Old notes

When the wiki is in _PROTECTED_MODE, the core ewiki_auth() function is used
to check if the current user has permission to access the requested function.
Permission levels are called 'rings', but auth/perm plugins may restrict
access to functions also based on $action or page $id.

If you just want to restrict your wiki, you will often find it
easier to write two different wrappers around ewiki. See the
paragraph in the HowTo+ section on top of the main README.

The $ewiki_ring scheme is the built-in way to handle all permission
granting. Use this variable to separate users into the four groups:
guests (ring 3), ordinary users (ring 2), moderators (ring 1) and
administrators (ring 0).

While ring permissions fit most usage restriction needs, and are
the default and built-in way to handle restrictions, they are
neither important nor required. You could write a customized
"auth_perm" plugin, which operates on a completely different basis,
and ignore those "ring levels" at all. With "auth_perm" it is
possbile to grant permissions much more controlled (finer
associations), for example by comparing $action and page $id with
allowed values for any given user.
prev << "Everything into auth_perm"
next >> "Available auth plugins"

You cannot modify the ProtectedMode file, but anyhow any ideas or suggestion should as usually get filed on BugReports, UserSuggestions or even better the ProtectedMode.Discussion.