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Experimental demonstration of phase-remapping attack in a practical quantum key distribution system

2010; IOP Publishing; Volume: 12; Issue: 11 Linguagem: Inglês

10.1088/1367-2630/12/11/113026

1367-2630

Feihu Xu, Bing Qi, Hoi‐Kwong Lo,

Quantum Computing Algorithms and Architecture

Unconditional security proofs of various quantum key distribution (QKD) protocols are built on idealized assumptions. One key assumption is: the sender (Alice) can prepare the required quantum states without errors. However, such an assumption may be violated in a practical QKD system. In this paper, we experimentally demonstrate a technically feasible "intercept-and-resend" attack that exploits such a security loophole in a commercial "plug & play" QKD system. The resulting quantum bit error rate is 19.7%, which is below the proven secure bound of 20.0% for the BB84 protocol. The attack we utilize is the phase-remapping attack (C.-H. F. Fung, et al., Phys. Rev. A, 75, 32314, 2007) proposed by our group.