Entanglement-based secure quantum cryptography over 1,120 kilometres

@article{Yin2020EntanglementbasedSQ,
  title={Entanglement-based secure quantum cryptography over 1,120 kilometres},
  author={Juan Yin and Yu-Huai Li and Shengkai Liao and Meng Yang and Yuan Cao and Liang Zhang and Ji-Gang Ren and Wenqi Cai and Weiyue Liu and Shuang-Lin Li and Rong Shu and Yongmei Huang and Lei Deng and Li Li and Qiang Zhang and Nai-Le Liu and Yu-Ao Chen and Chaoyang Lu and Xiang‐Bin Wang and Feihu Xu and Jian-Yu Wang and Cheng-Zhi Peng and Artur K. Ekert and Jian-Wei Pan},
  journal={Nature},
  year={2020},
  volume={582},
  pages={501-505}
}
Quantum key distribution (QKD) 1 – 3 is a theoretically secure way of sharing secret keys between remote users. It has been demonstrated in a laboratory over a coiled optical fibre up to 404 kilometres long 4 – 7 . In the field, point-to-point QKD has been achieved from a satellite to a ground station up to 1,200 kilometres away 8 – 10 . However, real-world QKD-based cryptography targets physically separated users on the Earth, for which the maximum distance has been about 100 kilometres 11… 
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