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

Authors:
Zhengan Huang , Pengcheng Laboratory
Junzuo Lai , Jinan University
Gongxian Zeng , Pengcheng Laboratory
Jian Weng , Jinan University
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Conference: ASIACRYPT 2024
Abstract: In these years, 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.
BibTeX
@inproceedings{asiacrypt-2024-34604,
  title={Mild Asymmetric Message Franking: Illegal-Messages-Only and Retrospective Content Moderation},
  publisher={Springer-Verlag},
  author={Zhengan Huang and Junzuo Lai and Gongxian Zeng and Jian Weng},
  year=2024
}