Michele Orrù

I believe that privacy is a human right and that cryptography can help foster an open society. My research seeks to build authentication mechanisms that preserve user anonymity. I work on:

In the past, I contributed to Python, Debian, and Tor. I co-designed Globaleaks, an open-source whistleblowing platform now translated in more than 90 languages and used by more than 300 organizations, and co-authored the cryptography behind Google’s Trust Tokens. Sometimes, I help NGOs on matters of digital security.

I am a chargé de recherche (Assistant Professor) at CNRS. Previously, I have been at UC Berkeley as research scholar. I got my PhD from École Normale Supérieure, and my MSc in math from the University of Trento. I attended the Recurse Center in Fall 2020 (W2’20).




In theoretical cryptography authors are listed in alphabetical order, regardless of their contribution amount.

  • A Fiat–Shamir Transformation From Duplex Sponges [ePrint]
    Alessandro Chiesa, Michele Orrù
    To appear.

  • Revisiting keyed-verification anonymous credentials [ePrint]
    Michele Orrù
    To appear.

  • Beyond the circuit: How to Minimize Foreign Arithmetic in ZKP Circuits [ePrint],
    Michele Orrù, George Kadianakis, Mary Maller, Greg Zaverucha
    IACR Communications in Cryptology (Volume 2, Issue 1)

  • Oblivious issuance of proofs [ePrint],
    Michele Orrù, Stefano Tessaro, Greg Zaverucha, Chenzhi Zhu
    CRYPTO 2024 (Proceedings of the 44th Annual International Cryptology Conference)

  • zk-Bench: A Toolset for Comparative Evaluation and Performance Benchmarking of SNARKs [ePrint],
    Jens Ernstberger, Stefanos Chaliasos, George Kadianakis, Philipp Jovanovic, Arthur Gervais, Benjamin Livshits, Michele Orrù
    SCN 2024 (Proceedings of the 14th International Conference on Security in Communication Networks)

  • Non-interactive Mimblewimble transactions, revisited [ePrint],
    Georg Fuchsbauer, Michele Orrù.
    ASIACRYPT 2022 (Proceedings of the 28th International Conference on the Theory and Application of Cryptology and Information Security)

  • Gemini: an elastic proof system for diverse environments [ePrint] [Talk] [Code],
    Jonathan Bootle, Alessandro Chiesa, Yuncong Hu, Michele Orrù
    EUROCRYPT 2022 (Proceedings of the 42nd Annual International Conference on Theory and Application of Cryptographic Techniques)

  • Publicly verifiable anonymous tokens with private metadata bit [ePrint],
    Fabrice Benhamouda, Tancrède Lepoint, Michele Orrù, Mariana Raykova
    Preprint.

  • A proposal for the standardization of ∑-protocols [PDF] [Talk] [Talk at NIST]
    Michele Orrù, Stephan Krenn
    4th ZKProof Workshop

  • On the (in)security of ROS [ePrint] [Talk],
    Best paper award
    Fabrice Benhamouda, Tancrède Lepoint, Julian Loss, Michele Orrù, Mariana Raykova
    EUROCRYPT 2021 (Proceedings of the 41st Annual International Conference on Theory and Application of Cryptographic Techniques)

  • Efficient Anonymous Tokens with Private Metadata Bit [ePrint] [Talk] [Code],
    Ben Kreuter, Tancrède Lepoint, Michele Orrù, Mariana Raykova
    CRYPTO 2020 (Proceedings of the 40th Annual International Cryptology Conference)

  • Aggregate cash systems: A cryptographic investigation of Mimblewimble [ePrint] [Talk],
    Georg Fuchsbauer, Michele Orrù, Yannick Seurin
    EUROCRYPT 2019 (Proceedings of the 38th Annual International Conference on Theory and Applications of Cryptographic Techniques)

  • Lattice-Based zk-SNARKs from SSPs [ePrint] [Talk] [Code],
    Rosario Gennaro, Michele Minelli, Michele Orrù, Anca Niţulescu
    ACM CCS 2018 (Proceedings of the 25th ACM Conference on Computer and Communications Security)

  • Non-Interactive Zaps of Knowledge [ePrint],
    Best paper award
    Georg Fuchsbauer, Michele Orrù
    ACNS 2018 (Proceedings of the 16th International Conference on Applied Cryptography and Network Security)

  • Homomorphic Secret Sharing: Optimizations and Applications [ePrint],
    Elette Boyle, Geoffroy Couteau, Niv Gilboa, Yuval Ishai, Michele Orrù
    ACM CCS 2017 (Proceedings of the 24th ACM Conference on Computer and Communications Security)

  • Actively Secure 1-out-of-N OT Extension with Application to Private Set Intersection [ePrint],
    Michele Orrù, Emmanuela Orsini, Peter Scholl
    CT-RSA 2017 (Proceedings of the The Cryptographers’ Track at the RSA Conference 2017)

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Code

I am actively involved in maintaining the arkworks.rs algebra crate. My recent contributions include:

  • zka.lc: Think of this as a calculator for the concrete performance of public-key cryptography operations. You add items to your shopping list and zkalc gives you the total time at the checkout.
  • tinybear: proving knowledge an AES-encrypted message using Schnorr proofs in 30 milliseconds and 80KB.
  • nimue: a dedicated library for transforming interactive cryptographic protocols into non-interactive ones (the Fiat-Shamir transform), streamlining security processes.