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.
The network 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.
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.
The Abstract from Optic Express:
Field test of a practical secure communication network with decoy-state quantum cryptography