Secure magnetic communication method and system based on key index

Abstract

The invention discloses a secure magnetic communication method and system based on a key index. The method comprises the following steps: generating four columns of chaotic sequences according to a set key initial value by using a four-dimensional hyper-chaotic model; inserting the two columns of chaos sequences into original transmission data, performing convolution encryption to obtain an encrypted bit stream, performing serial-parallel conversion on the encrypted bit stream to obtain a data matrix H, and performing subcarrier scrambling and symbol scrambling on the data matrix H in sequence according to the other two columns of chaos sequences to obtain a data matrix P; taking the key matrix as an index, performing QPSK mapping on elements in the data matrix P through a constellation codebook to obtain constellation points, and forming a constellation diagram by the constellation points; transmitting the constellation diagram to a receiver through a transmitter; in response to the constellation diagram received by the receiver, decrypting the constellation diagram to obtain original transmission data; according to the invention, the problem that the magnetic induction signal is easy to steal is solved, and the security of the communication system is improved.

Description

Technical Field

[0001] The present invention belongs to the field of magnetic communication technology, and in particular relates to a secure magnetic communication method and system based on a key index. Background Art

[0002] With the development of modern industry, magnetic communication is now the main candidate technology for multi-functional communication because of its lack of obvious multipath effect, low absorption and scattering, low power consumption and simple equipment. However, since magnetic induction signals are directly exposed to the air and are easily captured, it is extremely important to ensure the security of signal transmission.

[0003] At present, chaotic encryption schemes are widely used in communication systems to solve the problem of communication security. Traditional chaotic encryption schemes assume that the receiving end knows the key by default, and encrypt it by generating a chaotic sequence with a fixed key. Once the key is cracked, all the user's information will be leaked, causing huge losses. In order to further improve the security of the communication system, key transmission technology has emerged. The initial key is used to generate a chaotic sequence to encrypt the signal at the sending end, and the key is superimposed on the high-power signal in the form of low-power distribution and sent to the user together with the information. This will greatly improve the encryption efficiency of the communication system. However, in the magnetic communication system, the signal power is low and the noise interference is relatively large. The traditional single key transmission method increases the complexity of the transmission signal, which increases the bit error rate of the signal at the receiving end. In addition, the key generally transmitted in a low-power form is not easy to be decrypted. If the key cannot be correctly decrypted, the transmission security performance of the communication system will be greatly reduced. Summary of the invention

[0004] The present invention provides a secure magnetic communication method and system based on key indexing to solve the problem that magnetic induction signals are easily stolen and improve the security of the communication system.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A first aspect of the present invention provides a secure magnetic communication method based on a key index, comprising:

[0007] Using the four-dimensional hyperchaotic model to generate chaotic sequences according to the set initial key value , Chaotic Sequence , Chaotic Sequence and chaotic sequences ;

[0008] The chaotic sequence and chaotic sequences After inserting the original transmission data, convolution encryption is performed to obtain the encrypted bit stream, and the encrypted bit stream is converted into a data matrix H according to the chaotic sequence. and chaotic sequences Subcarrier scrambling and symbol scrambling are sequentially performed on the data matrix H to obtain the data matrix P;

[0009] The initial value of the key is converted into binary and repeatedly superimposed D times to obtain a key matrix; a constellation codebook is established using QPSK constellation A and QPSK constellation B; a mapping relationship is set between the cipher bits in the key matrix and the constellation codebook;

[0010] Using the key matrix as an index, QPSK mapping is performed on the elements in the data matrix P through the constellation codebook to obtain constellation points, and the constellation points form a constellation diagram; the constellation diagram is sent to the receiver through the transmitter;

[0011] In response to the receiver receiving the constellation map, the constellation map is decrypted to obtain the original transmission data.

