OMEMO

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.

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] The protocol was developed and first implemented by Andreas Straub as a Google Summer of Code project in 2015.

[4][5] A first experimental release of an OMEMO plugin for the cross-platform XMPP client Gajim was made available on December 26, 2015.