In July, hackers managed to compromise the email servers of the Democratic National Committee (DNC), releasing thousands of confidential emails to the public, some of which embarrassed senior Democrats, including presidential candidate Hillary Clinton. The attack was attributed to Russian hackers by all US intelligence agencies and the Obama administration in October. Reporters and activists talked about "election hacking."

But how could anyone hack an election and what exactly does that even mean?

A roundabout way of 'hacking' polls

"What the Russian hack had done was create more problems for the Clinton campaign than it had for the Trump campaign," US President Barack Obama told public radio NPR.

While it is still unclear how the DNC servers, which supposedly were strongly protected, could be hacked, the intent behind it seems clear: release emails that show several senior Democrats and party leadership in an unfavorable light, sway public opinion in favor of the Republicans and thus influence the elections.

Now senior US intelligence officials have come forward with accusations against the highest levels of Russian government. According to US broadcaster NBC, they believe with "a high level of confidence" that Russian President Vladimir Putin was personally involved in Moscow's attempts to interfere with the US presidential election. The two senior officials quoted by NBC claimed that Putin personally directed how the hacked material from Democrats was to be leaked and otherwise used.

"There is no doubt that when any foreign government tries to impact the integrity of our elections we need to take action," Obama said to NPR. "And we will - at a time and place of our own choosing. Some of it may be explicit and publicized; some of it may not be."

Going physical

Another way to hack elections: manipulate voting tools physically. Not everyone in the US uses pen and paper to make their political choice - some districts use electronic machines.

J. Alex Halderman, professor of computer science at the University of Michigan, hacked such a voting machine in an experiment in 2006 and again last summer. In a story he wrote for online publishing platform Medium after the most recent elections, Halderman describes how someone could do the same in a real-life environment.

He says that hackers would focus on swing states, where the race was projected to be close.

"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," Halderman writes. "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."

'Voting process most secure it's ever been'

However, Halderman emphasizes that he doesn't believe the 2016 US presidential elections were actually hacked this way. Other experts have spoken out before the elections, saying that it was highly unlikely someone would breach the polls by targeting the actual voting process. One reason for that: around 70 percent of US voters did use pen and paper to pick a president on November 8.

"The truth is, the voting process is the most secure it's ever been," Tom Hicks, a commissioner at the Election Assistance Commission, told Time magazine before the elections.

Another factor that contributes to that is the fact that voting is a state, not a federal matter. Each of the 50 US states has its own voting infrastructure. Each district reports its results independently and the roughly 9,000 polling places from Florida to Alaska are not connected by a centralized structure that could be infiltrated.     

Coming up: the Bundestag elections

For obvious reasons, election hacking has been a hot topic in the US. But other countries are also worried about someone tampering with their polls. In Germany, people will vote for a new government in September 2017.

"Unfortunately we cannot exclude such activities in Germany, either," Social Democrat Rolf Mützenich told daily newspaper "Kölner Stadtanzeiger." 

Members of the parliament and administration workers were victims of a hacker attack in 2015, when a group called "Sofacy" infiltrated 14 Bundestag servers and stole 16 Gigabytes worth of information. Politicians and intelligence officials alike are worried that information gathered in this attack could be used to discredit politicians closer to election day next year.

Fake news spreading in Germany

German politicians are also stressing the danger of fake news influencing the upcoming vote - another kind of election hacking. Stories that appeared to be news but were actually made-up partisan propaganda were shared in huge numbers on social media before the US elections. The majority of these fake news pieces worked against the Democrats' candidate, Hillary Clinton.

"We can already see that online media outlets controlled from Russia are spreading misinterpretations and false information" in Germany as well, head of the liberal FDP Christian Lindner told public broadcaster Deutschlandfunk. "That's supposed to destabilize our country."

With the head start that events in the US gave them, intelligence agencies and politicians in Germany hope they can prevent a similar election breach next fall.