permettent de projeter le code binaire et sa description textuelle dans un … Continue reading Tristan Benoît – Approche multimodale pour la génération de noms de fonctions à partir du code binaire

Lattice-based cryptanalysis using Coppersmith's techniques has emerged as a powerful approach to compromising the security of several cryptographic algorithms under specific conditions. This talk will provide an exploration of the lattice-based solving strategy, which leverages lattice basis reduction to find small roots of polynomial equations modulo an integer. This method is then used for examining … Continue reading Mengce Zheng – Lattice-based solving strategy using Coppersmith’s techniques and its applications

The partial sums cryptanalytic technique was introduced in 2000 by Ferguson et al., who used it to break 6-round AES with time complexity of $2^{52}$ S-box computations -- a record that has not been beaten ever since. In 2014, Todo and Aoki showed that for 6-round AES, partial sums can be replaced by a technique … Continue reading ​Victor Mollimard – Partial Sums Meet FFT: Improved Attack on 6-roued AES

L’Internet des objets (IoT : Internet of Things) et ses applications sont devenus indispensables dans notre vie quotidienne. Cependant, la croissance rapide des systèmes IoT a engendré d’importants défis en matière de sécurité. De nombreux dispositifs IoT sont naturellement vulnérables en raison des contraintes de ressources telles que la capacité de traitement et l’autonomie de … Continue reading ​Abdelhamid Garah – Gestion autonome des services de sécurité dans l’Internet des objets

L’apprentissage fédéré (FL) est un paradigme décentralisé permettant d'entraîner des modèles de machine learning sans partager les données brutes. Toutefois, il demeure vulnérable à diverses attaques, notamment les empoisonnements de données (data poisoning) et de modèles (model poisoning). Pour relever les défis de confiance, de confidentialité et de passage à l’échelle dans le FL décentralisé, … Continue reading Amine Bouchiha – Vers un Apprentissage Fédéré Décentralisé, Fiable et Évolutif

DDGR framework was introduced in Crypto 2020 as the first cryptanalysis framework that estimates the impact of some types of side information on the security of Learning with Errors (LWE). Side information can come from many sources either from the construction itself or from the implementation leakage. Some of them can be categorized into perfect … Continue reading Thi Thu Quyen Nguyen – Cryptanalysis of LWE with side information

Facial recognition systems exhibit varying levels of performance depending on demographic characteristics such as gender, age, or ethnic origin. These biases, extensively documented in empirical studies, raise critical concerns regarding reliability, fairness, and ethical compliance. This presentation will examine the underlying sources of these biases, whether they stem from dataset composition, algorithmic choices, or intersectional … Continue reading Neily Sanon – L’identification et la mesure des biais dans les systèmes de reconnaissance facial

Post-quantum digital signatures have sparked a lot of interest in the cryptographic community in recent years. Both the NIST-selected signature Dilithium and Heatae, winner of the Korean PQC competition, rely on hardness of lattice problems and employ the Fiat-Shamir with Aborts paradigm, in which rejection sampling is used to eliminate a secret’s dependency on a … Continue reading Henry Bambury – Polytopes in the Fiat-Shamir with Aborts Paradigm