Security Encyclopedia

Personal Identification Number (PIN)

A Personal Identification Number (PIN) is a numeric or alphanumeric string that is used to authenticate a person to a system.

The dominant use cases for PINs are financial services transactions such as at the Point of Sale (PoS) or at a bank’s Automated Teller Machine (ATM). PINs are also commonly used to unlock mobile devices and for authenticating users to applications as a substitute for the more difficult to manage (and remember) passwords.

PINs were pioneered in the UK along with the rise of the ATM. In 1967 Barclays introduced ATMs as an efficient means of dispensing cash to customers, and for ATM check deposits that used codes printed on checks to aid their proper accounting of such transactions. Lloyds Bank, also in the UK, in 1972 was the first to use bankcards with magnetic-strip technology. The cards worked in concert with PINs and expanded the services ATMs offered.

Scottish inventor James Goodfellow OBE invented both the PIN and ATM, patenting them in 1966. For that, he was knighted by the British royalty with the Most Excellent Order of the British Empire for contributions that positively impacted Britain, the Commonwealth, and other territories.


“PIN numbers are a kind of shorthand password — no more secure, no less — and are used for quicker access to devices and applications. The issue, just as with passwords, is where PINs are stored.”