Ex-U.S. cybersecurity chief Chris Krebs tells 60 Minutes how he knows the 2020 election wasn't rigged

Christopher Krebs and his team spent years working to build the new Cybersecurity and Infrastructure Security Agency (CISA) and help protect U.S. elections, among other critical infrastructure, before President Trump abruptly fired him over Twitter for putting out a joint statement calling the 2020 election the "most secure in American history." Krebs explained on Sunday's 60 Minutes why he's so sure the election was free from hacking and foreign meddling, and why Trump and his fringy lawyers are wrong to allege otherwise.

"I'm not a public servant anymore, but I feel I still got some public service left in me," Krebs told Scott Pelley, explaining why he's speaking out publicly. "And if I can reinforce or confirm for one person that the vote was secure, the election was secure, then I feel like I've done my job."

Krebs said his biggest priority after gaming out "countless" scenarios for foreign election interference was paper ballots. "Paper ballots give you the ability to audit, to go back and check the tape and make sure you go the count right," he said. "And that's really one of the keys to success for a secure 2020 election — 95 percent of the ballots cast in the 2020 election had a paper record associated with it." You can see how that worked in the Georgia hand recount, he added.

Krebs said he found the efforts from Trump and his lawyers to "undermine confidence in the election, to confuse people, to scare people" upsetting because it's actively "undermining democracy" but also because the some of the tens of thousands of election workers putting in 18-hour days are now "getting death threats for trying to carry out one of our core democratic institutions, an election."