Cross-medium equipment-independent and discrete modulation continuous variable quantum key distribution system

Abstract

The invention discloses a cross-medium equipment-independent and discrete modulation continuous variable quantum key distribution system. An eight-state quantum state is prepared by a trusted intermediate party through discrete modulation, the eight-state quantum state is sent to Alice and Bob after photon subtraction, Alice and Bob perform demodulation and homodyne detection on the received quantum state respectively, and a security key is established within an effective distance. According to the invention, a continuous variable quantum key distribution technology in a free space is improved, and the quantum state is prepared and sent by the trusted intermediate party, so that the system has equipment independence, and the communication security is ensured; the photon subtraction operation can improve the entanglement degree between the quanta so as to improve the transmission distance; the homodyne detection can effectively filter the interference of the outside on the optical signal, and the detection result can be well obtained even if the optical signal is influenced to a certain extent. The scheme is oriented to equipment independence under an air-water channel, discrete modulation continuous variable quantum key distribution is utilized, and more practicability is brought to free space communication of quanta.

Description

technical field [0001] The invention belongs to the technical field of free space continuous variable quantum key distribution, and relates to a device-independent and discretely modulated continuous variable quantum key distribution system across media. Background technique [0002] The law of quantum mechanics determines that Alice at the receiving end and Bob at the receiving end can use quantum key distribution (QKD) to achieve secure information transmission under an insecure quantum channel. Usually, QKD uses the phase information of weak laser pulses as the information carrier, and the farther the distance is, the lower the security of QKD is. One of the main reasons for this phenomenon is the rapid decay of inter-quantum entanglement, and the transmission distance between QKD protocols can be effectively improved by increasing the quantum entanglement. [0003] The transmission of quantum information in atmospheric channels faces a more complex environment than in o...

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Problems solved by technology

[0006] In order to achieve the above purpose, the present invention provides a device-independent and discretely modulated continuous variable quantum key distribution system across media, which solves the problems of low performance and short effective distance of continuous variable quantum key distribution existing in the prior art

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