Will the US elections be hacked? It's doubtful, but machines could be 'rigged'

The fact that most election machines are not connected to the internet makes hacking unlikely, but the software itself could be vulnerable

It's been a topic of debate ever since hackers - presumably working for Russia - stole thousands of private emails from the Democratic National Committee and leaked them on the net. Could a nation state or other adversary hack our elections and determine the next president of the United States?

The answer depends on how they try to go about it, says Avi Rubin, computer science professor at Johns Hopkins University and technical director of the university's Information Security Institute.