A Position-Related Security Information Transmission Method Based on Visible Polarization Interference

Abstract

This invention provides a position-dependent secure information transmission method based on visible polarized light interference, belonging to the field of internet device information transmission technology. It involves receiving incident spectra with different spectral characteristics at different locations; recording the correspondence between the incident spectrum and the received spectrum related to the receiving location; selecting an encoding method based on the correspondence, enabling authorized devices to successfully decode information transmitted through the selected encoding method, until the bit error rate of the 0 / 1 sequence received by unauthorized devices is maximized; and achieving secure directional information transmission based on the selected encoding method. This invention utilizes the fact that devices in different locations receive different light signals, increasing the difficulty for eavesdroppers and improving security. Through data analysis, a unique encoding method is designed, making it difficult for eavesdroppers to decode the correct information even if they receive the light signal.

Description

Technical Field

[0001] This invention relates to the field of information transmission technology for Internet devices, and specifically to a position-related secure information transmission method based on visible polarized light interference. Background Technology

[0002] Birefringence is an optical phenomenon that occurs in certain crystals and materials. When light passes through these birefringent materials, it splits into two beams of refracted light in different directions. These two beams are perpendicular to each other in polarization and have different refractive indices. One beam is called the ordinary ray (o-ray), which obeys the law of refraction; the other beam is called the extraordinary ray (e-ray), which does not obey the law of refraction and depends on the orientation of the incident ray and the crystal. Each direction has a different refractive index, thus changing the speed and direction of light propagation. Traditional wireless communication technology refers to wireless communication based on electromagnetic waves. Due to the limited spectrum resources of radio waves, people naturally thought of using light waves. Compared with traditional wireless communication technology, visible light communication not only has the advantages of ultra-high speed and low latency, but also has advantages such as being environmentally friendly and having no ionizing radiation. However, visible light communication technology has security vulnerabilities; eavesdroppers can intercept light signals to eavesdrop.

[0003] Interference of visible polarized light: When two beams of polarized light meet at a point, they interfere with each other. Their amplitudes and phases will affect each other. If the two light waves are in phase (i.e., the crests and troughs coincide), they will reinforce each other, leading to an increase in light intensity. If the two light waves are in phase (i.e., the crests and troughs align), they will cancel each other out, leading to a decrease in light intensity.

[0004] Visible light communication (VLC) is a novel wireless communication technology that uses high-frequency flashing of light-emitting diodes (LEDs) to transmit information. A VLC system consists of two parts: a transmitter and a receiver. The transmitter uses LEDs as the light source and performs (1) digital signal processing and conversion—encoding: converting digital signals into 0 / 1 sequences; (2) modulation: using changes in the intensity of LED light to transmit 0 / 1 sequences; (3) demodulation: the receiver converts the received light intensity back into 0 / 1 sequences, thereby decoding the information transmitted by the transmitter. VLC modulation techniques mainly include On-Offkeying (OOK), pulse modulation, and Color Shift Keying (CSK). Taking binary On-Offkeying (OOK) signal transmission as an example, we can adjust the brightness of the light to make it slightly brighter or slightly darker to represent different numbers, such as bright representing 1 and dark representing 0. The faster the communication speed, the faster the change in the brightness of the light. The naked eye cannot observe such subtle changes, but electronic devices can detect these subtle changes, thereby realizing digital communication. The visible polarization interferometry-based positioning technology, based on polarizers and birefringent materials, utilizes optical interference and spectral properties to derive a model that characterizes the relationship between direction, optical interference, and spectrum. This model provides a low-cost, high-precision indoor 2D and 3D positioning method, overcoming some limitations of traditional methods and offering an innovative way to utilize ambient light for indoor positioning.

[0005] Visible light communication technology suffers from low security: due to the openness of the VLC channel, eavesdroppers in the same space may intercept the light information, analyze the optical signal to convert it into a digital signal, and then eavesdrop. Some systems employ cryptographic schemes, encrypting the information at the transmitting end and decrypting it at the receiving end to protect the information from eavesdropping. However, this approach introduces computational overhead for encryption and decryption. Summary of the Invention

[0006] The purpose of this invention is to provide a method for transmitting position-related security information based on visible polarized light interference, so as to solve at least one of the technical problems in the background art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a method for transmitting position-related security information based on visible polarized light interferometry, comprising:

[0009] Receive incident spectra with different spectral characteristics at different locations;

[0010] Record the correspondence between the incident spectrum and the received spectrum related to the receiving position;

[0011] Based on the correspondence, an encoding method is selected so that authorized devices can successfully decode information transmitted through the selected encoding method, until the bit error rate of the 0 / 1 sequence received by unauthorized devices is maximized;

[0012] Based on the selected encoding method, secure and directional information transmission is achieved.

