IC Card

Preface This kind of post has been written to death years ago—there’s nothing particularly novel here. I’m posting it mainly as part of my learning process. A few days ago I got a milk-shop membership card as a bonus after topping up 100. It wasn’t tied to my real name. I just put the card on the reader, swiped once, and the payment went through, which caught my interest. For RFID hacking people usually use a Proxmark3; back when I didn’t know better, I bought an ACR122U. First I used Mifare Classic Tool on my Nexus 5 to verify whether the card provided by the milk shop was a Mifare Classic card (the Nexus 5 hardware doesn’t support this card type, so it can only read basic info). After confirming it was, I dug out my dusty ACR122U and started tinkering on Arch Linux. I’d also lost both of my meal cards while out, and I happened to have backups of the old cards, so I restored those two as well. …