Continuous variable quantum key distribution multi-dimensional negotiation method based on Polar code and lossy compression

Abstract

The invention provides a continuous variable quantum key distribution multi-dimensional negotiation method based on a Polar code and lossy compression, and the method comprises the steps that a quantum information sender prepares a quantum state, the quantum state is transmitted to a quantum information receiver through a quantum channel, the quantum information receiver obtains an original key by measuring the quantum state, and the original key is transmitted to the quantum information receiver through a quantum channel; the quantum information sender and the quantum information receiver respectively carry out lossy compression based on the Polar code on the quantum state and the original key, respectively output a first binary sequence and a second binary sequence, then respectively carry out mapping operation on the first binary sequence and the second binary sequence, and output the first binary sequence and the second binary sequence; a first mapping sequence and a second mapping sequence are generated, and finally, the quantum information sender and the quantum information receiver use the first mapping sequence and the second mapping sequence to carry out a subsequent negotiation process; according to the method, the amount of information needing to be processed in multi-dimensional negotiation is reduced, and the burden of a classical channel during information transmission is reduced.

Description

Technical Field

[0001] The present invention relates to the field of quantum communication, and in particular to quantum key distribution, and in particular to a continuous variable quantum key distribution multidimensional negotiation method based on Polar code and lossy compression. Background Art

[0002] With the development of quantum computing technology, the classical cryptographic system based on computational complexity is facing unprecedented security challenges. Quantum Key Distribution (QKD) technology came into being. QKD is one of the important applications of quantum mechanics combined with quantum information theory. The basic principles of quantum mechanics guarantee the security of QKD. When QKD is combined with the "One-Time Pad" encryption protocol, a quantum secure communication system with unconditional security can be realized. Continuous Variable Quantum Key Distribution (CV-QKD) uses the orthogonal components of the light field as the carrier of information. Most of the devices are common to classical coherent optical communications and have good compatibility with traditional optical communication networks. It has the characteristics of simple operating conditions and rich applications. It has become a major research hotspot in recent years.

[0003] Slice negotiation scheme and multi-dimensional negotiation scheme are the two most commonly used negotiation schemes. Slice negotiation is only suitable for CV-QKD systems with short-distance secure key transmission due to its low negotiation efficiency. The multi-dimensional negotiation process does not require quantization operations, so its negotiation efficiency is relatively higher, making it more suitable for application in CV-QKD systems with long-distance secure key transmission than Slice negotiation. However, the multi-dimensional negotiation process requires processing a large amount of information, which has become a bottleneck for realizing high-throughput CV-QKD systems, leading to the problem of overload of classical channels and bringing certain information transmission pressure to the system. Summary of the invention

[0004] The object of the present invention is to provide a continuous variable quantum key distribution multi-dimensional negotiation method based on Polar code and lossy compression, which is used to solve the problems pointed out in the above background technology.

