30.4. Authentication by PIN
In Section 30.2 we considered payment by cheque, credit card and debit card. In all of these cases a handwritten signature was the basis for authenticating the purchaser. In the next section we consider automatic teller machines (ATMs) which are EFT terminals which give cash dispensing and other banking services. For these machines a handwritten signature is not used. Before going on to the design of an ATM system we first consider authentication by personal identification numbers (PINs), a method suitable for banking and other applications. As well as being an authentication mechanism that is easier to automate than handwritten signatures, the PIN method has also been found to be very much less subject to fraud.