General information
XS2A interface offers embedded and decoupled SCA approaches with selection of SCA methods as mechanisms of payments and consents authorisation.
Within the embedded approach the communication between PSU and ASPSP is done through XS2A and TPP interfaces where
- ASPSP validates PSU credentials and the 2nd factor;
- XS2A provides TPP with authorisation instructions and error information;
- TPP provides PSU with authorisation instructions and error information.
The step when PSU receives the 2nd factor from ASPSP is handled directly between PSU and ASPSP - outside of the embedded SCA flow.
Within the decoupled approach the communication between PSU and ASPSP is done through XS2A and TPP interfaces where
- ASPSP validates PSU credentials and the 2nd factor;
- XS2A provides TPP with authorisation instructions and error information;
- TPP provides PSU with authorisation instructions and error information.
The steps when PSU receives the 2nd factor from ASPSP and provides it back to ASPSP for the validation are handled directly between PSU and ASPSP - outside of the decoupled SCA flow.
Flow diagrams
The diagrams below gives high-level overview of the embedded SCA message flow during payments and consent authorisation.
Consent authorisation with embedded SCA
Consent authorisation with decoupled SCA
Payment authorisation with embedded SCA
Payment authorisation with decoupled SCA
More details about payment authorisation are available at 3 How to initiate and authorise a payment.
More details about consent authorisation are available at 04. How to Create and Authorise an AIS Consent.
Supported SCA methods
Currently supported SCA methods
- CHIP_OTP - triggers embedded SCA
- SMS_OTP - triggers embedded SCA
- PUSH_OTP - triggers decoupled SCA
More information about SCA methods can be found in 09. Sandbox Test Accounts and Test Data.