How secure is a one-time verification code? Can anyone else use it?

One-time verification codes are sent at your request when you're asked to confirm it's you. You may be asked to confirm it's you when shopping online or using online services.

When we send you a code we only send it to your registered mobile phone number. It's valid for a short period of time, and it can only be used by you once. It's important never to tell anyone your code as only you should be requesting and using it online.