From 8 a.m. to noon on Election Day last November, voting in Johnson County, Ind., ground to a halt. Lines at precincts across the county, just south of Indianapolis, swelled. Some voters waited hours to cast a ballot; some left furious that they were unable to do so. “People weren’t happy. People had to leave and go to work,” said Cindy Rapp, the Democratic member on Johnson County’s election board. The county votes on electronic voting machines, which don’t provide a paper trail — something cybersecurity experts vehemently warn against. But those machines weren’t what caused the issue in November. Instead, the problem came from the computer system, known as an electronic poll book, that poll workers were using to check people in. Increasingly, more and more states and voting jurisdictions are using these systems to speed up and improve in-person voting. According to federal data, nearly half of all voters who voted in person in 2016 signed in at their polling place using an electronic poll book. That’s up from 27 percent just one presidential election prior. Like many issues surrounding elections, moving from paper to a digital process may bring convenience, but it also brings big questions about security and reliability.