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Unconditional Security of Coherent-State Quantum Key Distribution with a Strong Phase-Reference Pulse

2004; American Physical Society; Volume: 93; Issue: 12 Linguagem: Inglês

10.1103/physrevlett.93.120501

1092-0145

Masato Koashi,

Quantum Computing Algorithms and Architecture

We prove the unconditional security of a quantum key distribution protocol in which bit values are encoded in the phase of a weak coherent-state pulse relative to a strong reference pulse. In contrast to implementations in which a weak pulse is used as a substitute for a single-photon source, the achievable key rate is found to decrease only linearly with the transmission of the channel.