Information transmission method, information decryption method and electromagnetic regulation and control structure functional surface

Abstract

The application provides an information transmission method, an information decryption method and an electromagnetic regulation and control structure functional surface, and relates to the technical fields of information security and electromagnetic regulation and control. The method is applied to a sending end and comprises the following steps: encrypting to-be-transmitted information to generate encrypted information; mapping the encrypted information into a multi-dimensional electromagnetic state code according to a preset mapping rule; wherein the multi-dimensional electromagnetic state code represents a physical characteristic code sequence of an electromagnetic wave; and using the multi-dimensional electromagnetic state code to perform multi-dimensional modulation on an incident carrier wave through an electromagnetic regulation and control structure functional surface to generate a modulated signal; wherein the modulated signal is used for transmitting the encrypted information. The application maps the encrypted to-be-transmitted information into a plurality of physical characteristic code sequences of mutually independent electromagnetic wave dimensions as electromagnetic state codes after disguising the to-be-transmitted information, and uses the electromagnetic state codes to perform multi-dimensional modulation on an incident carrier wave to generate a modulated signal for transmission, thereby improving the security of information transmission.

Description

Technical Field

[0001] This application relates to the fields of information security and electromagnetic control technology, specifically to an information transmission method, an information decryption method, and a functional surface of an electromagnetic control structure. Background Technology

[0002] With the development of structural functional surface technology, existing information encryption technology has shifted from software algorithm encryption to utilizing structural functional surfaces for physical layer secure communication. This type of physical layer secure communication scheme encodes the transmission characteristics of electromagnetic waves by designing the geometry, material parameters, and spatial arrangement of subwavelength units, aiming to improve the concealment and anti-decryption capability of the communication link from the source of electromagnetic waves.

[0003] While existing technologies have begun to utilize structural functional surfaces for physical layer secure communication, the following shortcomings still exist: (1) Spatial coding static solidification: This type of scheme relies on a fixed phase distribution to achieve beamforming and directional encryption, but its coding itself has the characteristic of "written once and unchanged for life". Once the enemy reverses the spatial phase distribution pattern through near-field scanning or reverse algorithm, the physical channel will be completely transparent and cannot be dealt with by key refresh to deal with persistent network attacks.

[0004] (2) Single control dimension: This type of scheme is limited to the independent scalar control of a single dimension of electromagnetic waves, such as amplitude modulation only, phase modulation only, or polarization modulation only. Such single-dimensional time-domain jumps are prone to generating regular harmonic sidebands in the spectrum. Illegal receivers can remove the interference and recover the original baseband information by using high-order spectrum analysis. As a result, although the encrypted signal has time-domain dynamics, it loses its concealment due to the regularity of the spectrum, thus forming a security vulnerability.

[0005] Therefore, existing technologies are still insufficient to meet current needs for encrypted information transmission. Summary of the Invention

[0006] The purpose of this application is to provide an information transmission method, an information decryption method, and an electromagnetic control structure functional surface, which encrypts and disguises the information to be transmitted, maps it into multiple independent electromagnetic wave dimensions of physical feature encoding sequences as electromagnetic state codes, and uses the electromagnetic state codes to perform multidimensional modulation on the incident carrier to generate a modulated signal carrying encrypted information for transmission, thereby improving the security of information transmission.

[0007] In a first aspect, embodiments of this application provide an information transmission method applied at a transmitting end; the method includes: encrypting information to be transmitted to generate encrypted information; mapping the encrypted information into a multidimensional electromagnetic state code according to a preset mapping rule; wherein the multidimensional electromagnetic state code characterizes a physical feature encoding sequence of an electromagnetic wave; using the multidimensional electromagnetic state code, multidimensionally modulating an incident carrier wave through an electromagnetically controlled structural functional surface to generate a modulated signal; wherein the modulated signal is used to transmit the encrypted information.

[0008] In this embodiment, encrypted information is obtained by encrypting the information to be transmitted, thus ensuring the security of the original information. According to a preset mapping rule, the encrypted information is mapped into a multi-dimensional electromagnetic state code. Based on this multi-dimensional electromagnetic state code, the incident carrier wave incident on the functional surface of the electromagnetic control structure is multi-dimensionally modulated to generate a modulated signal for transmission, thereby ensuring the security of the encrypted information during transmission. Therefore, by ensuring the security of both the original information itself and the information transmission process, the security of information transmission is improved.

[0009] In some embodiments, encrypting the information to be transmitted to generate encrypted information includes: encrypting the information to be transmitted using a random key to generate initial encrypted information; using a steganography algorithm to write the initial encrypted information and the random key into corresponding spoofing carriers to generate initial spoofed encrypted information and key spoofing information; and generating encrypted information based on the initial spoofed encrypted information and key spoofing information.

[0010] In this embodiment, when encrypting the information to be transmitted, a random key is first used to encrypt the information to be transmitted, generating initial encrypted information. Then, a steganography algorithm is used to write the initial encrypted information and the random key into the corresponding disguised carriers, thereby obtaining the encrypted information. In this process, the initial encrypted information and key information are not transmitted separately, nor is the traditional pre-shared key method relied upon. Instead, the key information and the initial encrypted information are mixed and encrypted, so that the transmitted content no longer appears as a separate "encrypted information" on the surface, but rather as an information carrier with disguised characteristics. For a receiver unfamiliar with the decryption process, what they receive is often just a disguised image or invalid information, rather than the true initial encrypted information. Therefore, it not only achieves "not easily decryptable" but also "difficult to determine whether it is the initial encrypted information itself," making it more concealed than traditional direct ciphertext transmission methods.

[0011] In some embodiments, the information to be transmitted includes an original image; before encrypting the information to be transmitted using a random key to generate initial encrypted information, the method further includes: randomly generating a first key image and a second key image based on the attribute information of the original image; encrypting the information to be transmitted using the random key to generate initial encrypted information includes: performing an XOR operation on the original image, the first key image, and the second key image to generate initial encrypted information.

[0012] In this embodiment, when the information to be transmitted is an original image, a first key image and a second key image are randomly generated based on the attribute information of the original image. Then, an XOR operation is performed on the original image based on the first key image and the second key image to generate initial encrypted information. Since the key image is related to the original image, the security of the initial encrypted information is improved.

[0013] In some embodiments, the spoofing carrier includes a first spoofing image, a second spoofing image, and a third spoofing image; using a steganography algorithm, initial encryption information and a random key are written into the corresponding spoofing carriers to generate initial spoofing encryption information and key spoofing information, including: using a steganography algorithm, writing a first key image into the first spoofing image to generate first key spoofing information; writing initial encryption information into the second spoofing image to generate initial spoofing encryption information; and writing the second key image into the third spoofing image to generate second key spoofing information.

[0014] In this embodiment, a steganography algorithm is used to write the initial encryption information and the random key into the corresponding disguised carriers, generating corresponding disguised information and improving the concealment of the encrypted information. Furthermore, since the initial encryption information and the random key are written into different disguised carriers, their independence is ensured, facilitating the extraction of the initial encryption information and the random key during subsequent decryption.

[0015] In some embodiments, the physical characteristics of the electromagnetic wave include amplitude, phase, and polarization; the initial disguised encryption information, the first key disguised information, and the second key disguised information are all binary sequence images; the encryption information is mapped to a multidimensional electromagnetic state code according to a preset mapping rule, including: mapping the binary value of the initial disguised encryption information to a phase value, the binary value of the first key disguised information to an amplitude value, and the binary value of the second key disguised information to a polarization value; and taking the bit values ​​at the same position in the binary sequences of the initial disguised encryption information, the first key disguised information, and the second key disguised information to form a multidimensional electromagnetic state code.

