Charlotte Lefevre
I am a PhD student in the Digital Security Group at Radboud University Nijmegen since September 2021, under the supervision of Bart Mennink and with Joan Daemen as promotor. During my PhD, I had the opportunity to complete a 6-month internship at CSEM, under the supervision of Damian Vizár. Before that, I completed my Master's thesis at the University of Grenoble under the supervision of Pierre Karpman.
Most of my current research focuses on the provable security of symmetric cryptographic schemes, particularly permutation-based ones.
Publications
You can find below a list of. You can also find them on Google Scholar or DBLP.
International Conferences with proceedings
- To Pad or Not to Pad? Padding-Free Arithmetization-Oriented Sponges IACR Transactions on Symmetric Cryptology, 2025(1), pp. 97-137 (2025)
- SoK: Security of the Ascon Modes IACR Transactions on Symmetric Cryptology, 2025(1), pp. 138-210 (2025) (*)
- Permutation-Based Hash Chains with Application to Password Hashing IACR Transactions on Symmetric Cryptology 2024(4), pp. 249-286 (2024) (*)
- Permutation-Based Hashing Beyond the Birthday Bound IACR Transactions on Symmetric Cryptology 2024(1), pp. 71-113 (2024) (*)
- Generic Security of the Ascon Mode: On the Power of Key Blinding Selected Areas in Cryptography, SAC 2024. To appear (2024) (eprint) (*)
- Indifferentiability of the Sponge Construction with a Restricted Number of Message Blocks IACR Transactions on Symmetric Cryptology 2023(1), pp. 224-243 (2023) (*)
- Tight Preimage Resistance of the Sponge Construction CRYPTO 2022 (IV). LNCS, vol. 13510, pp. 185-204. Springer (2022) (*)
- Time-memory tradeoffs for large-weight syndrome decoding in ternary codes PKC 2022. LNCS, vol. 13177. pp. 82-111. Springer (2022) (*)
Preprints and Notes
- Permutation-Based Hashing with Stronger (Second) Preimage Resistance eprint 2025/963
- MacaKey: Full-State Keyed Sponge Meets the Summation-Truncation Hybrid eprint 2025/893
- A Note on Adversarial Online Complexity in Security Proofs of Duplex-Based Authenticated Encryption Modes eprint 2024/213
- Kirby: A Robust Permutation-Based PRF Construction eprint 2023/1520
Activities
Selected Presentations
I presented all the papers marked with an asterisk (*) in the “International Conferences” section, and have also given the following additional presentations:
- SoK: Security of the Ascon Modes GAPS 2025, Singapore, September 2025 Cryptography Seminar, Rennes, June 2025
- Permutation-Based Hash Chains with Application to Password Hashing Permutation-Based Crypto 2025, Madrid, May 2025
- Kirby: A Robust Permutation-Based PRF Construction Lorentz Center workshop on Beating Real-Time Crypto, Leiden, April 2024
- Tight Preimage Resistance of the Sponge Construction Lightweight Cryptography Workshop 2022, Online, May 2022
- Time-memory tradeoffs for large-weight syndrome decoding in ternary codes CWI Seminar, Amsterdam, April 2022
Teaching
Teaching assistant in Radboud University for the following bachelor courses:
- 2024-2025 Mathematical Structures (NWI-IPC020)
- 2023-2024 Logics and Applications (NWI-IPI004)
- 2022-2023 Logics and Applications (NWI-IPI004)
- 2021-2022 Logics and Applications (NWI-IPI004)
Editorial
External reviewer for:
- CRYPTO 2025, 2024, 2023
- Inscrypt 2024
- Journal of Cryptology 2024
- Designs, Codes, and Cryptography 2023
- ASIACRYPT 2023, 2022
Program Committee member for:
- Inscrypt 2025
Organization
- Co-organizer of GelreCrypt 2025 (Nijmegen, November 2025)
Contact
charlotte.lefevre@ru.nl
Address
Mercator 1 Toernooiveld 212 6525 EC Nijmegen, The Netherlands