In a message dated 96-11-25 22:17:41 EST, you write:

I also heard that the magnetic stripe on the back contains your card number (the shiny metallized numbers on the front) encrypted using DES using your PIN as the key. Way out to lunch? Too close for comfort?

This seems to be pretty unlikely, cuz I changed my PIN and was still able to use the same card. This means: 1) They can write to a card (pretty unlikely - but not ruling it out - jus don't know) 2) There are more PINs to a card than one (pretty unlikely cuz I chose my number) What I suspect is: Obtain card number Obtain PIN Send both to computer controlling transactions This computer inputs both to an algorithm that says Yea or Nay to continuing (like the numbers point to a valid check/credit/savings account or GL account)... Perform transaction (data likely encrypted the same way back and forth for defeating listening devices).... There may be a hash to the account, the result is not an account number, or some huge look-up database is in play matching PINs to card numbers to accounts.