[0016] In this embodiment, a multi-dimensional electromagnetic control structure is used to coordinately modulate multiple independent physical dimensions of electromagnetic waves, such as amplitude, phase, and polarization. Different encryption results are mapped to different electromagnetic dimensions, forming a multi-dimensional electromagnetic state code to control the transmission of encrypted information. Compared to existing schemes that encode based on only a single electromagnetic feature, this expands the information channel, originally limited to a single degree of freedom, into multiple parallel electromagnetic channels. In this process, since each dimension can independently carry information and participate in the final decryption, the number of available coded states increases significantly, and the equivalent key space and information capacity are correspondingly improved. This increases the difficulty for unauthorized analysts, thus balancing capacity improvement and enhanced security.

[0017] In some embodiments, the electromagnetic control structure functional surface includes an amplitude control device, a phase control device, and a polarization control device; the multidimensional electromagnetic state coding includes amplitude coding, phase coding, and polarization coding; using the multidimensional electromagnetic state coding, the incident carrier is multidimensionally modulated through the electromagnetic control structure functional surface to generate a modulated signal, including: adjusting the amplitude control device according to the amplitude coding, adjusting the phase control device according to the phase coding, and adjusting the polarization control device according to the polarization coding, so that the incident carrier presents the corresponding amplitude, phase, and polarization, thereby generating a modulated signal.

[0018] In this embodiment, the electromagnetic control structure functional surface includes an amplitude control device, a phase control device, and a polarization control device. By using the structure functional surface with multi-dimensional electromagnetic control capabilities, the amplitude, phase, and polarization are modulated according to multi-dimensional electromagnetic state encoding, making it difficult to directly recover the encrypted content by intercepting only a certain signal or a certain type of data even if signal interception occurs, thereby improving the security of information transmission.

[0019] Secondly, embodiments of this application provide an information decryption method, which is applied at a receiving end. The method includes: receiving a modulation signal generated by an information transmission method according to any embodiment of the first aspect; demodulating the modulation signal to obtain a multidimensional electromagnetic state code; decoding the multidimensional electromagnetic state code according to a preset inverse mapping rule to obtain encrypted information; and decrypting the encrypted information to obtain plaintext information.

[0020] In this embodiment, information is distributed and mapped across multiple independent electromagnetic dimensions, each carrying an encrypted and disguised result. Therefore, even if an unauthorized receiver intercepts a portion of the signal in a certain direction, they typically only obtain incomplete dimensional information or disguised intermediate information, making it difficult to recover the true information to be transmitted. Only by receiving complete dimensional information in the legitimate direction and performing joint demodulation and recovery of the dimensional information according to a predetermined decryption process can the true information be correctly extracted. Thus, this embodiment effectively constructs a dual constraint of "multi-dimensional complete reception + correct decryption process," significantly increasing the barrier to cracking compared to single-channel, single-feature encryption schemes.

[0021] In some embodiments, demodulating the modulated signal to obtain a multidimensional electromagnetic state code includes: performing polarization separation on the modulated signal to obtain a first polarization channel signal and a second polarization channel signal; performing envelope detection on the first polarization channel signal and the second polarization channel signal respectively to obtain a first envelope amplitude and a second envelope amplitude; determining the effective channel signal in the first polarization channel signal and the second polarization channel signal based on the first envelope amplitude and the second envelope amplitude; and determining the multidimensional electromagnetic state code based on the effective channel signal.

[0022] In this embodiment, by polarization separation of the modulated signal and by detecting and identifying valid channel signals, the purity of signal extraction is improved, the anti-interference capability is enhanced, and ultimately more reliable multidimensional electromagnetic state coding identification is achieved.

[0023] In some embodiments, the multidimensional electromagnetic state coding includes amplitude coding, phase coding, and polarization coding; determining the multidimensional electromagnetic state coding based on the effective channel signal includes: determining the polarization coding through the effective channel signal; determining the amplitude coding according to the envelope amplitude of the effective channel and a preset amplitude threshold; and determining the phase coding by differential demodulation of the effective channel signal.

[0024] In this embodiment of the application, the accuracy and reliability of multidimensional electromagnetic state coding are improved by determining multidimensional electromagnetic state coding based on effective channel signals.

[0025] Thirdly, embodiments of this application provide an electromagnetically modulated structural functional surface, comprising: a metal reflective layer, a metal ground layer, a metal feed layer, a first dielectric layer, and a second dielectric layer; the first dielectric layer is located between the metal reflective layer and the metal ground layer, and the second dielectric layer is located between the metal ground layer and the metal feed layer; the metal reflective layer includes multiple tunable active devices; wherein, by utilizing multidimensional electromagnetic state coding to adjust the multiple tunable active devices, the incident carrier is multidimensionally modulated to generate a modulated signal; wherein, the multidimensional electromagnetic state coding characterizes the physical characteristic coding sequence of the electromagnetic wave.

[0026] In this embodiment, the metal reflective layer on the functional surface of the electromagnetic control structure includes multiple tunable active devices. Because these tunable active devices are electrically programmable, they not only enable multi-dimensional collaborative coding but also provide a basis for further expansion into dynamic control, reconstructing transmission rules, and updating mapping relationships. Compared to traditional static, single-degree-of-freedom solutions, this approach offers greater adaptability and improves the security of information transmission.

[0027] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing embodiments of this application. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A flowchart illustrating an information transmission method provided in an embodiment of this application; Figure 2 A flowchart illustrating an information decryption method provided in an embodiment of this application; Figure 3 A schematic diagram of a subwavelength structural functional unit with multi-dimensional electromagnetic control capability provided in an embodiment of this application; Figure 4 The simulation results of a subwavelength structural functional unit in amplitude, phase and polarization dimensions provided in the embodiments of this application; Figure 5 Simulation results of radiation patterns of an electromagnetically modulated structural functional surface composed of multiple subwavelength structural functional units under different polarization states and different control conditions, provided for embodiments of this application; Figure 6 This application provides a schematic diagram of an information encryption process and an information decryption process based on an electromagnetically controlled structural functional surface. Detailed Implementation

[0030] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0031] It should be noted that all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0032] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0033] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0034] With the development of structural functional surface technology, existing information encryption technology has shifted from software algorithm encryption to utilizing structural functional surfaces for physical layer secure communication. This type of physical layer secure communication scheme encodes the transmission characteristics of electromagnetic waves by designing the geometry, material parameters, and spatial arrangement of subwavelength units, aiming to improve the concealment and anti-decryption capability of the communication link from the source of electromagnetic waves.

[0035] While existing technologies have begun to utilize structural functional surfaces for physical layer secure communication, the following shortcomings still exist: (1) Static spatial coding: This type of scheme relies on a fixed phase distribution to achieve beamforming and directional encryption. However, its coding inherently has the characteristic of "write once, never change", making it difficult to dynamically update the coding state, key rules, or transmission mode according to communication needs. Once the enemy reverses the spatial phase distribution pattern through near-field scanning or inverse algorithms, the physical channel will become completely transparent, and it will be impossible to deal with persistent network attacks by refreshing the key. Therefore, it is not conducive to meeting the requirements of real-time changes and dynamic updates in modern secure communication.

[0036] (2) Single control dimension: This type of scheme is limited to the independent scalar control of a single dimension of electromagnetic waves. For example, only amplitude modulation, only phase modulation, or only polarization modulation are used, which fails to make full use of the ability of electromagnetic waves to carry information in multiple physical dimensions.

