Zendo
Zendo makes mobile messaging conversations as private and natural as conversations with your friends “in real life.” You exchange Zendo keys in person with your friends. That way, nobody else ever has the keys, so nobody else can read your messages.
https://itunes.apple.com/us/app/zendo/id870719833?ls=1&mt=8
https://itunes.apple.com/us/app/zendo/id870719833?ls=1&mt=8