PandaTalk

PandaTalk is a messaging app that provides the highest possible security and privacy. It was designed from the very beginning with those two goals in mind.
All data is end-to-end encrypted with the strongest available encryption algorithms. Only published and well-proven algorithms have been used, as well as open source libraries. No proprietary libraries or operating system SDKs have been utilized in the software.
The main features are: messaging, sending files, photos and stickers, voice and video chat. You can invite others to join PandaTalk directly from your contact list, if you like. PandaTalk will not access or share any data on your phone without your explicit permission.