[0037] Furthermore, this single-dimensional time-domain jump can easily generate regular harmonic sidebands in the spectrum. Illegal receivers can remove the interference and recover the original baseband information by using high-order spectrum analysis. As a result, although the encrypted signal has time-domain dynamism, it loses its concealment due to the regularity of the spectrum, thus creating a security vulnerability.

[0038] In addition to the limitations of a single regulatory dimension, the following problems also exist: Limited information capacity and key space: Since modulation relies on only a single electromagnetic dimension, the number of mapping relationships that can be constructed is limited, the key space is small, and the information capacity is prone to reaching a bottleneck, which is not conducive to complex, high-capacity or high-security communication needs.

[0039] Security remains insufficient: When information is bound to a single physical feature, unauthorized recipients can deduce coding patterns or decipher the code by analyzing that single electromagnetic feature, thereby weakening the system's resistance to interception and cracking. Eavesdroppers may be able to decipher the key by analyzing a single electromagnetic feature.

[0040] Furthermore, existing technologies lack a comprehensive encryption mechanism that integrates real information, disguised information, and physical dimensions. Existing solutions typically focus on the single process of "loading information onto a certain electromagnetic dimension," while rarely considering the overall closed loop of real information splitting, disguised carrying, key collaborative transmission, and recovery by the legitimate receiving end according to a predetermined process. Therefore, their deceptiveness, concealment, and system-level security remain limited.

[0041] Therefore, although existing technologies have attempted to use structural functional surfaces for physical layer secure communication, they generally suffer from problems such as static and fixed spatial coding, limited degrees of freedom in regulation, and limited information capacity, resulting in insufficient security and making it difficult to meet current information encryption transmission requirements.

[0042] To address the aforementioned issues, this application provides an information transmission method, an information decryption method, and an electromagnetic control structure functional surface. This method encrypts and disguises the information to be transmitted, mapping it to multiple independent electromagnetic wave dimensions as physical feature encoding sequences as electromagnetic state codes. The electromagnetic state codes are then used to perform multidimensional modulation on the incident carrier wave, generating a modulated signal carrying encrypted information for transmission, thereby improving the security of information transmission.

[0043] Figure 1 This is a flowchart illustrating an information transmission method provided in an embodiment of this application, which is applied at the sending end; as follows: Figure 1 As shown, the method includes: Step S101: Encrypt the information to be transmitted to generate encrypted information.

[0044] Step S102: According to the preset mapping rules, the encrypted information is mapped into a multidimensional electromagnetic state code; wherein, the multidimensional electromagnetic state code represents the physical characteristic coding sequence of the electromagnetic wave.

[0045] Step S103: Using multidimensional electromagnetic state coding, the incident carrier is modulated in multiple dimensions through the functional surface of the electromagnetic control structure to generate a modulated signal; wherein, the modulated signal is used to transmit encrypted information.

[0046] In the above implementation process, the information to be transmitted can be text information, image information, or other information that needs to be transmitted in an encrypted manner.

[0047] The pre-defined mapping rule refers to the transformation rule that establishes a deterministic correspondence between encrypted information and multidimensional electromagnetic state codes. This rule specifies the mathematical mapping relationship from "encrypted information" to "combination of electromagnetic control parameters," ensuring that the sending and receiving ends can reliably embed and accurately demodulate information under the same rule.

[0048] In one implementation, the preset mapping rules can be adaptively set according to the characteristics of the information to be transmitted, and this application does not specifically limit them.

[0049] Multidimensional electromagnetic state coding refers to a structured digital sequence used to characterize the discrete distribution of multiple independent physical dimensions (such as amplitude, phase, polarization, etc.) of electromagnetic waves in the time or spatial domain. This coding serves as a "digital-physical" bridge between encrypted information and physical electromagnetic fields.

[0050] An electromagnetic control structure functional surface refers to an electromagnetic structure plane composed of subwavelength scale units arranged in a specific space. Each unit can independently or jointly control multiple physical parameters of the incident carrier through external excitation (such as electrical bias, optical control, thermal control, or mechanical deformation), thereby realizing dynamic programmable control of the propagation characteristics of electromagnetic waves.

[0051] For example, the electromagnetically modulated structural functional surface can be a programmable metasurface composed of M*N subwavelength units, each of which includes an active control device that modulates different physical parameters.

[0052] The sending end first encrypts the information to be transmitted, generating encrypted information. This can be done using existing common encryption algorithms (such as symmetric encryption algorithms); alternatively, after obtaining initial encrypted information using an encryption algorithm, a steganography algorithm can be used to steganize the initial encrypted information, ultimately generating encrypted information.

[0053] It should be understood that the process of encrypting transmitted information to obtain encrypted information can be set according to the actual situation, and this application does not make specific limitations on it.

[0054] Encrypted information is mapped into multidimensional electromagnetic state codes using preset mapping rules. When an incident carrier irradiates the functional surface of the electromagnetic control structure, the corresponding active control devices on the functional surface of the electromagnetic control structure are adjusted through the multidimensional electromagnetic state codes to perform multidimensional modulation of the incident carrier, generating a modulated signal, thereby enabling secure transmission of the encrypted information.

[0055] In this embodiment, encrypted information is obtained by encrypting the information to be transmitted, thus ensuring the security of the original information. According to a preset mapping rule, the encrypted information is mapped into a multi-dimensional electromagnetic state code. Based on this multi-dimensional electromagnetic state code, the incident carrier wave incident on the functional surface of the electromagnetic control structure is multi-dimensionally modulated to generate a modulated signal for transmission, thereby ensuring the security of the encrypted information during transmission. Therefore, by ensuring the security of both the original information itself and the information transmission process, the security of information transmission is improved.

[0056] In some embodiments, encrypting the information to be transmitted to generate encrypted information includes: encrypting the information to be transmitted using a random key to generate initial encrypted information; using a steganography algorithm to write the initial encrypted information and the random key into corresponding spoofing carriers to generate initial spoofed encrypted information and key spoofing information; and generating encrypted information based on the initial spoofed encrypted information and key spoofing information.

[0057] In the above implementation process, the generation of the random key can be determined based on the attribute information of the information to be transmitted. The attribute information refers to the set of quantifiable and identifiable structural features of the information to be transmitted, which determines the generation rules and data format of the random key.

[0058] For example, if the information to be transmitted is text information, then the random key is also text information; if the information to be transmitted is image information, then the random key is also image information.

[0059] When encrypting the information to be transmitted using a random key to generate initial encrypted information, the encryption method used can be XOR encryption, scrambling encryption, chaotic mapping encryption, or frequency domain encryption, etc. Two or more encryption methods can also be used in series or in combination, such as scrambling before XOR, or frequency domain transformation before chaotic mapping, etc. As long as the final result can achieve collaborative encryption of the key information and the information to be encrypted and is suitable for subsequent spoofing and multidimensional transmission, it is considered an alternative solution, and this application does not impose specific limitations on it.

[0060] Steganography algorithms can include least significant bit steganography (LSB), pixel value difference (PVD), discrete cosine transform (DCT), discrete wavelet transform (DWT), or discrete Fourier transform (DFT), etc. The specific steganography algorithm can be selected according to the actual situation, as long as it can disguise the initial encryption information and random key. This application does not impose specific limitations on this.

[0061] In information hiding technology, a disguised medium refers to a public, harmless, and legal digital medium used to carry, conceal, and transmit secret information. Its core characteristic is that it appears on the surface as ordinary, normal public information, but embeds processed confidential content inside, thereby achieving the covert communication purpose of "separation of form and content".

