Keeping this information separate means that election officials can verify that you voted without seeing how you voted. Another copy of the data is burned into a CD as a backup. On an individual level, the system is about as secure as an absentee ballot. But an interloper would have to obtain thousands of PINs and computers to influence any election. And one day online voting may be far more secure than absentee voting.
Election officials are far more worried about mass cheating.
Since regular polling places are scattered in thousands of locations around the country, large-scale fraud is almost impossible. But if a federal election was run from a central server, hackers could flood it with activity or jam phone lines, preventing people from logging on to vote. Software makers say they'll address that problem by using multiple servers and telephone lines. Any state that implements online voting may also have to contend with legal issues of representation. This clause applies to even minor changes that could reduce minority participation.