At the heart of the plan is three different card numbers used for every Bank Zero card, two of them invisible to customers.
In modern bank cards the card number is encoded in three different places, Narsai says in the patent application: visibly embossed onto the card face, plus in the magnetic strip on the back and in the microchip or "processor memory".
There is no reason those three numbers can't be different from one another – and that allows for "lane processing" differentiation.
The number actually displayed on the card "can be used in situations where highly secured 2-factor authentication can easily be implemented", such as online payments, Narsai says, and then locked for use only in such transactions. A second, different number in the mag strip can be locked for use only for swiping at point of sale devices where smart cards can not be used, and a third number can be unique to the smart card, for chip-and-PIN type transactions.
A card-skimming device of the type scammers attach to ATMs will be able to read the card number on the magnetic strip – but will not be able to use it for fraudulent online transactions, even if they capture a customer's PIN with a hidden camera too.
The system also means "that expiry dates can now be set for ultra-long durations", Narsai says in the patent, which will mean fewer deliveries that need to be organised by the online-only Bank Zero.
Perhaps more importantly for its customers, "the card number shown on the plastic need not change when the card is replaced" – so subscriptions to online services can remain intact even when a card is lost or stolen.
