Scientific article

Quantum relays for long distance quantum cryptography

Published inJournal of modern optics, vol. 52, no. 5, p. 735-753
Publication date2005

Quantum Cryptography is on the verge of commercial application. One of its greatest limitations is over long distance - secret key rates are low and the longest fibre over which any key has been exchanged is currently 100 km. We investigate the quantum relay, which can increase the maximum distance at which quantum cryptography is possible. The relay splits the channel into sections, and sends a different photon across each section, increasing the signal to noise ratio. The photons are linked as in teleportation, with entangled photon pairs and Bell measurements. We show that such a scheme could allow cryptography over hundreds of kilometers with today's detectors. It could not, however, improve the rate of key exchange over distances where the standard single section scheme already works. We also show that reverse key reconciliation, previously used in continuous variable quantum cryptography, gives a secure key over longer distances than forward key reconciliation.

Citation (ISO format)
COLLINS, Daniel Geoffrey, GISIN, Nicolas, DE RIEDMATTEN, Hugues. Quantum relays for long distance quantum cryptography. In: Journal of modern optics, 2005, vol. 52, n° 5, p. 735–753. doi: 10.1080/09500340412331283633
Main files (1)
Article (Published version)
ISSN of the journal0950-0340

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