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, with respect to a committed key. In this paper we introduce the notion of an exponent-VRF, or eVRF, which is a VRF that does not provide its output $y$ explicitly, but instead provides $Y = y \cdot G$, where $G$ is a generator of some finite cyclic group (or $Y = g^y$ 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 can be used to solve several long-standing open problems in threshold cryptography. In particular, we construct (1) a one-round fully simulatable distributed key-generation protocols (after a single two-round initialization phase), (2) a two-round fully simulatable signing protocols for multiparty Schnorr with a deterministic variant, (3) a two-party ECDSA protocol that has a deterministic variant, (4) a threshold Schnorr signing where the parties can later prove that they signed without being able to frame another group, (5) an MPC-friendly and verifiable HD-derivation. Efficient simulatable protocols of this round complexity were not known prior to this work. All of our 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: 2024-03-05: revised; 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},
      note = {\url{https://eprint.iacr.org/2024/397}},
      url = {https://eprint.iacr.org/2024/397}
}