Nonorthogonal decoy-state quantum key distribution based on conditionally prepared down-conversion source
Hu Hua-Peng, Jindong Wang, Huang Yu-Xian, Songhao Liu, Lu Wei, (1)华南师范大学信息光电子科技学院光子信息技术广东省高校重点实验室,广州 510006; (2)中国科学院合肥智能研究所，合肥 230031 · Acta Physica Sinica · 2010
The decoy-state method and the non-orthogonal encoding protocol, being capable of resisting the photon-number splitting attack, have become attractive recently. Here, we combine both the methods and propose a new protocol using a conditionally prepared down-conversion source, following Poisson photon number distribution. In the protocol, Alice randomly changes the intensities of the pump light so that the intensity of signal photon of photon pair is randomly changed. The signal state is used for generating keys, the decoy states for detecting the eavesdropping and estimating the fraction of single-photon and two-photon pulses. We have simulated the final key rate over transmission distance, showing our scheme can enhance the performance of quantum key distribution.