Overall Objectives
Research Program
Application Domains
Highlights of the Year
New Software and Platforms
New Results
Bilateral Contracts and Grants with Industry
Partnerships and Cooperations
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Section: New Results

Symmetric cryptology

Participants : Xavier Bonnetain, Christina Boura, Anne Canteaut, Pascale Charpin, Sébastien Duval, Gaëtan Leurent, María Naya Plasencia, Yann Rotella, Ferdinand Sibleyras, Tim Beyne, Mathilde de La Morinerie, André Schrottenloher.

Primitives: block ciphers, stream ciphers, ...

Our recent results mainly concern either the analysis and design of lightweight block ciphers.

Recent results:

Cryptographic properties and construction of appropriate building blocks

The construction of building blocks which guarantee a high resistance against the known attacks is a major topic within our project-team, for stream ciphers, block ciphers and hash functions. The use of such optimal objects actually leads to some mathematical structures which may be at the origin of new attacks. This work involves fundamental aspects related to discrete mathematics, cryptanalysis and implementation aspects. Actually, characterizing the structures of the building blocks which are optimal regarding to some attacks is very important for finding appropriate constructions and also for determining whether the underlying structure induces some weaknesses or not. For these reasons, we have investigated several families of filtering functions and of S-boxes which are well-suited for their cryptographic properties or for their implementation characteristics.

Recent results:

Side-channel attacks

Physical attacks must be taken into account in the evaluation of the security of lightweight primitives. Indeed, these primitives are often dedicated to IoT devices in pervasive environments, where an attacker has an easy access to the devices where the primitive is implemented.

Recent results:

Modes of operation and generic attacks

In order to use a block cipher in practice, and to achieve a given security notion, a mode of operation must be used on top of the block cipher. Modes of operation are usually studied through security, and we now that their use is secure as long as the underlying primitive are secure, and we respect some limits on the amount of data processed. The analysis of generic attack helps us understand what happens when the hypothesis of the security proofs do not hold, or the corresponding limits are not respected. Comparing proofs and attack also shows gaps where our analysis is incomplete, and improved proof or attacks are required.

Recent results: