Perdue University create a "temporal cloak" to thwart eavesdropper.

"Those perturbed about this week's news that government spies may be perusing all sorts of personal communications might be particularly enthusiastic about the work of Purdue researchers in developing a time cloak to hide data. Of course, it might not be altogether practical to turn on the phase modulator before sending every email message, but still, aren't the possibilities comforting?"
 Latest Wrinkle in Data Security: Time Cloaking