ACS Definition.
Access Control Server: the issuer’s authentication server in the 3-D Secure protocol. It assesses transaction risk, chooses between a frictionless flow and a challenge, and authenticates the cardholder (push notification in the banking app, biometrics, OTP). Its availability and configuration directly affect merchants’ conversion rates.
See also
Where this term appears
GuideThe role of banksGuideCentral banks and payment infrastructuresGuidePayments in the UKGuidePayments in Ukraine and the CaucasusGuidePayments in BrazilGuidePayments in CanadaGuidePayments in Oceania and CanadaGuidePayments in South Asia outside IndiaGuidePayments in SingaporeGuideB2B payments around the worldGuideChecks around the worldGuideA global history of payments