Paper 2024/846

Distributed Asynchronous Remote Key Generation

Mark Manulis, Universität der Bundeswehr München
Hugo Nartz, Universität der Bundeswehr München
Abstract

Asynchronous Remote Key Generation (ARKG) is a primitive introduced by Frymann et al. at ACM CCS 2020. It enables a sender to generate a new public key $pk'$ for a receiver ensuring only it can, at a later time, compute the corresponding private key $sk'$. These key pairs are indistinguishable from freshly generated ones and can be used in various public-key cryptosystems such as digital signatures and public-key encryption. ARKG has been explored for applications in WebAuthn credential backup and delegation, as well as for enhancing receiver privacy via stealth addresses. In this paper, we introduce distributed ARKG (dARKG) aiming to provide similar security properties in a distributed setting. Here, a sender generates $pk'$ for a group of $n$ receivers and the corresponding $sk'$ can only be computed by any sub-group of size $t\leq n$. This introduces threshold-based access protection for $sk'$, enabling for instance a set of proxies to jointly access a WebAuthn account or claim blockchain funds. We construct dARKG using one-round publicly verifiable asymmetric key agreement, called 1PVAKA, a new primitive formalized in this work. Unlike traditional distributed key generation protocols where users interact with one another, 1PVAKA is asynchronous and allows a third party to verify and generate a public key from users' outputs. We discuss 1PVAKA and dARKG instantiations tailored for use with bilinear groups and demonstrate practicality with implementation and performance analysis for the BLS12-381 curve.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Published elsewhere. Minor revision. ACNS 2025
Keywords
Asynchronous Remote Key GenerationDistributed Key GenerationUnlinkability
Contact author(s)
mark @ manulis eu
hugo nartz @ unibw de
History
2024-12-18: revised
2024-05-29: received
See all versions
Short URL
https://ia.cr/2024/846
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2024/846,
      author = {Mark Manulis and Hugo Nartz},
      title = {Distributed Asynchronous Remote Key Generation},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/846},
      year = {2024},
      url = {https://eprint.iacr.org/2024/846}
}
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