OMEMO /oˈmiːmoʊ/ (OMEMO Multi-End Message and Object Encryption) is an XMPP Extension Protocol (XEP) for secure multi-client end-to-end encryption. It is an open standard based on a Double Ratchet and PEP which can be freely used and implemented by anyone. The protocol has been audited by a third party.

OMEMO is available right now in the Android XMPP-Client Conversations (Buy on Google Play), the iOS client ChatSecure, or as a plugin for the Desktop client Gajim.

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The OMEMO encryption /oˈmiːmoʊ/ gives you all the advantages you would expect from a modern-day encryption protocol like Future and Forward Secrecy and deniability while allowing you to keep the benefits of message synchronization and offline delivery.

OMEMO not only gives you a better encryption features than OpenPGP and OTR but is also much easier to setup. OMEMO is the encryption you can actually use in your daily life. Turn it on once and forget you ever did.

# OpenPGP OX OTR OMEMO
Multiple Devices Yes Yes No Yes
Offline Messages / Backlog 5 Yes Yes No Yes
File Transfer Yes No 1 2 No 1 Yes
Verifiability No Yes Yes Yes
Deniability Yes No Yes Yes
Forward Secrecy 3 No No Yes Yes
Server side archive 3 5 Yes Yes No No
Per Message Overhead High High Low Medium 4

1 Not standardized
2 Can fallback to regular OpenPGP
3 The traits server-side archive and forward secrecy are mutually exclusive
4 Overhead increases linearly with number of devices
5 Backlog is the messages you receive on a device that were sent while the device was offline temporarily.
Server-side archive is all messages that were sent before that device ever existed.

Client URL
Conversations https://conversations.im
aTalk https://cmeng-git.github.io/atalk/
Movim https://movim.eu/
monocles chat (Conversations fork) https://codeberg.org/Arne/monocles_chat
Xabber Web https://web.xabber.com
Kaidan https://www.kaidan.im/
Converse.js https://conversejs.org/
Stork IM by Tigase, Inc. https://stork.im/
JSXC https://jsxc.org/
Quicksy (Conversations spin off) https://quicksy.im/
Snikket https://snikket.org
Dino https://dino.im/
Monal https://monal.im/
Libervia (formerly Salut à Toi) https://salut-a-toi.org/
Beagle IM by Tigase, Inc. https://beagle.im/
WeeChat (XMPP plugin) https://github.com/bqv/weechat-xmpp/
Poezio https://poez.io/
Profanity https://profanity-im.github.io/
Conv6ations (Conversations fork that prefers IPv6) https://dev.sum7.eu/sum7/Conversations
Gajim https://gajim.org/
Siskin IM by Tigase, Inc. https://siskin.im/
Psi https://psi-im.org/
Psi+ https://psi-plus.com/

https://conversations.im/omemo/ - OMEMO Multi-End Message and Object Encryption
https://omemo.top/ - Are we OMEMO yet?