I received a notification indicating that my contact's security code has changed. What does this mean?

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 may change. This is likely because someone reinstalled WhatsApp or switched phones.

Important: You and your contacts must be using the latest available version of WhatsApp for end-to-end encryption to be activated.

To receive notifications when security codes change:

  1. Open WhatsApp and tap on Settings.
  2. Tap Account and select Security.
  3. From here, you can enable security notifications by selecting Show security notifications.

Note: Your calls and the messages you send are end-to-end encrypted regardless of this setting, when possible.

Keep in mind that you can always verify that a contact's security code is legitimate. Learn how in this FAQ article.

Cheers,
WhatsApp Support Team