By integrating quantum noise protected data encryption (quantum data encryption or QDE) with Quantum Key Distribution (QKD), researchers at Northwestern University and BBN Technologies have developed a complete data communication system with extraordinary resilience to eavesdropping.

The research team recently demonstrated a new way of encrypting data that relies on both traditional algorithms and on physical principles. This QDE method, called AlphaEta, makes use of the inherent and irreducible quantum noise in laser light to enhance the security of the system and makes eavesdropping much more difficult. Unlike most other physical encryption methods, AlphaEta maintains performance on par with traditional optical communications links and is compatible with standard fiber optical networks.

Quantum Key Distribution exploits the unique properties of quantum mechanics to securely distribute electronic keys between two parties. Unlike traditional key distribution, the security of QKD can in theory provide quantitatively secure keys regardless of advances in technology. Typically, these ultra-secure keys would be used in traditional encryption algorithms to allow for high-speed encrypted communications.

The combined QKD/AlphaEta system has been demonstrated in a nine kilometer link between BBN headquarters and Harvard University in Cambridge, Mass. The AlphaEta encrypted signal carried OC-3 (155Mb/s) SONET data between the two nodes. A fresh encryption key of about 1 kilobit was repetitively loaded every three seconds.

Source: Northwestern University news