(4) A personal identification number (PIN) is a secret numeric password shared between a user and a system that can be used to authenticate the user to the system. Typically, the user is required to provide a non-confidential user identifier or token (the user ID) and a confidential PIN to gain access to the system. PIN s are most often used for automated teller machines (ATM s) but are increasingly used at the point of sale, for debit cards and credit cards