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Password length requirement
(feddit.org)
Last week, I tried to register for a service and was really surprised by a password limit of 16 characters. Why on earth yould you impose such strict limits? Never heard of correct horse battery staple?
I assumed as the card readers and cards are both offline devices they wouldn't have a way to do this, are card blocks local in general?
Modern cards have a chip inside them that’s basically a very tiny computer. It can check how many times the pin was incorrect.
That's pretty cool. I wonder what (if any) tinkering you can do with a card if you've got physical access and some very precise tools.
Even if you could you can’t recover the PIN from it. Since it’s not stored on the card, the chip checks the entered PIN against a secret key with cryptographic calculations if it is correct. But you can’t get the PIN from that secret key. Also if I remember correctly the chip will self destruct, as in wipes it’s data, when it detects that it’s being tampered with.
Good to know!