Research and Development

To establish secure photonic network using QKD technology, the basic performance enhancement and stability improvement of QKD system are necessary. Also an interfacing function to enlarge applicable area of the secure photonic network will be needed for crypto-key sharing among multiple user terminals. To achieve above purposes, we set following four subthemes.

Subtheme A-1: Stabilization Technique
For stable crypto-key generation, free from variations in ambient temperature and electric power supply, automatic recovery scheme against performance change is necessary. Adequate supervisory control and secure active feedback schemes will be established.
Subtheme A-2: Enhancing Application Platform
Applying keys shared through QKD needs special care to preserve security. Application platform needs dedicated security, especially authentication, in distributing and installing shared key.
Subtheme A-3: Next Generation Quantum Key Distribution System Technology
Higher key generation rate will be achieved by multiplexing quantum channels, and by using higher performance error correction and photon detection technologies. System downsizing will also be achieved by optimizing circuitry design and functions of QKD system.
Subtheme A-4: Long-term Operational Testing
Using stabilized QKD system developed through subtheme A-1, long-term key generation will be tested under practical conditions for quality guarantee of the QKD network. Data disclosure system will be developed, and part of transmission performance with environmental parameters will be available soon here.
Four subthemes QKD technology for mission critical applications

Fig. 1Four subthemes QKD technology for mission critical applications.

A higher priority in applications of our high-speed QKD systems is the one for state secret communications. Secure crypto-keys for one-time pad are conventionally delivered by trusted couriers. It is beneficial if this system can be replaced with an automatic key delivery by a QKD network.

Our QKD systems can also be applied to secure data-backup communications. After the Great East Japan Earthquake, the importance of business continuity planning and constructing data backup networks for it has been widely recognized. Data backup communications should be protected tightly especially when transmitting data concerning individuals' lives and property. Data centers should be located at least 100km apart in order to exert the site diversity performance. They are connected typically via 1Gbps transmission lines. Our WDM-high speed QKD, which will attain a 500kbps secure key rate over a 15dB loss channel, can support such communications. Secure keys shared by QKD can be used for one-time pad in a stored key mode, because backup communications are carried out for only limited times a day. These key can also be used for 1Gbps block cipher.

Secure data-backup communications using QKD.

Fig. 2Secure data-backup communications using QKD.