Exponent-VRFs and Their Applications

Dan Boneh; Iftach Haitner; Yehuda Lindell

Paper 2024/397

Exponent-VRFs and Their Applications

Dan Boneh

, Stanford University

Iftach Haitner

, Coinbase and Tel-Aviv University

Yehuda Lindell, Coinbase

Abstract

Verifiable random functions (VRFs) are pseudorandom functions with the addition that the function owner can prove that a generated output is correct (i.e., generated correctly relative to a committed key). In this paper we introduce the notion of an exponent-VRF (eVRF): a VRF that does not provide its output $y$ explicitly, but instead provides , where is a generator of some finite cyclic group (or in multiplicative notation). We construct eVRFs from DDH and from the Paillier encryption scheme (both in the random-oracle model). We then show that an eVRF is a powerful tool that has many important applications in threshold cryptography. In particular, we construct (1) a one-round fully simulatable distributed key-generation protocol (after a single two-round initialization phase), (2) a two-round fully simulatable signing protocol for multiparty Schnorr with a deterministic variant, (3) a two-party ECDSA protocol that has a deterministic variant, (4) a threshold Schnorr signing protocol where the parties can later prove that they signed without being able to frame another group, and (5) an MPC-friendly and verifiable HD-derivation. All these applications are derived from this single new eVRF abstraction. The resulting protocols are concretely efficient.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint.
Keywords: Threshold signatures Schnorr signatures distributed key generation
Contact author(s): dabo @ cs stanford edu
iftachh @ gmail com
yehuda lindell @ gmail com
History: 2024-06-22: last of 3 revisions; 2024-03-04: received; See all versions
Short URL: https://ia.cr/2024/397
License: CC BY

BibTeX

@misc{cryptoeprint:2024/397,
      author = {Dan Boneh and Iftach Haitner and Yehuda Lindell},
      title = {Exponent-{VRFs} and Their Applications},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/397},
      year = {2024},
      url = {https://eprint.iacr.org/2024/397}
}