By Patricia Daukantas
Recent research using ordinary technology to share quantum mechanically entangled photons, or quantum keys, may bring the prospect of secure telecommunications closer to reality.
A Chinese research team has field-tested a secure communications system that uses decoy-state quantum cryptography, according to a recent article in Optics Express.
The group, based at the University of Science and Technology of China (Hefei) and Ningbo University (Ningbo), demonstrated a real-world application connecting three nodes with two 20-km links of commercial telecom optical fiber. Much recent work on quantum key distribution technology has been on point-to-point operations only, instead of the more realistic situation of networks with multiple users. The application used the decoy state method to boost the key generation rate and increase the distance for secure message transmission.
Another team, based at Toshiba Research Europe Ltd. and Cambridge University (England), built a gigahertz-clocked quantum key distribution system using only “practical components.” Group members made asymmetric fiber Mach-Zender interferometers from off-the-shelf components, and their system employed decoy pulses to detect photon-number-splitting attacks. The team achieved a secure key rate of 1.02 Mbit/s over 20 km of ordinary fiber. The research was published in the New Journal of Physics.
As a Science editor wrote about the Optics Express article: “With such a demonstration, quantum privacy in your own home may not be a too distant prospect.”
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