Baptiste Lambin

Contact

Workgroup for Symmetric Cryptography
Horst Görtz Institute for IT-Security
Ruhr-University Bochum
Universitätsstr. 150
D-44780 Bochum
Visiting address: Wasserstraße 221, 44801 Bochum
E-mail : baptiste [dot] lambin [at] protonmail [dot] com

About me

I'm currently a post-doc under the supervision of Gregor Leander . I obtained my PhD on the October, 22nd 2019, under the supervision of Pierre-Alain Fouque and Patrick Derbez. My topic of research is symmetric cryptography, especially Division Property, Differential Attacks, Boomerang and others. I'm also interested in constraint programming tools (CP, MILP, etc.) and their applications to symmetric cryptography.

Publications

• Patrick Derbez, Pierre-Alain Fouque, Baptiste Lambin and Victor Mollimard
  Efficient Search for Optimal Diffusion Layers of Generalized Feistel Networks
  FSE 2020


• Patrick Derbez, Pierre-Alain Fouque, Jérémy Jean and Baptiste Lambin
  Variants of the AES Key Schedule for Better Truncated Differential Bounds
  SAC 2018
  Implementation available at https://github.com/TweakAESKS/TweakAESKS.


• Patrick Derbez, Pierre-Alain Fouque, Baptiste Lambin and Brice Minaud
  On Recovering Affine Encodings in White-Box Implementations
  CHES 2018 (Online video)
  Implementation available at https://recovaffeq.github.io/


• Patrick Derbez, Pierre-Alain Fouque, Baptiste Lambin
  Linearly equivalent S-boxes and the Division Property
  DCC 2020
  Implementation available at https://github.com/ExtendDivProp/ExtendDivProp

Talks

• On Recovering Affine Encodings in White-Box Implementations, presented :
  
  • at the CHES 2018 conference in Amsterdam, Netherlands
  • at the Séminaire C2 at the LIP6 lab in Paris, France
  
  


• Variants of the AES Key Schedule for Better Truncated Differential Bounds, presented :
  
  • at the SAC 2018 conference, in Calgary, Canada
  • at Journées Codage & Cryptographie 2018 workshop in Aussois, France
  • at the Caen Crypto seminar, in Caen, France
  
  


• Efficient Search for Optimal Diffusion Layers of Generalized Feistel Networks, presented :
  • at the SymCrypt team seminar in Bochum, Germany
  • at the COSMIQ team seminar in Paris, France
  • (in the future) at the FSE 2020 conference in Athens, Greece


• Making (near) Optimal Choices for the Design of Block Ciphers, a merged presentation of my SAC'18 and FSE'20 papers, presented :
  • at the LIMOS seminar in Clermont-Ferrand, France
  • at the CARAMBA team seminar in Nancy, France


• Linearly equivalent S-boxes and the Division Property, presented :
  • at the SymCrypt team seminar in Bochum, Germany
  • at the COSMIQ team seminar in Paris, France
  • (in the future) at the Journées Codage & Cryptographie 2020 workshop in Erdeven, France


• Attaque sur une implémentation en boîte blanche d’AES
  Presentation at the Journées Codage & Cryptographie 2017 workshop about a part of my CHES 2018 paper, in La Bresse, France


• Ma thèse en 180 secondes (video in French)
  Presentation of my PhD in 3 minutes, targeted for general audience (the public was mainly composed of high schoolers)

Teaching

All of these courses were done at Université de Rennes 1.
For most of them, I was in charge of some exercise courses (TD), practical courses (TP), as well as writing some of the exercise sheets for some (especially INF1).

• INF1 : Introduction to imperative programming based on the Java language for first year students.


• OIA : Follow-up course of INF1 for maths students. Introduction to complexity, sorting algorithms,...


• BCS : Fifth year course for non-crypto students. Basic implementation of some cryptographic primitives and attacks in C (CSS, MD4, AES) and Python (RSA), as well as some tools for cryptography (writing a big number library in C, using openssl,...)


• SECU : Fourth year course. Introduction to cryptography, HTML/PHP vulnerabilities, openssl, PGP etc.


• APS : Follow-up course of SECU. Emphasis on cryptanalysis (CSS, correlation attacks, padding oracle attacks, etc.)