StealthChat is an industrial strength chat and phone call app for professionals that value real privacy and security. StealthChat uses advanced end to end encryption to ensure that only the sender and recipient have access to the content of the message or phone call.
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
Confide - On the off chance that you need to get your messages private and encoded then utilize Confide that will fill in as your own and classified courier.
Element.io - Secure messaging app with strong end-to-end encryption, advanced group chat privacy settings, secure video calls for teams, encrypted communication using Matrix open network. Riot.im is now Element.
Handcent - Handcent – Free Messenger for Texting and MMS is the most customizable, powerful, and next-generation messenger app that makes user-experience more enjoyable and convenient.
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Reach - Mass messaging app for the iPhone