ATM passwords (PINs)

[Nathaniel Ingersoll]

The way I look at it, all ATM cards (at least all the ones
I've ever run across) do not have their PIN encoded on the card.
When you do a transaction, the following events must happen:
	1) enter card
	2) enter pin
	3) select transaction
	4) success: result of action
	5) failure: notification

Now, if your PIN was encoded on the card, you could be informed of
PIN failure immediately after (2).  However, the ATM waits to
perform all data transfer until it has all necessary information,
so it probably sends whatever you entered for a PIN, your transaction
data, and whatever else, to the remote computer, which then
validates the PIN and transaction.

Make sense?
-- 
Nathaniel Ingersoll
Altos Computer Systems, SJ CA
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