Comment by MBCook
5 hours ago
There are two forms of wireless. The first was “magstripe emulation” and it’s exactly what you think it is. The card would hand over the exact data on the magstripe.
It’s also exactly as secure as you think: it’s not.
That hasn’t been used for a long time, and I don’t even think people accept it anymore. May not have for years. At least for credit cards. It’s quite possible that’s still how door access cards or maybe gym membership cards work. I don’t really know.
Everything now and for many, many many years, has been EMV over NFC. And you’re right on that one it is essentially identical to sticking your card in the EMV reader.
The exact technologies used for "access cards" have varied over the years, but last time I checked most of them still aren't doing anything even vaguely secure. The card says "I'm card 1234-5678" and the access system checks that is on the list, welcome in. Like magnetic stripes it isn't obvious to the human operator, but just like magnetic stripes you can just clone it by listening and reciting the same, "I'm card 1234-5678".
Now to be fair, you'd often find these systems are so clumsily installed that you don't need to clone a card anyway, the out-of-hours access has an "emergency" generic key you can buy from a hardware store, the controller was placed on the wrong side of the door - that sort of thing. But even a well-installed system is typically vulnerable to a competent intruder.