[0012] Furthermore, a four-dimensional hyperchaotic model is used to generate a chaotic sequence according to the set initial value of the key. , Chaotic Sequence , Chaotic Sequence and chaotic sequences ; The process includes:

[0013] The initial value of the key is input into the four-dimensional hyperchaotic model to obtain state variables X, Y, Z and W. The expression formula is:

[0014]

[0015]

[0016]

[0017]

[0018] In the formula, and For the Second and The state variables of the output of the next cycle calculation ; and For the Second and The state variables of the output of the next cycle calculation ; and For the Second and The state variables of the output of the next cycle calculation ; and For the Second and The state variables of the output of the next cycle calculation ; , , , and are the coefficients of the four-dimensional hyperchaotic model; , , and The state variables , state variables , state variables and state variables The first derivative of ;

[0019] Generate chaotic sequences according to state variables X, Y, Z and W respectively , Chaotic Sequence , Chaotic Sequence and chaotic sequences .

[0020] Furthermore, the chaotic sequence and chaotic sequences After inserting the original transmission data, convolution encryption is performed to obtain the encrypted bit stream. The process includes:

[0021] According to the chaotic sequence and chaotic sequences Generate a chaotic insertion sequence S, expressed as:

[0022]

[0023] In the formula, is the remainder function; is the floor integer function; and is the intermediate transformation sequence;

[0024] The original transmission data is converted into binary to obtain the original bits, and the original bits are grouped; the chaotic bits in the chaotic insertion sequence S are inserted into each group of original bits and then input into the convolution device to obtain the encrypted bit stream.

[0025] Furthermore, the encrypted bit stream is serial-to-parallel converted to obtain the data matrix H, and the process includes:

[0026] Convert encrypted bit stream into data matrix ; The data matrix Every two columns of data are combined to obtain the data matrix H.

[0027] Furthermore, according to the chaotic sequence and chaotic sequences Subcarrier scrambling and symbol scrambling are performed on the data matrix H in sequence to obtain the data matrix P. The process includes:

[0028] The chaotic sequence and chaotic sequences After arranging in ascending order and taking the inverse, the chaotic sequence and chaotic sequences Multiply to get the scrambled matrix and scramble the matrix ;

[0029]

[0030] In the formula, is the ascending order function; Transpose the matrix;

[0031] By scrambling the matrix and scramble the matrix Extract the position of 1 to generate scrambled sequence M and scrambled sequence N;

[0032] The data matrix H is transformed column by column according to each column element of the scrambled sequence M, and the scrambled sequence N is transposed and then the data matrix H is transformed row by row to obtain the data matrix P.

[0033] Furthermore, the constellation diagram is sent to the receiver via the transmitter, and the process includes:

[0034] The constellation points in the constellation diagram are represented by the real part and the imaginary part to obtain the complex constellation points; the complex constellation points are inversely transformed by Fourier, and a cyclic prefix and a cyclic suffix are added to obtain a time domain transmission signal, and the time domain transmission signal is transmitted from the transmitter to the receiver through an optical fiber channel;

[0035] The cyclic prefix and cyclic suffix of the time domain transmission signal are removed and Fourier transform is performed to obtain the frequency domain reception signal, and the constellation diagram received by the receiver is recovered from the frequency domain reception signal.

[0036] Further, in response to the receiver receiving the constellation diagram, decrypting the constellation diagram to obtain original transmission data, the process includes:

[0037] The constellation diagram is converted into a receiving data matrix through a constellation codebook, and index bit information is extracted from the receiving data matrix; according to the mapping relationship between the cipher bit and the constellation codebook, the index bit information is key-combined to obtain a key matrix; and the receiving data matrix is ​​decrypted according to the key matrix to obtain the original transmission data.

