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

Code-based cryptography

Participants : Magali Bardet, Kevin Carrier, André Chailloux, Thomas Debris, Matthieu Lequesne, Rocco Mora, Nicolas Sendrier, Jean-Pierre Tillich, Valentin Vasseur.

In recent years, there has been a substantial amount of research on quantum computers. Such computers would be a major threat for all the public-key cryptosystems used in practice, since all these systems rely on the hardness of integer factoring or discrete logarithms, and these problems are easy on a quantum computer. This has prompted NIST to launch a standardization process in 2017 for quantum-safe alternatives to those cryptosystems. This concerns all three major asymmetric primitives, namely public-key encryption schemes, key-exchange protocols and digital signatures. There were 69 valid submissions to this call in November 2017, with numerous lattice-based, code-based and multivariate-cryptography submissions and some submission based either on hashing or on supersingular elliptic curve isogenies. NIST expects to perform multiple rounds of evaluation, over a period of three to five years. The goal of this process is to select a number of acceptable candidate cryptosystems for standardization. The second round of evaluation started in February 2019.

The research of the project-team in this field is focused on the design and cryptanalysis of cryptosystems making use of coding theory. The first cryptosystem based on error-correcting codes was a public-key encryption scheme proposed by McEliece in 1978; a dual variant was proposed in 1986 by Niederreiter. We proposed the first (and only) digital signature scheme in 2001. Those systems enjoy very interesting features (fast encryption/decryption, short signature, good security reduction) but also have their drawbacks (large public key, encryption overhead, expensive signature generation). Our recent work on code-based cryptography has to be seen in the context of the recently launched NIST competition for quantum-safe primitives. We have proposed five code-based candidates to the NIST call for the first two primitives, namely public key encryption and key exchange protocols. Our contributions in this area are two-fold and consist in:

We have also been organizing since 2015 a working group held every month or every two months on code-based cryptography that structures the French efforts on this topic: every meeting is attended by most of the groups working in France on this topic (project-team GRACE, University of Bordeaux, University of Limoges, University of Rennes and University of Rouen).

Design of new code-based solutions

The members of the project-team have submitted several candidates to the NIST competition and have designed new code-based primitives.

Recent results:

Cryptanalysis of code-based schemes

Recent results: