Paper 2025/879 Original: eprint.iacr.org/2025/879 ↗

Papercraft: Lattice-based Verifiable Delay Function Implemented

Michał Osadnik
Darya Kaviani
Valerio Cini
Russell W. F. Lai
Giulio Malavolta
Abstract

A verifiable delay function (VDF) requires a specified number of sequential steps to compute, yet the validity of its output can be verified efficiently, much faster than recomputing the function from scratch. VDFs are a versatile cryptographic tool, with many industrial applications, such as blockchain consensus protocols, lotteries and verifiable randomness. Unfortunately, without exceptions, all known practical VDF constructions are broken by quantum algorithms. In this work, we investigate the practicality of VDFs with plausible post-quantum security. We propose Papercraft, a working implementation of a VDF based entirely on lattice techniques and thus plausibly post-quantum secure. Our VDF is based on new observations on lattice-based succinct argument systems with many low-level optimisations, yielding the first lattice-based VDF that is implementable on today's hardware. As an example, our Papercraft implementation can verify a computation of almost 6 minutes in just 7 seconds. Overall, our work demonstrates that lattice-based VDFs are not just a theoretical construct, paving the way for their practical deployment.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint.
History
2026-06-23: last updated
2025-05-17: published
Short URL
https://ia.cr/2025/879
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2025/879,
      author = {Michał Osadnik and Darya Kaviani and Valerio Cini and Russell W. F. Lai and Giulio Malavolta},
      title = {Papercraft: Lattice-based Verifiable Delay Function Implemented},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/879},
      year = {2025},
      url = {https://eprint.iacr.org/2025/879}
}
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