A system used to manage the 3D Secure authentication service for the issuer. During an authentication session, the ACS communicates with the Card Scheme and Thredd systems, and may also interact with the cardholder, by providing Challenge screens. For more information, see the Web Services Guide.

Pass code or activation code which you supply to Thredd . You can use the access code to authenticate user access to card services or to request a user to activate the card by entering their access code. For more information, see the 3D Secure Guide (Apata).