The explicit use case means the Client provides the UserIdentityToken used to determine whether an Access Token is permitted and what claims are available in the call to RequestAccessToken. This use case is illustrated in Figure 22.
Figure 22 – Explicit Authorization
The Target Server is the Server that the Client wishes to access. The initial interactions are the same as with the Implicit use case described in 9.2.
The Session may be created explicitly with a call to CreateSession or it can be implicit via a Session-less Method Call.
After creating the Session, the Client reads the available UserTokenPolicies from the AuthorizationService Object if it has not previously cached the information. It then chooses one that matches credentials that it has been provided out-of-band. The Client then calls the RequestAccessToken Method on the AuthorizationService Object.
The Authorization Server determines if the Client is permitted to receive an Access Token. The rest of the interactions are the same as described in 9.2.