Viber also offers end-to-end encryption, allows you to hide chats behind PIN code
Of course, chat providers that have established themselves in the field will not want to fall out of favor with users, so it's only natural that they would add tighter security features to their own apps. Just a couple of weeks ago, popular messenger WhatsApp announced end-to-end encryption for its messages. Now, Viber offers the same, with its latest version – Viber 6.
In order for your chat sessions to be end-to-end encrypted, both participants need to have the latest update installed. To verify that the security is in place, you should be able to see a little padlock icon next to your chat.
Additional security features include the ability to hide chats — in order to access a hidden chat, one must either type a pre-set 4-digit PIN in the search bar, or use the TouchID sensor on an iPhone — and the ability to add certain contacts as "trusted".