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X-WR-CALNAME:GREYC UMR CNRS 6072 - Groupe de Recherche en Informatique, Image, et Instrumentation de Caen
X-ORIGINAL-URL:https://www.greyc.fr
X-WR-CALDESC:évènements pour GREYC UMR CNRS 6072 - Groupe de Recherche en Informatique, Image, et Instrumentation de Caen
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TZID:Europe/Paris
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TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20210328T010000
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TZNAME:CET
DTSTART:20211031T010000
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20210310T140000
DTEND;TZID=Europe/Paris:20210310T150000
DTSTAMP:20260826T073705
CREATED:20210303T171731Z
LAST-MODIFIED:20210303T171731Z
UID:10273-1615384800-1615388400@www.greyc.fr
SUMMARY:Matthieu Lequesne - Recovering short secret keys of RLCE in polynomial time
DESCRIPTION:The security of most modern public key encryption algorithms (such as RSA) relies on arithmetic problems. Today\, the hardness of these problems is threatened by the potential emergence of large quantum computers. For this reason\, cryptographers try to come up with new cryptographic schemes relying on families of problems which remain hard to solve even with a quantum computer. One possible solution is to use the hardness of decoding a random error-correcting code. This field is known as code-based cryptography. This idea was introduced by McEliece in 1978 and his proposal is still considered secure today. However\, McEliece’s scheme needs large public keys (about 1MB for 256 security bits)\, which makes it unfit for most use-cases. Therefore\, there are several attempts to replace the Goppa codes\, used by McEliece\, with other families of codes\, to obtain shorter keys. In this work\, we analyze a proposal from Wang\, named Random Linear Code-based Encryption (RLCE)\, and conclude that for all the short key parameters proposed by the author\, we can recover the secret key in polynomial time\, by using the dimension of the square code as a distinguisher. This is a joint work with Alain Couvreur and Jean-Pierre Tillich. \n  \nhttps://webconference.unicaen.fr/b/mor-7jm-rcy
URL:https://www.greyc.fr/event/matthieu-lequesne-recovering-short-secret-keys-of-rlce-in-polynomial-time/
CATEGORIES:Séminaire Cryptologie et sécurité
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20210330T100000
DTEND;TZID=Europe/Paris:20210330T110000
DTSTAMP:20260826T073705
CREATED:20210414T130548Z
LAST-MODIFIED:20210414T130700Z
UID:10331-1617098400-1617102000@www.greyc.fr
SUMMARY:Séminaire ALGO\, Antonin Callard : "Entropies et entropies de surfaces des sous-shifts 2D"
DESCRIPTION:Les sous-shifts 2D sont les ensembles de coloriages du plan $Z^2$\, par un nombre fini de couleurs\, et qui sont définis par des familles de motifs interdits. Les sous-shifts sont une classe de systèmes dynamiques qui profitent d’un lien étroit avec la calculabilité : d’abord un obstacle (indécidabilité du problème du domino)\, la calculabilité est progressivement devenue un outil indispensable pour leur étude. Par exemple\, Hochman et Meyerovitch ont obtenu la caractérisation des entropies des sous-shifts 2D comme étant les nombres réels récursivement énumérables à droite.\nDans cette présentation\, nous nous concentrons sur la notion d’entropie de surface introduite dans la thèse de Dennis Pace. À la manière de Hochman et Meyerovitch\, nous montrons que les entropies de surface des sous-shifts 2D correspondent exactement aux nombres réels $\Pi_3$ de la hiérarchie arithmétique.
URL:https://www.greyc.fr/event/seminaire-algo-antonin-callard-entropies-et-entropies-de-surfaces-des-sous-shifts-2d/
CATEGORIES:Amacc,Séminaire Algo
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20210330T103000
DTEND;TZID=Europe/Paris:20210330T120000
DTSTAMP:20260826T073705
CREATED:20210416T131818Z
LAST-MODIFIED:20210818T094330Z
UID:10334-1617100200-1617105600@www.greyc.fr
SUMMARY:Séminaire ELEC (Visio): Axe 1 - Physique des composants à semi-conducteurs : bruit\, température\, défauts électroniques
DESCRIPTION:Ce séminaire permettra de faire le point sur les résultats et les faits marquants de l’axe 1 dans la période juin 2020 – mars2021. \nYannick Guhel & Bogdan Cretu
URL:https://www.greyc.fr/event/seminaire-elec-visio-resultats-et-faits-marquants-axe-1-juin-2020-mars2021/
CATEGORIES:Electronique,Séminaire Électronique
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BEGIN:VEVENT
DTSTART;TZID=Europe/Paris:20210331T140000
DTEND;TZID=Europe/Paris:20210331T150000
DTSTAMP:20260826T073705
CREATED:20210316T105620Z
LAST-MODIFIED:20210322T110621Z
UID:10291-1617199200-1617202800@www.greyc.fr
SUMMARY:Weiqiang Wen - On algorithms for solving Euclidean lattice problems in cryptography
DESCRIPTION:In this talk\, we will try to review the state-of-the-art of the algorithms for solving the Euclidean lattice problems underlying cryptography. In more details\, this talk contains two parts. In the first part\, we will focus on the lattice problems such as approximate Shortest Vector Problem (approx-SVP) and the lattice reduction algorithms as the best known solving algorithms so far. In particular\, I will present an improved enumeration-based lattice reduction algorithm\, which is shown to be (potentially) relevant to cryptanalysis. In the second part\, we will instead consider a quantum problem that is computationally equivalent to approx-SVP. By directly solving a quantum problem\, we may expect to have a more powerful use of the quantum computation. However\, the best known algorithms for solving approx-SVP via solving this quantum problem\, is not better than lattice reduction yet. \n  \n  \nhttps://webconference.unicaen.fr/b/mor-7jm-rcy
URL:https://www.greyc.fr/event/weiqiang-wen-on-algorithms-for-solving-euclidean-lattice-problems-in-cryptography/
CATEGORIES:Séminaire Cryptologie et sécurité
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