WhatsApp

Windows Phone. Security and Privacy.

Security Code Change Notification.

Each of your chats has its own security code used to verify that your calls and the messages you send to that chat are end-to-end encrypted. This code can be found in the contact info screen, both as a QR code and a 60-digit number. These codes are unique to each chat and can be compared between people in each chat to verify that the messages you send to the chat are end-to-end encrypted. Security codes are just visible versions of the special key shared between you - and don't worry, it's not the actual key itself, that's always kept secret.
At times, the security codes used in end-to-end encryption might change. This is likely because you or your contact reinstalled WhatsApp or changed phones.
To receive notifications when security codes change:

1. Open WhatsApp Settings.
2. Tap Account > Security.
3. From here, you can enable security notifications by tapping Show Security Notifications.
   • Note: Your calls and messages are end-to-end encrypted regardless of this setting.

You can always verify that a contact's security code is legitimate.