ChatSecure is a messaging application for iOS which allows OTR and OMEMO encryption for the XMPP protocol. Developed by Chris Ballinger and The Guardian Project
License: Open Source
Off-the-Record Messaging is focused on providing secure one-on-one messaging with no logs, while ChatSecure offers a broader range of features including group chats and integration with the XMPP protocol. Both prioritize privacy and security but cater to slightly different use cases.