Verified by Visa is available for both merchants and customers. Customers can enroll any Visa-branded card to require the entry of an extra, personal password to authenticate their online purchases. Merchants who set up Verified by Visa on their store will be protected from high-risk transactions (transactions that do not match the data for the specific customer) by requiring an additional step of identity verification.
The additional verification takes the form of a password known only to the cardholder. The password isn't shared with the merchant, but goes straight to the financial institution by secure connection. Once the authentication goes through, the cardholder completes their purchase as normal.