OMEMO

OMEMO is an extension to the Extensible Messaging and Presence Protocol (XMPP) 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.

Features

In comparison with OTR, the OMEMO protocol offers many-to-many encrypted chat, offline messages queuing, forward secrecy, file transfer, verifiability and deniability at the cost of slightly larger message size overhead.^[3]

History

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.^[4]^[5]

A first experimental release of an OMEMO plugin for the cross-platform XMPP client Gajim was made available on December 26, 2015.^[6]

In June 2016, the non-profit computer security consultancy firm Radically Open Security published an analysis of the OMEMO protocol.^[7]

Client support

Selected clients supporting OMEMO (full list of clients also exists^[8]):

BeagleIM (macOS)^[9]
ChatSecure (iOS)^[10]
Conversations (Android)
Converse.js (Browser-based)^[11]
Dino (Linux, macOS)^[12]
Gajim (Linux, Windows, BSD)^[13]^[14]
Kaidan (Linux)^[15]
Movim (Browser-based)^[16]
Psi via official plugin (Linux, Windows, macOS)^[17]
Psi+ via official plugin (Linux, Windows, macOS, Haiku, FreeBSD)^[18]
libpurple clients such as Pidgin or Finch via experimental plugin ^[19]
Adium via an Xtra based on the libpurple plugin^[20]
Profanity via experimental plugin (BSD, Linux, macOS, Windows)^[21]
SiskinIM (iOS)^[22]

Library support

Smack supports OMEMO using the two modules smack-omemo and smack-omemo-signal^[23]
XMPPFramework (macOS, iOS, tvOS) ^[24] supports OMEMO via the OMEMOModule extension ^[25] when used in conjunction with the SignalProtocol-ObjC library.^[26]

References

^ ^a ^b "[Standards] NEW: XEP-0384 (OMEMO Encryption)". December 7, 2016. Retrieved December 23, 2016.
^ Daniel Gultsch. "OMEMO Multi-End Message and Object Encryption". Retrieved November 23, 2015.
^ "OMEMO Multi-End Message and Object Encryption". conversations.im. Retrieved January 22, 2019.
^ "ChatSecure iOS v3.2.3 - XMPP Push". July 25, 2016. Retrieved September 7, 2016.
^ "ChatSecure v4.0 - OMEMO and Signal Protocol". January 17, 2017. Retrieved February 7, 2017.
^ Bahtiar Gadimov (December 26, 2015). "Initial OMEMO commit". dev.gajim.org. Retrieved September 8, 2017.
^ OMEMO: Cryptographic Analysis Report. June 2016
^ "Are we OMEMO yet?". Are we OMEMO yet?. Retrieved January 22, 2019.
^ "Beagle OMEMO support". July 7, 2019.
^ "ChatSecure v4.0 - OMEMO and Signal Protocol". chatsecure.org. January 17, 2017. Retrieved January 17, 2017.
^ "XEP-0384: OMEMO Encryption · Issue #497 · conversejs/converse.js". GitHub. Retrieved November 20, 2019.
^ "Dino - Modern Jabber/XMPP Client using GTK+/Vala". dino.im. Retrieved November 6, 2017.
^ Bahtiar Gadimov; et al. "Omemogajimplugin · Wiki · gajim / gajim-plugins · GitLab". Retrieved December 4, 2016.
^ Developers, Gajim. "Gajim 1.8.0". Gajim. Retrieved June 15, 2023.
^ "Kaidan 0.9: End-to-End Encryption & XMPP Providers". Kaidan. May 5, 2023. Retrieved October 20, 2023.
^ "End to end encryption in Movim - OMEMO is (finally) there!". mov.im. Retrieved December 15, 2021.
^ Vyacheslav Karpukhin. "OMEMO for Psi · GitHub". GitHub. Retrieved March 4, 2018.
^ Vyacheslav Karpukhin. "Psi+ snapshots". GitHub. Retrieved March 4, 2018.
^ Richard Bayerle. "lurch - OMEMO for libpurple". GitHub. Retrieved February 12, 2017.
^ Olivier Mehani. "Lurch4Adium - OMEMO Xtra for Adium". GitHub. Retrieved June 8, 2017.
^ René Calles. "profanity-omemo-plugin: A Python plugin to use (axolotl / Signal Protocol) encryption for the profanity XMPP messenger". GitHub. Retrieved January 10, 2017.
^ "BeagleIM and SiskinIM just got OMEMO support". tigase.net. Retrieved June 7, 2019.
^ Schaub, Paul (June 6, 2017). "Ignite Realtime Blog: Smack v4.2 Introduces OME... | Ignite Realtime". community.igniterealtime.org. Retrieved July 11, 2017.
^ "Robbiehanson/XMPPFramework". GitHub. October 26, 2021.
^ "Robbiehanson/XMPPFramework". GitHub. October 26, 2021.
^ "SignalProtocolObjC". GitHub. January 30, 2021.

