Adam Stubblefield has become a champion at finding holes in supposedly secure systems. He proved that an early version of the wireless security protocol WEP was not secure, and helped crack the Secure Digital Music Initiatives electronic watermark. Stubblefield also helped reveal security flaws in Diebolds voting machine software -- the first serious security review of the electronic-voting-machines code, according to Cindy Cohn, legal director of the Electronic Frontier Foundation. Most recently, Stubblefield reverse-engineered a radio frequency ID cipher. Yet he modestly notes hes not much of a programmer and has yet to learn to speak a foreign language. "My brain isnt very good at many things," says Stubblefield, who received his doctorate from Johns Hopkins in the spring. But his brain is helping keep information systems from being used to encroach on civil liberties -- a good thing indeed.