This type of security allows you to control what actions are allowable for a group member to take on content within the site.
I think I have a rough idea what the security is about.
It is a system of checking at the security control when items carried by the staff in and out of the place are monitored and controlled to prevent pilferage.
It is like going through the security check in the airport before you board a plane.
Where did you get the text from?