External links

Homepage
XEP-0384: OMEMO Encryption (Experimental)
Python library for implementing OMEMO in other clients
OMEMO protocol implementation in C
OMEMO Top - OMEMO support toplist in instant message clients

[omemo-new-xep-1] "[Standards] NEW: XEP-0384 (OMEMO Encryption)". December 7, 2016. Retrieved December 23, 2016.

[home-2] Daniel Gultsch. "OMEMO Multi-End Message and Object Encryption". Retrieved November 23, 2015.

[3] "OMEMO Multi-End Message and Object Encryption". conversations.im. Retrieved January 22, 2019.

[4] "ChatSecure iOS v3.2.3 - XMPP Push". July 25, 2016. Retrieved September 7, 2016.

[5] "ChatSecure v4.0 - OMEMO and Signal Protocol". January 17, 2017. Retrieved February 7, 2017.

[gajim-omemo-initial-commit-6] Bahtiar Gadimov (December 26, 2015). "Initial OMEMO commit". dev.gajim.org. Retrieved September 8, 2017.

[7] OMEMO: Cryptographic Analysis Report. June 2016

[8] "Are we OMEMO yet?". Are we OMEMO yet?. Retrieved January 22, 2019.

[9] "Beagle OMEMO support". July 7, 2019.

[10] "ChatSecure v4.0 - OMEMO and Signal Protocol". chatsecure.org. January 17, 2017. Retrieved January 17, 2017.

[11] "XEP-0384: OMEMO Encryption · Issue #497 · conversejs/converse.js". GitHub. Retrieved November 20, 2019.

[12] "Dino - Modern Jabber/XMPP Client using GTK+/Vala". dino.im. Retrieved November 6, 2017.

[gajim-omemo-13] Bahtiar Gadimov; et al. "Omemogajimplugin · Wiki · gajim / gajim-plugins · GitLab". Retrieved December 4, 2016.

[14] Developers, Gajim. "Gajim 1.8.0". Gajim. Retrieved June 15, 2023.

[15] "Kaidan 0.9: End-to-End Encryption & XMPP Providers". Kaidan. May 5, 2023. Retrieved October 20, 2023.

[16] "End to end encryption in Movim - OMEMO is (finally) there!". mov.im. Retrieved December 15, 2021.

[psi-omemo-17] Vyacheslav Karpukhin. "OMEMO for Psi · GitHub". GitHub. Retrieved March 4, 2018.

[psi-plus-omemo-18] Vyacheslav Karpukhin. "Psi+ snapshots". GitHub. Retrieved March 4, 2018.

[lurch-19] Richard Bayerle. "lurch - OMEMO for libpurple". GitHub. Retrieved February 12, 2017.

[Lurch4Adium-20] Olivier Mehani. "Lurch4Adium - OMEMO Xtra for Adium". GitHub. Retrieved June 8, 2017.

[profanity-omemo-21] René Calles. "profanity-omemo-plugin: A Python plugin to use (axolotl / Signal Protocol) encryption for the profanity XMPP messenger". GitHub. Retrieved January 10, 2017.

[beagle-siskin-announcement-22] "BeagleIM and SiskinIM just got OMEMO support". tigase.net. Retrieved June 7, 2019.

[23] Schaub, Paul (June 6, 2017). "Ignite Realtime Blog: Smack v4.2 Introduces OME... | Ignite Realtime". community.igniterealtime.org. Retrieved July 11, 2017.

[24] "Robbiehanson/XMPPFramework". GitHub. October 26, 2021.

[25] "Robbiehanson/XMPPFramework". GitHub. October 26, 2021.

[26] "SignalProtocolObjC". GitHub. January 30, 2021.

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