3D-secure is an additional process of payment authorization for Internet transactions.
It appears as an extra step in payments process. You may be prompted by your bank with a screen where additional authorization is required. On this screen you authorize the amount Traffit should be allowed to charge in this and the following billing cycles.
This is how it looks like in the system:
The authorization may be executed by:
typing the SMS code send to the phone number provided in the billing data section,
logging in to your bank's mobile application and approving authorization,
logging in to your bank's Internet service and approving authorization
depending on the bank's requirements.