Multi-Party Revocation in Sovrin: Performance through Distributed Trust

Lukas Helminger, Daniel Kales, Sebastian Ramacher, Roman Walch*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference paper

Abstract

Accumulators provide compact representations of large sets and compact membership witnesses. Besides constant-size witnesses, public-key accumulators provide efficient updates of both the accumulator itself and the witness. However, bilinear group based accumulators come with drawbacks: they require a trusted setup and their performance is not practical for real-world applications with large sets.

In this paper, we introduce multi-party public-key accumulators dubbed dynamic (threshold) secret-shared accumulators. We present an instantiation using bilinear groups having access to more efficient witness generation and update algorithms that utilize the shares of the secret trapdoors sampled by the parties generating the public parameters. Specifically, for the q-SDH-based accumulators, we provide a maliciously-secure variant sped up by a secure multi-party computation (MPC) protocol (IMACC'19) built on top of SPDZ and a maliciously secure threshold variant built with Shamir secret sharing. For these schemes, a performant proof-of-concept implementation is provided, which substantiates the practicability of public-key accumulators in this setting.

We explore applications of dynamic (threshold) secret-shared accumulators to revocation schemes of group signatures and credentials system. In particular, we consider it as part of Sovrin's system for anonymous credentials where credentials are issued by the foundation of trusted nodes.
Original languageEnglish
Title of host publicationTopics in Cryptology – CT-RSA 2021
Subtitle of host publicationCryptographers’ Track at the RSA Conference 2021, Virtual Event, May 17–20, 2021, Proceedings
EditorsKenneth Paterson
Place of PublicationSan Francisco, CA, USA
PublisherSpringer, Cham
PagesPages 527-551
Number of pages25
VolumeLecture Notes in Computer Science
Edition12704
ISBN (Electronic)978-3-030-75539-3
ISBN (Print)978-3-030-75538-6
DOIs
Publication statusPublished - 17 May 2021
EventRSA Conference 2021 - Virtuell
Duration: 17 May 202120 May 2021

Publication series

NameLecture Notes in Computer Science
Volume12704
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

ConferenceRSA Conference 2021
Abbreviated titleRSAC 2021
CityVirtuell
Period17/05/2120/05/21

Keywords

  • multiparty computation
  • dynamic accumulators
  • distributed trust
  • threshold accumulators

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