[0038] A second aspect of the present invention provides a secure magnetic communication system based on a key index, comprising:

[0039] The key module uses a four-dimensional hyperchaotic model to generate a chaotic sequence based on the set initial key value. , Chaotic Sequence , Chaotic Sequence and chaotic sequences ;

[0040] Interference module, the chaotic sequence and chaotic sequences After inserting the original transmission data, convolution encryption is performed to obtain the encrypted bit stream, and the encrypted bit stream is converted into a data matrix H according to the chaotic sequence. and chaotic sequences Subcarrier scrambling and symbol scrambling are sequentially performed on the data matrix H to obtain the data matrix P;

[0041] A mapping module performs binary conversion on the initial value of the key and repeatedly superimposes it D times to obtain a key matrix; establishes a constellation codebook using QPSK constellation A and QPSK constellation B; and sets a mapping relationship between the cipher bits in the key matrix and the constellation codebook;

[0042] The encryption module uses the key matrix as an index, performs QPSK mapping on the elements in the data matrix P through the constellation codebook to obtain constellation points, and the constellation points form a constellation diagram; the constellation diagram is sent to the receiver through the transmitter;

[0043] The decryption module, in response to the receiver receiving the constellation diagram, decrypts the constellation diagram to obtain the original transmission data.

[0044] Furthermore, the decryption module decrypts the constellation diagram to obtain the original transmission data, and the process includes:

[0045] The constellation diagram is converted into a receiving data matrix through a constellation codebook, and index bit information is extracted from the receiving data matrix; according to the mapping relationship between the cipher bit and the constellation codebook, the index bit information is key-combined to obtain a key matrix; and the receiving data matrix is ​​decrypted according to the key matrix to obtain the original transmission data.

[0046] The third aspect of the present invention provides an electronic device, comprising a storage medium and a processor; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the key index-based secure magnetic communication method described in the first aspect.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The present invention performs binary conversion on the initial value of the key and repeatedly superimposes it D times to obtain a key matrix; selects the index bit with the largest number of occurrences as the correct key information, and finally extracts the absolutely correct key; because the key is repeated many times, the correctness of the key transmission can still be guaranteed even in the case of a very low signal-to-noise ratio.

[0049] The present invention utilizes a four-dimensional hyperchaotic model to generate four columns of chaotic sequences according to a set initial key value; two columns of chaotic sequences are inserted into original transmission data and then convolution encryption is performed to obtain an encrypted bit stream; the encrypted bit stream is serial-to-parallel converted to obtain a data matrix H; and subcarrier scrambling and symbol scrambling are performed on the data matrix H in sequence according to another two columns of chaotic sequences to obtain a data matrix P; the present invention utilizes a four-dimensional hyperchaotic model because of its high sensitivity and unpredictability to initial conditions, thereby improving the security and reliability of a communication system; at the same time, the chaotic encryption method of the present invention can resist external interference and noise to a certain extent, thereby improving the robustness of the communication system.

[0050] In the present invention, the key matrix is ​​used as an index, and the elements in the data matrix P are mapped to QPSK through a constellation codebook to obtain constellation points, and the constellation points form a constellation diagram; the constellation diagram is sent to a receiver through a transmitter; hiding the key in the constellation enhances the security of wireless magnetic communication transmission, and the method of hiding the key using the constellation codebook will not add extra bits of redundant information to the transmitted information, and is suitable for magnetic communication systems with limited bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a flow chart of a secure magnetic communication method based on key indexing provided in Embodiment 1 of the present invention;

[0052] Figure 2 is a phase trajectory diagram of the 4D hyperchaotic model provided in Example 1 of the present invention;

[0053] Figure 3 This is the principle of the high-security magnetic communication method based on key indexing provided by Embodiment 1 of the present invention;

[0054] Figure 4 is a constellation diagram received by the receiver provided in Embodiment 1 of the present invention;

[0055] Figure 5 It is a signal bit error rate curve diagram before and after convolution encryption provided by Example 1 of the present invention. DETAILED DESCRIPTION

[0056] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0057] Example 1

[0058] like Figure 1 As shown, this implementation provides a secure magnetic communication method based on a key index, including:

[0059] In this embodiment, the initial value of the key is set , , and They are 0.01001498, 0.49978643, 0.80056479 and 0.10078942 respectively. The chaotic sequence is generated by using the four-dimensional hyperchaotic model according to the set initial value of the key. , Chaotic Sequence , Chaotic Sequence and chaotic sequences ; The process includes:

