Consider the personal identification numbers (PINs) that many financial institutions use to control customer access to accounts-for example, withdrawal of funds by customers from their accounts using automatic teller machines (ATMs).

Required. List all the major functions you can identify that must be performed if PINs are to be an effective control to prevent unauthorized access to an account. Briefly explain why all these functions must be considered as a system if PINs are to operate as an effective control.