May 6, 2006 6:00 AM PDT
Gone in 60 seconds--the high-tech version
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How a keyless car gets stolen isn't exactly a state secret--much of the required knowledge is Basic Encryption 101. The authors of the Johns Hopkins/RSA study needed only to capture two challenge-and-response pairs from their intended target before cracking the encryption.
In an example from the paper, they wanted to see if they could swipe the passive code off the keyless ignition device itself. To do so, the authors simulated a car's ignition system (the RFID reader) on a laptop. By sitting close to someone with a keyless ignition device in his pocket, the authors were able to perform several scans in less than one second without the victim knowing. They then began decrypting the sampled challenge-response pairs. Using brute-force attack techniques, the researchers had the laptop try different combinations of symbols until they found combinations that matched. Once they had the matching codes, they could then predict the sequence and were soon able to gain entrance to the target car and start it.
In the case of Beckham, police think the criminals waited until he left his car, then proceeded to use a brute-force attack until the car was disarmed, unlocked and stolen.
Hear no evil, speak no evil
The authors of the Johns Hopkins/RSA study suggest that the RFID industry move away from the relatively simple 40-bit encryption technology now in use and adopt a more established encryption standard, such as the 128-bit Advanced Encryption Standard (AES). The longer the encryption code, the harder it is to crack.
The authors concede that this change would require a higher power consumption and therefore might be harder to implement; and it wouldn't be backward-compatible with all the 40-bit ignition systems already available.
The authors also suggest that car owners wrap their keyless ignition fobs in tin foil when not in use to prevent active scanning attacks, and that automobile manufacturers place a protective cylinder around the ignition slot. This latter step would limit the RFID broadcast range and make it harder for someone outside the car to eavesdrop on the code sequence.
Unfortunately, the companies making RFID systems for cars don't think there's a problem. The 17th annual CardTechSecureTech conference took place this past week in San Francisco, and CNET News.com had an opportunity to talk with a handful of RFID vendors. None wanted to be quoted, nor would any talk about 128-bit AES encryption replacing the current 40-bit code anytime soon. Few were familiar with the Johns Hopkins/RSA study we cited, and even fewer knew about keyless ignition cars being stolen in Europe.
Even Consumer Reports acknowledges that keyless ignition systems might not be secure enough for prime time, yet the RFID industry adamantly continues to whistle its happy little tune. Until changes are made in the keyless systems, any car we buy will definitely have an ignition key that can't be copied by a laptop.
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