[0060] The initial value of the key is input into the four-dimensional hyperchaotic model to obtain state variables X, Y, Z and W. The expression formula is:

[0061]

[0062]

[0063]

[0064]

[0065] In the formula, and For the Second and The state variables of the output of the next cycle calculation ; and For the Second and The state variables of the output of the next cycle calculation ; and For the Second and The state variables of the output of the next cycle calculation ; and For the Second and The state variables of the output of the next cycle calculation ; , , , and are the coefficients of the four-dimensional hyperchaotic model; , , and The state variables , state variables , state variables and state variables The first derivative of ;

[0066] The fourth-order Runge-Kutta method is used to solve the partial differential equation of the four-dimensional hyperchaotic model, and the phase trajectory diagram of the four-dimensional hyperchaotic model is obtained, as shown in Figure 2 As shown in the figure, the value ranges of the four chaotic sequences of the 4D hyperchaotic model are (-85,81), (-25,23), (-26,21) and (-31,32).

[0067] Generate chaotic sequences according to state variables X, Y, Z and W respectively , Chaotic Sequence , Chaotic Sequence and chaotic sequences .

[0068] The chaotic sequence and chaotic sequences After inserting the original transmission data, convolution encryption is performed to obtain the encrypted bit stream. The process includes:

[0069] According to the chaotic sequence and chaotic sequences Generate a chaotic insertion sequence S, expressed as:

[0070]

[0071] In the formula, the chaotic sequence and chaotic sequences Each has 1280 elements, is the remainder function; is the floor integer function; and is the intermediate transformation sequence;

[0072] The original transmission data is converted into binary to obtain the original bits, the original transmission data contains a total of 17920 original bits, and every 7 original bits are divided into a group, for a total of 2560 groups; the chaotic bits in the chaotic insertion sequence S are inserted into each group of original bits and then input into the convolution device to obtain a 1×40960 encrypted bit stream. In this embodiment, the size of the convolution device is 2×1×8.

[0073] Convert the 1×40960 encrypted bit stream into a 80×512 data matrix ; The data matrix Every two columns of data are merged to obtain a 80×256 data matrix H.

[0074] According to the chaotic sequence and chaotic sequences Subcarrier scrambling and symbol scrambling are performed on the data matrix H in sequence to obtain the data matrix P. The process includes:

[0075] The chaotic sequence and chaotic sequences After arranging in ascending order and taking the inverse, the chaotic sequence and chaotic sequences Multiply to get the scrambled matrix and scramble the matrix ;

[0076]

[0077] In the formula, is the ascending order function; Transpose the matrix;

[0078] By scrambling the matrix and scramble the matrix Extract the position of 1 to generate scrambled sequence M and scrambled sequence N; scrambled sequence M is a 1×256 matrix, and scrambled sequence N is a 1×80 matrix;

[0079] The data matrix H is transformed column by column according to each column element of the scrambled sequence M, and the scrambled sequence N is transposed and then the data matrix H is transformed row by row to obtain a 80×256 data matrix P.

[0080] The initial key value is converted into binary and repeatedly superimposed D times to obtain a 80×128 key matrix, where D is 80 in this embodiment; QPSK constellation A and QPSK constellation B are used to establish a constellation codebook; as shown in Table 1, a mapping relationship is set between the cipher bits in the key matrix and the constellation codebook;

[0081] Table 1, constellation index mapping rules;

[0082]

[0083] like Figure 3 As shown, the key matrix is ​​used as an index, and the elements in the data matrix P are QPSK mapped through the constellation codebook to obtain constellation points, and the constellation points form a constellation diagram.

