A financial protocol that provides additional authentication, such as a password, one-time password or PIN, when making a credit card purchase online. 3-D Secure is not the security code on the back of a credit card, and it also has nothing to do with three dimensions. The 3-D refers to the three domains that comprise the transaction: 1. payee; 2. bank that issued the card, and 3. type of card (credit, debit, prepaid, etc.). Visa calls 3-D Secure "Verified by Visa;" Mastercard is "Mastercard SecureCode" and American Express is "American Express SafeKey." See
one-time password,
password and
PIN.