Glossary
Strong customer authentication (SCA)
A European requirement that electronic payments be authenticated with two independent factors.
SCA applies to many online payments in the European Economic Area and the United Kingdom. Two of three factors are needed: something the customer knows, has, or is.
Exemptions exist for low-value, low-risk and merchant-initiated transactions, among others. For cards, 3-D Secure is the usual way to meet the requirement.