[0013] Furthermore, establishing a mapping from the position / incident spectrum to the output spectrum includes:

[0014] The sampling location information is obtained when sampling is performed at different spatial locations; at different locations, the color of the light emitted by the transmitting device is adjusted and the spectral characteristics used are recorded; the receiving end collects the output spectrum under different emission spectra at each location and records the spectral characteristics of the output light; the output of the sampling process is a mapping from position / incident spectrum to output spectrum.

[0015] Furthermore, the encoding process takes the location / mapping from the incident spectrum to the emitted spectrum obtained from the sampling, the data to be encoded, and the location of the target receiving device as inputs; the encoded output is a sequence of incident spectra, which is executed by the transmitting device for information transmission.

[0016] Furthermore, based on the sampled mapping and specific location information, the algorithm finds the most suitable encoding method to associate the 0 / 1 sequence with the incident spectrum mapping; using the selected encoding method, the sequence of the incident spectrum is generated based on the 0 / 1 sequence.

[0017] Furthermore, in the encoding process, a suitable encoding method is selected, including:

[0018] Collect sampling data: Collect the mapping data from the sampled position / incident spectrum to the output spectrum;

[0019] Performance metrics are defined as follows: Accuracy: Ensures that the information decoded by the authorized device is accurate, i.e., the bit error rate of the 0 / 1 sequence received by the target device is low; Security: Ensures that the bit error rate of the 0 / 1 sequence obtained by the eavesdropper based on the received spectral information is as high as possible compared to the 0 / 1 sequence of the transmitting end; Error tolerance: To improve security, error correction codes are introduced to ensure that the bit error rate of the target device is within the range that the error correction codes can correct, and not too high; Anti-error correction code security: Ensures that the bit error rate of other devices is higher than 40%, and that they cannot use error correction codes for decoding;

[0020] Select encoding parameters: Before determining the encoding method, select a set of possible encoding parameters;

[0021] Establish a performance model: Based on the sampled data and the selected encoding parameters, establish a performance model to evaluate the performance of different encoding methods;

[0022] Optimization Algorithm: Utilize optimization algorithms to search for the optimal combination of encoding parameters;

[0023] Evaluation results: For each coding attempt, its performance was evaluated using a performance model;

[0024] Selecting the best encoding method: The algorithm completes the search and selects the encoding method with the best performance.

[0025] Furthermore, the sampling process obtains a mapping from the position / incident spectrum to the output spectrum, the encoding process obtains a mapping from the 0 / 1 sequence to the incident spectrum, and the decoding process takes the obtained mapping from the output spectrum / position to the 0 / 1 sequence, the position of the receiving device, and the received output spectrum as inputs.

[0026] Furthermore, the decoding process is as follows:

[0027] The mapping from the output spectrum to the 0 / 1 sequence is obtained: the sampling process obtains the mapping from the position / incident spectrum to the output spectrum, the encoding process obtains the mapping from the 0 / 1 sequence to the incident spectrum, and finally the mapping from the output spectrum / position to the 0 / 1 sequence is obtained.

[0028] Determine the location and collect the emitted spectrum;

[0029] Based on the mapping from the emitted spectrum / position to the 0 / 1 sequence and the position of the receiver, the received spectrum is used to obtain the 0 / 1 sequence, which means successful decoding and obtaining the information that the transmitter wants to transmit.

[0030] Furthermore, after the authorized device enters space, it sends its location to the transmitting device. The transmitting device maintains the mapping relationship between the device ID and the location. The transmitting end will determine the incident spectrum sequence of the transmitting end based on the location of the authorized device and the 0 / 1 sequence sent.

[0031] The beneficial effects of this invention are: devices located in different positions receive different light signals, increasing the difficulty for eavesdroppers and improving security; through data analysis, a unique encoding method was designed, making it difficult for eavesdroppers to decode the correct information even if they receive the light signal.

[0032] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a flowchart of the position-related security information transmission method based on visible polarized light interference as described in Embodiment 1 of the present invention.

[0035] Figure 2 This is a structural diagram of a position-related security information transmission device based on visible polarization light interference, as described in an embodiment of the present invention.

