Epochal Signatures for Deniable Group Chats

Andreas Hülsing; Florian Weber

Paper 2020/1138

Epochal Signatures for Deniable Group Chats

Andreas Hülsing and Florian Weber

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.

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): mail @ florianjw de
andreas @ huelsing net
History: 2021-02-03: last of 3 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 Florian Weber},
      title = {Epochal Signatures for Deniable Group Chats},
      howpublished = {Cryptology ePrint Archive, Paper 2020/1138},
      year = {2020},
      note = {\url{https://eprint.iacr.org/2020/1138}},
      url = {https://eprint.iacr.org/2020/1138}
}