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

Abstract

The application provides a continuous variable quantum key distribution multi-dimensional negotiation method based on a Polar code and lossy compression, and the method comprises the following steps: a quantum information sender prepares a quantum state, transmits the quantum state to a quantum information receiver through a quantum channel, the quantum information receiver obtains an original key by measuring the quantum state, the quantum information sender and the quantum information receiver respectively perform lossy compression on the quantum state and the original key based on a Polar code, and respectively output a first binary sequence and a second binary sequence, then, the quantum information sender and the quantum information receiver respectively perform mapping operations on the first binary sequence and the second binary sequence, and generate a first mapping sequence and a second mapping sequence, finally, the quantum information sender and the quantum information receiver utilize the first mapping sequence and the second mapping sequence to perform a subsequent negotiation process; the application reduces the amount of information to be processed in multi-dimensional negotiation, and reduces the burden of a classical channel in information transmission.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of quantum communication, and relates to quantum key distribution, in particular to continuous variable quantum key distribution, and specifically to a continuous variable quantum key distribution multi-dimensional negotiation method based on Polar code and lossy compression. BACKGROUND

[0002] With the development of quantum computing technology, the classical cryptosystem based on computational complexity is facing unprecedented security challenges. Quantum key distribution (QKD) technology emerges as the times require. QKD is one of the important applications of quantum mechanics combined with quantum information theory, and 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 optical field as the carrier of information, most of the devices are compatible with classical coherent optical communication, and have good compatibility with traditional optical communication networks, simple operation conditions, rich applications, and have become a 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 short-distance key secure transmission CV-QKD system due to its low negotiation efficiency. The multi-dimensional negotiation process does not require quantization operation, so its negotiation efficiency is relatively higher, and it is more suitable for application to long-distance key secure transmission CV-QKD system than Slice negotiation. However, the multi-dimensional negotiation process needs to process a large amount of information, which becomes the bottleneck of realizing high-throughput CV-QKD system, resulting in the problem of heavy burden of classical channel, which brings certain information transmission pressure to the system. SUMMARY

[0004] The purpose of the present application 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 background.

[0005] The present application provides a continuous variable quantum key distribution multi-dimensional negotiation method based on Polar code and lossy compression, which comprises the following steps: step one, according to the Gaussian approximation algorithm, the length of the binary sequence is N s , the compression rate is R schannel estimation based on a Gaussian sequence, determining a polarization subchannel reliability ranking under the Gaussian sequence, and determining a high-entropy bit set and a low-entropy bit set according to the polarization subchannel reliability ranking; wherein the high-entropy bit set includes N polarization subchannels; the low-entropy bit set includes N s polarization subchannels; N = N s × R s ; step two, under the premise of reverse multi-dimensional negotiation, a quantum information sender prepares a quantum state x, and transmits the quantum state x to a 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 are subject to Gaussian distribution, and the length of the quantum state x and the length of the original key y are both N s ; step three, the quantum information sender losslessly compresses 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 losslessly compresses 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 four, the quantum information sender performs mapping operation on the first binary sequence x s to obtain a first mapping sequence x m ; the quantum information sender performs mapping operation on the second binary sequence y s to obtain a second mapping sequence y m ; the first mapping sequence x m and the second mapping sequence y m are subject to Gaussian distribution, and the length of the first mapping sequence x m and the length of the second mapping sequence y m are both N; step five, the quantum information sender groups the first mapping sequence x m , and the quantum information receiver groups the second mapping sequence y m , so as to respectively form a first d-dimensional vector composed of every d continuous Gaussian variables in the first mapping sequence x m and the second mapping sequence y mIn each d continuous Gaussian variables, a second d-dimensional vector is formed, and then a corresponding first normalized vector x' and a second normalized vector y' are obtained by normalizing the first d-dimensional vector and the second d-dimensional vector respectively; in step six, the quantum information receiver as a key sender generates a key sequence u, and the key sequence u is encoded by a Polar code to generate a code word c, and the norm information about the Polar code encoding is sent to the key receiver through a classical channel; the quantum information sender as the key receiver; in step seven, the key sender converts the code word c into a spherical sequence c'; all elements of the spherical sequence c' are located on a spherical surface with 0 as the center; in step eight, 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; in step nine, the key receiver rotates the first normalized vector x' by using the rotation mapping function to obtain a noisy information sequence v; in step ten, the key receiver decodes the noisy information sequence v by using the norm information to obtain a decoding result and judges whether the decoding is successful based on the decoding result If the decoding fails, the steps six to ten are repeated until the decoding is successful; if the decoding is successful, the key receiver and the key sender obtain a consistent secure key; the secure key is the decoding result

[0006] In the application, both communication parties (i.e. the quantum information sender and the quantum information receiver) use lossy compression based on a Polar code to perform lossy compression on quantum states x and original keys y, filter out high-entropy bit parts as effective information carriers, and obtain length-reduced sequences x m and y m , so as to realize effective information compression; by combining lossy compression with multi-dimensional negotiation, the amount of information to be processed in the multi-dimensional negotiation process is reduced, thereby reducing the burden of the classical channel in information transmission.