[0084] The constellation points in the constellation diagram are represented by the real part and the imaginary part to obtain the complex constellation points; the complex constellation points are inversely Fourier transformed, and a cyclic prefix and a cyclic suffix are added to obtain a 80×1320 time domain transmission signal, where the cyclic prefix length is 128 and the suffix length is 40; the time domain transmission signal is transmitted from the transmitter to the receiver through an optical fiber channel;

[0085] The cyclic prefix and cyclic suffix of the time domain transmitted signal are removed and then Fourier transformed to obtain the frequency domain received signal, such as Figure 4 As shown, the constellation diagram received by the receiver is recovered from the frequency domain received signal.

[0086] In response to the receiver receiving the constellation diagram, decrypting the constellation diagram to obtain original transmission data, the process includes:

[0087] The constellation diagram is converted into an 80×256 receiving data matrix through the constellation codebook, and the index bit information is extracted from the receiving data matrix; according to the mapping relationship between the password bit and the constellation codebook, the index bit information is key-combined to obtain the key matrix; the key initial value is obtained from the key matrix, and the index bit with the most occurrences is selected as the correct key initial value, and finally the absolutely correct key is extracted; because the key is repeated many times, the correctness of the key transmission can still be guaranteed even in the case of a very low signal-to-noise ratio. On the premise of ensuring that the final key extracted is completely correct, the key is brought into the four-dimensional hyperchaotic model to generate a chaotic sequence, and the receiving data matrix is ​​decrypted to obtain the original transmission data.

[0088] For the secure key transmission method, the transmission quality of the key is extremely important. Since the chaotic system itself is very sensitive to the initial value of the key, even a slight change in the initial value will result in the generation of a completely different chaotic sequence, making it impossible to correctly decrypt the signal. In order to ensure the absolute correctness of the key transmission in this embodiment, we repeated the key 80 times, which is equivalent to cyclically sampling the key 80 times. After extracting the key, we also compared the key information and selected the key with the most occurrences in the 80 groups as the final correct key, thereby ensuring the error-free transmission of the key. After simulation, when the signal-to-noise ratio is 5, the bit error rate of the key is zero, proving that even under very low signal-to-noise ratios, error-free key transmission can still be achieved.

[0089] Figure 5 The comparison graphs of the bit error rate curves after the original data is restored using the convolution encryption method (the secure magnetic communication method disclosed in this embodiment), the traditional encryption method, and the illegal receiving end signal are respectively shown. It can be seen from the figure that the bit error rate of the data after convolution encryption is close to 0 after the signal-to-noise ratio is greater than 7. The bit error rate of the signal using the traditional encryption method is close to 0 when the signal-to-noise ratio is 13. Since the illegal receiving end cannot obtain the correct key information, it cannot correctly decrypt the encrypted signal. It can be seen that the encryption method proposed by the present invention has higher information security and better information transmission performance.

[0090] Example 2

[0091] This embodiment provides a secure magnetic communication system based on a key index. The secure magnetic communication system of this embodiment can be used to execute the secure magnetic communication method described in Embodiment 1. The secure magnetic communication system includes:

[0092] The key module uses a four-dimensional hyperchaotic model to generate a chaotic sequence based on the set initial key value. , Chaotic Sequence , Chaotic Sequence and chaotic sequences ;

[0093] Interference module, the chaotic sequence and chaotic sequences After inserting the original transmission data, convolution encryption is performed to obtain the encrypted bit stream, and the encrypted bit stream is converted into a data matrix H according to the chaotic sequence. and chaotic sequences Subcarrier scrambling and symbol scrambling are sequentially performed on the data matrix H to obtain the data matrix P;

[0094] A mapping module performs binary conversion on the initial value of the key and repeatedly superimposes it D times to obtain a key matrix; establishes a constellation codebook using QPSK constellation A and QPSK constellation B; and sets a mapping relationship between the cipher bits in the key matrix and the constellation codebook;

[0095] The encryption module uses the key matrix as an index, performs QPSK mapping on the elements in the data matrix P through the constellation codebook to obtain constellation points, and the constellation points form a constellation diagram; the constellation diagram is sent to the receiver through the transmitter;

[0096] The decryption module, in response to the receiver receiving the constellation diagram, decrypts the constellation diagram to obtain the original transmission data.

