For example , in the UK , some banks send their OTAC for Internet banking authorization via post or registered mail .
When a user requests an OTAC , the service provider sends it via post or registered mail and then the user can use it for authentication .
In the UK , some banks send their OTAC for Internet banking authorization via post or registered mail .
When a user requests an OTAC , the service provider sends it via post or registered mail and then the user can use it for authentication .