Voting can be as easy as a click of the mouse – but is it secure?

Twenty-six states and the District of Columbia now allow some form of online voting, from casting your vote online to sending an email.

But after high-profile hacks like those at the Democratic National Committee, the Obama administration is looking at ways to protect online voting amid growing concerns about whether these systems are vulnerable.

“There's a vital national interest in our election process, so I do think we need to consider whether it should be considered by my department and others critical infrastructure,” Homeland Security Secretary Jeh Johnson said.

M.I.T. Professor Ron Rivest, an Internet voting expert, says despite the promise, online voting is not yet foolproof.

“Once you have something on the Internet, you are telling the world, please come hack me,” he said.

He added: “There's lots of wonderful ways the Internet can contribute to elections, but putting voting itself online for me is a step to far. It's over the line. We don't know how to do it securely, you're inviting trouble. Every country overseas that has an ax to grind with the U.S.”

These actors, he warned, could try to “get in and manipulate the election.”

In one example of how online voting has developed, Washington, D.C., is one of the areas that allows members of the military and other voters who live overseas to email their votes.

Officials there say they’ve had no problems.

"It’s been going well. We've had this program for a few years now, and the only downside that I can see to it is that the voter is required to waive the secrecy of their ballot,” said Margarita Mikhaylova, with the D.C. Board of Elections.

But even the U.S. Election Assistance Commission – a federal agency that oversees voting systems – is cautious.

"We are not at the point now where we can use the Internet to cast ballots securely, safely and simply. But at some point we should be able to do that -- I hope we can do that in my lifetime,” Commission Chairman Tom Hicks said.

Last month, Illinois shut down its voter registration system after it may have been hacked. Officials reportedly blamed a “highly sophisticated attack most likely from a foreign entity.”

Further, Arizona took its registration system offline after it, too, may have been compromised by a hacker. 

Fox News’ Jennifer Oliva contributed to this report.