What happens in the 2 seconds after you tap your card
Tap to pay: what your card asks before the screen says Approved
You tap your card on a shop's payment terminal. About two seconds later, the screen says Approved. But the terminal has never heard of your bank. So who said yes?
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1
Rono sells noodles from a stall at the night market. Your bowl costs $8, and he holds out a small machine for your card: his payment terminal.
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2
Your card has no battery. As you hold it close, the radio of the terminal wakes the chip in it, just long enough to hand over your card number and a few details.
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3
Your money is not in the card, though. It sits at your bank, so the terminal sends it a question: can this card pay $8 at Rono's stall? That question is an authorization request.
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4
Your bank checks a few things in a blink. Is the card real, and not reported stolen? Is there $8 in your account? Does this payment look like you? Then it sends back its answer: yes.
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5
The yes comes back, the screen says Approved, and Rono hands you your bowl, about two seconds after the tap. Yet his terminal has no direct line to your bank. It does not even know which bank is yours.
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Go further
Three names around the tap.