Last week, Secretary of Homeland Security Jeh Johnson revealed that 21 states had contacted his office over concerns about hackers accessing their electoral data.

Homeland security expert and host of the "Security Mom" podcast Juliette Kayyem said the many agencies responsible for overseeing elections could open up the system to risk, but that so far the risk may be exaggerated.

"There's over 9,000 governmental entities in the United States alone—counties, cities, states—that have some oversight over our democratic process," Kayyem said. "The magnitude of the vulnerability cuts across so many different aspects."

She noted that there was growing evidence of malware in some of these election systems. In Arizona, hackers accessed the state's online registration system. In Indiana, the directory of voter information—containing voters' names, addresses, sex, and birthdays—was breached. 

But Kayyem says, so far, the damage has been minimal.

"There's a difference between getting into a system to get data, including home addresses and voting records, and getting into a system to manipulate that data. That's a lot harder," she said.

Manipulation of data requires a hacker to spend a longer amount of time inside a system, increasing the chances of detection.

Kayyem noted that a potential solution to minimize risk would be to revert to what she called 'old-school' voting methods, like sending written ballots through the mail.

"The solution seems, to me, if you can protect the mail system or have a drop-off, is mailing," Kayyem said.

To hear more from Juliette Kayyem, tune in to Boston Public Radio above.