[0036] Figure 3 This is a flowchart illustrating the adoption process described in an embodiment of the present invention.

[0037] Figure 4 This is a flowchart of the encoding process described in an embodiment of the present invention.

[0038] Figure 5 This is a flowchart of the decoding process described in an embodiment of the present invention. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0040] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0041] It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as here.

[0042] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or groups thereof.

[0043] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0044] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0045] In the description of this specification, the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this technology and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this technology.

[0046] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of these terms in this art according to the specific circumstances.

[0047] To facilitate understanding of the present invention, the present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. However, the specific embodiments do not constitute a limitation on the embodiments of the present invention.

[0048] Those skilled in the art should understand that the accompanying drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily essential for implementing the present invention.

[0049] Traditional wireless communication technology refers to wireless communication based on electromagnetic waves. Due to the limited spectrum resources of electromagnetic waves, the use of light waves has naturally been considered. Compared to traditional wireless communication technologies, visible light communication not only has advantages such as ultra-high speed and low latency, but also advantages such as being environmentally friendly and free of ionizing radiation. However, visible light communication technology has security vulnerabilities; eavesdroppers can intercept light signals to conduct eavesdropping. This invention aims to improve the security of visible light communication by providing a position-related secure information transmission method based on visible polarized light interferometry, addressing the following technical issues:

[0050] Question 1: How to design an information transmission method using the principle of polarized light interference so that the receiver can successfully decode the information?

[0051] Question 2: How to achieve targeted transmission so that eavesdroppers cannot successfully receive information sent by the sender to an authorized location through their own receiving device?

[0052] Question 3: How can we ensure the security of information transmission through special encoding methods so that even if an eavesdropper intercepts the light signal, they will not be able to analyze the correct information?

[0053] like Figure 1 As shown, this embodiment provides a method for transmitting position-related security information based on visible polarized light interferometry, including:

[0054] The transmitter emits light with different spectral characteristics, and the receiver receives incident spectra with different spectral characteristics at different locations. The sampling results are recorded, that is, the correspondence between the incident light spectrum and the received spectrum related to the receiving location. By analyzing the collected data, an encoding method is selected based on the correspondence, so that authorized devices can successfully decode the information transmitted through the selected encoding method. The selection of encoding methods continues to be made to maximize the bit error rate of the 0 / 1 sequence received by unauthorized devices. Based on the selected encoding method, secure and directional information transmission is achieved.

[0055] like Figure 2 As shown, the position-related security information transmission device based on visible polarized light interference in this embodiment includes two parts: a transmitting end and a receiving end. For the transmitting end, a device capable of emitting polarized light and changing the incident spectrum is used as the transmitter (e.g., a liquid crystal display) to emit polarized light. The polarization direction is measured using a linear polarizer, and then several birefringent materials are fixed onto the linear polarizer. For the receiving end, a color-distinguishing device is used as the receiver (e.g., a camera or photodiode). When in use, the polarized light emitted by the transmitter enters from one end of the birefringent material. After passing through the birefringent material and the linear polarizer, the incident light exits from one end of the linear polarizer, and finally, the receiver captures the light signal and receives the specified information. Figure 2 As shown, the light emitted by the transmitter is polarized light. Two beams of polarized light, L1 and L2, enter the birefringent material at points A and B respectively, producing a birefringence phenomenon. L1 is divided into L... 1o (Ordinary light) and L 1e (Extraordinary light) Two refracted beams, L2 is also divided into L 2o (Ordinary light) and L 2e (Extraordinary light) Two-way refracted light. As shown in the figure, L 1e and L 2o Interference occurs at point C, and the interfered light is captured by the receiver. Because the light undergoes interference and birefringence, the resulting spectrum differs at different locations and distances; that is, the color information of the received light signal varies at different positions. Since the attacker and receiver are in different positions, the attacker cannot obtain the correct information about the receiver's location. When the incident spectrum emitted by the transmitter changes, the emitted spectrum also changes accordingly, allowing the receiver to continuously receive the changing light information.

[0056] like Figure 2 The transmitter emits two polarized beams, L1 and L2. L1 and L2 enter a birefringent material at points A and B, respectively, resulting in birefringence. 1e and L 2o These two components propagate at different speeds and undergo different phase changes as they pass through the material. Therefore, when they re-merge at point C, a phase difference exists between them. Depending on the magnitude and sign of this phase difference, they may be constructive or destructive (the phase difference is a half-integer multiple of the wavelength). This phase difference arises from the properties of the birefringent material and the difference in the path length of light propagating within it. The manipulation of this phase difference can be used to achieve interference effects, thereby influencing the properties and spectrum of the emitted light. Furthermore, the change in the light path due to different receiver positions also alters the interference result; that is, receivers at different locations in space receive different spectra.

