3D Secure (3DS) is an authentication protocol that adds an additional security layer to card transactions. By verifying that the person making a purchase is the legitimate cardholder, 3DS helps protect both your business and your customers from fraudulent activity. When 3DS is activated, the issuing bank might request cardholders authenticate—typically through a familiar security prompt like a password, one-time code sent to their mobile device, or biometric verification. Customers may recognize this process through card network branding such as Visa Secure, Mastercard Identity Check or American Express SafeKey.