Researchers at Johns Hopkins hacked the SpeedPass. I saw the story
here at Science News. They refer to the original posting at
rfid-analysis.org. Basically:
The Texas Instruments DST tag is a cryptographically enabled RFID transponder used in several wide-scale systems including vehicle immobilizers and the ExxonMobil SpeedPass system. [...] Only careful experimentation will permit accurate assessment of the degree of these two threats. Our cursory experiments, however, suggest that the threats are well within the realm of practical execution.
