Team, Visitors, External Collaborators
Overall Objectives
Research Program
Application Domains
Highlights of the Year
New Software and Platforms
New Results
Partnerships and Cooperations
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Section: New Results

Symmetric cryptology

Participants : Xavier Bonnetain, Christina Boura, Anne Canteaut, Daniel Coggia, Pascale Charpin, Daniel Coggia, Gaëtan Leurent, María Naya Plasencia, Léo Perrin, André Schrottenloher, Ferdinand Sibleyras.

Block ciphers

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

Recent results:

MACs and hash functions

The international research effort related to the selection of the new hash function standard SHA-3 has led to many important results and to a better understanding of the security offered by hash functions. However, hash functions are used in a huge number of applications with different security requirements, and also form the building-blocks of some other primitives, like MACs.

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:

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 provable security, and we know that their use is secure as long as the underlying primitive is secure, and we respect some limits on the amount of data processed. The analysis of generic attack helps us understand what happens when the hypotheses of the security proofs do not hold, or the corresponding limits are not respected. Comparing proofs and attacks also shows gaps where our analysis is incomplete, and when improved proof or attacks are required.

Recent results: