Is the use of a particular resource giving you the ability to deny or permit access as you feel free. Access Control can be used in many different ways, some examples of Access Control are as follows:
Digital Resources (Such as a document on a computer, if it is a private document that only certain users should be able to read, Access Control can be used to Control this).
Logical Resources (Such as a Bank Account that has a limit to the number of people which are able to withdraw from that account.
Physical Resources (Such as a Cinema where only ticketholders will be aloud entry to the movie.)
About Physical Access
Physical Access can be manned by a person where payment for entry systems could be in place. There may be a section that requires one way traffic of people, this can be enforced with a few different methods like a doorman, a border guard or a ticket checked. Extra Access Control systems could be put in place, Turnstiles being a good example of this. Fences can also be used, this well help avoid circumventing this Access Control.
The Operation of Access Control
A control panel will be the main processor of this operation and they are highly reliable, Information is sent to the control panel when the required item is presented at the other end of the Access Control (a credential presented to a reader) the information contained on the credential is taken by the reader and sent through to the control panel. The control panel holds an Access Control List, this contains all the information of credentials to be permitted access and those to be denied. It compares the data from the scanned credentials, sends a transaction log to the database where it is stored and access is either granted or denied. When the Access Control List receives the credentials information, the door will remain looked if access is denied. If Access is granted a relay is sent from the control panel to the door unlocking it. An indication of weather access has been granted or denied is usually given by means of an LED, Red will show you have been denied access and Green will show you have been permitted access .
However this can be bypassed and is not always 100% safe, for example an authorised member of staff could pass their credentials on to an unauthorised member of staff hereby rendering the Access Control ineffective. A way to protect against this happening is to use two-factor authentication. Two-factor authentication requires another form of verification in addition to the credentials. This identification could be a second credential, a PIN, operator intervention, but the most effective is a biometric input.
A credential can be a number of different things, it is something you know or have such as an access badge, a PIN or number, a biometric feature (a fingerprint or eye scan), it could even be a combination of these.
