World's First Quantum Cryptography Network Developed in China

[bananas]

World's First Quantum Cryptography Network Developed in China
2009-5-7

Safe quantum communication will be ready for daily use with the world's first optical quantum cryptography network completed in east China's Anhui Province recently. The American journal Science reported about the result, which was published in the latest issue of Optic Express in April.

Led by Pan Jianwei, researchers with the University of Science and Technology of China developed an operational network communication system, which allows real-time voice telephone among three users, or a broadcast from one user to the other two users by using one-time pad encryption.

The chained network topology allows secret keys to be forwarded, in a hop-by-hop fashion, along QKD links. Therefore unconditional authentication and encryption for information transmission by using one-time pad is possible. The middle node acts as trusted relays and increases the key generation rate to a higher degree, said researchers.

<snip>

Recent revolutionary progress has been achieved by introducing the idea of decoy state, and by turning the idea into systematical and rigorous theory and scheme. By using decoy state within the common setup, one can obtain much higher key generation rates and longer distances (typically from less than 30 km, to more than 100 km), in the same level compared with the case of using true single photon sources. This leads to the first successful demonstration by Lo's group from Canada for 15 km, and later for 60km. Recent research by Pan's group has extended the distance to 200km.

Field test of a practical secure communication network with decoy-state quantum cryptography

Teng-Yun Chen, Hao Liang, Yang Liu, Wen-Qi Cai, Lei Ju, Wei-Yue Liu, Jian Wang, Hao Yin, Kai Chen, Zeng-Bing Chen, Cheng-Zhi Peng, and Jian-Wei Pan

Optics Express, Vol. 17, Issue 8, pp. 6540-6549 doi:10.1364/OE.17.006540

Abstract

We present a secure network communication system that operated with decoy-state quantum cryptography in a real-world application scenario. The full key exchange and application protocols were performed in real time among three nodes, in which two adjacent nodes were connected by approximate 20 km of commercial telecom optical fiber. The generated quantum keys were immediately employed and demonstrated for communication applications, including unbreakable real-time voice telephone between any two of the three communication nodes, or a broadcast fromone node to the other two nodes by using one-time pad encryption.

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[ClarkUSA]

1. Wow... goodbye Thomas Edison, hello Pan Jianwei. This is fascinating. Thanks.

[xchrom]

2. i don't know what any of this is -- but it sounds way, way cool. nt

[bananas]

3. Telephones that can't be tapped. nt

[xchrom]

6. oooh! thank you! nt

[mainegreen]

4. World's first? By what definition?

Not by the definition of quantum encrypted network traffic.

It's cool, but it's not the worlds first.

Hell, commercial quantum cryptography systems already exist and are sold on the market.

[bananas]

5. Yeah, what they say in the paper is

Without using decoy state, a prototype setup cannot achieve
secure distance of more than 30 km generally <17, 14> with the standard BB84 protocol. The
implemented DARPA network <29>, the NIST network <30> and the network realized in <32> are
all without using decoy states. Therefore, these network, in fact, either are not secure, or cannot
accomplish the performance mentioned in their experiments. In addition, the distance for
secure network communication are quite short, namely, less than 10 km in the case of DARPA
network and only 1 km for NIST network.

The press release isn't quite accurate.