526 résultats
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PMNS for efficient arithmetic and small memory cost
Orateur : Fangan Yssouf Dosso - Ecole des Mines de Saint-Etienne
The Polynomial Modular Number System (PMNS) is an integer number system which aims to speed up arithmetic operations modulo a prime p. Such a system is defined by a tuple (p, n, g, r, E), where p, n, g and r are positive integers, E is a monic polynomial with integer coefficients, having g as a root modulo p. Most of the work done on PMNS focus on polynomials E such that E(X) = X^n – l, where l is[…] -
Isogenies over Hessian Model of Elliptic Curves
Orateur : Emmanuel Fouotsa - Université de Bamenda
In this talk we present explicit formulas for isogenies between elliptic curves in (twisted) Hessian form. We examine the numbers of operations in the base field to compute the formulas. In comparison with other isogeny formulas, we note that the obtained formulas for twisted Hessian curves have the lowest costs for processing the kernel and the X-affine formula has the lowest cost for processing[…] -
New uses in Symmetric Cryptography: from Cryptanalysis to Designing
Orateur : Clémence Bouvier - INRIA
New symmetric primitives are being designed to be run in abstract settings such as Multi-Party Computations (MPC) or Zero-Knowledge (ZK) proof systems. More particularly, these protocols have highlighted the need to minimize the number of multiplications performed by the primitive in large finite fields.<br/> As the number of such primitives grows, it is important to better understand the[…] -
On Rejection Sampling in Lyubashevsky's Signature Scheme
Orateur : Julien Devevey - ENS de Lyon
Lyubashevsky’s signatures are based on the Fiat-Shamir with aborts paradigm, whose central ingredient is the use of rejection sampling to transform (secret-key-dependent) signature samples into samples from a secret-key-independent distribution. The choice of these two underly- ing distributions is part of the rejection sampling strategy, and various instantiations have been considered up to this[…] -
Traceable Constant-Size Multi-Authority Credentials
Orateur : Chloé Hébant - ENS
Many attribute-based anonymous credential (ABC) schemes have been proposed allowing a user to prove the possession of some attributes, anonymously. They became more and more practical with, for the most recent papers, a constant-size credential to show a subset of attributes issued by a unique credential issuer. However, proving possession of attributes coming from K different credential issuers[…] -
Constant time implementation of rank based cryptography
Orateur : Nicolas Aragon - IRISA
Since the start of the NIST standardization project for post-quantum cryptography in 2017, rank metric based cryptography is becoming more popular as an alternative to code-based cryptography in the Hamming metric.<br/> While rank based cryptography has always been competitive in terms of keys and ciphertexts sizes, the lack of maturity in the implementations of these cryptosystems made them[…]