NEC touts quantum crypto advances

I can see the light

Japanese boffins have succeeded in achieving what's touted as the World's fastest continuous quantum cryptography key generation. Researchers from NEC, the National Institute of Information and Communications Technology and the Japan Science and Technology Agency achieved a fortnight-long, continuous quantum cryptography final-key generation1 at an average rate of 13kbps over a 16-km-long commercial optical network.

Developments in producing a low-noise photon receiver and an alternative-shift phase modulation method permitted the advance. An average quantum error rate is 7.5 per cent and the average final-key generation rate is 13.0 kbps was achieved during the experiment.

Quantum cryptography allows two users on an optical fibre network to exchange secret keys. It takes advantage of the particle-like nature of light. In quantum cryptography, each bit of the key is encoded upon a single light particle (or ‘photon’). Intercepting this data randomly changes the polarisation of the light, irreversibly altering the data. Because of this quantum mechanics affect any attempt by an eavesdropper to determine a key corrupts the same key. Quantum cryptography systems discard these corrupt keys and only use codes that are known to be secure. These quantum keys, once exchanged, can be used in a one-time pad.

Swiss firm ID Quantique, along with US start-up MagiQ, are the only companies selling quantum key distribution systems commercially though QinetiQ and Toshiba Cambridge are also heavily involved in research into "unbreakable" cryptography. NEC said that previous quantum cryptography systems have not been able to achieve long-time continuous key generation due to fibre delay variations, reflection and scattering in fibre.

NEC has developed Wavelength division multiplexing technologies to enable transmission of synchronizing signals and quantum signals in the same optical fibre, a feature touted as an advance of existing commercial systems. However the availability of commercial systems from NEC may be up to three years away, IDG reports. ®

1 The final-key is generated from the raw-key by eliminating bits that have possibilities of errors and eavesdropping. The raw-key is a set of random bits generated by single-photon transmission and detection.

Related stories

Aussie boffins patent single-photon generator
Quantum crypto moves out of the lab
Quantum crypto comes to Blighty

Sponsored: How to determine if cloud backup is right for your servers