[0062] The spoofing carrier can be an image, video frame, text, audio, two-dimensional coded pattern, modulation sequence, or other data carrier that can carry spoofing information. As long as the encryption result can exist in a non-explicit ciphertext form and is suitable for subsequent mapping to the electromagnetic dimension for transmission, it can be used as an alternative.

[0063] It should be noted that different steganography algorithms can be used depending on the type of spoofing carrier.

[0064] Finally, the initial spoofed encryption information and the key spoofed information are used together as the encrypted information.

[0065] In this embodiment, when encrypting the information to be transmitted, a random key is first used to encrypt the information to be transmitted, generating initial encrypted information. Then, a steganography algorithm is used to write the initial encrypted information and the random key into the corresponding disguised carriers, thereby obtaining the encrypted information. In this process, the initial encrypted information and key information are not transmitted separately, nor is the traditional pre-shared key method relied upon. Instead, the key information and the initial encrypted information are mixed and encrypted, so that the transmitted content no longer appears as a separate "encrypted information" on the surface, but rather as an information carrier with disguised characteristics. For a receiver unfamiliar with the decryption process, what they receive is often just a disguised image or invalid information, rather than the true initial encrypted information. Therefore, it not only achieves "not easily decryptable" but also "difficult to determine whether it is the initial encrypted information itself," making it more concealed than traditional direct ciphertext transmission methods.

[0066] In some embodiments, the information to be transmitted includes an original image; before encrypting the information to be transmitted using a random key to generate initial encrypted information, the method further includes: randomly generating a first key image and a second key image based on the attribute information of the original image; encrypting the information to be transmitted using the random key to generate initial encrypted information includes: performing an XOR operation on the original image, the first key image, and the second key image to generate initial encrypted information.

[0067] In the above implementation process, the information to be transmitted is set as an RGB image, denoted as the original image M. The RGB image consists of a red channel, a green channel, and a blue channel, and each color channel can be further converted into a binary bit sequence.

[0068] Therefore, the sending end can also convert the original image M into an original image bitstream according to a preset pixel scanning order. The pixel scanning order can be row-by-row scanning, column-by-column scanning, or block scanning, and the specific order can be selected according to the actual situation.

[0069] The sending end randomly generates two random key images corresponding to the size and data format of the original image M, denoted as the first key image K1 and the second key image K2, respectively. Both the first key image K1 and the second key image K2 can be random RGB images or random binary sequences with the same bitstream length as the original image.

[0070] After generating the key image, the sending end performs a pixel-by-pixel or bit-by-bit XOR operation on the original image M, the first key image K1, and the second key image K2 to obtain the initial encrypted information C, whose expression is: C=M⊕K1⊕K2 Here, ⊕ represents the XOR operation.

[0071] As shown in the above formula, the information M to be transmitted does not directly participate in subsequent transmission, but is converted into encrypted information protected by a mixture of two random keys. Even if an unauthorized recipient obtains the initial encrypted information C, they cannot recover the original image M without the first key image K1 and the second key image K2.

[0072] In this embodiment, when the information to be transmitted is an original image, a first key image and a second key image are randomly generated based on the attribute information of the original image. Then, an XOR operation is performed on the original image based on the first key image and the second key image to generate initial encrypted information. Since the key image is related to the original image, the security of the initial encrypted information is improved.

[0073] In some embodiments, the spoofing carrier includes a first spoofing image, a second spoofing image, and a third spoofing image; using a steganography algorithm, initial encryption information and a random key are written into the corresponding spoofing carriers to generate initial spoofing encryption information and key spoofing information, including: using a steganography algorithm, writing a first key image into the first spoofing image to generate first key spoofing information; writing initial encryption information into the second spoofing image to generate initial spoofing encryption information; and writing the second key image into the third spoofing image to generate second key spoofing information.

[0074] In the above implementation process, the steganography algorithm can be least significant bit (LSB) steganography, with the surreptitious carrier being an image.

[0075] The process of generating spoofing information using the least significant bit steganography algorithm is as follows: The initial encrypted information C, the first key image K1, and the second key image K2 are used as three hidden secrets, and each is embedded in one of three different disguised images. Specifically, three normally visible disguised images are selected and denoted as the first disguised image P1, the second disguised image P2, and the third disguised image P3.

[0076] The sending end uses the least significant bit steganography method to write the bit streams of the initial encryption information C, the first key image K1, and the second key image K2 into the least significant bits of the pixels of the three disguised images, respectively, to obtain three encrypted disguised images P1′, P2′, and P3′.

[0077] Among them, the first encrypted camouflage image P1′ carries the first key image K1, the second encrypted camouflage image P2′ carries the initial encryption information C, and the third encrypted camouflage image P3′ carries the second key image K2.

[0078] It should be noted that LSB steganography can be performed on the least significant bits of any one or more of the R, G, and B channels in an RGB image. The size, number of channels, and number of bits to be embedded in the spoofed image are determined based on the length of the bitstream to be embedded. That is, the total number of bits that can be embedded in the spoofing carrier is not less than the total number of bits of the information to be hidden, ensuring that the capacity of the spoofing carrier is not less than the number of bits of the information to be hidden. If the capacity of a single spoofed image is insufficient, hiding can be achieved by increasing the size of the spoofed image, using multiple color channels, using multiple least significant bit planes, or using a block embedding method.

[0079] In this embodiment, a steganography algorithm is used to write the initial encryption information and the random key into the corresponding disguised carriers, generating corresponding disguised information and improving the concealment of the encrypted information. Furthermore, since the initial encryption information and the random key are written into different disguised carriers, their independence is ensured, facilitating the extraction of the initial encryption information and the random key during subsequent decryption.

[0080] In some embodiments, the physical characteristics of the electromagnetic wave include amplitude, phase, and polarization; the initial disguised encryption information, the first key disguised information, and the second key disguised information are all binary sequence images; the encryption information is mapped to a multidimensional electromagnetic state code according to a preset mapping rule, including: mapping the binary value of the initial disguised encryption information to a phase value, the binary value of the first key disguised information to an amplitude value, and the binary value of the second key disguised information to a polarization value; and taking the bit values ​​at the same position in the binary sequences of the initial disguised encryption information, the first key disguised information, and the second key disguised information to form a multidimensional electromagnetic state code.

[0081] In the above implementation process, the three densely camouflaged images P1′, P2′ and P3′ are converted into binary digital code sequences and mapped to the three physical dimensions of electromagnetic wave amplitude, phase and polarization respectively.

[0082] In one implementation, the bitstream of the first densely camouflaged image P1′ is mapped to an amplitude coding sequence, the bitstream of the second densely camouflaged image P2′ is mapped to a phase coding sequence, and the bitstream of the third densely camouflaged image P3′ is mapped to a polarization coding sequence. The three dimensions are combined at the same time to form a three-digit code.

[0083] Based on the combination relationship of amplitude bits, phase bits, and polarization bits, each three-dimensional digital code is mapped to a corresponding multi-dimensional electromagnetic state code.

[0084] In the multidimensional electromagnetic state encoding, counting from right to left, the least significant bit encodes the amplitude state, with "0" representing a low amplitude state and "1" representing a high amplitude state; the middle bit encodes the phase state, with "0" representing the reference phase and "1" representing a 180° offset from the reference phase; and the most significant bit encodes the polarization state, with "0" representing the x-polarization state and "1" representing the y-polarization state.

