Explanation/Reference:
Explanation:
Advanced Maturity: Authorization as a Service
In the advanced level of maturity for authorization, role storage and management is consolidated and
authorization itself is a service available to any solution that is service-enabled.

* The Trusted Subsystems Model
Once authorization is available as an autonomous service, the need for impersonation is eliminated.
Instead of assuming the identity of the user, the application uses its own credentials to access services
and resources, but it captures the user's identity and passes it as a parameter (or token) to be used for
authorization when a request is made. This model is referred to as the trusted subsystem model, because
the application acts as a trusted subsystem within the security domain.