Every time you open a new webpage or launch an application, your monitor emits electromagnetic fields that represent the graphics displayed on-screen. An 80x80 white pixel box emits different EM fields than a 300x300 white pixel box. On tonight's "Screen Savers" I'll tell you about the people who use van Eck phreaking to pick up on these fields and see what's on your monitor. And I'll explain how to block the snoops.

What the heck is van Eck phreaking?

Over the years, programmers developed methods and algorithms to convert EM fields to screen ghosts to view your screen data without using cables or cameras. According to whatis.com, "Van Eck phreaking is a form of eavesdropping in which special equipment is used to pick up telecommunication signals or data within a computer device by monitoring and picking up the electromagnetic fields."