A pair of Princeton University researchers presented a paper this week on a method for sending secret messages over existing public fiber-optic networks.

Princeton's Bernard Wu and Evgenii Narimanov made their presentation at the annual Optical Society of America meeting in Rochester, N.Y.

Their encryption technology is hardware-oriented and uses the properties of optical fiber to disguise a message. The technique involves sending a signal so faint that it is hard to detect or unscramble, because it is hidden by the natural optical noise of the network.

More specifically, the technique involves use of commercially available optical CDMA encoders that spread short, intense pulses of light carrying messages. The recipient decodes the message using information about how the message was spread out in the first place, plus compression gear.

Wu said in a statement that he does not believe anyone is using this method yet, because optical CDMA technology is still undergoing much research. He also said there could be a speed tradeoff for increased security.

The paper presented is called "Achieving Secure Stealth Transmission via a Public Fiber-Optical Network."

As with any supersecret network technology, the benefits to companies and government agencies would need to be weighed against the benefits criminals could gain from a way of sending undetectable messages.