[0007] In an implementation manner of the application, in the step two, wherein, is the modulation variance of the quantum information sender; the quantum channel is an AWGN channel; the noise z of the quantum channel obeys a Gaussian distribution, wherein, is the noise variance of the quantum channel;

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

[0009] In an implementation form of the present application, the step three comprises: performing log-likelihood ratio (LLR) calculation on the quantum state x, and then outputting a decision of the polar sub-channels of the quantum state x based on the calculation result; if the polar sub-channels of the quantum state x belong to the low-entropy bit set, discarding; if the polar sub-channels of the quantum state x belong to the high-entropy bit set, outputting the first binary sequence x by a first decision formula s ; wherein the first decision formula is as follows:

[0010]

[0011] wherein, represents an LLR value of the i th bit of the quantum state x; i is 1 to N s ; represents a condition greater than or equal to represents a condition greater than

[0012] performing log-likelihood ratio (LLR) calculation on the original key y, and then outputting a decision of the polar sub-channels of the original key y based on the calculation result; if the polar sub-channels of the original key y belong to the low-entropy bit set, discarding; if the polar sub-channels of the original key y belong to the high-entropy bit set, outputting the second binary sequence y by a second decision formula s ; wherein the second decision formula is as follows:

[0013]

[0014] wherein, represents an LLR value of the i th bit of the original key y; represents a condition greater than or equal to represents a condition greater than

[0015] In an implementation form of the present application, in the step five,

[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, the value of d is any one of the following: 1, 2, 4, 8; x m(i) represents x m represents the i th value in y m(i) represents y m represents the i th value in y.

[0020] In an implementation form of the present application, in the step six, the raw key sequence u is a binary sequence randomly generated by the quantum information receiver, and the length of the raw key sequence u is K; the length of the code word c is N; K≤N.

[0021] In an implementation form of the present application, in the step seven,

[0022]

[0023] Wherein, c1, c2, c N respectively represent the 1st, 2nd and Nth values in the code word c.

[0024] In an implementation form of the present application, in the step eight, M(y', c') x y' = c'; wherein, M(y', c') is the rotation mapping function.

[0025] In an implementation form of the present application, in the step nine, v = M(y', c') x x'.

[0026] In an implementation form of the present application, the step ten comprises: 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 judges whether the decoding result is equal to the raw key sequence u; if equal, the decoding is successful; if not equal, the decoding fails.

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

[0028] (1) The present application provides a continuous variable quantum key distribution multi-dimensional negotiation method based on Polar code and lossy compression, which reduces the amount of information to be processed in the multi-dimensional negotiation process by using lossy compression based on Polar code, effectively alleviating 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.

[0029] (2) Compared with the traditional multi-dimensional negotiation scheme, the present application has a significant advantage in greatly reducing the amount of information required to be processed in the multi-dimensional negotiation process, which is beneficial to break the bottleneck of realizing a high-throughput CV-QKD system. The research of the present application not only provides strong technical support for the practical deployment of the CV-QKD system, but also further widens the application potential and scene of the CV-QKD system. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A flow chart of the continuous variable quantum key distribution multi-dimensional negotiation method based on Polar code and lossy compression according to the embodiment of the present application is shown.

[0031] Figure 2 A principle diagram of the continuous variable quantum key distribution multi-dimensional negotiation method based on Polar code and lossy compression according to the embodiment of the present application is shown. DETAILED DESCRIPTION

[0032] The embodiments of the present application will be described in detail below with specific reference to specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification. The present application can also be implemented or applied by different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application. 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 diagrams provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner, and only show the components related to the present application, not the number, shape and size of the components when actually implemented. The actual implementation of each component may be randomly changed in type, number and proportion, and the component layout pattern may be more complex.

[0034] Reference is made to Figure 1 and Figure 2The following embodiments of the present application provide a multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression. The present application provides a multi-dimensional negotiation method for continuous variable quantum key distribution based on Polar code and lossy compression. By using lossy compression based on Polar code, the amount of information to be processed in the multi-dimensional negotiation process is reduced, effectively alleviating 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. Compared with the traditional multi-dimensional negotiation scheme, the present application has significant advantages in significantly reducing the amount of information to be processed in the multi-dimensional negotiation process, which is beneficial to break the bottleneck of realizing a high-throughput CV-QKD system. The research of the present application not only provides strong technical support for the actual deployment of the CV-QKD system, but also further widens the application potential and scene of the CV-QKD system.

