Research On The Use Of Polar Codes In Quantum Key Distribution

Quantum communication is a new field which combines the characteristics of quantum mechanics with classical information science theory.With the help of complete security proof,quantum communication has incomparable advantages compared with classical communication.In recent years,it has been widely concerned and developed by all walks of life,especially quantum key distribution(QKD),because of its solid theoretical support and practical proof.It is gradually applied in commercial field.In this paper,we first introduce the development of traditional cryptography and the rise of quantum cryptography,as well as the proposed quantum key distribution based on unconditional security proof,which meets the security requirements of one-time-one-secret.Quantum secure communication theory is immature,laboratory short-distance verification,low bit rate gradually towards long-distance,networked,higher bit rate of commercial application development.However,although a large number of raw keys are obtained at each receiver of quantum communication,the security key coding rate generated by subsequent processing is very low.In order to further improve the communication distance and the security code coding rate,an efficient post-processing algorithm is necessary.This paper studies the post-processing flow of quantum key distribution.Aiming at the important link of data coordination which affects the net security code rate,a data coordination scheme based on polar codes is proposed.This scheme focuses on the effective construction of polar codes in BSC channel,fast coding algorithm and efficient decoding algorithm.According to the actual situation of quantum key distribution,a suitable application mode is proposed.Subsequently,the short code,medium-length code and long code schemes are simulated respectively,and the error-correcting efficiency under different code lengths and decoding algorithms is tested.Considering the flexibility and error-correcting performance,a 64 K medium-length code scheme is selected and compared with the existing schemes of Cascade,Turbo and LDPC.Cascade and LDPC can achieve high error-correcting efficiency.However,compared with Cascade,the polar codes scheme can complete error correction without multiple interactions.It has good real-time performance and improves the negotiation success rate under unstable channel conditions.At the same time,when the error rate is high,the polar codes scheme can provide higher error correction efficiency.Compared with LDPC,the polar codes scheme has lower coding and decoding complexity,and can adapt to higher data traffic.At the same time,the bit rate of LDPC is limited by the actual storage check matrix.It is difficult to maintain high error correction efficiency under all channel error conditions.The polar codes is flexible in construction,and shows stronger actual error correction performance in the actual collected quantum satellite experimental data.The feasibility of polar codes as a channel coding scheme with high throughput and efficiency in quantum key distribution system is verified by simulation and real data test results.