3D Secure (or 3DS) is an XML-based security protocol designed to add a layer of protection to credit and debit card transactions made on the Internet.

Basically, it seeks to perform user authentication through an online process with the issuing bank. When shopping in your store, the user typically types the card's data and then is redirected to the bank environment. There, they must complete the requested data to prove they are the owner of the card.

3DS only requires bank authentication, but doesn't determine how it should happen. Therefore, each institution has its own verification system. The most common, however, are password-based methods, in which the user informs the password attached to the card used in the purchase.

The main benefit of this entire authentication system is that by using it, most banks protect the purchase in case of chargeback. (cancellation of an online purchase made using a debit or credit card)