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Paul Largillier

About

I’m Paul Largillier, a PhD student at CEA-List under the supervision of Cédric Gouy-Pailler and Oana Stan, working toward more secure Federated Learning.

My research sits at the intersection of homomorphic encryption (FHE) and federated learning.

Background

I completed two years of classes préparatoires (MPSI/MP) before joining ESILV (École Supérieure d’Ingénieurs Léonard de Vinci), where I developed a strong foundation in mathematics and computer science. I then joined CEA-List to pursue my PhD.

Publications

Nothing published yet — I’m at the early stages of my thesis. A first paper is currently under review. Stay tuned.

Languages

This Site

This is my personal space for sharing research notes, blog posts on cryptography, machine learning, and anything else I find worth writing about. Feel free to reach out via LinkedIn or GitHub.

Professional Experience

PhD – Toward More Secure Federated Learning

CEA-List · Saclay, France · Nov. 2025 – Present
  • Research at the intersection of homomorphic encryption and federated learning.
  • Supervised by Cédric Gouy-Pailler and Oana Stan.

R&D Intern – Homomorphic Encryption & Federated Learning

CEA-List · Saclay, France · Mar. 2025 – Aug. 2025
  • State of the art on threshold homomorphic encryption and federated learning.
  • Design and development of a federated learning framework integrating threshold FHE.
  • Benchmarking gRPC applied to federated learning; evaluation of the Lattigo library.
  • Security analysis of a distributed protocol based on gRPC with a Go FHE library.

Cybersecurity Intern – Pentest & OSINT

Capgemini · Puteaux, France · Apr. 2024 – Aug. 2024
  • Web and infrastructure penetration testing.
  • Development of a tool integrating OSINT tools into the pentest reconnaissance workflow.
  • Contribution to the renewal of the PASSI certification.

Cybersecurity Intern – Cryptography

Capgemini · Puteaux, France · Jun. 2023 – Aug. 2023
  • Python scripting for network enumeration in pentesting contexts.
  • Cryptographic transition advisory for a European aerospace subcontractor.
  • Implementation and cryptanalysis of a NIST post-quantum candidate (Giophantus) using SageMath.

Education

International Semester – Mathematics & Computer Science

Hanyang University (한양대학교) · Seoul, South Korea · Sept. 2024 – Jan. 2025
  • Microprocessors, hardware vulnerabilities and countermeasures.
  • Final project on embedded systems and performance optimization in constrained environments.
  • Advanced C++ programming and algorithm analysis.

Engineering Degree – Cybersecurity & IoT, Mathematics & Computer Science

ESILV · La Défense, France · Sept. 2022 – Sept. 2025
  • Specialization in cybersecurity, cryptography, IoT and cloud.
  • Quantum track focused on post-quantum cryptography and quantum computing.
  • Industry-oriented projects in offensive security, audits and innovation.

Classes Préparatoires aux Grandes Écoles – MPSI / MP

Lycée Marceau · Chartres, France · Sept. 2020 – Jun. 2022
  • Two intensive years in mathematics, physics and engineering sciences.