qkd

do a google search and some SEN holders might be mightily disappointed.

here is a sample..

look likes plenty working on this appraoch.


Networks reap the benefits of quantum cryptography
31 August 2006

The first communications network to encrypt its data using quantum cryptography has been successfully demonstrated in a collaboration between Northwestern University and BBN Technologies of the US.

The researchers have combined the theoretically foolproof principle of quantum key distribution (QKD), used to share encryption keys between two distant parties, with a new procedure that generates the encryption itself - quantum data encryption (QDE).

It is through the use of this latter method, which the Northwestern team call AlphaEta, that quantum cryptography can be made feasible by exploiting the quantum noise inherent in laser light to make eavesdropping more difficult.

"The volume and type of sensitive information being transmitted over data networks continues to grow at a remarkable pace," said Prem Kumar, co-principal investigator at Northwestern's Robert R McCormick School of Engineering and Applied Science. "New cryptographic methods are needed to ensure that the privacy and safety of each user's information is secure."

BBN has demonstrated networks employing QKD before. For the past two years, a QKD network has been running non-stop between laboratories at BBN, Harvard University and Boston University. What makes Northwestern's new contribution significant, however, is the inclusion of the AlphaEta encryption, which is claimed to make the system fully compatible with existing optical networks without any degradation in performance.

Following preliminary tests of the AlphaEta encryption in a WDM optical network, the team has now managed to send encrypted 155 Mbit/s SONET data using the combined QKD/AlphaEta system over the 9 km link between BBN and Harvard University. A fresh encryption key of about 1 kbit was repetitively loaded every 3 s.

To prove the system's potential, the team then looped the signal back and forth -creating an effective 36 km link - and demonstrated more than 300 consecutive key exchanges. According to the researchers, this was the first example of a "true" quantum cryptographic network.

Henry Yeh, director of programs at BBN, said of the breakthrough: "As secure communications require both secure key distribution and strong encryption mechanisms, the combined QKD/AlphaEta system represents the state of the art in ultrasecure, high-speed optical communications."