In addition, Viber's also introduced encrypted messaging features to the app, with a color-coded icon indicating chat security and encryption.
A Secure Chat mode provides end-to-end encryption so that only you and your intended recipient can read it. You can share videos, documents and participate in group chats of up to 200 users.
Open Whisper Systems' Signal (Android, i OS) is another fantastic messaging solution for security-conscious mobile users.
Snapchat (Android, i OS) may have soared in popularity as a simple self-destructing photo and video sharing and messaging app, but it's also added so much more to its feature set, making it fantastically popular among younger users.
At its core, users can send each other Snaps — photos, short videos, or messages that are only visible for a limited time before disappearing.
Line covers your bases with chat, photo, video, and audio messaging, along with lively stickers and location sharing, as well as a social network-like Timeline system.