Experimental composable security decoy-state quantum key distribution using time-phase encoding
Hua-Lei Yina b, Peng Liub, Wei Daib, Zhao-Hui Cib, Jie Gua, Tianxiong Gaob, Qiang-Wei Wangb, Zishun Shenb
- aNational Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
- bZhongchuangwei Quantum Co., Ltd., Beijing 101400, China
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Abstract
Quantum key distribution (QKD) promises provably secure communications. In order to improve the secret key rate, combining a biased basis choice with the decoy-state method is proposed. Concomitantly, there is a basis-independent detection efficiency condition, which usually cannot be satisfied in a practical system, such as the time-phase encoding. Fortunately, this flaw has been recently removed theoretically and experimentally in the four-intensity decoy-state BB84 QKD protocol using the fact that the expected yields of single-photon states prepared in two bases stay the same for a given measurement basis. However, the security proofs do not fully consider the finite-key effects for general attacks. In this work, we provide the rigorous finite-key security bounds in the universally composable framework for the four-intensity decoy-state BB84 QKD protocol. We build a time-phase encoding system with 200 MHz clock to implement this protocol, in which the real-time secret key rate is more than 60 kbps over 50 km single-mode fiber.
TL;DRThis work provides the rigorous finite-key security bounds in the universally composable framework for the four-intensity decoy-state BB84 QKD protocol and builds a time-phase encoding system to implement this protocol, in which the real-time secret key rate is more than 60 kbps over 50 km single-mode fiber. (Semantic Scholar)