Access control refers to security features that control who can access resources in the operating system. Applications call access control functions to set who can access specific resources or control access to resources provided by the application. In computer security, general access control includes authorization, authentication, access approval, and audit. ... Authentication methods and tokens include RFID, biometric scans, social barriers like Boom barrier, Turnstile, Flap barrier, swing barrier and monitoring by humans and automated systems.
When a credential is presented to a reader, the reader sends the credential's information, usually a number, to a control panel, a highly reliable processor. The control panel compares the credential's number to an access control list, grants or denies the presented request, and sends a transaction log to a database. When access is denied based on the access control list, the door remains locked. If there is a match between the credential and the access control list, the control panel operates a relay that in turn unlocks the door.