[0097] The decryption module decrypts the constellation diagram to obtain the original transmission data, and the process includes:

[0098] The constellation diagram is converted into a receiving data matrix through a constellation codebook, and index bit information is extracted from the receiving data matrix; according to the mapping relationship between the cipher bit and the constellation codebook, the index bit information is key-combined to obtain a key matrix; and the receiving data matrix is ​​decrypted according to the key matrix to obtain the original transmission data.

[0099] This embodiment utilizes the four-dimensional hyperchaotic model because of its high sensitivity and unpredictability to initial conditions, thereby improving the security and reliability of the communication system. At the same time, the chaotic encryption method in this embodiment can resist external interference and noise to a certain extent, thereby improving the robustness of the communication system.

[0100] This embodiment hides the key in the constellation to enhance the security of wireless magnetic communication transmission. The method of hiding the key using the constellation code book will not add extra bits of redundant information to the transmission information, and is suitable for magnetic communication systems with limited bandwidth.

[0101] Example 3

[0102] This embodiment provides an electronic device, including a storage medium and a processor; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the secure magnetic communication method described in Example 1.

[0103] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0104] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0105] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0106] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0107] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A secure magnetic communication method based on key indexing, characterized in that: include: Using the four-dimensional hyperchaotic model to generate chaotic sequences according to the set initial key value , Chaotic Sequence , Chaotic Sequence and chaotic sequences ; The chaotic sequence and chaotic sequences After inserting the original transmission data, convolution encryption is performed to obtain the encrypted bit stream, and the encrypted bit stream is converted into a data matrix H according to the chaotic sequence. and chaotic sequences Subcarrier scrambling and symbol scrambling are sequentially performed on the data matrix H to obtain the data matrix P; The initial value of the key is converted into binary and repeatedly superimposed D times to obtain a key matrix; a constellation codebook is established using QPSK constellation A and QPSK constellation B; a mapping relationship is set between the cipher bits in the key matrix and the constellation codebook; Using the key matrix as an index, QPSK mapping is performed on the elements in the data matrix P through the constellation codebook to obtain constellation points, and the constellation points form a constellation diagram; the constellation diagram is sent to the receiver through the transmitter; In response to the receiver receiving the constellation map, the constellation map is decrypted to obtain the original transmission data.

2. The secure magnetic communication method according to claim 1, characterized in that: Using the four-dimensional hyperchaotic model to generate chaotic sequences according to the set initial key value , Chaotic Sequence , Chaotic Sequence and chaotic sequences ; The process includes: The initial value of the key is input into the four-dimensional hyperchaotic model to obtain state variables X, Y, Z and W. The expression formula is: ； ； ； ； In the formula, and For the Second and The state variables of the output of the next cycle calculation ; and For the Second and The state variables of the output of the next cycle calculation ; and For the Second and The state variables of the output of the next cycle calculation ; and For the Second and The state variables of the output of the next cycle calculation ; , , , and are the coefficients of the four-dimensional hyperchaotic model; , , and The state variables , state variables , state variables and state variables The first derivative of ; Generate chaotic sequences according to state variables X, Y, Z and W respectively , Chaotic Sequence , Chaotic Sequence and chaotic sequences .

3. The secure magnetic communication method according to claim 1, characterized in that: The chaotic sequence and chaotic sequences After inserting the original transmission data, convolution encryption is performed to obtain the encrypted bit stream. The process includes: According to the chaotic sequence and chaotic sequences Generate a chaotic insertion sequence S, expressed as: ； In the formula, is the remainder function; is the floor integer function; and is the intermediate transformation sequence; The original transmission data is converted into binary to obtain the original bits, and the original bits are grouped; the chaotic bits in the chaotic insertion sequence S are inserted into each group of original bits and then input into the convolution device to obtain the encrypted bit stream.

