Access means entering or using consuming so to restrict any of these is known as Access Control. It is a necessary tool to put restriction to access our important information and places.Several type of restriction are there like to restrict humans to enter highly secured place,to restrict one to access our information on computer. It is just like to create firewall at the place where you do not want anyone to enter.
Today is the world of Information. It can be of any type like Business information, Secret files and tenders, Person Information etc. so control on access is necessary.Traditional methods are there for access control like guards are kept at Corporate houses, Apartments, Secret places etc.Firewall is created which restricts to access our Computer. One can only enter if he has the permission of. After checking whole necessary things one is authorized to enter a respective place. This process is known as Authentication.
Access control consists of three W’s ;Who,Where and When. With the help of this system one can know that Who are allowed to enter or exit, Where they are allowed to enter or exit, and When they are allowed to enter or exit. This is partially implemented with keys and locks.Only the person who has key can the door. It has some limitations like it does not authorize a person which results in lack of privacy. Anybody with the key can access the place. If the key is lost you are helpless until you have a duplicate key or you break the lock.