[0085] For example, code 000 corresponds to low amplitude, reference phase, and x-polarization; code 001 corresponds to high amplitude, reference phase, and x-polarization; code 010 corresponds to low amplitude, 180° phase shift, and x-polarization; code 011 corresponds to high amplitude, 180° phase shift, and x-polarization; code 100 corresponds to low amplitude, reference phase, and y-polarization; code 101 corresponds to high amplitude, reference phase, and y-polarization; code 110 corresponds to low amplitude, 180° phase shift, and y-polarization; and code 111 corresponds to high amplitude, 180° phase shift, and y-polarization.

[0086] Table 1 shows the mapping relationship between multidimensional digital encoding and amplitude, phase, and polarization state provided in the embodiments of this application. As shown in Table 1, the embodiments of this application adopt a 3-bit multidimensional digital encoding method, wherein each code element is composed of amplitude bit, phase bit, and polarization bit. Counting from right to left, the least significant bit is the amplitude encoding bit, which is used to control the amplitude state of the electromagnetic wave; the middle bit is the phase encoding bit, which is used to control the phase offset state of the electromagnetic wave relative to the reference phase; and the most significant bit is the polarization encoding bit, which is used to control whether the electromagnetic wave is in x-polarization or y-polarization state.

[0087] This encoding method allows each symbol to correspond to a unique multidimensional electromagnetic state, enabling the three spoofing information to be carried together in the same carrier signal through the three dimensions of amplitude, phase, and polarization.

[0088] In Table 1, the reference phase is defined as 0, and π represents a 180° phase shift relative to the reference phase.

[0089] Table 1

[0090] It should be noted that the coding correspondence between the three densely camouflaged images P1′, P2′, and P3′ and the amplitude, phase, and polarization bits can be set according to the actual situation; and in the multidimensional electromagnetic state coding, the physical dimension represented by each coding bit can also be set according to the actual situation; and one dimension can carry one type of information, multiple dimensions can jointly carry one type of information, etc.; this application does not make any specific limitations on these.

[0091] It should also be noted that, in addition to amplitude, phase, and polarization, other electromagnetic dimensions such as frequency can be used, or any combination of two, three, or even more dimensions can be employed. For example, information can be carried out using methods such as amplitude-phase joint control, amplitude-polarization joint control, amplitude-phase-polarization joint control, phase-frequency joint control, and amplitude-frequency joint control. In other words, any method that maps different processing results to multiple independent or distinguishable electromagnetic degrees of freedom for transmission can be considered an alternative implementation of this application.

[0092] In this embodiment, a multi-dimensional electromagnetic control structure is used to coordinately modulate multiple independent physical dimensions of electromagnetic waves, such as amplitude, phase, and polarization. Different encryption results are mapped to different electromagnetic dimensions, forming a multi-dimensional electromagnetic state code to control the transmission of encrypted information. Compared to existing schemes that encode based on only a single electromagnetic feature, this expands the information channel, originally limited to a single degree of freedom, into multiple parallel electromagnetic channels. In this process, since each dimension can independently carry information and participate in the final decryption, the number of available coded states increases significantly, and the equivalent key space and information capacity are correspondingly improved. This increases the difficulty for unauthorized analysts, thus balancing capacity improvement and enhanced security.

[0093] In some embodiments, the electromagnetic control structure functional surface includes an amplitude control device, a phase control device, and a polarization control device; the multidimensional electromagnetic state coding includes amplitude coding, phase coding, and polarization coding; using the multidimensional electromagnetic state coding, the incident carrier is multidimensionally modulated through the electromagnetic control structure functional surface to generate a modulated signal, including: adjusting the amplitude control device according to the amplitude coding, adjusting the phase control device according to the phase coding, and adjusting the polarization control device according to the polarization coding, so that the incident carrier presents the corresponding amplitude, phase, and polarization, thereby generating a modulated signal.

[0094] In the above implementation process, the transmitting end loads the multidimensional electromagnetic state code onto the functional surface of the electromagnetic control structure.

[0095] The electromagnetically modulated structural functional surface includes multiple independently modulated structural functional devices, each of which can independently or collaboratively modulate the amplitude, phase, and polarization state of the incident electromagnetic wave.

[0096] In one implementation, the amplitude control device can be a PIN diode, the phase control device can be a varactor diode, and the polarization control device can be an orthogonally placed varactor diode.

[0097] By adjusting the working states of the amplitude controller, phase controller, and polarization controller through multidimensional electromagnetic state coding, the incident carrier signal can present corresponding amplitude, phase, and polarization coding states at different times or different unit positions, generating modulation information, thereby realizing the synchronous transmission of three densely camouflaged images in three electromagnetic dimensions.

[0098] In this embodiment, the electromagnetic control structure functional surface includes an amplitude control device, a phase control device, and a polarization control device. By using the structure functional surface with multi-dimensional electromagnetic control capabilities, the amplitude, phase, and polarization are modulated according to multi-dimensional electromagnetic state encoding, making it difficult to directly recover the encrypted content by intercepting only a certain signal or a certain type of data even if signal interception occurs, thereby improving the security of information transmission.

[0099] Figure 2 This is a flowchart illustrating an information decryption method provided in an embodiment of this application, as shown below. Figure 2 As shown, this method is applied to the receiving end, and the method includes: Step S201: Receive the modulated signal generated by the information transmission method of any of the above embodiments.

[0100] Step S202: Demodulate the modulated signal to obtain multidimensional electromagnetic state codes.

[0101] Step S203: Decode the multidimensional electromagnetic state code according to the preset inverse mapping rule to obtain encrypted information.

[0102] Step S204: Decrypt the encrypted information to obtain the plaintext information.

[0103] In the above implementation process, after the legitimate receiving end receives the electromagnetic signal modulated by the functional surface of the electromagnetic control structure, it demodulates the modulated signal.

[0104] In one implementation, if the multidimensional electromagnetic state codes obtained by the transmitting end correspond to polarization, amplitude, and phase respectively, the receiving end first separately receives the x-polarization channel and y-polarization channel of the modulated signal and obtains the amplitude and phase information in the two orthogonal polarization channels respectively. Then, based on the polarization channel energy, amplitude threshold, and phase difference information, the polarization code, amplitude code, and phase code are sequentially recovered to obtain the multidimensional electromagnetic state codes.

[0105] The receiving end reconstructs the encrypted information according to the amplitude-coded sequence, phase-coded sequence, and polarization-coded sequence obtained from demodulation, following a preset inverse mapping rule. Then, it decrypts the encrypted information using the same encryption process as the sending end to obtain the plaintext information. The preset inverse mapping rule is the inverse mapping of a preset mapping rule.

[0106] For example, three encrypted camouflaged images P1′, P2′, and P3′ are reconstructed according to a preset inverse mapping rule. Using the same steganography extraction rule as the sending end, the first key image K1, the initial encryption information C, and the second key image K2 are extracted from the three encrypted camouflaged images, respectively.

[0107] The receiving end performs an XOR operation on the extracted first key image K1, initial encryption information C, and second key image K2 to obtain the original image M, whose expression is: M=C⊕K1⊕K2 Therefore, the receiving end does not need to share the key in advance. Instead, it can recover the encrypted information and two key information from the three disguised information by completely demodulating the multidimensional electromagnetic signal, and further recover the original image.

[0108] In this embodiment, information is distributed and mapped across multiple independent electromagnetic dimensions, each carrying an encrypted and disguised result. Therefore, even if an unauthorized receiver intercepts a portion of the signal in a certain direction, they typically only obtain incomplete dimensional information or disguised intermediate information, making it difficult to recover the true information to be transmitted. Only by receiving complete dimensional information in the legitimate direction and performing joint demodulation and recovery of the dimensional information according to a predetermined decryption process can the true information be correctly extracted. Thus, this embodiment effectively constructs a dual constraint of "multi-dimensional complete reception + correct decryption process," significantly increasing the barrier to cracking compared to single-channel, single-feature encryption schemes.