4. The secure magnetic communication method according to claim 1, characterized in that: The encrypted bit stream is converted into a data matrix H by serial-to-parallel conversion. The process includes: Convert encrypted bit stream into data matrix ; The data matrix Every two columns of data are combined to obtain the data matrix H.

5. The secure magnetic communication method according to claim 1, characterized in that: According to the chaotic sequence and chaotic sequences Subcarrier scrambling and symbol scrambling are performed on the data matrix H in sequence to obtain the data matrix P. The process includes: The chaotic sequence and chaotic sequences After arranging in ascending order and taking the inverse, the chaotic sequence and chaotic sequences Multiply to get the scrambled matrix and scramble the matrix ; ； In the formula, is the ascending order function; Transpose the matrix; By scrambling the matrix and scramble the matrix Extract the position of 1 to generate scrambled sequence M and scrambled sequence N; The data matrix H is transformed column by column according to each column element of the scrambled sequence M, and the scrambled sequence N is transposed and then the data matrix H is transformed row by row to obtain the data matrix P.

6. The secure magnetic communication method according to claim 1, characterized in that: The constellation diagram is sent from the transmitter to the receiver. The process includes: The constellation points in the constellation diagram are represented by the real part and the imaginary part to obtain the complex constellation points; the complex constellation points are inversely transformed by Fourier, and a cyclic prefix and a cyclic suffix are added to obtain a time domain transmission signal, and the time domain transmission signal is transmitted from the transmitter to the receiver through an optical fiber channel; The cyclic prefix and cyclic suffix of the time domain transmission signal are removed and Fourier transform is performed to obtain the frequency domain reception signal, and the constellation diagram received by the receiver is recovered from the frequency domain reception signal.

7. The secure magnetic communication method according to claim 1, characterized in that: In response to the receiver receiving the constellation diagram, decrypting the constellation diagram to obtain original transmission data, the process includes: The constellation diagram is converted into a receiving data matrix through a constellation codebook, and index bit information is extracted from the receiving data matrix; according to the mapping relationship between the cipher bit and the constellation codebook, the index bit information is key-combined to obtain a key matrix; and the receiving data matrix is ​​decrypted according to the key matrix to obtain the original transmission data.

8. A secure magnetic communication system based on key indexing, characterized in that: include: The key module uses a four-dimensional hyperchaotic model to generate a chaotic sequence based on the set initial key value. , Chaotic Sequence , Chaotic Sequence and chaotic sequences ; Interference module, the chaotic sequence and chaotic sequences After inserting the original transmission data, convolution encryption is performed to obtain the encrypted bit stream, and the encrypted bit stream is converted into a data matrix H according to the chaotic sequence. and chaotic sequences Subcarrier scrambling and symbol scrambling are sequentially performed on the data matrix H to obtain the data matrix P; A mapping module performs binary conversion on the initial value of the key and repeatedly superimposes it D times to obtain a key matrix; establishes a constellation codebook using QPSK constellation A and QPSK constellation B; and sets a mapping relationship between the cipher bits in the key matrix and the constellation codebook; The encryption module uses the key matrix as an index, performs QPSK mapping on the elements in the data matrix P through the constellation codebook to obtain constellation points, and the constellation points form a constellation diagram; the constellation diagram is sent to the receiver through the transmitter; The decryption module, in response to the receiver receiving the constellation diagram, decrypts the constellation diagram to obtain the original transmission data.

9. The secure magnetic communication system according to claim 8, characterized in that: The decryption module decrypts the constellation diagram to obtain the original transmission data, and the process includes: The constellation diagram is converted into a receiving data matrix through a constellation codebook, and index bit information is extracted from the receiving data matrix; according to the mapping relationship between the cipher bit and the constellation codebook, the index bit information is key-combined to obtain a key matrix; and the receiving data matrix is ​​decrypted according to the key matrix to obtain the original transmission data.

10. An electronic device comprising a storage medium and a processor; the storage medium is used to store instructions; characterized in that: The processor is used to operate according to the instructions to execute the key index-based secure magnetic communication method according to any one of claims 1 to 7.

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