Code based signature schemes with special properties

Code based signature schemes with special properties

For one or two student(s)

Domain

Cryptography and coding theory

Presentation

Most of the cryptographic schemes used and studied today are based on number theory problems as factorisation or discrete logarithm. In 1994, Shor proposed an algorithm which can factorise in polynomial time using a quantum computer. So RSA and several others schemes are threatened by the quantum computer.

Code-based cryptography is one of the branches of post-quantum cryptography with lattice- based, multivariate-based and hash-based cryptography. Schemes based on problems as syndrome decoding or decoding random codes are well studied for years and there doesn't exist polynomial time algorithm to solve those problems even in a post quantum world. McEliece was the rst to propose a code-based cryptosystem and several improvements and derivation have been proposed so far.

There exists dierent code-based signature schemes (Stern identication and signature scheme, Courtois Finiasz and Sendrier signature scheme) and several schemes proposed additional prop- erties like identity-based constructions or threshold ring signatures.

Purpose

After a state of the art of code-based signature schemes, the dierent properties that a signature scheme can oer and the generic constructions in each context, the student will have to propose a code-based signature scheme with one of this property (undeniable, designated verier or time- released for example). A proof of security of the scheme in the random oracle model or in the standard model would be appreciate.

The student will have to write an article on his research in a L

TEX format and give an english presentation to the team.

Goals

The outcome of the thesis is supposed to be a publishable result on code-based signature scheme

with a special property.

Required Skills

The required skills, in order of importance, are:

ˆ High motivation and creativity;

ˆ Skills in C;

ˆ Good knowledge of cryptographic constructions;

ˆ Experience with reading research papers.

Knowledge of the English language goes without saying.

Bibliography

[1] - C. Aguilar, P.-L. Cayrel and P.Gaborit : A New Ecient Threshold Ring Signature Scheme, PQCrypto 2008.

[2] - P.-L. Cayrel, P.Gaborit and M. Girault : Identity-based identication and signature schemes using correcting codes, WCC 2007.

Institute

Laboratoire Hubert Curien : http://laboratoirehubertcurien.fr/spip.php?rubrique29

Place : Saint-Etienne - France

Team : Applied Cryptography and Telecom

Thesis supervisor : Pierre-Louis Cayrel (Maître de conférences)

Contact

If you are interested, please contact Pierre-Louis Cayrel Laboratoire Hubert Curien, UMR CNRS 5516

Bâtiment F 18 rue du professeur Benoît Lauras 42000 Saint-Etienne France

Phone: 0033-4 77 91 57 94

e-mail supervisor: pierre.louis.cayrel@univ-st-etienne.fr

web : http://www.cayrel.net/