Experimental Unconditionally Secure Bit Commitment

Yang Liu, Yuan Cao, Marcos Curty, Sheng-Kai Liao, Jian Wang, Ke Cui, Yu-Huai Li, Ze-Hong Lin, Qi-Chao Sun, Dong-Dong Li, Hong-Fei Zhang, Yong Zhao, Teng-Yun Chen, Cheng-Zhi Peng, Qiang Zhang, Adán Cabello, and Jian-Wei Pan
Phys. Rev. Lett. 112, 010504 – Published 10 January 2014
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Quantum physics allows for unconditionally secure communication between parties that trust each other. However, when the parties do not trust each other such as in the bit commitment scenario, quantum physics is not enough to guarantee security unless extra assumptions are made. Unconditionally secure bit commitment only becomes feasible when quantum physics is combined with relativistic causality constraints. Here we experimentally implement a quantum bit commitment protocol with relativistic constraints that offers unconditional security. The commitment is made through quantum measurements in two quantum key distribution systems in which the results are transmitted via free-space optical communication to two agents separated with more than 20 km. The security of the protocol relies on the properties of quantum information and relativity theory. In each run of the experiment, a bit is successfully committed with less than 5.68×102 cheating probability. This demonstrates the experimental feasibility of quantum communication with relativistic constraints.

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  • Received 8 October 2013


© 2014 American Physical Society

Authors & Affiliations

Yang Liu1, Yuan Cao1, Marcos Curty2, Sheng-Kai Liao1, Jian Wang1, Ke Cui1, Yu-Huai Li1, Ze-Hong Lin1, Qi-Chao Sun1, Dong-Dong Li1, Hong-Fei Zhang1, Yong Zhao1,3, Teng-Yun Chen1, Cheng-Zhi Peng1,*, Qiang Zhang1,†, Adán Cabello4, and Jian-Wei Pan1,‡

  • 1Shanghai Branch, Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
  • 2Department of Signal Theory and Communications, University of Vigo, E-36310 Vigo, Spain
  • 3Shandong Institute of Quantum Science and Technology Co., Ltd, Jinan, Shandong 250101, P. R. China
  • 4Departamento de Física Aplicada II, Universidad de Sevilla, E-41012 Sevilla, Spain

  • *pcz@ustc.edu.cn
  • qiangzh@ustc.edu.cn
  • pan@ustc.edu.cn

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Vol. 112, Iss. 1 — 10 January 2014

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