QKD post-processing data negotiation method based on polarization code

Abstract

The invention discloses a polarization code-based QKD post-processing data negotiation method, which is used for a QKD system, the QKD system comprises N pairs of senders and receivers, N is greater than or equal to 1, and the method comprises the following steps: S1, obtaining a first sequence through a polarization code construction algorithm; s2, encoding to obtain a second sequence; s3, performing XOR operation to generate a third sequence; s4, sending the third sequence to a receiver; s5, performing XOR operation to generate a fourth sequence; s6, decoding and coding the fourth sequence to obtain an errorless polarization code sequence; and S7, performing an XOR operation to obtain a final safe screening key, and completing data negotiation. The invention discloses a QKD post-processing data negotiation method based on a polarization code, which carries out data negotiation by taking the polarization code as a carrier, and transfers errors generated by quantum channel transmission in a QKD process to a classical polarization code for error correction, so that the overall complexity of the scheme is relatively low, and the negotiation efficiency is effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of quantum secure communication and quantum network technology, and in particular to a QKD post-processing data negotiation method based on polarization codes. Background Art

[0002] Quantum Key Distribution (QKD) uses the principles of quantum mechanics and combines it with One Time Pad (OTP) technology to provide a theoretically unconditionally secure solution for key distribution in actual systems.

[0003] QKD mainly includes quantum physics control and post-processing. Due to the existence of eavesdropping, the key transmitted through the quantum channel is only partially secure. In order to obtain a completely secure key, the two communicating parties (sender Alice and receiver Bob) also need to perform post-processing through the classical channel, such as Figure 1 The quality of the post-processing process will directly affect the final security coding rate of the system, which generally includes key screening, parameter estimation, data negotiation, confidentiality enhancement and other operations. Among them, data negotiation is the most complex part of data processing in the post-processing process.

[0004] According to Shannon's second theorem, if the information transmission rate R is not greater than the channel capacity C, channel coding can be used to make the errors generated by information transmission arbitrarily small. The function of data negotiation is to use some error correction technology to eliminate the differences in the screening code. The key output by data negotiation is called the negotiation code. The key characteristics at this time are no bit errors and partial security. Compared with the input key characteristics of partial bit errors and partial security, the data negotiation process eliminates the erroneous parts of the screening code, thereby improving the security of the codeword.

[0005] However, the existing data negotiation schemes are highly complex, and the negotiation efficiency of the QKD system post-processing process is relatively low. Summary of the invention

[0006] In order to solve the problem of low negotiation efficiency of existing data negotiation solutions, the present invention provides a QKD post-processing data negotiation method based on polarization codes.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A QKD post-processing data negotiation method based on polarization code is used in a QKD system, wherein the QKD system includes N pairs of senders and receivers, N≥1, and the method includes performing the following steps at the sender:

[0009] S1: obtain the first sequence through the polar code construction algorithm;

[0010] S2: Encode the first sequence to obtain a second sequence;

[0011] S3: performing an XOR operation on the second sequence and the screening key sequence of the sender to generate a third sequence;

[0012] S4: sending the third sequence to the receiver via the classical channel;

[0013] And perform the following steps on the receiving side:

[0014] S5: performing an XOR operation on the third sequence and the screening key sequence of the receiver to generate a fourth sequence;

[0015] S6: Decode and re-encode the fourth sequence to obtain a correct polar code sequence;

[0016] S7: Perform an XOR operation on the polar code sequence and the third sequence to obtain a final secure screening key, thereby completing data negotiation.

[0017] In the above scheme, data negotiation is carried out by using polarization codes as carriers, and the errors generated by quantum channel transmission in the QKD process are transferred to classical polarization codes for error correction. The overall complexity of the scheme is low, which effectively improves the negotiation efficiency.

[0018] Preferably, the polar code construction algorithm is a polar code construction algorithm based on a genetic algorithm.

