The world’s first secure quantum communication line in China has passed technical inspection and is able to operate, according to the University of Science and Technology of China on Sept. 4.

The secure quantum communication line spans more than 2,000 kilometers, linking the four cities of Beijing, Jinan, Hefei, and Shanghai.

Construction of the line, approved by China’s National Development and Reform Commission in July 2013, was completed late last year after 42 months of effort in overcoming technical difficulties to achieve quantum key distribution, technology of single photon detection, and reliable data transmission.

Quantum communication is ultra-secure, as a quantum photon can neither be separated nor duplicated. Accordingly, it is impossible to wiretap, intercept, or crack the information it transmits.

China has achieved many “firsts” in the field of quantum communication, such as the world’s first secure quantum communication line connecting Beijing and Shanghai, and the first quantum communication satellite nicknamed “Micius.”

The success in building the line shows that China continues to lead the world in practical application and industrialization of quantum technology.