content: What technology permits my girlfriends dorm card to open the door My girlfriend has to have a card to get into her dorm building. It's not like a credit card where she has to swipe it through a magnetic strip reader.  It's been in her pocket it and she kind of just hip-checks the scanner and it lets her in. Is it RFID or NFC, or what? I don't see any obvious signs of a RFID chip, but I am not sure how small and thin they can be nowadays. Anyways, I basically have two questions: 1.) What technology do you guys think it is?  2.) Is there anyway for me to essentially spoof her card that way I can let myself into the building instead of waiting for her to come down?