Access control a is way of limiting access to a system or to physical or virtual resources. In computing, access control is a process by which users are granted access and certain privileges to systems, resources or information.
In good old day access control systems, users must present credentials before they can be granted access. In current physical systems, these credentials may come in many forms, but credentials that can't be transferred in order to provide a heavy security.
The following topics discuss the various features that are key to access control.