Shannon-limit approached information reconciliation for quantum key distribution

Abstract

Information reconciliation (IR) corrects the errors in sifted keys and ensures the correctness of quantum key distribution (QKD) systems. Polar codes-based IR schemes can achieve high reconciliation efficiency; however, the incidental high frame error rate decreases the secure key rate of QKD systems. In this article, we propose a Shannon-limit approached (SLA) IR scheme, which mainly contains two phases: the forward reconciliation phase and the acknowledgment reconciliation phase. In the forward reconciliation phase, the sifted key is divided into sub-blocks and performed with the improved block checked successive cancellation list decoder of polar codes. Afterward, only the failure corrected sub-blocks perform the additional acknowledgment reconciliation phase, which decreases the frame error rate of the SLA IR scheme. The experimental results show that the overall failure probability of SLA IR scheme is decreased to $$10^{-8}$$ 10 - 8 and the efficiency is improved to 1.091 with the IR block length of 128 Mb. Furthermore, the efficiency of the proposed SLA IR scheme is 1.055, approached to Shannon limit, when the quantum bit error rate is 0.02 and the input scale of 1 Gb, which is hundred times larger than the state-of-the-art implemented polar codes-based IR schemes.

Polar Codes-based Information Reconciliation Scheme with Frozen Bits Erasure Strategy for Quantum Key Distribution

“…The efficiency and the failure probability are shown in Table 3 of supplementary when the optimal yield is achieved and the list size L ∈ {1, 2, 8, 16, 32, 64}. Our scheme reaches the optimal yield of 0.8362 with the list size of 64, which is much higher than the conventional one-way polar codesbased IR schemes [12,[16][17][18]. The performance of polar codes-based IR schemes could be further improved by appending the feedback procedure or improving the decoders, such as the scheme in Ref.…”

“…The performance of polar codes-based IR schemes could be further improved by appending the feedback procedure or improving the decoders, such as the scheme in Ref. [18].…”

“…Moreover, the proposed FBE strategy can be directly adapted into the existing polar codes-based IR schemes to adapt the improved SCL decoders without true random numbers [18,25]. And the proposed polar codes-based IR scheme is suitable in the practical QKD systems with the ultra worse link conditions, such as the satellite-to-ground QKD systems and drone-based QKD systems.…”

“…In our previous work, we proposed the polar codesbased feedback IR scheme (with the BFD strategy), which decreased the failure probability to 10 −8 with the efficiency of 1.055 when the list size of SCL decoder is 16, the block size is 1 Gb and the QBER is 0.02 [18]. Nevertheless, the throughput of the polar codes-based IR scheme is limited by inefficient implementations.…”

Free-Running Long-Distance Reference-Frame-Independent Quantum Key Distribution

“…The sampling interval T is set to 5 seconds. The slice number m is set as 16 and the error correction efficiency is 1.16 [24].…”