Device-independent and discretely modulated continuous-variable quantum key distribution system across media

Abstract

The invention discloses a device-independent and discrete modulation continuous variable quantum key distribution system under cross-medium. A trusted middle party prepares eight-state quantum states through discrete modulation, and then sends them to Alice and Bob respectively after photon subtraction. , Alice and Bob respectively demodulate and homodyne the received quantum state to establish a secure key within the effective distance. The invention will improve the continuous variable quantum key distribution technology in free space, and the quantum state is prepared and sent by the trusted intermediate party, so that the system is device-independent and ensures the security of communication; the photon subtraction operation can improve the degree of entanglement between quantum to improve Transmission distance; homodyne detection can effectively filter the external interference to the optical signal, and achieve good detection results even if it has a certain impact on the optical signal. This scheme is oriented towards the device independence under the air-water channel, and uses discrete modulation continuous variable quantum key distribution to bring more practicality to quantum communication in free space.

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 discrete modulation continuous variable quantum key distribution system under cross-media. Background technique [0002] The laws of quantum mechanics determine that the receiver Alice and the receiver Bob can use quantum key distribution (QKD) to achieve secure information transmission under a non-secure quantum channel. Generally, QKD uses the phase information of weak laser pulses as the information carrier, and the longer the distance, the lower the security of QKD. One of the main reasons for this phenomenon is the rapid decay of inter-quantum entanglement, which can effectively improve the transmission distance between QKD protocols by increasing the quantum entanglement. [0003] The transmission of quantum information in atmospheric channels faces a more complex environment than in optical fiber chann...

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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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