Paper 2023/1537 Original: eprint.iacr.org/2023/1537 ↗

DEFEND: Towards Verifiable Delay Functions from Endomorphism Rings

Knud Ahrens
Jens Zumbrägel
Abstract

We present a verifiable delay function based on isogenies of supersingular elliptic curves, using Deuring correspondence and computation of endomorphism rings for the delay. For each input x a verifiable delay function has a unique output y and takes a predefined time to evaluate, even with parallel computing. Additionally, it generates a proof by which the output can efficiently be verified. In our approach the input is a path in the 2-isogeny graph and the output is the maximal order isomorphic to the endomorphism ring of the curve at the end of that path. This approach is presumably quantum-secure, does not require a trusted setup or special primes and the verification is independent from the delay. It works completely within the isogeny setting and the computation of the proof causes no overhead. The efficient sampling of challenges however remains an open problem.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint.
History
2023-10-20: last updated
2023-10-07: published
Short URL
https://ia.cr/2023/1537
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2023/1537,
      author = {Knud Ahrens and Jens Zumbrägel},
      title = {DEFEND: Towards Verifiable Delay Functions from Endomorphism Rings},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/1537},
      year = {2023},
      url = {https://eprint.iacr.org/2023/1537}
}
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