In 2019, Antoine Joux proposed a FHE based on Fermat numbers, with an aim to express all cryptographic functions in simple operations on the ciphertext components and their binary decompositions. We use recent results on sub-Gaussian variables to find better

Fresh re-keying is a recent and promising direction to handle side-channel attacks in cryptographic solutions. It is a simple, plug-in, efficient function that handles the core of side-channel protection directly on the secret key of cryptographic computations. State-of-the-art re-keying schemes

The last event of the crypto seminar will be dedicated to the ongoing NIST competition on lightweight cryptography. We plan to have different speakers to present both some second round candidates to the competition while also to expose some recent

We introduce a new signature scheme, SQISign, (for Short Quaternion and Isogeny Signature)  from isogeny graphs of supersingular elliptic curves. The signature scheme is derived from a new one-round, high soundness, interactive identification protocol. Targeting the post-quantum NIST-1 level of

Les fonctions faiblement pseudoaléatoires (WPRFs) sont des fonctions F_K indistinguables d'une fonction totalement aléatoire à partir de paires (x, F_K(x)) pour des x aléatoires. Ces fonctions ont diverses applications en cryptographie symétrique - elles permettent par exemple de construire des

Fully Homomorphic Encryption (FHE) schemes enable to compute over encrypted data. Among them, TFHE has the great advantage of offering an efficient method for bootstrapping noisy ciphertexts, i.e., reduce the noise. Indeed, homomorphic computation increases the noise in ciphertexts and

Vectorial Boolean functions map n bits to m. These functions and their properties are of particular interest to cryptographers since they correspond to the S-boxes used in block ciphers, to the filter functions of stream ciphers, etc. Quadratic functions are

In this talk we will present a novel MPC framework, Manticore, with full threshold and semi-honest security model, supporting a combination of real number arithmetic (arithmetic shares), Boolean arithmetic (Boolean shares) and garbled circuits (Yao shares). We establish a parallel

Do you think you know ElGamal encryption? Think twice. We uncover vulnerabilities in the OpenPGP ecosystem stemming from confusion about the definition of ElGamal encryption (and the lack of an unequivocable standard). The first vulnerability leads to practical plaintext recovery

Dans cette présentation, nous présenterons l'article publié à Eurocrypt 2021 . Nous montrerons comment retrouver l'état interne dans ces deux chiffrements, encore utilisés dans la communication 2G. Notre attaque nécessite 44 GB de mémoire et peut se faire avec un