You can configure PingFederate to require that client applications provide credentials to access the security token service (STS).
While this is an optional configuration, it is recommended for identity provider (IdP) configurations using the Username Token Processor. For other token processors and token generators, trust in the identity of the client is conveyed within the token itself and verified as part of processing. However, you can still configure authentication requirements to add another layer of security by limiting access to only authenticated clients.
You can configure STS authentication to either apply globally to all token formats and for all IdP and service provider (SP) partner connections, or token-to-token mappings, using more fine-grained controls at the connection level through issuance criteria.