[0005] The present invention provides a multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression, the method comprising: step 1, according to the Gaussian approximation algorithm, s , the compression ratio is R sA Gaussian sequence is used to perform channel estimation, a reliability ranking of polarization subchannels under the Gaussian sequence is determined, and a high entropy bit set and a low entropy bit set are determined according to the reliability ranking of the polarization subchannels; wherein the high entropy bit set includes N polarization subchannels; and the low entropy bit set includes N s -N polarization sub-channels; N = N s ×R s ; Step 2: Under the premise of reverse multi-dimensional negotiation, the quantum information sender prepares a quantum state x, and transmits the quantum state x to the quantum information receiver through a quantum channel, so that the quantum information receiver measures the quantum state x to obtain an original key y associated with the quantum information sender; the quantum state x and the original key y obey Gaussian distribution, and the length of the quantum state x and the length of the original key y are both N s ; Step 3: The quantum information sender performs lossy compression on the quantum state x based on the high entropy bit set and the low entropy bit set to obtain a first binary sequence x s The quantum information sender performs lossy compression on the original key y based on the high entropy bit set and the low entropy bit set to obtain a second binary sequence y s ; Step 4: The quantum information sender sends the first binary sequence x s Perform a mapping operation to obtain the first mapping sequence x m ; The quantum information sender sends the second binary sequence y s Perform a mapping operation to obtain the second mapping sequence y m ; The first mapping sequence x m and the second mapping sequence y m obeys Gaussian distribution, and the first mapping sequence x m The length of the second mapping sequence y m The length of each of them is N; Step 5: the quantum information sender performs a quantum information mapping on the first mapping sequence x m The quantum information receiver groups the second mapping sequence y m to group the first mapping sequence x m Each d continuous Gaussian variable in the first d-dimensional vector is formed, and the second mapping sequence y mIn the step, each d continuous Gaussian variables form a second d-dimensional vector, and then the first d-dimensional vector and the second d-dimensional vector are normalized respectively to obtain the corresponding first normalized vector x′ and second normalized vector y′; step six, the quantum information receiver generates a key sequence u as the key sender, and performs Polar code encoding on the key sequence u to generate a code word c, and at the same time sends the norm information about the Polar code encoding to the key receiver through the classical channel; the quantum information sender acts as the key receiver; step seven, the key sender converts the code word c into is replaced by a spherical sequence c′; all elements of the spherical sequence c′ are located on a sphere centered at 0; Step 8, the key sender calculates a rotation mapping function according to the second normalized vector y′ and the spherical sequence c′, and sends the rotation mapping function to the key receiver through a classical channel; Step 9, the key receiver uses the rotation mapping function to perform rotation mapping on the first normalized vector x′ to obtain a noisy information sequence v; Step 10, the key receiver uses the norm information to perform Polar code decoding on the noisy information sequence v to obtain a decoding result Based on the decoding result Determine whether the decoding is successful; if the decoding fails, repeat steps 6 to 10 until the decoding is successful; if the decoding is successful, the key receiver and the key sender obtain the same security key; the security key is the decoding result

[0006] In the present invention, the two communicating parties (i.e., the quantum information sender and the quantum information receiver) use lossy compression based on Polar code to perform lossy compression on the quantum state x and the original key y, select the high entropy bit part as the effective information carrier, and obtain a shortened sequence x. m and m , achieving effective information compression; by combining lossy compression with multi-dimensional negotiation, the amount of information that needs to be processed during the multi-dimensional negotiation is reduced, thereby reducing the burden of classical channels during information transmission.

[0007] In one implementation of the present invention, in step 2, in, is the modulation variance of the quantum information sender; the quantum channel is an AWGN channel; the noise z of the quantum channel obeys Gaussian distribution, in, is the noise variance of the quantum channel;

[0008] y=x+z,y~N

[0009] In one implementation of the present invention, the step three includes: using the quantum state x to calculate the log-likelihood ratio, and then judging and outputting the polarization subchannel of the quantum state x based on the calculation result; if the polarization subchannel of the quantum state x belongs to the low entropy bit set, discarding it; if the polarization subchannel of the quantum state x belongs to the high entropy bit set, outputting the first binary sequence x through the first judgment formula s ; Wherein, the first decision formula is as follows:

[0010]

[0011] in, represents the LLR value of the polariton channel of the i-th bit in the quantum state x; i ranges from 1 to N s ; Indicates the conditions Greater than or equal to Indicates the conditions Greater than

[0012] The log-likelihood ratio is calculated using the original key y, and then the polarization subchannel of the original key y is judged and output based on the calculation result; if the polarization subchannel of the original key y belongs to the low entropy bit set, it is discarded; if the polarization subchannel of the original key y belongs to the high entropy bit set, the second binary sequence y is output through a second judgment formula s ; Wherein, the second decision formula is as follows:

[0013]

[0014] in, represents the LLR value of the polarization subchannel of the i-th bit in the original key y; Indicates the conditions Greater than or equal to Indicates the conditions Greater than

[0015] In one implementation of the present invention, in step 5,

[0016] x′=x m / ||x m ||;

[0017] y′=y m / ||y m ||;

[0018]

[0019] Wherein, d is the dimension of the reverse multi-dimensional negotiation, and the value of d is any one of the following: 1, 2, 4, 8; x m(i) Represents x m The i-th value in y m(i) Represents y m The i-th value in .

