Single sign-on (SSO) is a method of access control that enables a user to authenticate once and gain access to the resources of multiple software systems. [Wikipedia] As you can see from the definition the Method helps in the Authentication Level, not in the Authorization Level, which is a completely different level. The basic occurrence, thus most common, is in one of the following: a homogeneous IT infrastructure a single user entity authentication scheme exists a user database is centralized In...