title: Feasible attack on detector-device-independent quantum key distribution.
abstract: Recently, to bridge the gap between security of Measurement-device-independent quantum key distribution (MDI-QKD) and a high key rate, a novel protocol, the so-called detector-device-independent QKD (DDI-QKD), has been independently proposed by several groups and has attracted great interest. A higher key rate is obtained, since a single photon bell state measurement (BSM) setup is applied to DDI-QKD. Subsequently, Qi has proposed two attacks for this protocol. However, the first attack, in which Bob's BSM setup is assumed to be completely a "black box", is easily prevented by using some additional monitoring devices or by specifically characterizing the BSM. The second attack, which combines the blinding attack and the detector wavelength-dependent efficiency, is not explicitly discussed, and its feasibility is not experimentally confirmed. Here, we show that the second attack is not technically viable because of an intrinsically wavelength-dependent property of a realistic beam splitter, which is an essential component in DDI-QKD. Moreover, we propose a feasible attack that combines a well-known attack-detector blinding attack with intrinsic imperfections of single-photon detectors. The experimental measurement and proof-of-principle test results confirm that our attack can allow Eve to get a copy of quantum keys without being detected and that it is feasible with current technology.
authors.affiliation: School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, 100876, China.|Guangxi Key Laboratory for Relativistic Astrophysics, School of Physics Science and Technology, Guangxi University, Nanning, 530004, China.
authors.forename: Kejin
authors.initials: K
authors.lastname: Wei
authors.affiliation: School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, 100876, China.
authors.forename: Hongwei
authors.identifier: 0000-0003-1553-9677
authors.initials: H
authors.lastname: Liu
authors.affiliation: School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, 100876, China. hqma@bupt.edu.cn.
authors.forename: Haiqiang
authors.initials: H
authors.lastname: Ma
authors.affiliation: School of Science, Beijing Jiaotong University, Beijing, 100044, China.
authors.forename: Xiuqing
authors.initials: X
authors.lastname: Yang
authors.affiliation: School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, 100876, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, 100876, China.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Sun
authors.affiliation: School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, 100876, China.
authors.forename: Jinghua
authors.initials: J
authors.lastname: Xiao
authors.affiliation: School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, 100876, China.
authors.forename: Yuefeng
authors.initials: Y
authors.lastname: Ji