Baptiste Lambin

Contact

E-mail : baptiste [dot] lambin [at] protonmail [dot] com

About me

I am currently looking for a new job :). I obtained my PhD on the October, 22nd 2019, under the supervision of Pierre-Alain Fouque and Patrick Derbez. This was followed by a post-doc at Ruhr-University Bochum under the supervision of Gregor Leander . I then went for another post-doc with Alex Biryukov in the University of Luxembourg from April 2022 to April 2024. 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

• Alex Biryukov, Baptiste Lambin, Aleksei Udovenko
  Cryptanalysis of ARX-based White-box Implementations
  TCHES 2023-3, Conference CHES 2023
  Implementation available here


• Baptiste Lambin, Gregor Leander, Patrick Neumann
  Pitfalls and Shortcomings for Decompositions and Alignment
  EUROCRYPT 2023
  Supplementary code available here


• Patrick Derbez, Baptiste Lambin
  Fast MILP Models for Division Property
  ToSC 2022-2, Conference FSE 2023
  Implementation available here


• Phil Hebborn, Baptiste Lambin, Gregor Leander, Yosuke Todo
  Strong and Tight Security Guarantees against Integral Distinguishers
  ASIACRYPT 2021
  Implementation available here


• Dušan Božilov, Maria Eichlseder, Miroslav Knežević, Baptiste Lambin, Gregor Leander, Thorben Moos, Ventzislav Nikov, Shahram Rasoolzadeh, Yosuke Todo, Friedrich Wiemer
  PRINCEv2: More Security for (Almost) No Overhead
  SAC 2020
  


• Phil Hebborn, Baptiste Lambin, Gregor Leander, Yosuke Todo
  Lower Bounds on the Degree of Block Ciphers
  ASIACRYPT 2020
  Implementation available here


• Patrick Derbez, Pierre-Alain Fouque, Baptiste Lambin
  Linearly equivalent S-boxes and the Division Property
  DCC 2020
  Implementation available here


• Patrick Derbez, Pierre-Alain Fouque, Baptiste Lambin and Victor Mollimard
  Efficient Search for Optimal Diffusion Layers of Generalized Feistel Networks
  ToSC 2019-2, Conference 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 here.


• Patrick Derbez, Pierre-Alain Fouque, Baptiste Lambin and Brice Minaud
  On Recovering Affine Encodings in White-Box Implementations
  CHES 2018 (Online video)
  Implementation available here

Talks

• Strong and Tight Security Guarantees Against Integral Distinguishers, presented :
  
  • at the ASIACRYPT 2021 online conference, full version of the talk here


• Lower Bounds on the Degree of Block Ciphers, presented :
  
  • at the ASIACRYPT 2020 online conference, full version of the talk here
  • at the EMSEC Team at IRISA in Rennes, France


• On Recovering Affine Encodings in White-Box Implementations, presented :
  
  • at the CHES 2018 conference in Amsterdam, Netherlands; full version of the talk here
  • 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
  • at the FSE 2020 online conference, full version of the talk here


• 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
  • at the Journées Codage & Cryptographie 2020 online workshop


• 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.)

I was also Teaching Assistant for the Discrete Maths 1 course (first year course) at the University of Luxembourg.