As the need to protect people and assets has grown, it’s become equally important to control and monitor those who need access to what is protected. The most universal application to limit access has been common door locks. Access is granted by the use of a key to mechanically unlock the door. Mechanical locks have always been effective in controlling access, but very ineffective in controlling who has permissible access. Managing keys is difficult. They are easily reproduced and very difficult to keep track of. In addition, skilled individuals are capable of picking the mechanical lock.

While maintaining the integrity of a secure space, one lost or missing key would require the lock to be replaced and new keys issued. For this reason, technology has evolved into sophisticated computerized electronic access control systems.