[0057] For the fabrication of the device, a transmitter capable of emitting polarized light with variable spectra is used. Multiple birefringent materials are then fixed onto a linear polarizer, and the positional relationship between the birefringent materials and the angle between their optical axes and the polarized light emitted by the transmitter are adjusted. A color-distinguishing device is used as a receiver to acquire information at a designated receiving point. After receiving the information, color analysis is performed on each transmitted light signal.

[0058] In this embodiment, the transmitting and receiving devices are first deployed. The transmitting end emits polarized light with different spectral characteristics. The light first passes through a birefringent material, generating o (ordinary ray) and e (extraordinary ray) beams respectively. The o and e rays interfere with each other as they pass through a polarizer. The receiving ends at different locations receive the spectrum of the emitted light signal. The sampling results, i.e., the correspondence between the emitted spectrum and the received spectrum related to the receiving position, are recorded. The 0 and 1 sequences of the decoded light signals received at different locations are enumerated under different spectral characteristic settings and encoding methods. A suitable encoding method is selected to ensure that authorized devices can successfully decode the information transmitted through the selected encoding method. Furthermore, it is observed which method results in the highest bit error rate for the 0 and 1 sequences received by unauthorized devices, and this method is selected as the encoding method.

[0059] Establishing a mapping from position / incident spectrum to output spectrum includes: acquiring sampling position information when sampling at different spatial locations; adjusting the color of the light emitted by the transmitting device at different locations and recording the spectral characteristics used; the receiving end acquiring the output spectrum at each location under different emission spectra and recording the spectral characteristics of the output light; the output of the sampling process is the mapping from position / incident spectrum to output spectrum. For example... Figure 3 As shown, the sampling process aims to establish a mapping from (location, incident spectrum) to the emitted spectrum. Sampling involves the following steps:

[0060] 1. Obtaining location: Sampling is performed at different spatial locations. To obtain the location information of the samples, such as through a ruler or laser rangefinder, it is necessary to obtain the location information.

[0061] 2. Incident spectrum sampling: At different positions, adjust the color of the light emitted by the emitting device and record the spectral characteristics used, such as HSL value or RGB.

[0062] 3. Emission spectrum sampling: Similarly, the receiver collects the emission spectrum at each location under different emission spectra and records the spectral characteristics of the emitted light, such as HSL value or RGB.

[0063] The output of the sampling process is a mapping from (position, incident spectrum) to the output spectrum.

[0064] The encoding process takes the sampled location / mapping from the incident spectrum to the emitted spectrum, the data to be encoded, and the location of the target receiving device as input. The encoded output is a sequence of incident spectra, which is executed by the transmitting device for information transmission. Based on the sampled mapping and specific location information, the algorithm finds the most suitable encoding method to associate the 0 / 1 sequence with the incident spectrum mapping; using the selected encoding method, the sequence of incident spectra is generated based on the 0 / 1 sequence.

[0065] In the encoding process, a suitable encoding method is selected, including:

[0066] Collect sampling data: Collect the mapping data from the sampled position / incident spectrum to the output spectrum;

[0067] Performance metrics are defined as follows: Accuracy: Ensures that the information decoded by the authorized device is accurate, i.e., the bit error rate of the 0 / 1 sequence received by the target device is low; Security: Ensures that the bit error rate of the 0 / 1 sequence obtained by the eavesdropper based on the received spectral information is as high as possible compared to the 0 / 1 sequence of the transmitting end; Error tolerance: To improve security, error correction codes are introduced to ensure that the bit error rate of the target device is within the range that the error correction codes can correct, and not too high; Anti-error correction code security: Ensures that the bit error rate of other devices is higher than 40%, and that they cannot use error correction codes for decoding;

[0068] Select encoding parameters: Before determining the encoding method, select a set of possible encoding parameters;

[0069] Establish a performance model: Based on the sampled data and the selected encoding parameters, establish a performance model to evaluate the performance of different encoding methods;

[0070] Optimization Algorithm: Utilize optimization algorithms to search for the optimal combination of encoding parameters;

[0071] Evaluation results: For each coding attempt, its performance was evaluated using a performance model;

[0072] Selecting the best encoding method: The algorithm completes the search and selects the encoding method with the best performance.

