Modified continuous-variable quantum key distribution method for resisting actual attack

Abstract

The invention provides a modified continuous-variable quantum key distribution method for resisting an actual attack. The method comprises the following steps of step A carrying out continuous-variable quantum information transmission and carrying out real-time monitoring on local oscillator light; and step B carrying out a data post-processing step including a preprocessing operation, wherein the step B includes the steps that Bob obtains an original key according to peak-to-valley value lookup and Gaussian post-selection, obtains accurate parameter estimation through combination with local oscillator light intensity evaluation monitored by real-time AD oversampling and finally obtains a final key through data negotiation and privacy amplification. According to the method in the invention, the limited sampling bandwidth effect can be effectively eliminated, and meanwhile, all existing actual attacks for Gaussian-modulation CVQKD are defended, the method only changes the steps of a local oscillator light intensity monitoring method and a data post-processing software algorithm, the actual cost for defending the actual attack is simplified and the system complexity is reduced. The method can eliminate the limited sampling bandwidth effect, so that the key output rate of a Gaussian-modulation CVQKD system is improved.

Description

technical field [0001] The invention relates to the technical field of information security, in particular to an improved continuous variable quantum key distribution method capable of resisting actual attacks. Background technique [0002] As information security is getting more and more attention, quantum secure communication with unique security is gradually becoming familiar to everyone. At present, there are two implementation methods of quantum secure communication, namely quantum secure communication based on discrete variable technology and continuous variable technology, among which quantum key distribution (quantum key distribution, QKD) technology is the research focus. Discrete-variable quantum key distribution (DVQKD) has developed relatively maturely, while continuous-variable quantum key distribution (CVQKD) appeared relatively late, but developed rapidly, and is currently Conduct applied research. Like discrete variable techniques, continuous variable QKD i...

AI Technical Summary

Problems solved by technology

However, this scheme needs to insert an intensity modulator in the signal path. On the one hand, it changes the optical path structure of the original Gaussian modulation CVQKD scheme, which increases the complexity of the system implementation. On the other hand, the introduction of the intensity modulator reduces the intensity of the signal path, etc. effectively reduces the system detector efficiency, thereby reducing the final key rate of the system

However, a recent paper has analyzed the limited bandwidth effect of data sampling in practical CVQKD systems, and the results show that for high-speed CVQKD systems, the limited bandwidth effect at limited sampling frequency will become obvious, which will cause the actual Homodyne detector output signal to be no longer accurate peak-to-valley value

Therefore, the results obtained by monitoring the light intensity of the local oscillator through the optical power meter to evaluate the variance of the shot noise will no longer be consistent with the output results of the Homodyne detector, resulting in no accurate evaluation of key parameters such as system over-noise

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