Title speaks for itself :-)
Also consider the Axolotol ratchet: https://www.whispersystems.org/blog/advanced-ratcheting/
Conversations already implemented OMEMO: http://conversations.im/omemo

https://github.com/igniterealtime/Smack/blob/4.3/documentation/extensions/omemo.md
(Future) https://github.com/igniterealtime/Smack/blob/master/documentation/extensions/omemo.md