Epochal Signatures for Deniable Group Chats

Andreas Hülsing; Fiona Johanna Weber

Paper 2020/1138

Epochal Signatures for Deniable Group Chats

Andreas Hülsing

, Eindhoven University of Technology

Fiona Johanna Weber

, Eindhoven University of Technology

Abstract

We introduce formal definitions for deniability in group chats by extending a pre-existing model that did not have this property. We then introduce “epochal signatures” as an almost drop-in replacement for signatures, which can be used to make certain undeniable group-chats deniable by just performing that replacement. Following that we provide a practical epochal signature scheme and prove its security.

Note: Author list in alphabetical order, see: https://www.ams.org/profession/leaders/culture/CultureStatement04.pdf

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Published elsewhere. Minor revision. IEEE S&P 2021
Keywords: Deniability Signature Epochal Signature Group Chat
Contact author(s): andreas @ huelsing net
crypto @ fionajw de
History: 2023-09-25: last of 5 revisions; 2020-09-21: received; See all versions
Short URL: https://ia.cr/2020/1138
License: CC BY

BibTeX

@misc{cryptoeprint:2020/1138,
      author = {Andreas Hülsing and Fiona Johanna Weber},
      title = {Epochal Signatures for Deniable Group Chats},
      howpublished = {Cryptology {ePrint} Archive, Paper 2020/1138},
      year = {2020},
      url = {https://eprint.iacr.org/2020/1138}
}