Commercial security seals are routinely used to detect when a container have been opened, such as is found on mayonnaise and medicine jars. Users are warned: "Do not use if seal is broken."

 

 

Seals are also used to establish trust between parties by providing a means of detecting when that trust has been violated, though a major concern is whether the seal technology is itself reliable. This is particularly important when inspectors must confirm the uninterrupted containment and surveillance of nuclear material.

 

Now, using an Oak Ridge National Laboratory quantum seal technology, inspectors of containers of nuclear material will be able to know with unprecedented confidence whether an intruder has tampered with a seal. The system addresses a known tampering vulnerability pertaining to certain types of optical security seals.

 

"Optical security seals are a class of security seals that use laser optics to monitor for tampering," said Oak Ridge senior scientist Travis Humble, co-director of ORNL's Quantum Computing Institute. Humble said an example of this is the laser tripwires that show up in James Bond movies. If an intruder breaks the path of the laser, then the loss in power is detected and an alarm is sounded.

 

The vulnerability addressed by the ORNL technology is that it is actually fairly simple to replicate or clone the laser. If an intruder does clone the laser, then no loss in power is detected and the alarm doesn't sound.

 

Humble told Homeland1 that his contribution closes this cloning vulnerability by using techniques from quantum physics.

 

In terms of homeland protection, a major concern for the enforcement of non-proliferation treaties is asserting with confidence that a sealed container has indeed remained secure.

 

"Our quantum security seal raises the level of confidence that can be expected by the inspectors who must make sound judgments based on quantified observations," Humble said. Consequently, the unique features of quantum security seals provide policy makers with additional tools to enforce treaty compliance.

 

It works like this. The quantum security seal transmits a pulse of light down a path, but instead of using a conventional moderately powered laser Humble uses a unique quantum optical light source. This source is unique in two ways. First, it operates at extremely low power levels; that is, down to a pair of individual photons. Second, quantum correlations (aka entanglement) are generated between these two photons.

 

"We transmit the photons to separate sensor receivers and then we detect whether the initial correlations exist between the photons," Humble said. "If not, then tampering is suspected and the alarm is raised. The reason this works is that the two-photon state we prepare cannot be cloned. This is a postulate of quantum physics."

 

Humble said his system is advancing toward a prototype stage. The major technical challenge, he said, is developing the quantum optical light source.

 

"You can't buy those off the shelf," he said.  

 

About the author

 

Since leaving a withering aerospace engineering career in 1994, Doug Page has been writing about technology, medicine, and marriage peril from the Panic Room in Pine Mountain, Calif. He won a 2006 Tabby Award for a story titled "Life in a Disaster Morgue" that appeared in the January 2006 issue of Forensic Magazine. From 1998-2008 he was the Technology Correspondent for Fire Chief Magazine. Page is also a former contributing editor for Homeland Protection Professional and Science Spectra magazines. Contact Doug Page. 

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