Security of quantum key distribution with state-dependent imperfections

  • Authors:

  • Hong-Wei Li;Zhen-Qiang Yin;Shuang Wang;Wan-Su Bao;Guang-Can Guo;Zheng-Fu Han

  • Affiliations:

  • Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei and Zhengzhou Information Science and Technology Institute, Zhengzhou, China;Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, China;Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, China;Zhengzhou Information Science and Technology Institute, Zhengzhou, China;Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, China;Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, China

  • Venue:
  • Quantum Information & Computation
  • Year:
  • 2011

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Abstract

In practical quantum key distribution system, the state preparation and measurement have state-dependent imperfections comparing with the ideal BB84 protocol. If the state-dependent imperfection can not be regarded as an unitary transformation, it should not be considered as part of quantum channel noise introduced by the eavesdropper, the commonly used secret key rate formula GLLP can not be applied correspondingly. In this paper, the unconditional security of quantum key distribution with state-dependent imperfections will be analyzed by estimating upper bound of the phase error rate in the quantum channel and the imperfect measurement. Interestingly, since Eve can not control all phase error in the quantum key distribution system, the final secret key rate under constant quantum bit error rate can be improved comparing with the perfect quantum key distribution protocol.