From BoingBoing comes this wonderful information:
A Platform for RFID Security and Privacy Administration is a paper by Melanie R. Rieback and Georgi N. Gaydadjiev that won the award for Best Paper at the USENIX LISA (Large Installation Systems Administration) conference today. It proposes a “firewall for RFID tags” — a device that sits on your person and jams the signals from all your personal wireless tags (transit passes, etc), then selectively impersonates them according to rules you set. Your contactless transit card will only send its signal when you authorize it, not when some jerk with an RFID scanner snipes it as you walk down the street. The implementation details are both ingenious and plausible — it’s a remarkable piece of work. Up until now, the standard answer to privacy concerns with RFIDs is to just kill them — put your new US Passport in a microwave for a few minutes to nuke the chip. But with an RFID firewall, it might be possible to reap the benefits of RFID without the cost.
This is a must-read paper for anyone who cares about electronic privacy and who wants to catch a glimpse of the future.