What is an Access Control List?

As the name indicates the Access Control List specifies the types of rights that a particular user has for a particular system object. A system object is a file or a directory. You know that a file or a directory has the security attributes and these can be modified by the administrator of that system. These attributes identify the privileges available for each of the user using the system.

The attributes that are available for the user through the Access Control List are the read permissions, write permissions, and the execute permissions. Access Control Lists are used in the Operating Systems like Windows NT/2000, Novell Netware, UNIX based systems, and Digital OpenVMS.

If you look at the Access Control List in the Windows Operating System you can find one or more access control entries. These contain the name of the user, the role of the user, and the access privileges. A string of bits are used to specify the access privileges. These bits are called the access masks. For any object the access control list is created by the Administrator of the system.