[0109] In some embodiments, demodulating the modulated signal to obtain a multidimensional electromagnetic state code includes: performing polarization separation on the modulated signal to obtain a first polarization channel signal and a second polarization channel signal; performing envelope detection on the first polarization channel signal and the second polarization channel signal respectively to obtain a first envelope amplitude and a second envelope amplitude; determining the effective channel signal in the first polarization channel signal and the second polarization channel signal based on the first envelope amplitude and the second envelope amplitude; and determining the multidimensional electromagnetic state code based on the effective channel signal.

[0110] In some embodiments, the multidimensional electromagnetic state coding includes amplitude coding, phase coding, and polarization coding; determining the multidimensional electromagnetic state coding based on the effective channel signal includes: determining the polarization coding through the effective channel signal; determining the amplitude coding according to the envelope amplitude of the effective channel and a preset amplitude threshold; and determining the phase coding by differential demodulation of the effective channel signal.

[0111] In the above implementation process, firstly, the receiver performs polarization coding demodulation. Since there is a high polarization isolation between the x-polarization state and the y-polarization state, the receiver can use an envelope detection method combined with an amplitude-based decision rule to determine the polarization state of the current symbol.

[0112] Since the modulated signal at any given moment corresponds to only one polarization state, amplitude coding and phase coding should be extracted from the currently effective polarization channel.

[0113] Specifically, the received envelope amplitudes of the x-polarization channel and the y-polarization channel are detected separately. When the signal amplitude of one polarization channel is attenuated by more than a first preset amplitude threshold relative to the signal amplitude of the other polarization channel, it is determined to be a cross-polarization channel, and the polarization channel with stronger energy is determined to be the current effective polarization channel.

[0114] When the polarization code is "1", the y-polarization channel is used as the effective channel, and the amplitude code and phase code are extracted from the y-polarization channel; when the polarization code is "0", the x-polarization channel is used as the effective channel, and the amplitude code and phase code are extracted from the x-polarization channel.

[0115] For example, the first preset amplitude threshold can be set to 10dB. When the current effective polarization channel is determined to be the x-polarization channel, the polarization code is "0"; when the current effective polarization channel is determined to be the y-polarization channel, the polarization code is "1".

[0116] Secondly, the receiver demodulates the amplitude coding. Unlike polarization demodulation, which uses a higher threshold to distinguish orthogonal polarization channels, amplitude coding is used to distinguish between high-amplitude and low-amplitude states within the same valid polarization channel, thus allowing for the use of a lower amplitude decision threshold.

[0117] Specifically, in the effective polarization channel determined by polarization coding, the receiver detects the symbol envelope amplitude and compares the detected value with a second preset amplitude threshold. When the received amplitude is higher than the second preset amplitude threshold, the amplitude code is determined to be "1"; when the received amplitude is lower than the second preset amplitude threshold, the amplitude code is determined to be "0".

[0118] For example, the second preset amplitude threshold can be set to about 3dB to distinguish between high amplitude encoding state and low amplitude encoding state.

[0119] Next, the receiver demodulates the phase code. The phase code uses two states: a reference phase and a state offset by 180° relative to the reference phase. The receiver recovers the phase code using differential demodulation in the effective polarization channel, that is, by comparing the phase difference between adjacent symbols or the reference symbol to determine the phase state of the current symbol. When the phase is close to the reference phase, the phase code is determined to be "0"; when the phase is offset by approximately 180° relative to the reference phase, the phase code is determined to be "1".

[0120] Finally, the receiving end performs multidimensional encoding integration to obtain a complete three-dimensional digital code composed of polarization bits, phase bits, and amplitude bits.

[0121] In this embodiment, by polarization separation of the modulated signal and by detecting and identifying valid channel signals, the purity of signal extraction is improved, the anti-interference capability is enhanced, and ultimately more reliable multidimensional electromagnetic state coding identification is achieved.

[0122] This application provides an electromagnetically modulated structural functional surface, including: a metal reflective layer, a metal ground layer, a metal feed layer, a first dielectric layer, and a second dielectric layer; the first dielectric layer is located between the metal reflective layer and the metal ground layer, and the second dielectric layer is located between the metal ground layer and the metal feed layer; the metal reflective layer includes multiple tunable active devices; wherein, by using multidimensional electromagnetic state coding to adjust the multiple tunable active devices, the incident carrier is multidimensionally modulated to generate a modulated signal; wherein, the multidimensional electromagnetic state coding characterizes the physical characteristic coding sequence of the electromagnetic wave.

[0123] In the above implementation process, the shape of the metal patch of the metal reflective layer can be any combination of cross, trapezoid, circle, square, rectangle, triangle, polygon, etc.

[0124] Metallic materials can be conductive materials such as gold, silver, aluminum, and copper.

[0125] The dielectric materials for the first and second dielectric layers can be FR-4, F4B, Rogers series, Taconic series, etc.

[0126] The number of metal layers, dielectric layers, patch topology, and interlayer connections can all be equivalently replaced according to design requirements. Metal thickness, dielectric thickness, dielectric constant, and loss parameters can all be adjusted according to the target frequency, bandwidth, and modulation requirements. The inductance value, PIN diode type, varactor diode type, and modulation bit depth of adjustable active devices can also be adjusted according to the operating frequency, bandwidth, and system requirements.

[0127] Figure 3 A schematic diagram of a subwavelength structural functional unit with multi-dimensional electromagnetic control capability is provided in an embodiment of this application, as shown below. Figure 3 As shown, the unit includes three dielectric layers and four metal layers, with the top metal layer serving as a metal reflective layer, the second metal layer serving as a metal grounding layer, and the last two metal layers serving as metal feed layers.

[0128] The metal reflective layer includes a central cross-shaped metal patch, four rotationally symmetrical rectangular patches, four rotationally symmetrical trapezoidal patches, and four rotationally symmetrical triangular patches, as well as four rotationally symmetrical PIN diodes (SMP-1345), four rotationally symmetrical varactor diodes (SMV-2020), and four rotationally symmetrical inductors. All metal patches are connected to a metal ground plane or metal feed plane via metal vias, and a programmable voltage source applies a bias voltage to achieve independent control of the operating state of each active device.

[0129] The first dielectric layer is made of F4B with a thickness of h1, the second dielectric layer is made of FR-4 with a thickness of h2, and the third dielectric layer is made of FR-4 with a thickness of h3.

[0130] In one specific embodiment, the metal material can be copper with a thickness of 0.018 mm; the dielectric layer can be F4B with a thickness of 3 mm and two layers of FR-4 with a thickness of 0.254 mm in sequence; the cell period can be 20 mm; the side length of the triangular patch can be 7.5 mm, the width of the central cross-shaped patch can be 3 mm, the arm length can be 6.3 mm, and the side length of the rectangular patch can be 1.87 mm; the PIN diode can be SMP1345-079LF, the varactor diode can be SMV2020-079LF, and the inductor can be LQW15AN33NH00D.

[0131] The working principle of this subwavelength structure functional unit is as follows: by adjusting the voltage across the PIN diode to change its on-resistance, the amplitude response of the electromagnetic wave is altered; by adjusting the voltage across the varactor diode to change its equivalent capacitance, the phase response of the electromagnetic wave is altered; and by independently controlling the varactor diodes in the orthogonal directions, the equivalent capacitance values ​​in the two orthogonal directions are made different, thereby achieving the regulation of the polarization state. Thus, a single unit can achieve independent or coordinated regulation of the amplitude, phase, and polarization dimensions.

