If you enable SafeKey on your eCommerce website, an extra level of verification takes place when a customer attempts to check out. Usually, this takes place in the background and leaves the customer out of the process — keeping their checkout frictionless.
In the rare occasion (about 5% of the time) that the verification process identifies the transaction as "high-risk," the customer will be prompted to take one additional step to authenticate their purchase. This can take the form of a One-Time Code (OTC), a 6-digit number emailed to the customer. Verification can also request the 3-digit number from the back of the cardholder's American Express card, which differs from the security code that appears on the card's front. Sometimes, both pieces of information are requested.
The customer will have 10 minutes to authenticate with the requested information. If they fail, they'll need to restart the transaction. If they succeed, the purchase will be completed.