Here’s an article in Wired Magazine about RFID hacking, which means using your own equipment in place of the official equipment to send and receive data connected with RFID tags. Hackers can do things like steal the code off a key card in someone’s pocket and then use it to get through a door, or erase the data in a library book RFID tag in order to walk out with it. The uses of RFID are expanding, as we know, and already include some economic transactions (like automatic toll-booths). Most commercial uses of RFID, apparently, don’t use any encryption and are hence completely insecure. Among other things, the article talks a bit about RFID hacking in library contexts.