Thomas Baignères


Since 2010, I am a Cryptography & Security Expert for CryptoExperts in Paris.


I received a Ph.D. in 2008 under the direction of Prof. Serge Vaudenay , head of the Cryptography and Security Laboratory (LASEC) at EPFL, Switzerland. My main research areas cover block ciphers and their cryptanalysis. I then spent some time in Belgium where I worked as a consultant and researcher for Smals.


Thomas Baignères - CryptoExperts
41 boulevard des Capucines
75002, Paris, France
+33 6 48 44 74 92
first.last @

ECRYPT Workshop on Lightweight Cryptography

Posted in November 2011

I am part of the program committee of the 2011 edition of the ECRYPT Workshop on Lightweight Cryptography.

LC 2011 is organized by the UCL Crypto Group and sponsored by the SymLab and VAMPIRE virtual labs of the Network of Excellence in Cryptology - ECRYPT II. It will be held on November 28-29, 2011, in Louvain-la-Neuve in Belgium.

Dial C for Cipher

Joint work with Matthieu Finiasz
Published in the Proceedings of SAC 2006

We introduce C, a practical provably secure block cipher with a slow key schedule. C is based on the same structure as AES but uses independent random substitution boxes instead of a fixed one. Its key schedule is based on the Blum-Blum-Shub pseudo-random generator, which allows us to prove that all obtained security results are still valid when taking into account the dependencies between the round keys. C is provably secure against several general classes of attacks. Strong evidence is given that it resists an even wider variety of attacks. We also propose a variant of C with simpler substitution boxes which is suitable for most applications, and for which security proofs still hold.

PDF PS Slides