TRENTON, N.J. - A Princeton University computer science professor added new fuel Wednesday to claims that electronic voting machines used across much of the country are vulnerable to hacking that could alter vote totals or disable machines. In a paper posted on the university's Web site, Edward Felten and two graduate students described how they had tested a Diebold AccuVote-TS machine they obtained, found ways to quickly upload malicious programs and even developed a computer virus able to spread such programs between machines. The marketing director for the machine's maker — Diebold Inc.'s Diebold Election Systems of Allen, Texas —...