Touchscreen voting machines at the center of recent vote-flipping reports can be easily and maliciously recalibrated in the field to favor one candidate in a race, according to a report prepared by computer scientists for the state of Ohio.



At issue are touchscreen machines manufactured by ES&S, 97,000 of which are in use in 20 states, including counties in the crucial swing states of Ohio and Colorado. The process for calibrating the touchscreens allows poll workers or someone else to manipulate specific regions of the screen, so that a touch in one region is registered in another. Someone attempting to rig an election could thus arrange for votes for one candidate to be mapped to the opponent.

"If one candidate has a check box in one place and a different candidate has it in a different place, you can set it up so that if you press on one candidate it gets recorded for another candidate," said Matt Blaze, a computer scientist at the University of Pennsylvania who led one of three teams that co-wrote the report (.pdf) last year. "But if you press on the other candidate, it gets recorded correctly for that candidate. You can make it work perfectly normally in most of the screen, but have it behave the way you want in small parts of it."

The report illustrates a shocking vulnerability in a charged race that's already seen voter-fraud allegations on both sides, and an ugly spate of voter suppression tactics targeting Democratic voters in several states. The behavior described is also eerily similar to problems already observed in early voting on ES&S machines and during a 2006 race in Sarasota, Florida.

Such miscalibration, however, would affect any other candidate or race that uses the same part of the screen on a different page of the ballot; and an alert voter would likely notice the check mark appearing next to the wrong candidate's name.

Blaze said the calibration function on the ES&S machine isn't password-protected, making it easy for a poll worker – or even a voter

– to access the calibration menu in the middle of an election using a

PEB device (Personalized Electronic Ballot), which election officials insert in a port on the face of the machine. A PEB might be stolen or purchased online, or an intruder can simulate a PEB by using a Palm Pilot or other handheld device with an infrared port.

With no more than a minute's access to a voting machine, someone could recalibrate the screen, and to observers the action would be indistinguishable from the normal behavior of a voter in front of a machine or of a poll worker starting up a machine in the morning, said

Blaze, who discusses the issue on his blog.

Voters have recently complained in a number of states about vote-flipping occurring on touchscreen voting machines made by

ES&S. Voters in West Virginia and Texas complained that when they tried to vote for Democratic presidential candidate Barack Obama, their ES&S machine registered a vote for

Republican presidential candidate John McCain instead. Voters in Tennessee complained of the opposite occurring – that when they tried to vote for McCain, their ES&S machine registered a vote for Obama instead.

The problem in West Virginia was presumed to be calibration issues with the machine that can occur when the machine is moved or jostled or used for long periods of time without being recalibrated. Secretary of State

Betty Ireland directed election officials in 34 counties where the

ES&S machines are used to recalibrate their machines every morning during early election and on Election Day.

Voters who complained about the vote-flipping have said that after several tries they were able to get the screen to successfully register their vote for the candidate they selected. Blaze said that in a scenario involving a malicious calibration, the attacker would essentially shrink or move the region on the screen that is connected to a specific candidate so that voters hit that region only after several attempts touching areas around the candidate. But voters might also find the "sweet spot" for the candidate in the same way if the machine simply fell out of calibration naturally.

Blaze said it's impossible to know, from the information that's been published about the vote-flipping incidents, whether the calibration issue is a naturally-occurring one or one that has been aided.

"There is nowhere near enough information from what I've seen to conclude that malicious calibration is actually what's going on, but we can't rule it out either," Blaze said.

A West Virginia election official recently demonstrated on video how to calibrate an ES&S machine.

A computer science professor at Auburn University has a different take on what might be occurring with the vote-flipping reports.

Juan Gilbert, who directs the Human Centered Computing Lab at Auburn University in Alabama, said he believes the problem is a usability issue coupled with bad ballot design. He said that on ballots that use a windowbox design with the candidate's name inside a windowbox on the screen, voters tend to touch on the candidate's name, rather than the center of the windowbox. If the windowboxes for two candidates are placed too closely together on top of each other, a voter who casts a ballot for the candidate in the lower box is likely to press on the area between the two boxes, causing the machine to register a vote for the candidate in the upper box. See the video below for a demonstration of his theory.

Blaze said that Gilbert's theory is entirely plausible.

"This may not be a tech problem at all," Blaze said. "It may in fact be that some of what is being reported may be usability and user interface issues. In order to figure out what's going on in a particular case, though, you have to look at the exact ballot design and exact machine configuration in each case."

Blaze added that due to the recent reports from voters who have experienced problems with machines, other voters are very much on alert and may have a tendency to attribute any problem they experience with the machines to vote flipping. But that shouldn't keep them from reporting it.

"If it is a calibration problem – whether malicious or not – it's important that a voter who thinks that that is going on report it and not just go home and complain about it later. If there is a miscalibration, it can be fixed right then and there ... in the field."

ES&S did not immediately return a phone call on the issue Monday.

Image of voting machine from EVEREST report courtesy of Ohio Secretary of State

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