PBS Newshour: How the NSA used special devices, radio waves to spy on offline computers

The newest revelations from documents leaked by Edward Snowden show that since at least 2008, the National Security Agency has implanted hardware to tap into as many as 100,000 offline computers overseas. Gwen Ifill talks to David Sanger of The New York Times and Cedric Leighton, a former deputy training director for the NSA.