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Floodlight quantum key distribution method and system without phase feedback

A quantum key distribution and phase feedback technology, which is applied in the field of quantum communication, can solve problems such as complexity, multiple resources, and the inability to prove the effectiveness of the phase feedback method, and achieve the effect of increasing the coding rate and reducing overlap

Active Publication Date: 2021-04-20
NANJING UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the paper uses the attenuator to replace the real optical fiber at the same time, so it cannot reflect the phase drift that occurs in the real implementation, so it cannot prove the effectiveness of its phase feedback method in the real implementation
In addition, the traditional phase feedback method used to deal with phase drift is complex and consumes a lot of resources. It also requires a lot of precision instruments for measurement and feedback modulation, but it is impossible to achieve perfect phase feedback.

Method used

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  • Floodlight quantum key distribution method and system without phase feedback
  • Floodlight quantum key distribution method and system without phase feedback
  • Floodlight quantum key distribution method and system without phase feedback

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Embodiment 1

[0047] This embodiment proposes a flood quantum key distribution method without phase feedback. In this method, the sending end is marked as Alice, the receiving end is marked as Bob, and the listener is marked as Eve. The method includes the following steps:

[0048] In the first step, Alice prepares the local oscillator light and the signal light. The local oscillator light and the signal light can be prepared by the same light source or by different light sources. In this embodiment, the same light source is used as an example for illustration. Alice prepares a phase-random wide-spectrum continuous laser, and divides the laser into two beams. The beam with a smaller light intensity is used as the signal light to carry the key information, and the beam with a higher light intensity is used as the local oscillator light to carry the key information. The signal light of the key is subjected to homodyne measurement to achieve decoding to obtain the key. The local oscillator ligh...

Embodiment 2

[0062] This embodiment is a further preferred implementation of Embodiment 1. The rest of the steps in this embodiment are the same as those in Embodiment 1, and only one post-selection step is added in the fifth step. After the addition, the entire post-selection process is as follows Figure 4shown. The post-selection step is also called the screening step, which is an operation performed after Alice finally obtains the measurement results. The method of operation is to pre-set a filter parameter , the value of the real number result obtained by Alice's measurement is exactly at The results of the interval are discarded, and the rest are kept, and then the discarded position is told to Bob through the classical channel, and Bob removes the bit of the corresponding position from his own bit string to ensure that the initial key held by Bob is consistent with Alice's. Therefore, post-selection is actually a kind of screening and selection. This filter parameter can choo...

Embodiment 3

[0065] This embodiment proposes a system for implementing the above method, its functional architecture is as follows figure 1 shown. The system can be divided into three parts functionally: the key distribution optical circuit part divided by three solid circles; the key distribution monitoring part divided by a dotted circle, and the key distribution part divided by a dotted circle Distributing the classical information processing part.

[0066] For the part of the optical path divided by the solid circles, the three solid circles from left to right respectively represent the communication user Alice, the eavesdropper Eve, and the communication user Bob.

[0067] Alice has associated light source, detector one, detector two, broadband light source, coupler, first tapper, retarder, homodyne measurer.

[0068] The purpose of the associated light source is to generate a pair of associated associated lights that can be used to monitor the attack intensity, that is, the first a...

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Abstract

The present invention provides a floodlight quantum key distribution method and system without phase feedback, the bit key strings obtained by the sending end and the receiving end are processed by adopting the near-bit exclusive-OR operation, so that the bit error caused by phase drift in the signal light transmission process can be reduced, and the key is extracted from the bit key strings. Through adoption of the method, the phase feedback operation in the key distribution process can be omitted, so that the distribution system is greatly simplified, and the code rate can be effectively extracted under the condition of continuous and random phase drift. Before the exclusive-OR operation, the post-selection operation is supplemented, so that the code forming rate can be further greatly improved. As long as proper light source spectrum width and coding speed are ensured, the code rate can be ensured to break the PLOB upper limit, and the method has great advantages in a metropolitan area range.

Description

technical field [0001] The invention relates to the field of quantum communication, in particular to a flood-light quantum key distribution method and system without phase feedback. Background technique [0002] Since the existing classical key encryption method is basically based on computational complexity, and the quantum computer that is being realized can provide a calculation speed far exceeding that of a classical computer, thereby cracking the classical key, so the new key generation method has become the focus of cryptography research . Quantum key distribution is a key distribution method designed based on the basic principles of quantum mechanics. The generated key is used for communication encryption according to the principle of one-time pad, so that unconditional security guaranteed by information theory can be obtained. This kind of security is resistant to attacks by quantum computers, so a lot of research resources are invested in the hope of developing and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B10/70H04L9/08
Inventor 尹华磊刘文博陈增兵
Owner NANJING UNIV
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