--- Advancement toward realizing cryptographic key distribution with the ultimate information security ---
We have achieved ultra fast quantum key distribution (QKD)* over a 97-km installed telecom fiber. The cryptographic key generation rate was 100 times higher than the previous field experiments and about 10 times higher than the best rate ever reported including laboratory experiments.
Cryptography used in the internet now is public key cryptography. This method is, however, always threatened by advancement of computers, which allows an eavesdropper to decrypt the key with ultrafast computers. In contract, QKD can ensure unbreakable cryptographic scheme regardless of how technologies would advance in future.
Recently leakage of confidential information from information systems becomes a serious concern. This accelerates an effort to construct a network in which confidential data are managed in a data center, and terminals are linked through secure lines with it. QKD demonstrated here is suitable for such a network.
Most of QKD experiments so far were done in ideal laboratory environment. Our experiment is, however, done in an installed telecom fiber in a city. We have achieved the key generation rate 100 times higher than the previous field experiments, and 10 times higher than the previous labolatory experiments. This is a significant step toward realizing cryptographic key distribution with the ultimate information security.
(This experiment was done in the field test-bed optical fiber network of NICT, called JGN2, with the cooperation of NEC Corporation and National Institute of Standards and Technology (NIST).)