A recent report that showed touch-screen voting machines could be vulnerable to hackers spurred the National Association of Secretaries of State, a majority of whose members are in charge of their states' elections, to consider whether the standards for the machines should be beefed up to prevent tampering.

Within a half-hour of examining the code made by Diebold, the first red flag was found. The password was embedded in the source code. "You learn (not to do) that in security 101" said Tadayoshi Kohno, one of the report's co-authors.

More than 40,000 Diebold voting machines are in use in 37 states. Most use touch-screen technology, while the rest use optical-scanning equipment, said Mike Jacobsen, a company spokesman.