Personal identification number

A Personal identification number (abbreviated as PIN) is a number that is used to authenticate a user of a system. It is used to make sure only certain people can get, use, or change information in the system.
PINs were created to be used with automated teller machines. Once someone inserts a bank card into the machine, they would be asked to enter a PIN using the buttons on a keypad, and would only be allowed to get their money if they entered the correct PIN. In a similar way, EMV technology makes use of PIN numbers to make sure only the person holding a credit card can make a transaction with it.
Early PIN numbers only consisted of digits. Today, some banks use PINs made of digits and letters. There are also many new technologies being created to be used instead of PINs, such as using fingerprint scanners.