[0020] In one implementation of the present invention, in step six, the key sequence u is a binary sequence randomly generated by the quantum information receiver, and the length of the key sequence u is K; the length of the codeword c is N; K≤N.

[0021] In one implementation of the present invention, in step seven,

[0022]

[0023] Among them, c1, c2, c N Respectively represent the first, second, and Nth values ​​in the codeword c.

[0024] In one implementation of the present invention, in step eight, M(y′, c′)×y′=c′; wherein M(y′, c′) is the rotation mapping function.

[0025] In one implementation of the present invention, in step nine, v=M(y′,c′)×x′.

[0026] In one implementation of the present invention, the step ten includes: the key receiver calculates a decoding initialization message based on the norm information, and performs Polar code decoding on the noisy information sequence v based on the decoding initialization message to obtain the decoding result Determine the decoding result Is it equal to the generated key sequence u? If they are equal, the decoding is successful; if not, the decoding fails.

[0027] As described above, the continuous variable quantum key distribution multi-dimensional negotiation method based on Polar code and lossy compression described in the present invention has the following beneficial effects:

[0028] (1) The present invention provides a multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar codes and lossy compression. By utilizing lossy compression based on Polar codes to reduce the amount of information that needs to be processed in the multi-dimensional negotiation process, the problem of information transmission pressure caused by the need to process a large amount of information in the prior art is effectively alleviated.

[0029] (2) Compared with the traditional multi-dimensional negotiation scheme, the present invention shows significant advantages in greatly reducing the amount of information required to be processed in the multi-dimensional negotiation process, which is conducive to breaking the bottleneck of realizing a high-throughput CV-QKD system; the research of the present invention not only provides strong technical support for the actual deployment of the CV-QKD system, but also further broadens the application potential and scenarios of the CV-QKD system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Shown is a flowchart of a multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar codes and lossy compression as described in an embodiment of the present invention.

[0031] Figure 2 Shown is a schematic diagram of a multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar codes and lossy compression according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0033] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0034] See also Figure 1 and Figure 2. The following embodiments of the present invention provide a multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar codes and lossy compression. The present invention provides a multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar codes and lossy compression. By utilizing lossy compression based on Polar codes to reduce the amount of information that needs to be processed in the multi-dimensional negotiation process, the problem of information transmission pressure caused by the need to process a large amount of information in the multi-dimensional negotiation process in the prior art is effectively alleviated; compared with traditional multi-dimensional negotiation schemes, the present invention shows significant advantages in significantly reducing the amount of information that needs to be processed in the multi-dimensional negotiation process, which is conducive to breaking the bottleneck of realizing a high-throughput CV-QKD system; the research of the present invention not only provides strong technical support for the actual deployment of the CV-QKD system, but also further broadens the application potential and scenarios of the CV-QKD system.

[0035] The technical solutions in the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0036] like Figure 1 and Figure 2 As shown, in one embodiment, the present invention provides a multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression, the method comprising:

[0037] Step S1: use the Gaussian approximation algorithm to calculate the length of N s , the compression ratio is R s A Gaussian sequence is used to perform channel estimation, a polarization subchannel reliability ranking under the Gaussian sequence is determined, and a high entropy bit set and a low entropy bit set are determined according to the polarization subchannel reliability ranking.

[0038] Specifically, take the length N s Gaussian sequence, and set the compression rate of the Gaussian sequence to R s , performing channel estimation on the Gaussian sequence according to a Gaussian approximation algorithm to determine a reliability ranking of polarization subchannels under the Gaussian sequence.

[0039] In this embodiment, according to the reliability ranking of the polarization subchannels, N=N s ×R s subchannels are set to high entropy bit set E, and the remaining N s -N subchannels are set to low entropy bit set E c .

