How would computer hackers have rigged the US election against Hillary Clinton? A computer scientists explains

The election might have been rigged against Hillary Clinton, some experts have claimed. And activists are now launching campaigns to have those votes checked.

It isn't yet clear how that hacking would have taken place, in such a way to ensure that Donald Trump won the vote, if it did happen. But one of the experts that is consulting with the Democrats has laid out a possible scenario of how that hacking might have happened – and why it would have gone unnoticed.

J Alex Halderman, a professor at the Univeristy of Michigan, has written about how it might have been that a state or other hackers broke into the election process and allowed it to be swung for Donald Trump. If such a scenario did happen, it would represent one of the most significant cyber attacks in history, and could throw the entire Presidential election into disrepute.

"First, the attackers would probe election offices well in advance in order to find ways to break into their computers," he wrote. "Closer to the election, when it was clear from polling data which states would have close electoral margins, the attackers might spread malware into voting machines in some of these states, rigging the machines to shift a few percent of the vote to favor their desired candidate.

"This malware would likely be designed to remain inactive during pre-election tests, do its dirty business during the election, then erase itself when the polls close. A skilled attacker’s work might leave no visible signs — though the country might be surprised when results in several close states were off from pre-election polls."

Professor Halderman made clear that was just one way that the election might be hacked, and that it could have happened in a number of different ways. But he did say that it would make sense that someone would try such an attack – even if it does seem like it would be noticed and probably foiled.

He pointed to the example of hacking of the email account of the Democratic National Committee as well as John Podesta, Hillary Clinton's campaign manager, both of which led to personal emails being leaked. He also pointed to clear hacking of voter registration systems as an example of the fact that people have already looked to interfere with the running of the election.

In those hacking attempts, official have put the blame on Russian hackers. It does appear that people within the country have sophisticated enough cyber weapons to make their way into voting systems.

Even in advance of the election, concerns were widespread that it would be easy to hack into the voting machines that were being used and . Edward Snowden shared a video just before the election that showed hackers breaking into a voting machine using only a £24 memory card.

Professor Halderman wrote that the strange results probably weren't a consequence of the cyber attack, and were probably a consequence of polling data being wrong. But he nonetheless urged that people in the battleground states that might ahve been hacked – critical places like Wisconsin, Michigan and Pennsylvania – petition for urgent recounts so that the paper votes can be counted and the chance that the election was rigged can be checked.