CRes — Challenge Response

The CRes message is the ACS response to the CReq message. It can indicate the result of the Cardholder authentication or, in the case of an App-based model, also signal that further Cardholder interaction is required to complete the authentication. • App-based—Elements of the CRes message provide the necessary data for the 3DS SDK to generate and display the user interface (UI) for the challenge. There are two or more CRes messages per transaction to complete Cardholder authentication. • Browser-based—The CRes message contains the authentication result and completes the Cardholder challenge. There is only one CRes message per challenge.