[0073] The sampling process obtains a mapping from the position / incident spectrum to the output spectrum. The encoding process obtains a mapping from the 0 / 1 sequence to the incident spectrum. The decoding process takes the obtained mapping from the output spectrum / position to the 0 / 1 sequence, the position of the receiving device, and the received output spectrum as inputs.

[0074] The decoding process is as follows:

[0075] The mapping from the output spectrum to the 0 / 1 sequence is obtained: the sampling process obtains the mapping from the position / incident spectrum to the output spectrum, the encoding process obtains the mapping from the 0 / 1 sequence to the incident spectrum, and finally the mapping from the output spectrum / position to the 0 / 1 sequence is obtained.

[0076] Determine the location and collect the emitted spectrum;

[0077] Based on the mapping from the emitted spectrum / position to the 0 / 1 sequence and the position of the receiver, the received spectrum is used to obtain the 0 / 1 sequence, which means successful decoding and obtaining the information that the transmitter wants to transmit.

[0078] After an authorized device enters space, it sends its location to the transmitting device. The transmitting device maintains the mapping relationship between device IDs and locations. The transmitting end determines the incident spectrum sequence of the transmitting end based on the location of the authorized device and the 0 / 1 sequence sent.

[0079] Specifically, such as Figure 4 As shown, the encoding process takes the mapping from (position, incident spectrum) to the emitted spectrum obtained from sampling, the data to be encoded, and the position of the target receiving device as input. The encoding process is as follows:

[0080] 1. Encoding method selection: Based on the sampling mapping and specific location information, the algorithm finds the most suitable encoding method to associate the 0 / 1 sequence with the incident spectrum mapping.

[0081] When it comes to choosing a suitable encoding method during the encoding process, an algorithm or method is usually needed to determine the optimal encoding scheme. This process involves the following steps:

[0082] (1) Collect sampling data: Collect the mapping data from (position, incident spectrum) to the output spectrum obtained from sampling.

[0083] (2) Define performance metrics:

[0084] Indicator 1 – Accuracy: Ensure that the information decoded by the authorized device is accurate, i.e., the bit error rate of the 0 / 1 sequence received by the target device is low.

[0085] Indicator 2 – Security: The bit error rate (BER) between the 0 / 1 sequence obtained by the eavesdropper based on the received spectral information and the 0 / 1 sequence at the transmitting end should be as high as possible. A high BER increases the security of the information.

[0086] Indicator 3 – Error Tolerance: To improve security, error correction codes are introduced, but it is also necessary to ensure that the bit error rate of the target device is within the range that the error correction codes can correct, and not allow them to be too high.

[0087] Indicator 4 – Anti-error correction code security: Ensure that the bit error rate of other devices is higher than 40% and that the error correction code cannot be used for decoding.

[0088] (3) Select encoding parameters: Before determining the encoding method, select a set of possible encoding parameters. This includes the color space used (the color representation method used in the encoding and decoding process), the complexity of the encoding scheme, the type of birefringent material used, etc.

[0089] (4) Establish a performance model: Based on the sampled data and the selected encoding parameters, establish a performance model to evaluate the performance of different encoding methods.

[0090] (5) Optimization Algorithms: Optimization algorithms are used to search for the best combination of encoding parameters. These algorithms try different combinations of parameters, evaluate their performance, and find the best solution in the parameter space.

[0091] (6) Evaluation results: For each attempted coding method, its performance is evaluated using a performance model. Based on the defined performance metrics, a suitable coding method is determined.

[0092] (7) Select the best encoding method: The algorithm completes the search and selects the encoding method with the best performance.

[0093] (8) Implementation and testing: After selecting the best encoding method, implement it and test it to verify its performance.

[0094] 2. Generate the incident spectrum sequence: Using the selected encoding method, generate the incident spectrum sequence based on the 0 / 1 sequence. This sequence will be executed in the transmitting device.

[0095] The encoded output is a sequence of incident spectra, which is executed by the transmitting device for information transmission.

