About

I am a CNRS research scientist at IRIF, Université Paris Cité. I received my PhD from École Normale Supérieure de Paris (ENS) in November 2017, under the supervision of David Pointcheval and Hoeteck Wee. In 2017 – 2019, I was a postdoctoral researcher at Karlsruhe Institute of Technology (KIT), in the team of Dennis Hofheinz.

My main research interests are secure multiparty computation and zero-knowledge proofs (both foundational and practical aspects), as well as the theoretical foundations of cryptography. For an up-to-date list of my publications, you can check my publication page, my dblp profile, or my Google scholar profile. All my publications become available at some point in open access format on the ePrint archive; see the list here. Here are links to my PhD thesis and my HDR manuscript.


News

June 2024: The Algorithms & Complexity team at IRIF (CNRS, Université Paris-Cité) in Paris, France is inviting applications for several fully-funded postdoctoral positions (1-2 years) to work on cryptography. Areas of interest include, but are not limited to, zero-knowledge proofs, secure computation, post-quantum cryptography, foundations of cryptography, connections with complexity theory, confidential transactions, anonymous credentials. The candidate will work alongside Geoffroy Couteau and Michele Orrù.

  • Required qualifications. The ideal candidate for the postdoc position will hold a PhD (or be close to completion) in cryptography and be an expert in any of the areas of interest.
  • Salary. €3080 to €4291 gross monthly salary depending on the past experience of the candidate.
  • Dates. The starting date is flexible from October 2024.
  • Working at IRIF, Paris: IRIF (the computer science department of Université Paris Cité) is a French institute focused on foundational computer science. It provides a stimulating environment with researchers from many areas of theoretical computer science. CNRS is the largest European research institution.
  • How to apply

    Update (August 2024): this opening is now closed! You can still check the link above to be informed about other positions at IRIF in the Algorithm and Complexity group, now or in the future (the page is updated regularly).

    March 2024: I defended my Habilitation à Diriger des Recherches on March 20. An HDR is a French diploma needed to supervize PhD students (without it, a co-supervisor with HDR is required). It proceeds essentially like a second PhD defense. You can find my HDR manuscript here; it provides an overview of secure computation in the correlated randomness model, and a step-by-step introduction to pseudorandom correlation generators, which might be useful for anyone wanting to get into this research area. More information about the defense here.

    September 2023: I was awarded an ERC Starting Grant for my project OBELiSC (Overcoming Barriers and Efficiency Limitations in Secure Computation). See here and here for interviews where I explain (in French) the goals of the project, and here for a short abstract (still in French).

    June 2023: I was invited to deliver a Spotlight Talk to the 2023 Conference on Information-Theoretic Cryptography (ITC). My talk, titled On Correlated Pseudorandomness, covered pseudorandom correlation generators, their impact on secure computation, and some of the latest advances in the area. You can check the slides here.

    April 2022: Our Eurocrypt’22 paper, On Building Fine-Grained One-Way Functions from Strong Average-Case Hardness, has been invited to the Journal of Cryptology. In this work, we prove weak feasibility results and strong barriers for basing extremely limited forms of cryptography on powerful average-case hardness assumptions. Working on this paper has been a long, but thrilling journey with my amazing coauthor, Chris Brzuska.

    January 2022: We just completed a book chapter for an upcoming book with Elette Boyle, Niv Gilboa, and Yuval Ishai. It is an up-to-date overview of homomorphic secret sharing, function secret sharing, and some of their many applications (including pseudorandom correlation generators). Check it out!


    Resources

    This website contains a few posts which might be useful to students in cryptography, gathered in the blog section. It includes in particular:


    Students and postdocs

    I have the pleasure to advise several amazing PhD students, and I will not be accepting any new PhD requests in the next year or so. However, I have openings for postdocs. Topics of interest include, but are not limited to, secure computation, zero-knowledge proofs, post-quantum cryptography, code-based cryptography, and foundational aspects of cryptography (including black-box separations and connections to learning theory).