[0035] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings in the embodiments of the present application.

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

[0037] Step S1, according to the Gaussian approximation algorithm, channel estimation is performed on a Gaussian sequence with length N s and compression rate R s , the polarization subchannel reliability order under the Gaussian sequence is determined, and the high-entropy bit set and the low-entropy bit set are determined according to the polarization subchannel reliability order.

[0038] Specifically, a Gaussian sequence with length N s is taken, and the compression rate of the Gaussian sequence is set to R s . According to the Gaussian approximation algorithm, channel estimation is performed on the Gaussian sequence to determine the polarization subchannel reliability order under the Gaussian sequence.

[0039] In this embodiment, according to the polarization subchannel reliability order, N=N s ×R s subchannels with higher channel reliability are set as a high-entropy bit set E, and the remaining N s -N subchannels are set as a low-entropy bit set E c .

[0040] It should be noted that the Gaussian approximation (GA) is a conventional technical means in the art, and details can be referred to the introduction in https: / / marshallcomm.cn / 2017 / 03 / 07 / polar-code-4-encoding-channel-est / and will not be described in detail here; in the embodiment, the Gaussian approximation algorithm is used to perform channel estimation on the Gaussian sequence to determine the reliability ordering of the polar sub-channels under the Gaussian sequence, and the main principle is to calculate the LLR by using the simplified formula, and the reliability of each sub-channel can be calculated by the reliability measurement formula, and the reliability ordering of the polar sub-channels is obtained.

[0041] It should be noted that LLR, the full name in English: Log-Likelihood Ratio, Chinese translation: 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 an original key y associated with the quantum information sender.

[0043] It should be noted that the quantum channel is used to transmit quantum states carrying information or randomness.

[0044] In the embodiment, the quantum state x and the original key y are subject to Gaussian distribution.

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

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

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

[0048] y=x+z, y~N Wherein, Respectively represent the first, second, …, N s Value of x; Respectively represent the first, second, …, N s Value of y.

[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 for simulating the channel between the transmitter and the receiver. This model is a linearly increasing wideband noise with constant spectral density and Gaussian distribution of amplitude. AWGN is not suitable for fading, intermodulation and interference test.

[0051] Step S3, the quantum information sender lossy compresses the quantum state x based on the high entropy bit set and the low entropy bit set, and obtains a first binary sequence x s ; the quantum information sender lossy compresses the original key y based on the high entropy bit set and the low entropy bit set, and obtains a second binary sequence y s .

[0052] In an embodiment, the step S3 includes: calculating the log-likelihood ratio (LLR) of the quantum state x, and then 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, it is discarded; if the polarization subchannel of the quantum state x belongs to the high entropy bit set, the first binary sequence x s Is output through the first decision formula; wherein the first decision formula is as follows:

[0053]

[0054] Wherein, LLR value of the polarization subchannel of the i-th bit in the quantum state x; i takes 1 to N s ; Indicates that the condition Is greater than or equal to Indicates that the condition Is greater than

[0055] It should be noted that w.p. represents a decision made based on probability; specifically, by calculating the values of and respectively, and comparing the sizes of the two; if the value of is larger or the two are equal, it is determined that x s is 0; if the value of is larger, it is determined that x s is 1.

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

[0057]

[0058] wherein, represents the LLR value of the polarization sub-channel of the i-th bit in the original key y; i takes 1 to N s . represents the condition is greater than or equal to represents the condition is greater than

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

[0060] It should be noted that the calculation of the log-likelihood ratio (i.e. the LLR value) described above uses conventional technical means in the art, and therefore will not be described in detail here.

[0061] Step S4, the quantum information sender performs mapping operation on the first binary sequence x s to obtain a first mapping sequence x m ; the quantum information sender performs mapping operation on the second binary sequence y s to obtain a second mapping sequence y m .

[0062] In the embodiment, the first mapping sequence x m and the second mapping sequence y m are subject to Gaussian distribution, and the length of the first mapping sequence x m and the length of the second mapping sequence y m are both N.

[0063] In step S5, the quantum information sender groups the first mapping sequence x m , and the quantum information receiver groups the second mapping sequence y m , so as to respectively form a first d-dimensional vector by every d continuous Gaussian variables in the first mapping sequence x m and a second d-dimensional vector by every d continuous Gaussian variables in the second mapping sequence y m , and then obtain a corresponding first normalized vector x' and a second normalized vector y' by normalizing the first d-dimensional vector and the second d-dimensional vector respectively.