[0019] Preferably, the specific steps of the polar code construction algorithm based on the genetic algorithm are as follows:

[0020] S11: Generate codeword structures under different signal-to-noise ratio conditions as the initial population;

[0021] S12: Calculate the fitness of each individual in the population and perform selection operations based on the fitness;

[0022] S13: Perform mutation and crossover operations on the individuals left by the selection operation, and the resulting offspring individuals are combined into a new population;

[0023] S14: Repeat steps S12 and S13 until the preset maximum number of evolution times is reached;

[0024] S15: Select an optimal solution from the output codeword set to obtain an optimal codeword structure.

[0025] Preferably, in step S11, a Gaussian approximation construction algorithm is used to generate codeword structures under different signal-to-noise ratio conditions.

[0026] Preferably, in step S12, the selection operation is specifically: according to the truncation selection method, sorting is performed according to fitness, and excellent individuals are selected to be retained, and other individuals are eliminated.

[0027] Preferably, the fitness is a block error rate of a codeword.

[0028] Preferably, in step S13, the crossover operation is a single-point crossover operation, specifically: randomly selecting a crossover point between two parent individuals, then performing segmentation and exchanging information, thereby obtaining two different offspring individuals.

[0029] Preferably, the decoding adopts an SCL decoding algorithm, an SC decoding algorithm or a CRC-SCL decoding algorithm.

[0030] Preferably, the correct polar code sequence obtained in step S6 is the same as the second sequence.

[0031] Beneficial technical effects of the present invention:

[0032] The present invention provides a QKD post-processing data negotiation method based on polarization codes. By using polarization codes as carriers for data negotiation, the errors generated by quantum channel transmission in the QKD process are transferred to classical polarization codes for error correction. The overall complexity of the scheme is low, and the negotiation efficiency is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a principle block diagram of the QKD process in the prior art;

[0034] Figure 2 It is a schematic diagram of the implementation process of the technical solution of the present invention;

[0035] Figure 3 It is a schematic diagram of the single-point crossover operation in the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments, but the scope of protection claimed in the present invention is not limited to the following specific embodiments.

[0037] Example 1

[0038] like Figure 2 As shown, a QKD post-processing data negotiation method based on polarization code is used in a QKD system, wherein the QKD system includes N pairs of senders and receivers, N≥1, and the method includes performing the following steps at the sender:

[0039] S1: Obtain the first sequence (sequence to be encoded) {00u2u30u5u6} according to the true random number sequence {u2u3u5u6} through the polar code construction algorithm;

[0040] S2: Encode the first sequence {00u2u30u5u6} to obtain the second sequence {w0w1w2w3w4w5w6};

[0041] S3: Perform an XOR operation on the second sequence and the sender's screening key sequence {x0x1x2x3x4x5x6} to generate a third sequence;

[0042] S4: sending the third sequence to the receiver via the classical channel;

[0043] And perform the following steps on the receiving side:

[0044] S5: Perform an XOR operation on the third sequence and the receiver's screening key sequence (incorrect screening key) {y0y1y2y3y4y5y6} to generate a fourth sequence {z0z1z2z3z4z5z6};

[0045] S6: Decode and re-encode the fourth sequence to obtain a correct polar code sequence {00u2u30u5u6};

[0046] S7: Perform an XOR operation on the polar code sequence {00u2u30u5u6} and the third sequence to obtain the final secure screening key {x0x1x2x3x4x5x6}, and complete the data negotiation.

[0047] During the specific implementation process, data negotiation is carried out by using polarization codes as the carrier, and the errors generated by quantum channel transmission in the QKD process are transferred to classical polarization codes for error correction. The overall complexity of the solution is low, which effectively improves the negotiation efficiency.

[0048] More specifically, the specific steps of the polar code construction algorithm based on the genetic algorithm are as follows:

[0049] S11: Generate codeword structures under different signal-to-noise ratio conditions as the initial population;

[0050] S12: Calculate the fitness of each individual in the population and perform selection operations based on the fitness;

[0051] S13: Perform mutation and crossover operations on the individuals left by the selection operation, and the resulting offspring individuals are combined into a new population;

[0052] S14: Repeat steps S12 and S13 until the preset maximum number of evolution times is reached;

[0053] S15: Select an optimal solution from the output codeword set to obtain an optimal codeword structure.

[0054] More specifically, in step S11, a Gaussian approximation construction algorithm is used to generate codeword structures under different signal-to-noise ratio conditions.

