Experts successfully took over digital voting machines, some of which are still in use, using a variety of vulnerabilities that allowed them to explore files on the machines, hijack them to play music and in some cases change votes, according to Defcon officials. Separately, as part of the r00tz Asylum series of Defcon events for young people, children and teens learned about security vulnerabilities that have previously been found in state election reporting sites. They got to practice using them on replica sites that had been set up for the conference, with one 11-year-old successfully making it appear that Libertarian Party candidate Darrell Castle had carried Florida in 2016, BuzzFeed News reports. And Defcon officials said some election officials praised the event

“It’s been incredible the response we’ve received,” Voting Village cofounder Matt Blaze said in a statement. “We’ve had over 100 election officials come through here and they expressed over and over again how much they have appreciated learning from this opportunity.”

But the National Association of Secretaries of State, which represents the officials in charge of counting elections in most states, said the access hackers at Defcon are given to experiment with voting machines doesn’t reflect real-world election conditions.

“Our main concern with the approach taken by DEFCON is that it utilizes a pseudo-environment which in no way replicates…