US spies and Sony executives are speculating that North Korea hacked Sony to retalizate for a film opening in February 2015 in which the leader of North Korea is targeted for assassination.

Hacking doesn’t cost much; all it takes is some technical skill, readily available hardware and access to venues where hackers trade bits of code and information about vulnerabilities. The entry barriers are low; it’s possible to do billions of dollars of damage with an investment of tens of thousands.

That’s why it’s impossible to know whether it was a rogue government or a bunch of high-school students that brought down Sony’s network, distributed its unreleased films online and published its internal documents. We should ask ourselves how much of our vital information should be online at all. For North Korea, the answer is none, which gives it the advantage.