Some election watchers are expressing concern over the fact that about one in four registered voters in next week's general elections will be casting their ballots using electronic voting machines that offer no verifiable paper records.
Paperless direct-recording electronic voting systems have drawn flak in past elections for being unreliable, too hard to audit and too prone to all sorts of tampering.
Such concerns have prompted 32 states and the District of Columbia to pass laws mandating the use of voting systems that support voter-verified paper records over the past few years.
Election officials in another six states have adopted similar systems even though they are not required by law to do so.
However, six states -- Delaware, Georgia, Louisiana, Maryland, New Jersey and South Carolina -- still use paperless e-voting systems statewide, according to a tally maintained by the election watchdog Verified Voting Foundation. In Indiana, Pennsylvania, Texas, Tennessee, and Virginia, direct-recording electronic voting systems account for a vast majority of voting systems.
In addition, paperless voting systems are in use to varying degrees in several other states, including Kansas, where at least 40% of the vote is paperless, according to Verified Voting.
The problem with using paperless voting systems is the relative difficulty of verifying the accuracy of electronic tallies, said the watchdog group's president, Pamela Smith.
Voter-marked paper ballots that are scanned and tallied by electronic systems, along with paper copies of electronically cast votes, together give election officials a reliable way to verify the accuracy of tallies, she said. "Paper enables the properties of recounting that we need right now," Smith said.
The fact that electronic voting systems can run into technical issues and are susceptible to tampering makes the need for a paper trail all the more important, said Bo Lipari, founder of New Yorkers for Verified Voting.
In November 2006, for instance, paperless touch-screen voting machines used in a congressional district race in Sarasota County, Fla., came under intense scrutiny after 18,000 ballots didn't record a vote in a tight race that was decided by a mere 369 votes.
The incident prompted calls by lawmakers for a review of paperless e-voting systems, and for the use of systems that produced a paper trail of every vote.
Last year, California officials disclosed that they had discovered numerous software errors and data deletion functions in e-voting systems, after nearly 200 votes were deleted from the official results for Humboldt County during the 2008 presidential elections.
Over the past few years, security researchers have also reported various flaws in e-voting systems that they have claimed make the systems easy to compromise.
One of the most sensational was a report by researchers at Princeton University that showed how attackers could install vote-stealing code in an electronic voting machine in less than a minute.
"The problem when you are dealing with pure software is that you really have no way to verify if the software has been operating correctly," Lipari said. "We know software can be hacked and that it has flaws and that programmers make mistakes."
"We see it happening every year, and there is no way to verify the results you are getting from the software. You've got to trust it," he said.
Since the Help America Vote Act (HAVA) was passed in 2002, most states have moved to systems that have some sort of a verifiable paper record, Lipari said. Some systems require voters to mark ballots and then scan them into an optical reading device, while others are direct-recording systems that generate paper copies.
"We have seen a lot of progress over the last four or five years," Smith said. "But we still have nearly a quarter of the voters using some kind of paperless voting system."
Merle King, executive director of the Center for Election Systems, a cooperative venture between Georgia's secretary of state's office and Kennesaw State University, refuted the notion that paperless systems are inherently unreliable.
Most arguments for paper-based systems are based on the assumption that credible auditing has to always be centered on paper, he said.
"I think the notion that electronic systems are not auditable would come as a shock to every accounting firm, every auditing firm, the federal government, the airline industry and all who have paperless systems," King said. "The notion that paper equals auditability is old-fashioned at best and ill-informed overall."
Most election fraud has historically happened with paper ballots, which even today is more prevalent with mail-in absentee ballots, he said.
Likewise, concerns about the security of e-voting systems are somewhat misplaced, King argued. In many cases where researchers have broken into voting systems, the models that were used to simulate hacking have been divorced from how the systems are used in an actual election, he said.
The real question should not be about just how well-protected e-voting systems are, but rather how easy it is to detect tampering, King said.
Jaikumar Vijayan covers data security and privacy issues, financial services security and e-voting for Computerworld. Follow Jaikumar on Twitter at @jaivijayan or subscribe to Jaikumar's RSS feed . His e-mail address is firstname.lastname@example.org.