This optional parameter specifies a Perl hook that can be used
to compare password retrieved from a user database with the submitted
password received from the client. The retrieved passwords must start with
the leading prefix {OSC-pw-hook}. The hook must return true when the
password is deemed correct. This hook is for proprietary hash formats and
other custom password check methods. This hook runs after
TranslatePasswordHook. The hook is passed the following arguments:
- $_[0] A reference to the current RADIUS request
- $_[1] The password submitted by the user
- $_[2] The correct password as retrieved from the user database
without the prefix
