2004/11/03 by Nicolas Gisin, Gregoire Ribordy, Gisin, Nicolas +10 · 1 citation
Computer Science · Physics and Astronomy · #Laser-Matter Interactions and Applications #Quantum Information and Cryptography #Quantum Mechanics and Applications #quant-ph
paper · pdf · doi:10.48550/arxiv.quant-ph/0411022
arxiv created 2004/11/03 · arxiv updated 2009/12/01
We present a new protocol for practical quantum cryptography, tailored for an implementation with weak coherent pulses. The key is obtained by a very simple time-of-arrival measurement on the data line; an interferometer is built on an additional monitoring line, allowing to monitor the presence of a spy (who would break coherence by her intervention). Against zero-error attacks (the analog of photon-number-splitting attacks), this protocol performs as well as standard protocols with strong reference pulses: the key rate decreases only as the transmission t of the quantum channel. We present also two attacks that introduce errors on the monitoring line: the intercept-resend, and a coherent attack on two subsequent pulses. Finally, we sketch several possible variations of this protocol.