International Association for Cryptologic Research

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One Tree to Rule Them All: Optimizing GGM Trees and OWFs for Post-Quantum Signatures

Authors:
Carsten Baum , Technical University of Denmark
Ward Beullens , IBM Research - Europe
Shibam Mukherjee , Graz University of Technology, Know Center
Emmanuela Orsini , Bocconi University
Sebastian Ramacher , AIT Austrian Institute of Technology
Christian Rechberger , Graz University of Technology
Lawrence Roy , Aarhus University
Peter Scholl , Aarhus University
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Conference: ASIACRYPT 2024
Abstract: The use of MPC-in-the-Head (MPCitH)-based zero-knowledge proofs of knowledge (ZKPoK) to prove knowledge of a preimage of a one-way function (OWF) is a popular approach towards constructing efficient post-quantum digital signatures. Starting with the Picnic signature scheme, many optimized MPCitH signatures using a variety of (candidate) OWFs have been proposed. Recently, Baum et al. (CRYPTO 2023) showed a fundamental improvement to MPCitH, called VOLE-in-the-Head (VOLEitH), which can generically reduce the signature size by at least a factor of two without decreasing computational performance or introducing new assumptions. Based on this, they designed the FAEST signature which uses AES as the underlying OWF. However, in comparison to MPCitH, the behavior of VOLEitH when using other OWFs is still unexplored. In this work, we improve a crucial building block of the VOLEitH and MPCitH approaches, the so-called all-but-one vector commitment, thus decreasing the signature size of VOLEitH and MPCitH signature schemes. Moreover, by introducing a small Proof of Work into the signing procedure, we can improve the parameters of VOLEitH (further decreasing signature size) \emph{without} compromising the computational performance of the scheme. Based on these optimizations, we propose three VOLEitH signature schemes FAESTER, KuMQuat, and MandaRain based on AES, MQ, and Rain, respectively. We carefully explore the parameter space for these schemes and implement each, showcasing their performance with benchmarks. Our experiments show that these three signature schemes outperform MPCitH-based competitors that use comparable OWFs, in terms of both signature size and signing/verification time.
BibTeX
@inproceedings{asiacrypt-2024-34606,
  title={One Tree to Rule Them All: Optimizing GGM Trees and OWFs for Post-Quantum Signatures},
  publisher={Springer-Verlag},
  author={Carsten Baum and Ward Beullens and Shibam Mukherjee and Emmanuela Orsini and Sebastian Ramacher and Christian Rechberger and Lawrence Roy and Peter Scholl},
  year=2024
}