It's an authentication system for your online purchases. This enables us to increase the level of security.
It's also called 3DS, Verified By Visa or MasterCard SecureCode.
When paying with Visa or MasterCard, we redirect you to your bank's website. Your bank identifies you by its own procedure which is different for every bank, for example: enter your date of birth, enter a code received by SMS, answer a personal question, etc. This is how your bank ensures that the payment is carried out by the cardholder. No bank will ask you for this confidential data by telephone. Do not answer if you're asked questions in this way.