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Logo of OMEMO

OMEMO is an extension to the Extensible Messaging and Presence Protocol (XMPP, "Jabber") for multi-client end-to-end encryption developed by Andreas Straub. According to Straub, OMEMO uses the Double Ratchet Algorithm "to provide multi-end to multi-end encryption, allowing messages to be synchronized securely across multiple clients, even if some of them are offline".[1] The name "OMEMO" is a recursive acronym for "OMEMO Multi-End Message and Object Encryption". It is an open standard based on the Double Ratchet Algorithm and the Personal Eventing Protocol (PEP, XEP-0163).[2] OMEMO offers future and forward secrecy and deniability with message synchronization and offline delivery.


The protocol was developed and first implemented by Andreas Straub as a Google Summer of Code project in 2015. The project's goal was to implement a double-ratchet-based multi-end to multi-end encryption scheme into an Android XMPP-based instant messaging client called Conversations. It was introduced in Conversations and submitted to the XMPP Standards Foundation (XSF) as a proposed XMPP Extension Protocol (XEP) in the autumn of 2015 and got accepted as XEP-0384 in December 2016.[1]

In July 2016, the ChatSecure project announced that they would implement OMEMO in the next releases. ChatSecure v4.0 supports OMEMO and was released on January 17, 2017.[3][4]

A first experimental release of an OMEMO plugin for the cross-platform XMPP client Gajim was made available on December 26, 2015.[5]

In June 2016, the non-profit computer security consultancy firm Radically Open Security published an analysis of the OMEMO protocol.[6]

Client Support[edit]

Library Support[edit]

  • Smack supports OMEMO using the two modules smack-omemo and smack-omemo-signal[17]
  • XMPPFramework (macOS, iOS, tvOS) [18] supports OMEMO via the OMEMOModule extension [19] when used in conjunction with the SignalProtocol-ObjC library [20].


  1. ^ a b "[Standards] NEW: XEP-0384 (OMEMO Encryption)". 2016-12-07. Retrieved 2016-12-23. 
  2. ^ Daniel Gultsch. "OMEMO Multi-End Message and Object Encryption". Retrieved 2015-11-23. 
  3. ^ "ChatSecure iOS v3.2.3 - XMPP Push". 2016-07-25. Retrieved 2016-09-07. 
  4. ^ "ChatSecure v4.0 - OMEMO and Signal Protocol". 2017-01-17. Retrieved 2017-02-07. 
  5. ^ Bahtiar Gadimov (2015-12-26). "Initial OMEMO commit". Retrieved 2017-09-08. 
  6. ^ OMEMO: Cryptographic Analysis Report. June 2016
  7. ^ "ChatSecure v4.0 - OMEMO and Signal Protocol". Retrieved 2017-01-17. 
  8. ^ "Cryptocat - Security". Retrieved 2016-05-24. 
  9. ^ "Dino - Modern Jabber/XMPP Client using GTK+/Vala". Retrieved 2017-11-06. 
  10. ^ Bahtiar Gadimov; et al. "Omemogajimplugin · Wiki · gajim / gajim-plugins · GitLab". Retrieved 2016-12-04. 
  11. ^ Vyacheslav Karpukhin. "OMEMO for Psi · GitHub". Retrieved 2018-03-04. 
  12. ^ Vyacheslav Karpukhin. "Psi+ snapshots". Retrieved 2018-03-04. 
  13. ^ Richard Bayerle. "lurch - OMEMO for libpurple". Retrieved 2017-02-12. 
  14. ^ Olivier Mehani. "Lurch4Adium - OMEMO Xtra for Adium". Retrieved 2017-06-08. 
  15. ^ René Calles. "profanity-omemo-plugin: A Python plugin to use (axolotl / Signal Protocol) encryption for the profanity XMPP messenger". Retrieved 2017-01-10. 
  16. ^ "Zom mobile messenger". 
  17. ^ Schaub, Paul. "Ignite Realtime Blog: Smack v4.2 Introduces OME... | Ignite Realtime". Retrieved 2017-07-11. 
  18. ^
  19. ^
  20. ^

External links[edit]