[0132] Figure 4 The simulation results of a subwavelength structural functional unit in amplitude, phase and polarization dimensions are provided for the embodiments of this application.

[0133] like Figure 4 As shown, for independent amplitude modulation, the varactor diode capacitance value C1=C2=0.61pF can be set, and the equivalent resistance of the PIN diode can be set to 1Ω, 10Ω, 20Ω and 30Ω; for independent phase modulation, the equivalent resistance of the PIN diode can be fixed to 1Ω, and the varactor diode capacitance value C1=C2 can be set to 0.35pF, 0.61pF, 1.10pF and 3.20pF; for independent polarization modulation, different combinations of C1 and C2 can be set to produce different polarization states.

[0134] Based on the above settings for capacitance and resistance values, according to Figure 4 (a) It can be seen that near the target frequency of 5.0 GHz, amplitude adjustment can be achieved by keeping the varactor diode capacitance constant and only changing the equivalent resistance of the PIN diode; according to Figure 4 (b) It can be seen that phase adjustment can be achieved by keeping the equivalent resistance of the PIN diode constant while changing the capacitance of the varactor diode; according to Figure 4 (c) It can be seen that when the equivalent resistance value of the PIN diode remains unchanged and the capacitance values ​​of the varactor diodes in the two orthogonal directions are changed independently, the polarization state can be adjusted.

[0135] The results show that the structural unit has independent control capabilities in the three electromagnetic dimensions of amplitude, phase and polarization, which can provide a hardware foundation for multidimensional information mapping.

[0136] Figure 5 The simulation results of the radiation pattern of an electromagnetically modulated structural functional surface composed of multiple subwavelength structural functional units provided in this application embodiment are shown under different polarization states and different control conditions. Multiple subwavelength structural functional units with multi-dimensional electromagnetic control capabilities are arranged in an array to form an electromagnetically modulated structural functional surface with multi-dimensional electromagnetic control capabilities.

[0137] Beam scanning can be achieved under different polarization states by adjusting the capacitance distribution of the varactor diodes in each element on the array surface; according to Figure 5 (a) Figure 5 (b) Figure 5 (c) and Figure 5 (d) shows that amplitude modulation in the target direction can be achieved by changing the equivalent resistance value of the PIN diode while keeping the phase distribution unchanged; according to Figure 5 (c) and Figure 5 (f) shows that phase modulation in the target direction can be achieved by changing the phase distribution of the array while keeping the state of the PIN diode unchanged.

[0138] Simulation results show that the functional surface of the electromagnetic control structure can achieve ±60° beam scanning, amplitude control of more than 3dB, and phase control of 180° at 5.0 GHz, thus demonstrating that the multidimensional control not only exists at the unit level but can also be extended to the array level to achieve directional and secure physical layer transmission.

[0139] To further understand the technical solution provided in this application, the following embodiments are given for illustration.

[0140] Figure 6 This application provides a schematic diagram illustrating the information encryption and decryption process based on an electromagnetically controlled structural functional surface. For example... Figure 6 As shown, this embodiment provides an information encryption transmission method based on three-dimensional electromagnetic control of amplitude, phase, and polarization. The original information to be transmitted is an RGB image, denoted as M.

[0141] The sending end first randomly generates two key images corresponding to the original image size and data format, denoted as the first key image K1 and the second key image K2, respectively. Then, the sending end performs a bit-by-bit XOR operation on the original image M, the first key image K1, and the second key image K2 to obtain the initial encrypted information C, i.e.: C=M⊕K1⊕K2 After completing the hybrid encryption, the sending end selects three normally visible disguised images to hide the initial encryption information C, the first key image K1, and the second key image K2, respectively.

[0142] Specifically, the least significant bit steganography (LSB steganography) method is used to embed the binary bit stream of the first key image K1 into the least significant bit of the first disguised image, embed the binary bit stream of the initial encryption information C into the least significant bit of the second disguised image, and embed the binary bit stream of the second key image K2 into the least significant bit of the third disguised image, thus obtaining three encrypted disguised images respectively.

[0143] Subsequently, the transmitting end converts the three camouflaged images into binary coded sequences, mapping them to the three electromagnetic dimensions of amplitude, phase, and polarization. The amplitude, phase, and polarization bits together constitute a three-bit multidimensional digital coded state. The three bits are encoded in the order of "polarization bit-phase bit-amplitude bit," for example, 000 represents x-polarization, reference phase, and low amplitude state, while 111 represents y-polarization, 180° phase offset, and high amplitude state. In this way, the three camouflaged images are carried through three independent electromagnetic dimensions and transmitted synchronously during the modulation of the carrier signal on the structural functional surface.

[0144] After receiving the modulated electromagnetic signal, the receiver recovers the corresponding digital encoding sequences from the three dimensions of polarization, amplitude, and phase, and further reconstructs three encrypted camouflage images. Subsequently, according to the LSB extraction rules preset by the transmitter, the receiver extracts the first key image K1, the initial encryption information C, and the second key image K2 from the three encrypted camouflage images, and performs the following XOR operation to obtain the original image M: M=C⊕K1⊕K2 The process of multidimensional demodulation of the received modulated signal at the receiving end is described in the above embodiment and will not be repeated here.

[0145] In summary, the beneficial effects of this application are as follows: 1. Improved information transmission security and reduced system risks caused by key leakage: This application's solution does not separate the information to be transmitted from the key information, nor does it rely on the traditional pre-shared key method. Instead, it first performs mixed encryption processing on the key information and the information to be transmitted, and then transmits the encryption results simultaneously in different electromagnetic dimensions. Since the key information is no longer transmitted separately as independent, explicit auxiliary information, but participates in encryption together with the information to be transmitted and is embedded in the entire transmission link, even if signal interception occurs, it is difficult to directly recover the key content by intercepting only one signal or one type of data. Therefore, this application's solution weakens the risk of "once the key is leaked, the entire information can be cracked" in traditional solutions from the transmission mechanism, and improves the overall anti-eavesdropping and anti-cracking capabilities of the system.

[0146] 2. Enhanced Concealment and Deception in Information Transmission: After hybrid encryption, this application's solution does not directly send the encrypted data stream. Instead, it further hides the encrypted information within a disguised carrier using steganography, then maps it to different electromagnetic dimensions for modulation and transmission. Through this method, the transmitted content no longer appears as obvious "encrypted information" on the surface, but rather as a normal information carrier with disguised characteristics. For receivers unfamiliar with the decryption process or lacking complete dimensional information, what they receive is often merely a disguised image or invalid information, rather than the true secret content. Therefore, this invention not only achieves "not easily decryptable" but also "difficult to determine if it is a secret information transmission," resulting in significantly stronger concealment compared to traditional direct encrypted transmission methods.

[0147] 3. Expanded information carrying channels, improved system capacity and encryption complexity: This application utilizes a multi-dimensional electromagnetic control structure functional surface to coordinately modulate multiple independent physical dimensions of electromagnetic waves, such as amplitude, phase, and polarization, mapping different encryption results to different electromagnetic dimensions for transmission. Compared to existing schemes that encode based on only a single electromagnetic feature, this invention expands the information channel, originally limited to a single degree of freedom, into multiple parallel electromagnetic channels. Since each dimension can independently carry information and participate in the final decryption, the number of available encoded states of the system is significantly increased, and the equivalent key space and information capacity are correspondingly improved. In other words, multi-dimensional carrying is not simply "multi-path transmission," but rather increases the difficulty of detection for unauthorized analysts from the perspective of joint design of information theory and physical layer, thus balancing capacity improvement and security enhancement.

