Enter the new RakEM app, which was just released for Android and iOS. Not only does it offer all the basics, like direct device-to-device delivery and "self-mutating encryption algorithms" of industrial strength, but it can also encrypt your streaming voice and video as well, how about that?
The added beauty of RakEM is that you will also be able to erase an angry drunk text sent at 4am not only on your phone, but on the recipient's side, too. Check it out from the source links below, if you are in need of a good-looking private messaging app that does voice and video encryption, too. Your ex will hate this one, which is one more bonus point.