Cryptology ePrint Archive: Report 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.

Category / Keywords: cryptographic protocols / Deniability, Signatures, Epochal Signatures, Group Chats

Date: received 18 Sep 2020, last revised 21 Sep 2020

Contact author: mail at florianjw de, andreas@huelsing net

Available format(s): PDF | BibTeX Citation

Version: 20200921:123316 (All versions of this report)

Short URL: ia.cr/2020/1138