[0064] In an 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, and according to the Hurwitz theorem of synthetic algebra, the value of d is any one of 1, 2, 4, and 8; x m(i) represents the i-th value in x m ; and y m(i) represents the i-th value in y m .

[0070] In step S6, the quantum information receiver as the key sender generates a key sequence u, and performs Polar code encoding on the key sequence u to generate a code word c, and sends the norm information about the Polar code encoding to the key receiver through a classical channel.

[0071] In the embodiment, the quantum information sender is the key receiver.

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

[0073] It should be noted that the Polar code, i.e. the polarization code, is a forward error correction coding method for signal transmission, and the core idea thereof is to make each sub-channel present different reliability through channel polarization processing. When the code length continuously increases, part of the channels will tend to be perfect channels (no error) with a capacity close to 1, and another part of the channels will tend to be pure noise channels with a capacity close to 0. Selecting the channels with a capacity close to 1 to directly transmit information to approach the channel capacity is the only method that can be strictly proved to reach the Shannon limit.

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

[0075] In step S7, the key sender converts the code word c into a spherical sequence c'.

[0076] In the embodiment, all elements of the spherical sequence c' are located on a sphere centered at 0.

[0077] In an embodiment, in the step S7,

[0078]

[0079] wherein c1, c2, c N respectively represent the 1st, 2nd and Nth values in the code word c.

[0080] In 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 an embodiment, in the step S8, M(y', c') x y' = c'; wherein M(y', c') is the rotation mapping function.

[0082] In step S9, the key receiver performs rotation mapping on the first normalized vector x' by using the rotation mapping function, to obtain a noisy information sequence v.

[0083] In an embodiment, in the step S9, v = M(y', c') x x'.

[0084] In step S10, the key receiver performs Polar code decoding on the noisy information sequence v by using the norm information, to obtain a decoding result and judges whether the decoding is successful based on the decoding result .

[0085] If the decoding fails, the steps S6 to S10 are repeated, the key sender continues to generate the raw key sequence and calculate the rotation mapping function and send to the key receiver, until the key receiver decodes successfully; if the decoding succeeds, the key receiver and the key sender obtain consistent secure keys; the secure keys are the decoding results

[0086] In an embodiment, the step S10 comprises: 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 results determines whether the decoding results are equal to the raw key sequence u; if yes, the decoding succeeds; if no, the decoding fails.

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

[0088]

[0089] wherein, L(v i ) represents the decoding initialization message; v i represents the i-th value of the noisy information sequence v; i takes 1 to N.

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

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

[0092] The protection scope of the continuous variable quantum key distribution multi-dimensional negotiation method based on Polar code and lossy compression according to the embodiments of the present application is not limited to the execution order of the steps listed in the embodiments, and any scheme realized by adding, replacing or replacing the steps of the prior art according to the principle of the present application is included in the protection scope of the present application.

[0093] Those skilled in the art should further understand that units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware, computer software, or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, each example has been described in general terms in the above description. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0094] The description of the flow or structure corresponding to each of the above figures has its own emphasis. The parts not described in detail in a certain flow or structure can be referred to the related description of other flows or structures.

[0095] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical idea disclosed by the present application should be covered by the claims of the present application.

