Researchers at Johns Hopkins University and RSA Laboratories have demonstrated how too crack the encryption of a Texas Instrument RFID transponder used in many "immobilizer-equipped" car keys and ExxonMobile SpeedPass e-payment fobs. From the press release:
Security verification takes place through a procedure called a challenge/response protocol. When the key or tag is nearby, the reader transmits a random string of ones and zeroes to it. The transponder in the key or tag then processes these numbers in a specific way and sends a numeric message back to the reader for authentication.The researchers from Johns Hopkins and RSA Laboratories were able to unravel the mathematical process used in this verification. They then purchased a commercial microchip costing less than $200 and programmed it to find the secret key for a gasoline purchase tag owned by one of the researchers. By linking 16 such chips together, the group cracked the secret key in about 15 minutes… The researchers had similar success with a chip-equipped car key.
Link to Johns Hopkins press release, Link to Science News article, Link to the technical report
