Description
Designing secure protocols based on passwords is a difficult task. Indeed, passwords, and more generally low-entropy secrets, are potentially vulnerable to guessing attacks, that is, exhaustive, "brute force" searches. Preventing guessing attacks typically requires a protocol to conceal any partial information on the password (e.g. its checksum) which could help the attacker confirm his guess during the searching process.<br/> Ensuring such a property is not obvious. Based on the seminal work of Lowe, several models and automatic tools have been proposed to analyze protocols with respect to guessing attacks. Unfortunately, these works rely on different symbolic models for which no computational justifications exist so far. (That is, a protocol may be secure in a symbolic model, and yet a feasible attack exists.) In this talk, we will study a recent, symbolic definition of security against guessing attacks, based on static equivalence. First, we will present a decision procedure for a large class of protocols, for a finite number of sessions. Then, we will provide a computational justification in the case of a passive adversary, that is, a pure eavesdropper. [This part is a joint work with M. Abadi and B. Warinschi.]
Next sessions
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Random lattices that are modules over the ring of integers
Speaker : Nihar Gargava - Institut de Mathématiques d'Orsay
We investigate the average number of lattice points within a ball where the lattice is chosen at random from the set of unit determinant ideal or modules lattices of some cyclotomic number field. The goal is to consider the space of such lattice as a probabilistic space and then study the distribution of lattice point counts. This is inspired by the connections of this problem to lattice-based[…]-
Cryptography
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Schéma de signature à clé publique : Frobénius-UOV
Speaker : Gilles Macario-Rat - Orange
L'exposé présente un schéma de signature à clé publique post-quantique inspiré du schéma UOV et introduisant un nouvel outil : les formes de Frobénius. L'accent est mis sur le rôle et les propriétés des formes de Frobénius dans ce nouveau schéma : la simplicité de description, la facilité de mise en oeuvre et le gain inédit sur les tailles de signature et de clé qui bat RSA-2048 au niveau de[…] -
Yoyo tricks with a BEANIE
Speaker : Xavier Bonnetain - Inria
TBD-
Cryptography
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Symmetrical primitive
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