[0040] It should be noted that Gaussian approximation (GA) is a conventional technical means in this field. For details, please refer to the introduction in “https: / / marshallcomm.cn / 2017 / 03 / 07 / polar-code-4-encoding-chan-rel-est / ”, so it will not be described in detail here. In this embodiment, a Gaussian approximation algorithm is used to perform channel estimation on the Gaussian sequence to determine the reliability ranking of the polarization sub-channel under the Gaussian sequence. The conventional technical means in this field are also used. The main principle is to calculate the LLR using a simplified formula. The reliability of each sub-channel can be calculated by the reliability measurement formula, and the reliability ranking of the polarization sub-channel can be obtained.

[0041] It should be noted that LLR, the full English name: Log-Likelihood Ratio, is translated into Chinese as log-likelihood ratio.

[0042] Step S2: Under the premise of reverse multi-dimensional negotiation, the quantum information sender prepares a quantum state x, and transmits the quantum state x to the quantum information receiver through a quantum channel, so that the quantum information receiver measures the quantum state x to obtain the original key y associated with the quantum information sender.

[0043] It should be noted that quantum channels are used to transmit information-carrying or random quantum states.

[0044] In this embodiment, the quantum state x and the original key y obey Gaussian distribution.

[0045] It should be noted that reverse multi-dimensional negotiation refers to a method of negotiating the original key in a quantum key distribution system. In the process of quantum key distribution, due to channel noise and eavesdropper interference, the original keys obtained by the legitimate communicating parties may be asymmetric. In order to obtain a symmetric key, the original key needs to be negotiated during data post-processing. The multi-dimensional negotiation scheme can transform the information negotiation problem into a channel coding problem, and combined with high-performance error correction codes, it can achieve high key rate and long-distance secure key distribution.

[0046] In this embodiment, the lengths of the quantum state x and the original key y are the same as the length of the Gaussian sequence in step S1, that is, N s .

[0047] like Figure 1 and Figure 2 As shown, in one embodiment, in step S2, in, is the modulation variance of the quantum information sender; the quantum channel is an AWGN channel; the noise z of the quantum channel obeys Gaussian distribution, in, is the noise variance of the quantum channel;

[0048] y=x+z,y~N in, They represent the 1st, 2nd, ...Nth occurrences of x respectively. s values; They represent the first, second, ...Nth occurrences of y respectively. s value.

[0049] It should be noted that, in step S2, after the quantum information sender transmits the quantum state x to the quantum information receiver, the quantum information sender still contains the quantum state x.

[0050] It should be noted that AWGN, namely additive white Gaussian noise, is a mathematical model used to simulate the channel between the transmitter and the receiver. This model is a linearly increasing broadband noise with a constant spectral density and a Gaussian distributed amplitude. AWGN is not suitable for fading, intermodulation and interference tests.

[0051] Step S3: The quantum information sender performs lossy compression on the quantum state x based on the high entropy bit set and the low entropy bit set to obtain a first binary sequence x. s The quantum information sender performs lossy compression on the original key y based on the high entropy bit set and the low entropy bit set to obtain a second binary sequence y s .

[0052] In one embodiment, step S3 includes: calculating a log-likelihood ratio using the quantum state x, and then judging and outputting the polarization subchannel of the quantum state x based on the calculation result; if the polarization subchannel of the quantum state x belongs to the low entropy bit set, discarding it; if the polarization subchannel of the quantum state x belongs to the high entropy bit set, outputting the first binary sequence x through the first judgment formula s ; Wherein, the first decision formula is as follows:

[0053]

[0054] in, represents the LLR value of the polariton channel of the i-th bit in the quantum state x; i ranges from 1 to N s ; Indicates the conditions Greater than or equal to Indicates the conditions Greater than

[0055] It should be noted that wp represents a decision based on probability; specifically, by calculating and and compare the two values; if If the value of is larger or the two are equal, then x s is 0; if The value of is larger, then x s is 1.

