Connecting real world products and appliances to the internet is setting us up for a disaster, according to cyber security expert Bruce Schneier.

The former chief technology officer for BT Managed Security Solutions said that hackers can do three things with data: steal it, modify it, and prevent the owner from getting it. The last two type of hacks could become extremely powerful, as we enter a more connected world.

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“It’s one thing if your smart door lock can be eavesdropped upon to know who is home,” said Schneier in a Motherboard op-ed. “It’s another thing entirely if it can be hacked to allow a burglar to open the door—or prevent you from opening your door. A hacker who can deny you control of your car, or take over control, is much more dangerous than one who can eavesdrop on your conversations or track your car’s location.”

Schneier doesn’t mince words, he says that the Internet of Things (IoT) will bring about “attacks we can’t even imagine.”

Hackers could reduce the temperature on smart thermostats to freeze water pipes, crash airplanes and cars, and even attack connected medical devices that are required to keep people alive.

Threats to your life aren’t all you need to worry about, according to another article wrote by Schneier for the Washington Post, we must also worry about voter manipulation from governments and hackers.

Recent Russian hacks could show the way

Schneier warns that if Russian hackers were able to gain control of DNC emails that it wouldn’t take much for them to be able to hack into online voting machines. In the same article, Schneier warns against online voting, listing a variety of security reasons.

“There are other ways to attack our election system on the Internet besides hacking voting machines or changing vote tallies: deleting voter records, hijacking candidate or party websites, targeting and intimidating campaign workers or donors,” said Schneier.

Ethical hackers could be a major force for good, in Schneier’s eyes, helping identify faulty systems that can be broken into. He also calls for more government support to keep foreign governments and other adversaries out of U.S. cyberspace.