Description
We consider a generalisation of the encryption from "one-to-one'' to "one-to-many'' communication, i.e. broadcast encryption. The objective is to allow a center to send secret messages to a large number of receivers. The security notion in “one-to-many” communications needs to be extended beyond the notion of confidentiality in “one-to-one” encryption in order to meet practical requirements. Two main functionalities are studied: (1) traitor tracing which identifies the malicious users who leak their secrets to a pirate and (2) revocation which prevents malicious users and/or non-legitimate ones from decrypting broadcasted information.<br/> In the first part of the talk, we focus on combinatorial schemes. We consider the Exclusive Set System (ESS) which has been originally designed to support revocation. We propose a method to integrate the black-box tracing capacity in ESS by introducing a technique called "shadow group testing''.<br/> The second part of the talk discusses the techniques for constructing algebraic schemes which can overcome some limitations of combinatorial schemes. We propose a lattice-based traitor tracing of which the security is based on the hardness of a new variant of the Learning With Errors problem, namely k-LWE (for k traitors). We then prove the hardness of the k-LWE problem which implies that the proposed traitor tracing scheme is asymptotically as efficient as the Regev LWE-based encryption. Our technique can also be used to improve the Boneh-Freeman reduction from SIS to k-SIS from exponential loss to polynomial loss in k (thus answer their open problem of a tighter reduction from SIS to k-SIS). We finally consider the combination of algebraic and combinatorial methods and discuss some promising directions.
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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