[0056] The log-likelihood ratio is calculated using the original key y, and then the polarization subchannel of the original key y is judged and output based on the calculation result; if the polarization subchannel of the original key y belongs to the low entropy bit set, it is discarded; if the polarization subchannel of the original key y belongs to the high entropy bit set, the second binary sequence y is output through a second judgment formula s ; Wherein, the second decision formula is as follows:

[0057]

[0058] in, represents the LLR value of the polarization subchannel of the i-th bit in the original key y; i ranges from 1 to N s ; Indicates the conditions Greater than or equal to Indicates the conditions Greater than

[0059] Specifically, by calculating and and compare the two values; if If the value of is larger or the two are equal, then y s is 0; if The value of is larger, then it is determined that y s is 1.

[0060] It should be noted that the above calculation of the log-likelihood ratio (ie, LLR value) adopts conventional technical means in the art, so it will not be described in detail here.

[0061] Step S4: The quantum information sender sends the first binary sequence x s Perform a mapping operation to obtain the first mapping sequence x m ; The quantum information sender sends the second binary sequence y s Perform a mapping operation to obtain the second mapping sequence y m .

[0062] In this embodiment, the first mapping sequence x m and the second mapping sequence y m obeys Gaussian distribution, and the first mapping sequence x m The length of the second mapping sequence y m The length of is N.

[0063] Step S5: The quantum information sender performs a quantum information mapping on the first mapping sequence x m The quantum information receiver groups the second mapping sequence y m to group the first mapping sequence x m Each d continuous Gaussian variable in the first d-dimensional vector is formed, and the second mapping sequence y m Every d continuous Gaussian variables in form a second d-dimensional vector, and then the first d-dimensional vector and the second d-dimensional vector are normalized respectively to obtain the corresponding first normalized vector x′ and second normalized vector y′.

[0064] In one embodiment, in step S5,

[0065] x′=x m / ||x m ||;

[0066] y′=y m / ||y m ||;

[0067]

[0068]

[0069] Wherein, d is the dimension of the reverse multi-dimensional negotiation. According to the Hurwitz theorem of synthetic algebra, the value of d can be any of the following: 1, 2, 4, 8; x m(i) Represents x m The i-th value in y m(i) Represents y m The i-th value in .

[0070] Step S6: The quantum information receiver generates a key sequence u as a key sender, and encodes the key sequence u with a Polar code to generate a codeword c, and at the same time sends the norm information about the Polar code encoding to the key receiver through a classical channel.

[0071] In this embodiment, the quantum information sender serves as the key receiver.

[0072] It should be noted that the classical channel is used to ensure that some necessary information can be exchanged between the sender and receiver of quantum information.

[0073] It should be noted that Polar code is a forward error correction coding method used for signal transmission. Its core idea is to make each sub-channel present different reliability through channel polarization processing. When the code length continues to increase, some channels will tend to perfect channels with a capacity close to 1 (error-free), and other channels will tend to pure noise channels with a capacity close to 0. Choosing to directly transmit information on a channel with a capacity close to 1 to approach the channel capacity is the only method that can be strictly proved to reach the Shannon limit.

[0074] In one embodiment, in step S6, the key sequence u is a binary sequence randomly generated by the quantum information receiver, and the length of the key sequence u is K; the length of the codeword c is N; K≤N.

[0075] Step S7: The key sender converts the codeword c into a spherical sequence c′.

[0076] In this embodiment, all elements of the spherical sequence c′ are located on a sphere with 0 as the center.

[0077] In one embodiment, in step S7,

[0078]

[0079] Among them, c1, c2, c N Respectively represent the first, second, and Nth values ​​in the codeword c.

[0080] Step S8: The key sender calculates a rotation mapping function according to the second normalized vector y′ and the spherical sequence c′, and sends the rotation mapping function to the key receiver through a classical channel.

[0081] In one embodiment, in step S8, M(y′, c′)×y′=c′; wherein M(y′, c′) is the rotation mapping function.

[0082] Step S9: The key receiver uses the rotation mapping function to perform rotation mapping on the first normalized vector x′ to obtain a noisy information sequence v.

[0083] In one embodiment, in step S9, v=M(y′,c′)×x′.

