About me

I am a PhD student in the CRYPTO team at Université de Versailles Saint-Quentin-en-Yvelines under the supervision of Christina Boura, Henri Gilbert (ANSSI), and Yann Rotella. My main interest is in symmetric cryptanalysis, although I enjoy chatting about pretty much anything that is cryptography-related.

During my PhD, I have mainly studied the security of permutation-based cryptography, starting with an algebraic cryptanalysis of a reduced-version of the Keccak hash function. My interest in permutation-based crypto also led me to work on generic attacks on permutation-based AEAD modes, which gave me a taste for generic attacks using random functions statistics. I have also taken an interest on the cryptanalysis of block ciphers, mainly looking at differential cryptanalysis. My most recent result is a paper that fully breaks the Elisabeth-4 stream cipher tailored for FHE use cases.

Publications

Here is my dblp. Below is a list of my most recent publications.

Christina Boura, Nicolas David, Patrick Derbez, Rachelle Heim Boissier, María Naya-Plasencia. A generic algorithm for efficient key recovery in differential attacks – and its associated tool. EUROCRYPT 2024. eprint version

Henri Gilbert, Rachelle Heim Boissier, Jérémy Jean, Jean-René Reinhard. Cryptanalysis of Elisabeth-4. ASIACRYPT 2023. eprint version

Henri Gilbert, Rachelle Heim Boissier, Louiza Khati, Yann Rotella. Generic Attack on Duplex-Based AEAD Modes Using Random Function Statistics. EUROCRYPT 2023. 348-378. eprint version

Christina Boura, Nicolas David, Rachelle Heim Boissier, María Naya-Plasencia. Better Steady than Speedy: Full Break of SPEEDY-7-192. EUROCRYPT 2023. eprint version

Christina Boura, Rachelle Heim Boissier, Yann Rotella. Breaking Panther. AFRICACRYPT 2022. eprint version

Rachelle Heim Boissier, Yann Rotella. Algebraic Collision Attacks on Keccak. Transactions on Symmetric Cryptology 2021. ToSC version here

Preprints

Xavier Bonnetain, Rachelle Heim Boissier, Gaëtan Leurent, André Schrottenloher. Improving Generic Attacks Using Exceptional Functions. 2024. eprint version

Talks

Conferences

Journées C2 2023. Cryptanalysis of Elisabeth-4. October 16th 2023. slides

Eurocrypt 2023. Generic Attack on Duplex-Based AEAD Modes Using Random Function Statistics. April 26th 2023. slides

Africacrypt 2022. Breaking Panther. July 18th 2022. slides

Journées C2 2022. Attaque structurelle par échange contre des versions réduites d'AES-128. April 14th 2022. slides

FSE 2022. Algebraic Collision Attacks on Keccak. March 22nd 2022. slides, video

Seminars

Rennes Crypto Seminar. Generic attacks based on functional graphs. September 22nd 2023. slides

Teaching

I have given tutorials for the following classes at Université de Versailles Saint-Quentin-en-Yvelines.

• Applications informatiques (IN202) for first-year Computer Science students (Spring)
• Introduction to (Python) programming (IN100) for first-year Computer Science students (Fall)

• Cryptography for third-year students (Spring)
• Cryptography for first-year master students (Fall)

• Mathematics for computer science (IN310) for second-year students (Fall)
• Cryptography for first-year master students (Fall)

Contact