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Secure quantum key distribution with an uncharacterized source

Masato Koashi·John Preskill
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Abstract

We prove the security of the Bennett-Brassard (BB84) quantum key distribution protocol for an arbitrary source whose averaged states are basis-independent, a condition that is automatically satisfied if the source is suitably designed. The proof is based on the observation that, to an adversary, the key extraction process is equivalent to a measurement in the sigma_x-basis performed on a pure sigma_z-basis eigenstate. The dependence of the achievable key length on the bit error rate is the same as that established by Shor and Preskill for a perfect source, indicating that the defects in the source are efficiently detected by the protocol.

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Masato Koashi, John Preskill. 2002-12-21. Secure quantum key distribution with an uncharacterized source. https://doi.org/10.1103/physrevlett.90.057902

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