Secure Messaging App.

A communications app whose default mode applies end-to-end encryption, identity verification, and forward secrecy so that only the participants can read the messages. It belongs to the Identity & Access category of cybersecurity.

A communications app whose default mode applies end-to-end encryption, identity verification, and forward secrecy so that only the participants can read the messages.

A secure messaging app delivers private one-to-one and group chat with end-to-end encryption by default, sender/receiver identity verification (safety numbers, security codes, or key transparency logs), forward secrecy and post-compromise security, and disappearing-message options. The reference implementation is Signal, run by the non-profit Signal Foundation; other widely used examples include Wire (formerly Wire Swiss), the Matrix federation with the Element client, Threema, Session, and WhatsApp (which licenses the Signal Protocol). EFF historically maintained a Secure Messaging Scorecard, and academic surveys evaluate apps against criteria from Frosch et al. and Unger et al. (SoK papers). Differentiators today include open-source clients and servers, metadata protection (sealed sender, Tor / Mix routing), independent audits and reproducible builds.

Defences for Secure Messaging App typically combine technical controls and operational practices, as detailed in the full definition above.

Common alternative names include: E2EE messenger, Private messaging app.