But the new system depends on voters to ensure that their ballots reflect their choices, according to the study. Only human verification of paper ballots can detect if malware altered ballots printed by the touchscreens, called ballot-marking devices.
“Error detection and reporting rates are dangerously low,” according to the study. “Unless verification performance can be improved dramatically, BMD paper trails … cannot be relied on to reflect voter intent if the machines are controlled by an attacker.”
Georgia election officials say the state's voting system is secure, and computer-printed paper ballots will be used during recounts and audits to check the accuracy of electronically tabulated results.
Critics of the system say they're concerned that printed ballots could be altered, and it wouldn't take many falsified and undetected ballots to swing a close election. They prefer paper ballots filled out by hand rather than ballots printed by a computer.
The University of Michigan study was conducted at two public libraries where 241 people voted in a simulated election. Votes were changed on every printed ballot, and researchers studied how often voters reported the alterations.