Johanna Loyer

Postdoctoral researcher in Cryptology – Inria Saclay

I am a postdoctoral researcher at Inria Saclay in the GRACE team. My work focuses on post-quantum cryptanalysis, particularly on lattice and code-based problems, in both classical and quantum settings. I am especially interested in transferring techniques between these domains.
Previously, I was a postdoc at CWI in Amsterdam. From 2020 to 2023, I did my PhD under the supervision of André Chailloux in the COSMIQ team at Inria Paris.

CV 🇬🇧 CV 🇫🇷

Publications

ASIACRYPT 2021 Lattice sieving via quantum random walks
André Chailloux and Johanna Loyer
PQCrypto 2023 Classical and quantum 3 and 4-sieves to solve SVP with low memory
André Chailloux and Johanna Loyer
DCC 2024 Limitations of Quantum Sieving-Based Information-Set Decoding
Lynn Engelberts, Simona Etinski and Johanna Loyer
CRYPTO 2025 Wagner's Algorithm Provably Runs in Subexponential Time for SIS^∞
Léo Ducas, Lynn Engelberts and Johanna Loyer

Preprints

Lattice Reduction via Dense Sublattices: A Cryptanalytic No-Go
Léo Ducas and Johanna Loyer Quantum security analysis of Wave
Johanna Loyer

Standardisation

NIST 2023 Post-Quantum Cryptography contest Round 1 Wave signature scheme
Gustavo Banegas, Kévin Carrier, André Chailloux, Alain Couvreur, Thomas Debris-Alazard, Philippe Gaborit, Pierre Karpman, Johanna Loyer, Ruben Niederhagen, Nicolas Sendrier, Benjamin Smith, Jean-Pierre Tillich.

Ph.D. thesis

Quantum cryptanalysis of lattices and codes

Defended the 18th december 2023.

Scientific Outreach

Popularization of my PhD

All audiences 🇫🇷

What is the use of maths in daily life?

High school 🇫🇷

Introduction to cryptology

9th grade 🇫🇷

Elliptic curve cryptography

All audiences 🇬🇧

Lattice sieving via quantum walks (in 5 min)

Expert 🇬🇧

I was interviewed for an article in the science outreach magazine Epsiloon, you can read it (in French) here!