Multi-user wavelength division multiplexing QKD network system and secret key distributing and sharing method thereof

Abstract

The invention discloses a multi-user wavelength division multiplexing quantum key distribution network system and a secret key distributing and sharing method thereof. The system comprises an Alice control end, a pulse conveying line and a Bob user end. The secret key distributing and sharing method comprises two stages of secret key distributing and sharing, wherein Alice and a plurality of Bob users carry out quantum secret key distributing and storing, and secret key priority is set; and Alice uses a secret key with low priority for encrypting a secret key with high priority into a ciphertext, then the ciphertext is sent to a user with low priority, the user with the low priority uses the secret key with low priority for decrypting the ciphertext, and the secret key with high priority is obtained. The system is reasonable, convenient to operate and low in cost, users in a network are relatively independent, the stability of the secret key generating rate of a single user is guaranteed, the secret key generating rate cannot be decreased along with increasing of users, meanwhile, a two-level equal-difference frequency space wave length planning scheme and an accurate pulse delaying technology are used, and mutual interference of pulses between different users is removed.

Description

technical field [0001] The present invention relates to the field of optical fiber communication and quantum communication network, more specifically, relates to a multi-user wavelength division multiplexing QKD (quantum key distribution) network system and its key distribution and sharing method. Background technique [0002] The security of traditional cryptography is guaranteed by mathematical computational complexity, but in the face of increasingly powerful computing power, its security is under great threat. The security of quantum cryptography does not depend on the complexity of calculation, but is based on the basic principles of quantum mechanics, namely Heisenberg's uncertainty principle and the principle of uncloning of unknown quantum states. Quantum Key Distribution (Quantum Key Distribution, QKD) can allow legitimate participants in different geographical locations (usually represented by Alice and Bob) to share keys in an absolutely secure manner. The key tra...

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Problems solved by technology

Although the early multi-user QKD scheme of tunable wavelength light source based on wavelength division multiplexing technology (Wavelength Division Multiplexing, WDM) can no longer equally distribute the pulses emitted by the transmitter Alice to different users, the pulses generated by the laser at the same time are still A single wavelength pulse can only serve a single user, which creates a dilemma that multiple users cannot work at the same time, and from the perspective of global time, the key

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