Viber has added full end-to-end encryption for video, voice and text message services for its millions of users. The encryption means only you and the person you are communicating with can read the content, and nobody in between, not even the company. Viber is the latest messaging platform to join WhatsApp Telegram, and Apple iMessage, who strengthened their default privacy features in recent times. The company will also provide a new PIN-protected hidden chat feature to help its users hide conversations from the main chat list.
Source: https://thehackernews.com/2016/04/secure-messaging-app.html