Research

Send and Pretend: Exploiting Transcript Consistency Issues in End-to-End Encrypted Group Chats

Following earlier findings in Threema and WhatsApp, researchers now show Signal and iMessage also suffer transcript-consistency flaws in E2EE group chats, enabling a server to show different messages to different participants.

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Filed by arXiv Crypto & Security31 July 20261 min readRead at source ↗

arXiv:2607.27510v1 Announce Type: new Abstract: End-to-end encrypted (E2EE) messaging apps are widely praised for their security and thus also used for sensitive coordination in group chats (e.g., by political decision makers). After Threema and WhatsApp, also Signal and iMessage have recently introduced polls to aid agreement processes in groups. This implicitly sets the expectation that all participants see the same outcome and thus have the same view of the conversation. This property is com

Editorial Analysis

Why it matters

Executives and boards increasingly rely on E2EE group chats for sensitive decisions; if a compromised server can make participants see different messages, coordinated decision-making integrity is at risk.

What to do

Brief leadership on transcript-consistency risks in E2EE group messaging and consider out-of-band message verification for critical decisions.

Board brief

Major E2EE messaging platforms including Signal and iMessage have group-chat integrity flaws that could let a compromised server manipulate what each participant sees.

Forward-looking interpretation drafted by editorial AI under human review — not a reproduction of the source. See methodology.

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