Mild Asymmetric Message Franking: Illegal-Messages-Only and Retrospective Content Moderation

Zhengan Huang; Junzuo Lai; Gongxian Zeng; Jian Weng

Paper 2024/1608

Mild Asymmetric Message Franking: Illegal-Messages-Only and Retrospective Content Moderation

Zhengan Huang

, Pengcheng Laboratory

Junzuo Lai

, Jinan University

Gongxian Zeng

, Pengcheng Laboratory

Jian Weng

, Jinan University

Abstract

Many messaging platforms have integrated end-to-end (E2E) encryption into their services. This widespread adoption of E2E encryption has triggered a technical tension between user privacy and illegal content moderation. The existing solutions either support only unframeability or deniability, or they are prone to abuse (the moderator can perform content moderation for all messages, whether illegal or not), or they lack mechanisms for retrospective content moderation. To address the above issues, we introduce a new primitive called \emph{mild asymmetric message franking} (MAMF) to establish illegal-messages-only and retrospective content moderation for messaging systems, supporting unframeability and deniability simultaneously. We provide a framework to construct MAMF, leveraging two new building blocks, which might be of independent interest.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: A major revision of an IACR publication in ASIACRYPT 2024
Contact author(s): zhahuang sjtu @ gmail com
laijunzuo @ gmail com
gxzeng @ cs hku hk
cryptjweng @ gmail com
History: 2024-10-11: approved; 2024-10-09: received; See all versions
Short URL: https://ia.cr/2024/1608
License: CC BY

BibTeX

@misc{cryptoeprint:2024/1608,
      author = {Zhengan Huang and Junzuo Lai and Gongxian Zeng and Jian Weng},
      title = {Mild Asymmetric Message Franking: Illegal-Messages-Only and Retrospective Content Moderation},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/1608},
      year = {2024},
      url = {https://eprint.iacr.org/2024/1608}
}