511 résultats
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Supersingular isogeny Diffie-Hellman
Orateur : Leonardo Colo - Univesité Aix-Marseille
Supersingular isogeny graphs have been used in the Charles–Goren–Lauter cryptographic hash function and the supersingular isogeny Diffie–Hellman (SIDH) protocole of De\,Feo and Jao. A recently proposed alternative to SIDH is the commutative supersingular isogeny Diffie–Hellman (CSIDH) protocole, in which the isogeny graph is first restricted to $\FF_p$-rational curves $E$ and $\FF_p$-rational[…] -
Lossy trapdoor primitives, zero-knowledge proofs and applications
Orateur : Chen Qian - soutenance de thèse salle Métivier à l'IRISA, 14h
In this thesis, we study two differentprimitives. Lossy trapdoor functions and zero-knwoledge proof systems.The lossy trapdoor functions (LTFs) arefunction families in which injective functionsand lossy ones are computationally indistin-guishable. Since their introduction, they havebeen found useful in constructing various cryp-tographic primitives. We give in this thesisefficient constructions of[…] -
Cryptanalyse algébrique de DAGS
Orateur : Magali Bardet - université de Rouen
Elise Barelli et Alain Couvreur ont présenté une attaque dévastatrice sur le cryptosystème DAGS soumis au 1er tour de la compétition du NIST autour d'algorithmes de cryptographie post-quantiques. Je présenterai une explication précise de la résolution par bases de Gröbner de leur modélisation algébrique, expliquant l'efficacité de l'attaque pour les paramètres de DAGS publiés au[…] -
Unifying Leakage Models on a Renyi Day
Orateur : Thomas Prest - PqShield
In the last decade, several works have focused on finding the best way to model circuit leakage in order to obtain provably secure implementations. One of the most realistic models is the noisy leakage model, introduced in (Prouff, Rivain'13) and (Duc-Dziembowski-Faust'14) together with secure constructions. These works suffer from various limitations, in particular the use of ideal leak[…] -
Cocks-Pinch curves of embedding degree five to eight and optimal ate pairing computation
Orateur : Simon Masson - Loria, Nancy
Recent algorithmic improvements of discrete logarithm computation in special extension fields threaten the security of pairing-friendly curves used in practice. A possible answer to this delicate situation is to propose alternative curves that are immune to these attacks, without compromising the efficiency of the pairing computation too much. We follow this direction, and focus on embedding[…] -
Improved Veron Identification and Signature Schemes in the Rank Metric
Orateur : Florian Caullery - Darkmatter
Abstract—It is notably challenging to design an efficient and secure signature scheme based on error-correcting codes. An approach to build such signature schemes is to derive it from an identification protocol through the Fiat-Shamir transform.<br/> All such protocols based on codes must be run several rounds, since each run of the protocol allows a cheating probability of either 2/3 or 1/2[…]