Lots of modern vehicles use RFID technology to deter vehicle theft. A small RFID chip is embedded into the key, and its presence is required to enable the fuel-injection system, and start the vehicle.
RFID technology is also used for automated transactions, specifically, in the automotive industry, for quick gas purchases, such as with the ExxonMobil SpeedPass system.
Texas Instruments produces a lot of these types of RFID's, but does so with an outdated encryption algorithm. As a result, they've now become rather insecure.
Here's an interesting study, done by some crackers in conjunction with Texas Instruments and Johns Hopkins University, that demonstrates why this type of RFID authentication is insecure. Lots of details, pics, and even videos of the cracks taking place.
To validate our attack, we extracted the key from our own SpeedPass token and simulated it in our independent programmable RF device. We purchased gasoline successfully at an ExxonMobil station multiple times in the course of a single day using this digital simulator. Similarly, we recovered the cryptographic key from a DST in the ignition key of our 2005 model Ford Escape SUV. By simulating the DST, we spoofed the immobilizer authentication system and started the vehicle with a bare ignition key, that is, with one that possessed no DST at all. Viewed another way, we created the pre-conditions for hot-wiring the vehicle.
More information: http://rfidanalysis.org/
Full academic paper from Johns Hopkins Information Security Institute: http://rfidanalysis.org/DSTbreak.pdf
We've previously discussed RFID technology on this board. Walmart uses them as miniature electronic barcodes, and they've stirred up quite a bit of public interest in doing so. Also, here's a link to a previous discussion about someone implanting an RFID chip in his hand for keyless-entry to his vehicle: biometric rfid keyless entry