Illinois’ top election officials insist that the recent hack into state voter rolls, which contain the names of 8 million active voters, doesn’t pose a threat to the Nov. 8 election and shouldn’t undermine public confidence in the results.

And even though GOP presidential candidate Donald Trump has talked about a “rigged” election, most experts say large-scale voter fraud isn’t possible.

The cyberattack on the Illinois database, as well as a similar one on Arizona, prompted more anxiety than any claims about a fixed election, State Board of Elections general counsel Kenneth R. Menzel said, adding: “That is something that gets my attention more than a candidate making allegations.”

A look at key questions regarding voter fraud:

Q: Generally, how big a problem is election fraud in Illinois?

A: Humorists for decades have riffed that Chicago’s voter registration rolls are filled with names of the deceased; jokes like: How do we know Elvis is really dead? Because he’s registered to vote in Chicago.

But rampant and overt election fraud is a thing of the past, officials say. An Arizona State University project that tracks cases of alleged election fraud found 2,068 instances nationwide between 2000 and 2012, but just 23 in Illinois out of tens of millions of votes over that 12-year period. Six were registration fraud and two were double voting.

Kane County State’s Attorney Joseph H. McMahon said this week that in the 15 years since establishing a voter complaint hotline, his office hasn’t identified a single major violation of election laws. Most complaints, the Republican said, have to do with campaign signs or electioneering too close to polling stations.

Q: How was the database hacked?

A: The cyberattack began June 23 but wasn’t detected until mid-July by the State Board of Elections, according to documents.

It was later discovered that hackers were probing the data computers five times a second, 24 hours a day. They likely viewed the names, addresses and other information of around 90,000 Illinois voters, the documents say.

Q: What harm did the hacking do?

A: Voting machines aren’t online, so hackers weren’t going to be able to change or delete votes, Menzel explained. The chief concern, he said, was that the hackers were engaging in standard identity theft, and election officials sent notices to any voters whose information might have been stolen.

Q: Who were the hackers?

A: Illinois officials say they don’t know, though speculation has focused on Russia. “The FBI and Homeland Security are working feverishly on the who,” Menzel said. “We are more interested in the how.”

Officials spent weeks upgrading security procedures for the database, including requiring managers to always use a two-step authorization process to get into the database and mandating more complex passwords.

Q: Are Illinois election officials taking extra precautions because of Trump’s warnings?

A: It doesn’t seem to be the case. Menzel said it’s healthy to have “a reasonable level of paranoia” heading into Election Day, but hasn’t noticed more than usual.

Standard precautions include polling station workers that are supplemented by watchers dispatched by political parties to guard against voting intimidation or fraud. It’s also standard for voting machines to be tested and retested.

“Every couple years, there are people who … say, ‘The elections are being stolen,’” Menzel said, but noted such claims invariably lack specifics, which makes it hard for officials to respond.