Soutenance HDR de Christina Boura

Christina Boura soutient son HDR intitulée « On the security of symmetric primitives and the properties of their inner components »

le vendredi 17 février 2023 à 10h, à l’Inria Paris, 2 rue Simone Iff, 75012, salle Jacques-Louis Lions (venir à l’Inria).


Résumé :

Symmetric cryptography is a central discipline for ensuring information security. Indeed, the use of cryptographic algorithms allows to protect sensitive information when stored on some physical device and permits two parties to communicate safely via an unreliable communication channel. Among these algorithms, those known as symmetric are the only ones that can guarantee a good performance in terms of speed or circuit size for most applications.

This manuscript is centred around the understanding of the security offered by symmetric primitives. This understanding can be achieved via different processes and some of these processes are described in this thesis. The first part of this document presents a careful study and analysis of some existing cryptanalysis techniques and permitted notably to generalize and improve some well-known families of attacks, such as differential and impossible differential ones. A new cryptanalysis technique that combines differential and meet-in-the-middle (MITM) attacks is then presented followed with new heuristic modeling approaches for the research of distinguishers with MILP solvers.  The second part of this thesis focuses on the analysis of some newly proposed cryptanalysis techniques and proposes an alternative approach to two of them, namely the division property and the multiple-of-n distinguishers. Finally, the last chapter presents results on the resistance of symmetric algorithms against differential and boomerang attacks by studying the mathematical properties of the underlying S-boxes.

Soutenance HDR de Christina Boura