[0084] Step S10: The key receiver uses the norm information to perform Polar code decoding on the noisy information sequence v to obtain a decoding result. Based on the decoding result Determine whether the decoding is successful.

[0085] If the decoding fails, repeat the steps S6 to S10, the key sender continues to generate the key sequence, and calculates the rotation mapping function and sends it to the key receiver until the key receiver decodes successfully; if the decoding is successful, the key receiver and the key sender obtain the same security key; the security key is the decoding result

[0086] In one embodiment, the step S10 includes: the key receiver calculates a decoding initialization message based on the norm information, and performs Polar code decoding on the noisy information sequence v based on the decoding initialization message to obtain the decoding result Determine the decoding result Is it equal to the generated key sequence u? If they are equal, the decoding is successful; if not, the decoding fails.

[0087] Specifically, the calculation formula for decoding the initialization message is as follows:

[0088]

[0089] Among them, L(v i ) indicates decoding initialization message; v i Represents the i-th value of the noisy information sequence v; i ranges from 1 to N.

[0090] It should be noted that the above i represents an index bit.

[0091] It should be noted that in the multi-dimensional negotiation scheme of the prior art, the communicating parties (i.e., the quantum information sender and the quantum information receiver) need to process a large amount of information and transmit a large amount of information through a classical channel; in the present invention, the quantum state x and the original key y are lossily compressed, and the high entropy bit part is selected as the effective information carrier to obtain a shortened sequence x m and m (by length N s shortened to N), achieving effective lossy compression of the quantum state x and the original key y, thereby reducing the amount of information that needs to be processed in multi-dimensional negotiation and reducing the burden of classical channels during information transmission.

[0092] The protection scope of the continuous variable quantum key distribution multi-dimensional negotiation method based on Polar code and lossy compression described in the embodiment of the present invention is not limited to the execution order of the steps listed in this embodiment. All solutions implemented by adding, reducing or replacing steps in the prior art based on the principles of the present invention are included in the protection scope of the present invention.

[0093] Those of ordinary skill in the art should further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0094] The descriptions of the processes or structures corresponding to the above-mentioned figures have different emphases. For parts that are not described in detail in a certain process or structure, please refer to the relevant descriptions of other processes or structures.

[0095] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar codes and lossy compression, characterized in that: The method comprises: Step 1: Use the Gaussian approximation algorithm to calculate the length of N s , the compression ratio is R s A Gaussian sequence is used to perform channel estimation, a reliability ranking of polarization subchannels under the Gaussian sequence is determined, and a high entropy bit set and a low entropy bit set are determined according to the reliability ranking of the polarization subchannels; wherein the high entropy bit set includes N polarization subchannels; and the low entropy bit set includes N s -N polarization sub-channels; N = N s ×R s ; Step 2: Under the premise of reverse multi-dimensional negotiation, the quantum information sender prepares a quantum state x, and transmits the quantum state x to the quantum information receiver through a quantum channel, so that the quantum information receiver measures the quantum state x to obtain an original key y associated with the quantum information sender; the quantum state x and the original key y obey Gaussian distribution, and the length of the quantum state x and the length of the original key y are both N s ; Step 3: The quantum information sender performs lossy compression on the quantum state x based on the high entropy bit set and the low entropy bit set to obtain a first binary sequence x s The quantum information sender performs lossy compression on the original key y based on the high entropy bit set and the low entropy bit set to obtain a second binary sequence y s ; Step 4: The quantum information sender sends the first binary sequence x s Perform a mapping operation to obtain the first mapping sequence x m ; The quantum information sender sends the second binary sequence y s Perform a mapping operation to obtain the second mapping sequence y m ; The first mapping sequence x m and the second mapping sequence y m obeys Gaussian distribution, and the first mapping sequence x m The length of the second mapping sequence y m The length of is N; Step 5: The quantum information sender performs the first mapping sequence x m The quantum information receiver groups the second mapping sequence y m to group the first mapping sequence x m Each d continuous Gaussian variable in the first d-dimensional vector is formed, and the second mapping sequence y m Each d continuous Gaussian variables in the vector form a second d-dimensional vector, and then the first d-dimensional vector and the second d-dimensional vector are normalized respectively to obtain a corresponding first normalized vector x′ and a second normalized vector y′; Step 6: The quantum information receiver acts as the key sender to generate a key sequence u, and performs Polar code encoding on the key sequence u to generate a codeword c, and at the same time sends the norm information about the Polar code encoding to the key receiver through a classical channel; the quantum information sender acts as the key receiver; Step 7: The key sender converts the codeword c into a spherical sequence c′; all elements of the spherical sequence c′ are located on a sphere centered at 0; Step 8: The key sender calculates a rotation mapping function according to the second normalized vector y′ and the spherical sequence c′, and sends the rotation mapping function to the key receiver through a classical channel; Step nine, the key receiver uses the rotation mapping function to perform rotation mapping on the first normalized vector x′ to obtain a noisy information sequence v; Step 10: The key receiver uses the norm information to perform Polar code decoding on the noisy information sequence v to obtain a decoding result. Based on the decoding result Determine whether the decoding is successful; If the decoding fails, repeat steps 6 to 10 until the decoding succeeds; If the decoding is successful, the key receiver and the key sender obtain the same security key; the security key is the decoding result.

