You can fulfill the request policy contract in PingFederate.
On the Contract Fulfillment tab, fulfill the request policy contract with values from the original identity hint, datastores, dynamic text values, or attribute mapping expressions (if enabled).
This contract is used to map into the OAuth grant (the USER_KEY attribute), the Client Initiated Back channel Authentication (CIBA) authenticator (attributes vary depending on the authenticator), and the user code Password Credential Validator (PCV) (the USER_CODE_USER_NAME attribute). The USER_CODE_USER_NAME attribute is shown only if a PCV instance is selected on the Manage Policy window.