Integrating concur expenses with Oracle cloud for Amex corporate cards

Hi,

We have a requirement where we need to integrate Concur with Oracle Fusion expenses. We can do the integration for cash expenses but the issue is with Amex corporate cards. Amex is integrated with Concur & we are getting the expense feed from Concur. We are storing the employee's corporate cards in Oracle. How do we decrypt the credit cards & generate a remittance file for Amex with Corporate card numbers? I need to know what are the possible options I have.