2. The multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression according to claim 1, characterized in that: In the step 2, in, is the modulation variance of the quantum information sender; the quantum channel is an AWGN channel; the noise z of the quantum channel obeys Gaussian distribution, in, is the noise variance of the quantum channel; 3. The multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression according to claim 1, characterized in that: The step three comprises: using the quantum state x to calculate the log-likelihood ratio, and then judging and outputting the polarization subchannel of the quantum state x based on the calculation result; If the polariton channel of the quantum state x belongs to the low entropy bit set, discard it; If the polariton channel of the quantum state x belongs to the high entropy bit set, the first binary sequence x is outputted by the first decision formula. s ; Wherein, the first decision formula is as follows: in, represents the LLR value of the polariton channel of the i-th bit in the quantum state x; i ranges from 1 to N s ; Indicates the conditions Greater than or equal to Indicates the conditions Greater than Calculating a log-likelihood ratio using the original key y, and then determining and outputting a polarization subchannel of the original key y based on the calculation result; If the polarization subchannel of the original key y belongs to the low entropy bit set, discard it; If the polarization subchannel of the original key y belongs to the high entropy bit set, the second binary sequence y is outputted through the second decision formula s ; Wherein, the second decision formula is as follows: Among them, LLRy Ns (i) represents the LLR value of the polarization subchannel of the i-th bit in the original key y; Indicates the conditions Greater than or equal to Indicates the conditions Greater than 4. The multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression according to claim 1, characterized in that: In the step five, x′=x m / ||x m ||; and′=y m / ||and m ||; Wherein, d is the dimension of the reverse multi-dimensional negotiation, and the value of d is any one of the following: 1, 2, 4, 8; x m(i) Represents x m The i-th value in y m(i) Represents y m The i-th value in .

5. The multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression according to claim 1, characterized in that: In step six, the key sequence u is a binary sequence randomly generated by the quantum information receiver, and the length of the key sequence u is K; the length of the codeword c is N; K≤N.

6. The multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression according to claim 1, characterized in that: In the step seven, Among them, c1, c2, c N Respectively represent the first, second, and Nth values ​​in the codeword c.

7. The multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression according to claim 1, characterized in that: In the step eight, M(y′, c′)×y′=c′; wherein M(y′, c′) is the rotation mapping function.

8. The multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression according to claim 7, characterized in that: In the step nine, v=M(y′,c′)×x′.

9. The multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression according to claim 1, characterized in that: The step ten includes: the key receiver calculates a decoding initialization message based on the norm information, and performs Polar code decoding on the noisy information sequence v based on the decoding initialization message to obtain the decoding result Determine the decoding result Is it equal to the key sequence u? If they are equal, the decoding is successful; if they are not equal, the decoding fails.

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