599 résultats
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ANNULÉ et reporté au 29 avril. Toutes nos excuses.
Orateur : ANNULÉ Pierre_Karpman - Rennes 1 et Singapour
ANNULÉ et reporté au 29 avril. -
Better Bias-Dimension Trade-offs---Some Results on Solving Hard Learning Problems Using Coding Theory
Orateur : Qian Guo - Lund
Hard learning problems (e.g., LPN, LWE and their variants) are attractive topics recently in the cryptographic community due to the numerous cryptosystems (symmetric or public-key) based on them. Normally these systems employ an instantiation of the underlying problem with a large dimension and relatively small noise to ensure the security and the high decryption success probability, respectively[…] -
Sanitization of FHE Ciphertexts
Orateur : Damien Stehlé - ENS Lyon
By definition, fully homomorphic encryption (FHE) schemes support homomorphic decryption, and all known FHE constructions are bootstrapped from a Somewhat Homomorphic Encryption (SHE) scheme via this technique. Additionally, when a public key is provided, ciphertexts are also re-randomizable, e.g. by adding to them fresh encryptions of~$0$. From those two operations we devise an algorithm to[…] -
Finding ECM-Friendly Curves through a Study of Galois Properties
Orateur : Cyril Bouvier - Institut de mathématiques de Bordeaux
In this talk, I'll prove some divisibility properties of the cardinality of elliptic curve groups modulo primes. These proofs explain the good behavior of certain parameters when using Montgomery or Edwards curves in the setting of the elliptic curve method (ECM) for integer factorization. The ideas behind the proofs can be used to find new infinite families of elliptic curves with good[…] -
Algorithms for polynomial selection in the number field sieve
Orateur : Shi Bai - Australian National University
The general number field sieve (GNFS) is the most efficient algorithm known for factoring large integers. It consists of several stages, the first one being polynomial selection. The running-time of the number field sieve depends on the quality of the chosen polynomials. The quality of the chosen polynomials can be modeled in terms of size and root properties. In this talk, we will describe some[…] -
Certification de représentations galoisiennes modulaires
Orateur : Nicolas Mascot - Université de Bordeaux 1
Nous verrons comment certifier algorithmiquement des calculs de représentations galoisiennes associés à des formes modulaires, en nous appuyant notamment sur le théorème de Khare-Wintenberger (ex conjecture de modularité de Serre) et des calculs de cohomologie des groupes afin de déterminer le groupe de Galois de certains polynômes.