For the first time in our country, the new quantum key is the least number of pulses and the safest distance

The reporter learned from China University of Science and Technology on the 3rd that the CAS Key Laboratory of Quantum Information of CAS led by Academician Guo Guangcan has for the first time achieved the RRDPS protocol with the lowest number of packet pulses and the longest safe distance in the world and solved the problem that under the actual channel conditions The number of grouped pulses is too much, the problem of low efficiency.The results published in January 31, the international authoritative academic journal "Nature".

RRDPS is a new type of quantum key distribution protocol proposed by Japanese and American scientists in 2014. Since the protocol does not need to monitor the signal perturbation parameters, it can estimate the eavesdropper's information.In the practical application, the channel-free disturbance monitoring brings System simplification and high bit error rate tolerance, which aroused much interest in the academic community.However, the protocol still exists in the calculation of security certification is rough, it can not quantitatively describe the eavesdropper attack behavior, the system error rate and the inherent information leakage Relationship; the experimental device to achieve effective measurement more complicated, thus limiting the practical application of the agreement.

To this end, researchers first theoretically improve the security proof of the RRDPS protocol.By constructing eavesdropper's general collective attack model and taking full account of the decoherence effect of the random phase on the eavesdropper's auxiliary state on each pulse of the encoding state, Out of the compactness of the eavesdropper on key information.This new security proves physically clear the security mechanism of the RRDPS protocol, significantly improves the performance of RRDPS, and provides security for other high dimensional QKD protocols The new ideas are given.The simulation results show that the key indexes such as the key rate and the security distance of RRDPS protocol have been significantly improved, and the number of required pulse packets L is greatly reduced compared with the original protocol.Experiments at 30km Fiber Channel to achieve a free error-detection key distribution; if combined with channel disturbance parameters, the safe distance can reach 140km.

This achievement is of great value for enriching the theory and method of security analysis of high dimensional quantum key distribution and improving the practicality of the system.

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