[0148] 4. Increased Difficulty in Illegal Reception and Decryption: Because this application's scheme disperses information across multiple independent electromagnetic dimensions, and each dimension carries the result of hybrid encryption and disguise processing, even if an illegal receiver intercepts part of the signal in a certain direction, they can usually only obtain incomplete dimensional information, or only disguised intermediate information, making it difficult to recover the true secret content. Only by receiving complete dimensional information in the legitimate direction and jointly demodulating and recovering the information in each dimension according to the established decryption process can the true information be correctly extracted. Therefore, this application's scheme actually constructs a dual constraint of "multi-dimensional complete reception + correct decryption process," significantly increasing the decryption threshold compared to single-channel, single-feature encryption schemes.

[0149] 5. Combining the advantages of physical layer encryption and reconfigurable control: This application's scheme modulates amplitude, phase, and polarization through a structural functional surface with multi-dimensional electromagnetic control capabilities. Amplitude control can be achieved through PIN diodes, phase control through varactor diodes, and polarization control through independently controlled orthogonally arranged varactor diodes. Because this type of control method is inherently programmable, it not only enables multi-dimensional collaborative coding but also provides the foundation for further expansion into dynamic control, reconfiguration of transmission rules, and updating of mapping relationships. This means that this application's scheme is not only suitable for static secure transmission but also provides the hardware and methodological foundation for the subsequent development of high-security-capacity, dynamically updatable physical layer secure communication systems. Compared to traditional static, single-degree-of-freedom schemes, it offers greater adaptability.

[0150] 6. This application elevates the protection mechanism from "simple algorithm protection" to "coordinated protection of algorithm and physical layer": In existing technologies, even with strong digital encryption algorithms, the physical transmission channel can still be compromised and vulnerable to analysis and cracking. This application moves the encryption mechanism forward to the electromagnetic wave modulation and propagation stage, employing a complete link of "hybrid encryption—information camouflage—multi-dimensional mapping—structural functional surface modulation—joint demodulation and recovery," ensuring the security mechanism permeates the entire information processing and physical transmission process. This results not in a single-layer improvement but in a comprehensive protection mechanism covering the coding layer, carrier layer, and propagation layer, thus possessing greater practical value in complex wireless environments.

[0151] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0152] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0153] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0154] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An information transmission method, characterized in that, The method is applied at the sending end; the method includes: Encrypt the information to be transmitted to generate encrypted information; According to a preset mapping rule, the encrypted information is mapped into a multidimensional electromagnetic state code; wherein, the multidimensional electromagnetic state code represents a sequence of physical characteristic codes for electromagnetic waves; Using the aforementioned multidimensional electromagnetic state encoding, the incident carrier is modulated in multiple dimensions through the functional surface of the electromagnetic control structure to generate a modulated signal; wherein, the modulated signal is used to transmit the encrypted information.

2. The method according to claim 1, characterized in that, The process of encrypting the information to be transmitted to generate encrypted information includes: The information to be transmitted is encrypted using a random key to generate initial encrypted information; Using a steganography algorithm, the initial encryption information and the random key are written into the corresponding disguise carriers to generate initial disguised encryption information and key disguised information; The encrypted information is generated based on the initial disguised encryption information and the key disguised information.

3. The method according to claim 2, characterized in that, in, The information to be transmitted includes the original image; Before encrypting the information to be transmitted using a random key to generate initial encrypted information, the method further includes: randomly generating a first key image and a second key image based on the attribute information of the original image; The step of encrypting the information to be transmitted using a random key to generate initial encrypted information includes: performing an XOR operation on the original image, the first key image, and the second key image to generate the initial encrypted information.

4. The method according to claim 3, characterized in that, in, The camouflage carrier includes a first camouflage image, a second camouflage image, and a third camouflage image; The step of using a steganography algorithm to write the initial encryption information and the random key into corresponding spoofing carriers to generate initial spoofed encryption information and key spoofing information includes: Using the steganography algorithm, the first key image is written into the first disguised image to generate the first key disguise information; The initial encryption information is written into the second disguised image to generate the initial disguised encryption information; The second key image is written into the third disguised image to generate second key disguise information.

5. The method according to claim 4, characterized in that, in, The physical characteristics of the electromagnetic wave include amplitude, phase, and polarization; the initial camouflage encryption information, the first key camouflage information, and the second key camouflage information are all binary sequence images; The step of mapping the encrypted information into multidimensional electromagnetic state codes according to a preset mapping rule includes: The binary value of the initial disguised encryption information is mapped to the phase value, the binary value of the first key disguised information is mapped to the amplitude value, and the binary value of the second key disguised information is mapped to the polarization value; The multidimensional electromagnetic state code is constructed by taking the bit values ​​at the same position in the binary sequences of the initial disguised encryption information, the first key disguised information, and the second key disguised information, respectively.

6. The method according to any one of claims 1-5, characterized in that, in, The electromagnetic control structure's functional surface includes an amplitude control device, a phase control device, and a polarization control device; the multidimensional electromagnetic state encoding includes amplitude encoding, phase encoding, and polarization encoding. The method of using the multidimensional electromagnetic state encoding to perform multidimensional modulation of the incident carrier through the functional surface of the electromagnetic control structure to generate a modulated signal includes: The amplitude controller is adjusted according to the amplitude encoding, the phase controller is adjusted according to the phase encoding, and the polarization controller is adjusted according to the polarization encoding, so that the incident carrier presents the corresponding amplitude, phase and polarization, thereby generating the modulation signal.

7. An information decryption method, characterized in that, The method is applied at the receiving end, and the method includes: Receive the modulated signal generated by the information transmission method according to any one of claims 1-6; The modulated signal is demodulated to obtain a multidimensional electromagnetic state code; According to a preset inverse mapping rule, the multidimensional electromagnetic state code is decoded to obtain encrypted information; The encrypted information is decrypted to obtain the plaintext information.

8. The method according to claim 7, characterized in that, The demodulation of the modulated signal to obtain the multidimensional electromagnetic state code includes: The modulation signal is polarized to obtain a first polarization channel signal and a second polarization channel signal; Envelope detection is performed on the first polarization channel signal and the second polarization channel signal respectively to obtain the first envelope amplitude and the second envelope amplitude; Based on the first envelope amplitude and the second envelope amplitude, the effective channel signal in the first polarization channel signal and the second polarization channel signal is determined; Based on the effective channel signal, the multidimensional electromagnetic state code is determined.

9. The method according to claim 8, characterized in that, in, The multidimensional electromagnetic state coding includes amplitude coding, phase coding, and polarization coding; Determining the multidimensional electromagnetic state code based on the effective channel signal includes: The polarization code is determined using the effective channel signal; The amplitude encoding is determined based on the envelope amplitude of the effective channel and a preset amplitude threshold. Differential demodulation is performed on the effective channel signal to determine the phase code.

10. A functional surface for electromagnetic control structure, characterized in that, include: Metal reflective layer, metal ground layer, metal feed layer, first dielectric layer and second dielectric layer; The first dielectric layer is located between the metal reflective layer and the metal ground layer, and the second dielectric layer is located between the metal ground layer and the metal feed layer; The metal reflective layer includes multiple tunable active devices; Specifically, by using multidimensional electromagnetic state coding to adjust the multiple tunable active devices, the incident carrier is multidimensionally modulated to generate a modulated signal; wherein, the multidimensional electromagnetic state coding represents the physical characteristic coding sequence of the electromagnetic wave.

Images