Even the most secure network often has weak points a sneaky hacker can use to get access. Click here to learn about five of those weak points on your own wireless network and how to make them stronger.
So you might think that to have a totally secure computer - like a computer used for finance - you should make sure it isn't connected to any network at all. That's what many companies and government agencies do with their most secure systems.
Unfortunately, that's not safe enough anymore. Researchers at the Cyber Security Labs at Ben Gurion University in Israel have found a way to snoop on a computer even with no network connection.
It's called AirHopper. Basically, the researchers install a keylogger - a program that records what you type on your keyboard - on a computer. This keylogger is special because it tweaks the computer monitor to send FM radio signals.
The researchers can then pick up the FM signals on a nearby smartphone and translate the FM signals into the typed text.