Claims

1. A method for continuous variable quantum key distribution multi-dimensional negotiation based on Polar code and lossy compression, characterized in that, The method comprises: Step one, according to the Gaussian approximation algorithm, the length of the Gaussian sequence is , the compression rate is Channel estimation is performed on the Gaussian sequence to determine the polarization subchannel reliability ranking under the Gaussian sequence, and the high-entropy bit set and the low-entropy bit set are determined according to the polarization subchannel reliability ranking; wherein the high-entropy bit set includes polarization subchannels; the low-entropy bit set includes - polarization subchannels; ; In step two, the quantum information sender prepares a quantum state x and transmits the quantum state x to the quantum information receiver through a quantum channel under the premise of reverse multi-dimensional negotiation, 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 are subject to Gaussian distribution, and the length of the quantum state x and the length of the original key y are both . Step three, 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 ; and the quantum information receiver performs lossy compression on the original secret key y based on the high-entropy bit set and the low-entropy bit set, to obtain a second binary sequence y s . Further comprising: using the quantum state x to calculate the log-likelihood ratio, and then based on the calculation result, output the decision of the polar subchannel of the quantum state x; If the polar subchannel of the quantum state x belongs to the low entropy bit set, it is discarded; If the polarization subchannel of the quantum state x belongs to the high-entropy bit set, output the first binary sequence x by a first decision formula s ; wherein the first decision formula is as follows: ； wherein, represents the LLR value of the polar sub-channel of the i-th bit in the quantum state x; takes the value 1 to ; represents the condition is greater than or equal to ; represents the condition is greater than ;​ Using the original key y to calculate the log-likelihood ratio, and then based on the calculation result, output the decision of the polar subchannel of the original key y; If the polar subchannel of the original key y belongs to the low entropy bit set, it is discarded; If the polar subchannel of the original key y belongs to the high entropy bit set, output the second binary sequence y by a second decision formula s ; wherein the second decision formula is as follows: ； wherein, represents the LLR value of the polar subchannel of the i-th bit in the original key y; represents the LLR value of the polar subchannel of the i-th bit in the original key y; represents the condition is greater than or equal to ; represents the condition is greater than ; Step four, the quantum information sender performs a mapping operation on the first binary sequence x s to obtain a first mapping sequence x m ; the quantum information receiver performs a mapping operation on the second binary sequence y s to obtain a second mapping sequence y m ; the first mapping sequence x m and the second mapping sequence y m are subjected to Gaussian distribution, and the length of the first mapping sequence x m and the length of the second mapping sequence y m are both ; Step five, the quantum information sender groups the first mapping sequence x m Step six, the quantum information receiver groups the second mapping sequence y m to respectively realize that each d continuous Gaussian variables in the first mapping sequence x m forms a first d-dimensional vector, and each d continuous Gaussian variables in the second mapping sequence y m forms a second d-dimensional vector, and then obtains a corresponding first normalized vector and a second normalized vector by respectively normalizing the first d-dimensional vector and the second d-dimensional vector. Step six, the quantum information receiver as the key sender generates a key sequence u, and encodes the key sequence u by using the Polar code to generate a code word c, and sends the norm information about the Polar code encoding to the key receiver through the classical channel; the quantum information sender as the key receiver; Step seven, the key sender converts the code word c into a spherical sequence ; all elements of the spherical sequence are located on a sphere centered at 0. Step eight, the key sender calculates a rotation mapping function based on the second normalized vector and the spherical sequence computes a rotation mapping function and sends the rotation mapping function to the key receiver through a classical channel; Step nine, the key receiver rotates the first normalized vector using the rotation mapping function to obtain a noisy information sequence v. Step ten, the key receiver decodes the noisy information sequence v using the norm information to obtain a decoding result and judges whether the decoding is successful based on the decoding result or not. If the decoding fails, repeat the step six to the step ten until the decoding succeeds; If the decoding is successful, the key receiver and the key sender obtain a consistent security key; the security key is the decoding result .

2. The method of claim 1, wherein the method is a Polar code and lossy compression based continuous variable quantum key distribution multi-dimensional negotiation method. In the second step, x ~ N (0, ), wherein, is the modulation variance of the quantum information sender; the quantum channel is an AWGN channel; the noise z of the quantum channel obeys a Gaussian distribution, z ~ N (0, ), wherein, is the noise variance of the quantum channel. y = x + z, y ~ N(0, ).​ 3.The Polar code and lossy compression based continuous variable quantum key distribution multi-dimensional negotiation method according to claim 1, wherein, In the step five, ； ； ； ； Wherein, d is the dimension of the reverse multi-dimensional negotiation, the value of d takes any one of the following: 1, 2, 4, 8; represents x m in the th value; represents y m in the th value.

4. The method of claim 1, wherein the method is a Polar code and lossy compression based continuous variable quantum key distribution multi-dimensional negotiation method. In the step six, the raw key sequence u is a binary sequence randomly generated by the quantum information receiver, the length of the raw key sequence u is ; the length of the code word c is ; .

5. The method of claim 1, wherein the method is a Polar code and lossy compression based continuous variable quantum key distribution multi-dimensional negotiation method. In the step seven, ； in, , , They respectively represent the 1st, 2nd, and 3rd codewords in the codeword c. Values.

6. The method of claim 1, wherein the method is a Polar code and lossy compression based continuous variable quantum key distribution multi-dimensional negotiation method. In step eight, ; wherein, is the rotation mapping function.

7. The method of claim 1, wherein, In step nine, .

8. The method of claim 1, wherein the method is a Polar code and lossy compression based continuous variable quantum key distribution multi-dimensional negotiation method. The step ten comprises: 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 ; determining whether the decoding result is equal to the key generation sequence u. If equal, the decoding succeeds; if not equal, the decoding fails.

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