Despite the theoretical advantages of the quantum key code, Myers said researchers had to ensure the quantum network would be as secure as the equations suggest it should be.

“The equation says there is no way anybody can eavesdrop on this without causing errors you can detect,” Myers said. “That’s a very hard thing to test because maybe I can come in and not [be able to hack the system without being detected], but how do I know there isn’t someone smarter than I am?”

Myers said researchers have been intrigued by the possibility of an encryption network using weak light since a 1984 scientific paper broached the possibility of such an impregnable system. He added that Harvard has been working on making the quantum code key a reality since 2001.

In June, a network connecting Harvard, Boston University and BBN Technologies—a Fresh Pond company that helped invent the internet—was created.

Myers said the system—which because of high costs would likely only be utilized by the government—is not yet complete.

He said the researchers hope to be able to squeeze all the materials needed for the quantum network into a box small enough to be placed in a sewer.

He added that the current optic fibers along which the weak light impulses are sent would only allow for two locations a maximum of 60 miles apart to communicate securely. Myers said this barrier could be overcome either with improved optic wiring, or by finding a way to send the weak light to a satellite.

Myers said the researchers hope to hope to have the system up and running by the year 2012.

—Staff writer Alan J. Tabak can be reached at tabak@fas.harvard.edu.