"Imagine how nervous you would be if the only copy of your term paper was on one disc somewhere," Rubin said. "Now, we're talking about a whole bunch of votes sitting on a cartridge somewhere. Even before we worry about tampering, we have to worry about accidental loss."

Vote hacking

While there have been no documented cases of foul play, experts say the potential for malicious hacking is very real.

"It would be a simple, high-school level programming project to do something like this," Rubin said. "I've seen the code. A lot of the code has already been seen on the Internet. You could see exactly how to encode a ballot. Someone with a proficient high-school level programming capability would be able to do it. Definitely any experienced programmer could do it."

He said a standard, touchscreen voting machine could have its data changed with $20 worth of hardware and a paper clip, a fact that gets more troubling now that expanded early voting has put votes on machines stored in schools, churches and other polling places for weeks before Election Day.

As early as 2003, a team of researchers commissioned by the state of Maryland reported that machines from vendor Diebold were poorly engineered and showed a "high risk of compromise." Their findings, as noted by the CalTech/MIT report, included the fact that every one of the company's voting systems used the exact same "secret" encryption key.

After a wave of negative press, including a 2006 HBO documentary called "Hacking Democracy" that explored the vulnerability of its electronic voting machines, Diebold removed its name from its voting systems in 2007 and was later bought by another company.

Thankfully, critics say, such issues are now being minimized on multiple fronts.

However, there are still some concerns in hotly contested states like Ohio. While all machines in Ohio are equipped with printers that create paper ballots, about half the counties in the state use the sort of touchscreen electronic machines that concern observers like Smith.

Those machines have been retrofitted with printers, but tampering risks still exist and comparing electronic ballots with separately created paper ones can be confusing, analysts say.

More secure?

In the short term, observers like California Institute of Technology political science professor R. Michael Alvarez say elections officials are almost universally aware of the security risks that electronic voting presents.

"There are security issues associated with both the electronic voting machines that are used in polling places, as well as the ballot reading devices. ... In many cases, those kinds of security vulnerabilities are relatively well known at this point," said Alvarez, whose research includes voting technology.

"Many of them have been studied, although certainly new ones may arise," he said. "Over the last four to six years, elections officials throughout the country have tested and really tried to work to better secure those voting systems."

With an eye to the future, elections officials throughout the United States have stopped purchasing machines that don't create a paper trail, with a return to optical- or digital-scanner machines using paper ballots being the preferred alternative.

Some states are retrofitting electronic voting machines with hardware that creates a paper ballot as well. Smith said it has been about seven years since the last significant purchase of electronic-only voting machines in the United States.

"It's not always the newest, shiniest thing that's the best thing and, in voting, that tends to be particularly true," she said.

In the meantime, she's got a simple piece of advice for anyone worried about the security of their ballot.

"The most important thing for voters to keep in mind is that one way to make sure your vote won't count is to not show up," she said. "Whatever system is presented to you, avail yourself of it."