3D secure transaction process flow

1. Cardholder is on the merchant’s checkout page, ready to pay for their order. They will input and submit their card details on the payment page hosted by the Gateway.
2. The Gateway will proceed to check if the card in use is enrolled in 3DS by sending a request to the Directory Server.
3. Directory Server will respond with enrollment status. 
   Considering the response is positive and the card is enrolled for 3DS, 
4. The Gateway will redirect to the issuer ACS for authentication
   The ACS will prompt the cardholder to insert and submit OTP/Password/credential(etc.)
5. Considering the authentication was successful, the response is returned to the gateway to confirm successful authentication
6. Gateway then forwards the transaction details to the acquirer for authorization (Debit)
7. The acquirer sends an authorization request to the issuer
8. Issuer authorizes the transaction and sends response to the acquirer
9. Acquirer sends response to the Gateway
10. Gateway in turn reflects the response to the merchant by calling corresponding callback url set by the merchant in their implementation.