Which authorizations should you redesign?

You are designing an enterprise-level Windows Communication Foundation (WCF) application. User accounts
will migrate from the existing system. The new system must be able to scale to accommodate the increasing
load.
The new servers are experiencing significant stress under load of large-scale role changes.
You need to ensure that the application can handle the stress.
Which authorizations should you redesign? (Each correct answer presents a complete solution. Choose all that
apply.)

A.
Role-based approach

B.
Identity-based approach

C.
Resource-based trusted subsystem model

D.
Resource-based impersonation/delegation model

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.