Matthew Green starts his 2005 Ford Escape with a duplicate key he had made at Lowe's. Nothing unusual about that, except that the automobile industry has spent millions of dollars to keep him from being able to do it. Mr. Green, a graduate student at Johns Hopkins University, is part of a team that plans to announce on Jan. 29 that it has cracked the security behind "immobilizer" systems from Texas Instruments Inc. All that would be required to steal a car, the researchers said, is a moment next to the car owner to extract data from the key, less than an hour of computing, and a few minutes to break in, feed the key code to the car and hot-wire it. Graduate Cryptographers Unlock Code of 'Thiefproof' Car Key | 
