How does a new bank card know whether you have entered your pin once to then activate contactless payments? And how did all bank cards know when the contactless limit on card went up from £30 to £45 in the UK?

Question

A customer asked me this at work and I didn’t know the answer!

In: Technology

Answer 1

Your bank card doesn’t know much at all. I’ve never looked into this in depth, but in theory all it has to know is its number. Everything else is done between the card system and the bank.

Say you tap your card at a store.

Card: Hiii! I’m card number XXXXXXXXX!
Card reader: *rings Visa* ‘ey yo, I got this card here, number so-and-so. Is he legit? Also, he tapped.
Visa: Yup, he’s legit. Under the limit, too, so just tell him it’s accepted and I’ll note it down.