RFID Cracks

Wired 14.05: The RFID Hacking Underground:

The coil in Westhues' hand is the antenna for the wallet-sized device he calls a cloner, which is currently shoved up his sleeve. The cloner can elicit, record, and mimic signals from smartcard RFID chips. Westhues takes out the device and, using a USB cable, connects it to his laptop and downloads the data from Van Bokkelen's card for processing. Then, satisfied that he has retrieved the code, Westhues switches the cloner from Record mode to Emit. We head to the locked door.

I like the owner's reaction once it works, muttering, "I always thought this might be a lousy security system."