599 résultats
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Soutenance de thèse: Conception de courbes elliptiques et applications
Orateur : Rémi Clarisse - Rennes
Le thème de la sécurité de l’information est prédominant dans nos vies actuelles. En particulier, les utilisateurs de service, plus précisément en ligne, s’attendent de plus en plus à ce que leurs données à caractère personnel soient traitées dignement et avec leur consentement. Cela incite donc à concevoir des systèmes se pliant à de telles exigences. Le recours à la cryptographie permet de[…] -
Soutenance de thèse: Autour de la sécurité des messageries instantanées: des solutions pour des applications multi-appareils et les communications de groupe.
Orateur : Céline Duguey - DGA-Rennes
Les applications de messagerie instantanée sécurisée, telles WhatsApp ou Signal, sont devenues incontournables pour nos communications quotidiennes.<br/> Elles apportent une sécurité caractérisée notamment par le chiffrement de bout en bout, la confidentialité persistante ou encore la sécurité après compromission. Mais ces propriétés sont généralement limitées aux communications deux à deux.[…] -
Soutenance de thèse: Study and design of new encryption primitives based on rank metric error correcting codes
Orateur : Ba Duc Pham - Rennes
In 2005, Faure and Loidreau proposed a new rank-metric cryptosystem inspired from the Hamming metric scheme of Augot-Finiasz in 2003. In 2018, it was broken by the attack of Gaborit, Otmani and Kalachi. Recently, there are some attempts of repairing the Faure-Loidreau scheme, for example the work of Renner, Puchinger and Wachter–Zeh which is called LIGA. In this thesis, we also introduce a new[…] -
PARASITE: PAssword Recovery Attack against Srp Implementations in ThE wild
Orateur : Daniel De Almeida Braga - Université Rennes 1
Protocols for password-based authenticated key exchange (PAKE) allow two users sharing only a short, low-entropy password to establish a secure session with a cryptographically strong key. The challenge in designing such protocols is that they must resist offline dictionary attacks in which an attacker exhaustively enumerates the dictionary of likely passwords in an attempt to match the used[…] -
Ransomware Detection Using Markov Chain Models Over File Headers
Orateur : David Lubicz (DGA-MI)
In this paper, a new approach for the detection of ransomware based on the runtime analysis of their behaviour is presented. The main idea is to get samples by using a mini-filter to intercept write requests, then decide if a sample corresponds to a benign or a malicious write request. To do so, in a learning phase, statistical models of structured file headers are built using Markov chains. Then[…] -
Quantum cryptanalysis of block ciphers: beyond quadratic speedups
Orateur : André Schrottenloher - CWI
The security of modern cryptosystems relies on computational assumptions, which may be challenged by the advent of large-scale quantum computing devices.<br/> While Shor's algorithm is known to break today's most popular public-key schemes, secret-key cryptosystems are generally expected to retain half of their pre-quantum bits of security. However, the precise advantage of quantum[…]