[0055] More specifically, in step S12, the selection operation is as follows: according to the truncation selection method, the individuals are sorted according to fitness, and the excellent individuals are selected to be retained, and the other individuals are eliminated.

[0056] More specifically, the fitness is the block error rate of the codeword.

[0057] In the specific implementation process, the block error rate can directly show the performance of the codeword and facilitate statistical analysis.

[0058] The process of using the SCL decoding algorithm is as follows: first, the received channel information and decoding variables are initialized, and the various parameters required for decoding are calculated based on the acquired information; then the SCL cyclic decoding is started. If the decoding is successful, nums is increased by one, otherwise it remains unchanged. The loop is exited until the maximum number of runs is reached, and the block error rate BLERs is counted. Among them, nums is the number of times the codeword passes the decoding.

[0059] More specifically, if Figure 3 As shown, in step S13, the crossover operation is a single-point crossover operation, specifically: randomly selecting a crossover point between two parent individuals, then performing segmentation and exchanging information, thereby obtaining two different offspring individuals.

[0060] More specifically, the decoding adopts an SCL decoding algorithm, an SC decoding algorithm or a CRC-SCL decoding algorithm.

[0061] More specifically, the correct polar code sequence obtained in step S6 is the same as the second sequence.

[0062] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A QKD post-processing data negotiation method based on polarization code, used in a QKD system, wherein the QKD system includes N pairs of senders and receivers, N≥1, characterized in that: The method comprises performing the following steps at the sending side: S1: obtain the first sequence through the polar code construction algorithm; S2: Encode the first sequence to obtain a second sequence; S3: performing an XOR operation on the second sequence and the screening key sequence of the sender to generate a third sequence; S4: sending the third sequence to the receiver via the classical channel; And perform the following steps on the receiving side: S5: performing an XOR operation on the third sequence and the screening key sequence of the receiver to generate a fourth sequence; S6: Decode and re-encode the fourth sequence to obtain a correct polar code sequence; S7: Perform an XOR operation on the polar code sequence and the third sequence to obtain a final secure screening key, thereby completing data negotiation.

2. According to claim 1, a QKD post-processing data negotiation method based on polarization code is characterized in that: The polar code construction algorithm is a polar code construction algorithm based on a genetic algorithm.

3. The method for negotiating QKD post-processing data based on polarization code according to claim 2, characterized in that: The specific steps of the polar code construction algorithm based on genetic algorithm are as follows: S11: Generate codeword structures under different signal-to-noise ratio conditions as the initial population; S12: Calculate the fitness of each individual in the population and perform selection operations based on the fitness; S13: Perform mutation and crossover operations on the individuals left by the selection operation, and the resulting offspring individuals are combined into a new population; S14: Repeat steps S12 and S13 until the preset maximum number of evolution times is reached; S15: Select an optimal solution from the output codeword set to obtain an optimal codeword structure.

4. The method for negotiating QKD post-processing data based on polarization code according to claim 3, characterized in that: In step S11, a Gaussian approximation construction algorithm is used to generate codeword structures under different signal-to-noise ratio conditions.

5. The method for negotiating QKD post-processing data based on polarization code according to claim 3, characterized in that: In step S12, the selection operation is specifically as follows: according to the truncation selection method, the individuals are sorted according to fitness, the excellent individuals are selected and retained, and the other individuals are eliminated.

6. A QKD post-processing data negotiation method based on polarization code according to claim 3 or 5, characterized in that: The fitness is the block error rate of the codeword.

7. The method for negotiating QKD post-processing data based on polarization code according to claim 3, characterized in that: In step S13, the crossover operation is a single-point crossover operation, specifically: randomly selecting a crossover point between two parent individuals, then performing segmentation and exchanging information, thereby obtaining two different offspring individuals.

8. The method for negotiating QKD post-processing data based on polarization code according to claim 1, characterized in that: The decoding adopts SCL decoding algorithm, SC decoding algorithm or CRC-SCL decoding algorithm.

9. The method for negotiating QKD post-processing data based on polarization code according to claim 1, characterized in that: The correct polar code sequence obtained in step S6 is the same as the second sequence.

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