Imagine a war where governments use computers to disrupt their enemy's electric power grids or communication networks.
Imagine one country taking virtual control over an enemy's missile defence computer network.
These cyber war scenarios are no longer confined to sci-fi cinema.
This, experts say, is the reality of 'war' in the 21st century and some are warning that Canada isn't doing enough to prepare.
"If you look at what the U.S. and U.K. has spent on cyber defence and compare to what Canada has spent there is a huge difference,"
Rafal Rohozinski, a cyber security expert with The SecDev Group in Ottawa told CBC's The Current.
"Canada has committed...95 million. The U.K. committed £650 million. The U.S. is spending above that as well."
The first international attack of note used a computer virus called Stuxnet and was launched several years ago against an Iranian nuclear facility.
It almost certainly had some U.S. involvement.
Last week, a report to the U.S. congress suggested Chinese cyberwarfare would pose a genuine risk to the U.S. military in a conflict, for instance over Taiwan or disputes in the South China Sea.
U.S. Defense Secretary Leon Panetta told CBS News: "There's a strong likelihood that the next Pearl Harbor that [the United States] confronts could very well be a cyberattack."
And Canada is clearly not immune to these attacks.
Last January, CBC News reported that that foreign hackers from China gained access to highly classified information at the Finance Department, Treasury Board, and Defence Research and Development Canada.
"The reality is that all of our peer states as well what you might call our strategic competitors...like China, have all clearly identified that control and ability to act in the cyber domain is as important in the information age as was the ability to generate force - either through nuclear weapons or through large armies - in the industrial era," Rohozinski said.
"It has become part of the marker of state power. If Canada is going to play a role as a middle power or otherwise, we need to get up to scratch."