Support for Financial-grade API (FAPI) with private_key_jwt?

[kmukku]

I have a use case where I as a Relying Party (RP) need to provide keys via JWKS-uri to OpenID Connect Provider (OP).

This is related to Financial-grade API (FAPI) requirements and especially to use of asymmetrical key pairs and to the exchange of JWT.

The spec for FAPI can be found from here and 8.9. states:

This profile requires both Clients and Authorization Servers to verify payloads with keys from the other party.

Any insight on how can I provide keys?