BBN Technologies unveils real-world quantum-cryptography network
Cambridge, MA, June 4, 2004--BBN Technologies announced that it has built the world's first quantum-cryptography network and is operating it continuously beneath the streets of Cambridge, Massachusetts. Today, the Defense Advanced Research Projects Agency (DARPA) Quantum Network links BBN's campus to Harvard University; soon it will stretch across town to include Boston University as a third link. The Harvard University Applied Physics Department and the Boston University Photonics Center have worked in close collaboration with BBN to build the network under DARPA sponsorship.
Currently, complex mathematical algorithms are the most-common method used to scramble (encrypt) and descramble (decrypt) Internet messages that require secure transmission. Although this method can provide high levels of security, it is not infallible. In contrast, the DARPA Quantum Network introduces extremely high levels of security for Internet-based communications systems by encrypting and decrypting messages based on the principles of keys created by quantum cryptography.
Quantum cryptography, invented by Charles Bennett of IBM Research (Yorktown Heights, NY) and Giles Brassard of the University of Montreal (Montreal, Que., Canada) in the 1980s, prepares and transmits single photons of light (through either fiberoptic cable or the atmosphere) to distribute cryptographic keys used to encrypt and decrypt messages. This method of securing information is radically different from methods based on mathematical complexity, relying instead on fundamental physical laws. Because quantum particles behave discontinuously and are changed by any observation or measurement, eavesdropping on messages encrypted through a quantum cryptography system is always detectable.
The DARPA Quantum Network improves on these techniques to create a highly robust, six-node network that is both extremely secure and 100% compatible with today's Internet technology. BBN protocols pave the way for robust quantum networks on a larger scale by providing "any-to-any" networking of quantum cryptography through a mesh of passive optical switches and cryptographic key relays.
People think of quantum cryptography as a distant possibility," said Chip Elliott, a principal scientist at BBN and leader of its quantum-computing engineering team, "but the DARPA Quantum Network is up and running today underneath Cambridge. BBN has built a set of high-speed, full-featured quantum-cryptography systems and has woven them together into an extremely secure network."
BBN Technologies was established as Bolt Beranek and Newman Inc. in 1948. From its roots as an acoustical-design consulting firm, BBN grew to implement and operate the Arpanet (the forerunner of today's Internet) and develop the first network email, which established the @ sign as an icon for the digital age.