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Unconditional security of coherent-state quantum key distribution with strong phase-reference pulse

Masato Koashi
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Abstract

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.

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Masato Koashi. 2004-03-18. Unconditional security of coherent-state quantum key distribution with strong phase-reference pulse. https://doi.org/10.1103/physrevlett.93.120501

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