Lightweight Asynchronous Verifiable Secret Sharing with Optimal Resilience

Victor Shoup; Nigel P. Smart

Paper 2023/536

Lightweight Asynchronous Verifiable Secret Sharing with Optimal Resilience

Victor Shoup

, Offchain Labs

Nigel P. Smart

, COSIC, KU Leuven, Zama Inc

Abstract

We present new protocols for *Asynchronous Verifiable Secret Sharing* for Shamir (i.e., threshold $t<n$) sharing of secrets. Our protocols: * Use only "lightweight" cryptographic primitives, such as hash functions; * Can share secrets over rings such as $\mathbb{Z}_{p^k}$ as well as finite fields $\mathbb{F}_q$; * Provide *optimal resilience*, in the sense that they tolerate up to $t < n/3$ corruptions, where $n$ is the total number of parties; * Are *complete*, in the sense that they guarantee that if any honest party receives their share then all honest parties receive their shares; * Employ *batching* techniques, whereby a dealer shares many secrets in parallel, and achieves an amortized communication complexity that is linear in $n$, at least on the "happy path", where no party *provably* misbehaves.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Published by the IACR in JOC 2024
Keywords: asynchronous vss secret sharing
Contact author(s): victor @ shoup net
nigel @ zama ai
History: 2024-03-07: last of 4 revisions; 2023-04-13: received; See all versions
Short URL: https://ia.cr/2023/536
License: CC BY-NC-ND

BibTeX

@misc{cryptoeprint:2023/536,
      author = {Victor Shoup and Nigel P. Smart},
      title = {Lightweight Asynchronous Verifiable Secret Sharing with Optimal Resilience},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/536},
      year = {2023},
      url = {https://eprint.iacr.org/2023/536}
}