A policy level consists of a set of code groups organized
into a single rooted tree, a set of named permission sets that are referenced
by the code groups to specify permissions to be granted to code belonging to
the code group and a list of fully-trusted assemblies.
Enterprise: security policy for all managed code in an enterprise. This
is the topmost hierarchy for applying policy level settings.
Machine: security policies for all managed code run on the computer
User: Security policy for all managed code run by the user. For the
current user the security settings get applied.
Application domain: security policy for all managed code in an application
The figure below shows the configuration wizard for the .NET
Framework 2.0. The policy level Enterprise security policy has Code Groups,
Permission Sets and Policy Assemblies within it.