Authentication to a SharePoint environment is the process in which a firm's architecture approves a user's credentials; most commonly a Windows-based authentication. Once the user has been authenticated to a SharePoint environment, the SharePoint authorization process takes over and determines which objects within the system the user can access and act on.
To fully understand the spectrum involved with managing permissions in a SharePoint environment, you need to know the components involved with permissions and how they work with one another. This whitepaper will discuss the finer points and give a greater understanding of securable objects, permissions, permission levels, and access scenarios.
Information Security Research Library
