Verify End-To-End Encryption: Trusted Contacts List
Security breaches are rare; however, they can happen.
To ensure that your contact’s phone number hasn’t been compromised, you can add them to your Trusted Contacts list and then monitor any changes made in your connection.
Notes
This article explains how to identify secure 1-on-1 calls and chats through the Trusted Contacts list. Please refer to our article on end-to-end encryption in chats, for more general information on encryption.
What is a Trusted Contacts list?
A Trusted Contacts list contains a list of contacts with whom you have manually confirmed you have an encrypted connection. If the connection was breached or changes were made, you will be alerted.
Turn on the Trusted Contacts list
To turn on your Trusted Contacts list:
- Open Viber on your Phone
- Tap on More (Android) (iOS)
- Tap on Settings
- Tap on Privacy
- Tap Trusted Contacts
(Android) 
(iOS)
Add a contact to your Trusted Contacts list
To add a contact to your Trusted Contacts list:
- Ask your contact to turn on Trusted Contacts using the steps in the previous section
- Call your contact
- Tap the grey shield displayed on your screen
- Ask your contact to also tap the shield on their screen
- Your unique identification key will be displayed on the screen. Verify with your contact that your keys match (you both see the same series of numbers)
- If the keys match, tap Trust this contact
displayed on your screenOnce a contact has been added to your Trusted Contacts list, the grey shield will turn green. From now on, every time you call your contact or open their Info screen, you should see a green shield.
A red shield suggests that the identification key has changed, which could be due to your contact changing their phone or reinstalling Viber; however, it could also indicate a man-in-the-middle attack (security breach).
If you’re sure that the communication line is still secure, you can re-add the contact to your Trusted Contacts list by following the steps above.
Remove a contact from your Trusted Contacts list
To remove a contact from your Trusted Contacts list:
- Open Viber on your Phone
- Tap on More (Android) (iOS)
- Tap on Settings
- Tap on Privacy
- Tap Clear Trusted Contacts
- Tap Clear next to the contact you want to remove
- Confirm
(Android) 
(iOS)