Viber has announced that it will soon be introducing End to End encryption for Android, Mac and iOS platforms. As soon as you upgrade to Version 6.0, ever private and Group chat, Voice and video call, text, video and photo sharing will become Encrypted. The Hidden Chat feature in the service will not show a particular chat in home screen.
Viber does not unveil that for which protocol, it is making this chat service secure. Two renowned services Signal and WhatsApp has added the feature of matching Fingerprint with one another. However, Viber thinks it might not use this.
Viber has to verify its protocol before making everything official and get in the list of encrypted chat services like WhatsApp and Signal.