549 résultats
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Divisible E-Cash from Constrained Pseudo-Random Functions
Orateur : Olivier Sanders - Orange
Electronic cash (e-cash) is the digital analogue of regular cash which aims at preserving users' privacy. Following Chaum's seminal work, several new features were proposed for e-cash to address the practical issues of the original primitive. Among them, divisibility has proved very useful to enable efficient storage and spendings. Unfortunately, it is also very difficult to achieve and, to date,[…] -
Lattice-based signatures: from construction to implementation
Orateur : Pauline Bert - soutenance de thèse, amphi P de l'ISTIC, 14h
Lattice-based cryptography is one of the major line of research to build post-quantum public key primitives. In this thesis, we discuss about digital signatures constructions and their implementation. We first describe a Fiat-Shamir transformation from an identification scheme using rejection sampling to a digital signature secure in the random oracle model. Then we describe an identity-based[…] -
Considérations Pratiques sur les Compromis Temps-Mémoire Cryptanalytiques
Orateur : Florent Tardif - soutenance de thèse salle Métivier à l'IRISA, 14h30
Un compromis temps-mémoire cryptanalytique est une technique qui vise à réduire le temps nécessaire pour effectuer certaines attaques cryptographiques telles que l’inversion d’une fonction à sens unique. Une telle inversion intervient dans une des principales applications des compromis temps-mémoire : le cassage de mots de passe. La technique requiert un très lourd pré-calcul qui génère des tables[…] -
Tunnels sécurisés pour environnements contraints
Orateur : Loic Ferreira - soutenance de thèse salle Métivier à l'IRISA, 14h30
Avec l’extension de l’Internet des Objets et l’usage croissant de terminaux à bas coût, de nombreux protocoles de sécurité sont déployés à grande échelle. Cette thèse étudie le champ des protocoles d’échange de clé authentifié basés sur des fonctions cryptographiques symétriques. Nous montrons que les protocoles existants n’atteignent pas un niveau de sécurité correspondant à l’état de l’art en[…] -
Cryptography based on rank metric codes
Orateur : Nicolas Aragon - Université de Limoges, exceptionnellement salle Jersey à l'ISTIC
In the past few years, the interest for rank metric based cryptography has drastically increased, especially since the beginning of the NIST Post-Quantum Cryptography standardization process : five rank metric based proposals were submitted to the first round. This talk will present the different approaches and tradeoffs for building Key Encapsulation Mechanisms and Public Key Encryption schemes[…] -
Post-quantum cryptography based on supersingular isogeny problems?
Orateur : Christophe Petit - University of Birmingham
The security of many cryptographic protocols in use today relies on the computational hardness of mathematical problems such as integer factorization. These problems can be solved using quantum computers, and therefore most of our security infrastructures will become completely insecure once quantum computers are built. Post-quantum cryptography aims at developing security protocols that will[…]