Intrinsic imperfection of self-differencing single-photon detectors harms the security of high-speed quantum cryptography systems
Mu-Sheng Jiang, Shi‐Hai Sun, Guang‐Zhao Tang, Xiang-Chun Ma, Chunyan Li, Lin-Mei Liang · Physical Review A · 2013
Thanks to the high-speed self-differencing single-photon detector (SD-SPD), the secret key rate of quantum key distribution (QKD), which can, in principle, offer unconditionally secure private communications between two users (Alice and Bob), can exceed 1 Mbit/s. However, the SD-SPD may contain loopholes, which can be exploited by an eavesdropper (Eve) to hack into the unconditional security of the high-speed QKD systems. In this paper, we analyze the fact that the SD-SPD can be remotely controlled by Eve in order to spy on full information without being discovered, then proof-of-principle experiments are demonstrated. Here, we point out that this loophole is introduced directly by the operating principle of the SD-SPD, thus, it cannot be removed, except for the fact that some active countermeasures are applied by the legitimate parties.