    Postdocs

      Time period Notes
    Sihang Pu Apr. 2024 – current  
    Christop Egger Oct. 2022 – current  
    Alexander Koch Oct. 2022 – current  
    Balthazar Bauer Oct. 2022 – Sep. 2023 Now holding the Chaire de Professeur Junior at UVSQ.
    Sven Maier Nov. 2022 – Mar. 2023  

    PhD students

      Time period Notes
    Dung Bui Oct. 2021 – Secure Computation for Privacy-Preserving Analysis of Medical Data
    Clément Ducros Oct. 2021 – Linear Codes for Quantum-Resistant Secure Computation (co-advised with Alain Couvreur)
    Eliana Carozza Oct. 2021 – Quantumly hard algebraic problems and their advanced cryptographic applications (co-advised with Antoine Joux)
    Ulysse Léchine Oct.2021 – Average-case hardness, entropy, and one-way functions (co-advised with Thomas Seiller)
    Pierre Meyer Sep. 2020 – Sep. 2023 Secure computation with constrained communication (co-advised with Elette Boyle). Now postdoc at Aarhus University, supervised by Claudio Orlandi. You can check Pierre’s PhD thesis here.

    Master students

      Time period Notes
    Alexandros Themelis Apr. 2024 – Sep. 2024 Advanced Post-Quantum Signatures
    Dung Bui Mar. 2021 – Aug. 2021 Batch equality tests and secure comparison from pseudorandom correlation generators. Dung’s work led to a paper, presented at PKC’23.
    Clément Ducros Mar. 2021 – Aug. 2021 Secure computation meets linear-time encodable codes. Clément’s work led to a paper, presented at PKC’23.
    Michael Reichle Feb. 2020 – Aug. 2020 Efficient range proofs with transparent setup from bounded integer commitments. Michael’s work led to a paper, presented at EUROCRYPT’21. Now postdoc at ETH Zurich under the supervision of Dennis Hofheinz.
    Dominik Hartmann Feb. 2019 – Aug. 2019 Compilers for non-interactive zero-knowledge proofs. Dominik’s work led to a paper, presented at CRYPTO’20. Now PhD student at Ruhr Universität Bochum.

    Other: visitors, interns, bachelor students

      Time period Status Notes
    Naman Kumar June 2024 – Sep. 2024 Internship  
    Aditya Hegde June 2024 – July. 2024 Internship  
    Willy Quach Feb. 2024 – May 2024 Visiting postdoctoral researcher  
    Kelsey Melissaris Feb. 2024 – Jun. 2024 Visiting postdoctoral researcher  
    Nikolas Melissaris Feb. 2024 – Jun. 2024 Visiting PhD
    student
     
    Sacha Servan-Schreiber Sep. 2023 – March 2024 Visiting PhD
    student
     
    Naman Kumar May 2023 – Jun. 2023 Internship Naman’s work led to a paper, to be presented at CRYPTO’24.
    Elahe Sadeghi Jun. 2022 – Jul. 2022 Visiting PhD
    student
    Elahe’s work led to a paper, presented at EUROCRYPT’23.
    Milan Gonzalez-Thauvin May 2021 – Jul. 2021 Internship Constructions of Non-Interactive Zero-Knowledge Proofs: Efficiency and Generality
    Maryam Zarezadeh Nov. 2020 – Apr. 2021 Visiting PhD
    student
    Non-interactive inner products from LPN. Maryam’s work led to a paper, presented at ASIACRYPT’22.
    Elahe Sadeghi Jul. 2020 – Oct. 2020 Internship Statistical ZAPs from group-based assumptions. Elahe’s work led to a paper, presented at TCC’21.
    Pierre Meyer Nov. 2020 – Jan. 2020 Internship Breaking the circuit size barrier for secure computation under quasi-polynomial LPN. Pierre’s work led to a paper, presented at EUROCRYPT’21.
    Sebastian Faller Oct. 2018 – Feb. 2019 Bachelor Lattice-based implicit zero-knowledge arguments. Now PhD student at ETH Zurich under the supervision of Dennis Hofheinz and Julia Hesse.
    Michael Reichle May 2018 – Sep. 2018 Bachelor Non-interactive keyed-verification anonymous credentials. Michael’s work led to a paper, presented at PKC’19. Now postdoc at ETH Zurich under the supervision of Dennis Hofheinz.
    Samuel Kopmann Nov. 2017 – Mar. 2018 Bachelor Improved designated-verifier non-interactive zero-knowledge arguments

    Program Committees

    The list of conferences, workshops, and journals where I served as a member of the program committee (conferences, workshops) or editorial board (journals).

    Year Venues
    2024 Communications in Cryptology, TCC
    2023 CSF, CRYPTO
    2022 PKC, CSF, SCN, TCC
    2021 EUROCRYPT, IWSEC, WAHC
    2020 EUROCRYPT, IWSEC, WAHC
    2019 TCC, WAHC
    2018 INDOCRYPT