[0096] like Figure 5 As shown, in the decoding stage, the sampling obtains the mapping from (incident spectrum, position) to the emitted spectrum, and the encoding stage obtains the mapping from the 0 / 1 sequence to the incident spectrum. Combining these, we can obtain the mapping from (emitted spectrum, position) to the 0 / 1 sequence. The decoding stage uses the obtained mapping from (emitted spectrum, position) to the 0 / 1 sequence, the position of the receiving device, and the received emitted spectrum as input. The decoding process is as follows:

[0097] 1. Obtain the mapping from the outgoing spectrum to the 0 / 1 sequence: The sampling process obtains the mapping from (incoming spectrum, position) to the outgoing spectrum, and the encoding process obtains the mapping from the 0 / 1 sequence to the incoming spectrum. By combining these, we can obtain the mapping from (outgoing spectrum, position) to the 0 / 1 sequence.

[0098] 2. Determine the location and collect the emitted spectrum.

[0099] 3. Based on the mapping from (emission spectrum, position) to the 0 / 1 sequence and the position of the receiver, the received spectrum can be used to obtain the 0 / 1 sequence, that is, successful decoding, and the information that the transmitter wants to transmit can be obtained.

[0100] In summary, the position-related secure information transmission method based on visible polarized light interferometry described in this invention utilizes a series of schemes proposed using polarized visible light technology to combine visible light signals with the information to be transmitted, achieving directional information transmission. These schemes fully leverage the characteristics of polarized light and improve communication security. The unique encoding method enhances the security of visible light communication technology, making it difficult for unauthorized devices to eavesdrop.

[0101] This invention utilizes the principles of birefringence and polarized light interference, employing a sampling and encoding process to select a suitable encoding method using an algorithm. The authorized device sends its location to the transmitter, which, based on this location, the designed encoding method, and the 0 / 1 sequence to be transmitted, determines the emission spectrum sequence. The receiver can also successfully decode the signal using the decoding process. This solves the technical problem (1).

[0102] Different spatial locations result in different received spectra. Due to the need for covert eavesdropping, the location of the eavesdropper and the location of the authorized equipment are often different, and the received spectrum is different from that received at the authorized location. This ensures that the eavesdropper cannot obtain the information that the transmitter wants to transmit based on the spectral information it receives, thus solving the technical problem (2).

[0103] The design of the encoding method takes security issues into account, making the bit error rate of information received by unauthorized devices very high, thus solving the technical problem (3).

[0104] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solutions disclosed in the present invention, various modifications or variations that can be made by those skilled in the art without creative effort should be included within the scope of protection of the present invention.

Claims

1. A method for transmitting position-related security information based on visible polarized light interference, characterized in that, include: Receive incident spectra with different spectral characteristics at different locations; Record the correspondence between the incident spectrum and the received spectrum related to the receiving position; Based on the correspondence, an encoding method is selected so that authorized devices can successfully decode information transmitted through the selected encoding method, until the bit error rate of the 0 / 1 sequence received by unauthorized devices is maximized; Based on the selected encoding method, secure and directional information transmission is achieved; The encoding process takes the location / mapping from the incident spectrum to the emitted spectrum obtained from the sampling, the data to be encoded, and the location of the target receiving device as inputs; the encoded output is a sequence of incident spectra, which is executed by the transmitting device for information transmission. Based on the sampled mapping and specific location information, the algorithm finds the most suitable encoding method to associate the 0 / 1 sequence with the incident spectrum mapping; using the selected encoding method, the sequence of the incident spectrum is generated based on the 0 / 1 sequence. In the encoding process, the most suitable encoding method is selected, including: Collect sampling data: Collect the mapping data from the sampled position / incident spectrum to the output spectrum; Performance metrics are defined as follows: Accuracy: Ensures that the information decoded by the authorized device is accurate, i.e., the bit error rate of the 0 / 1 sequence received by the target device is low; Security: Ensures that the bit error rate of the 0 / 1 sequence obtained by the eavesdropper based on the received spectral information is as high as possible compared to the 0 / 1 sequence of the transmitter; Error tolerance: To improve security, error correction codes are introduced to ensure that the bit error rate of the target device is within the range that the error correction codes can correct; Anti-error correction code security: Ensures that the bit error rate of other devices is higher than 40%, and that they cannot use error correction codes for decoding; Select encoding parameters: Before determining the encoding method, select a set of encoding parameters; Establish a performance model: Based on the sampled data and the selected encoding parameters, establish a performance model to evaluate the performance of different encoding methods; Optimization Algorithm: Utilize optimization algorithms to search for the optimal combination of encoding parameters; Evaluation results: For each coding attempt, its performance was evaluated using a performance model; Selecting the best encoding method: The algorithm completes the search and selects the encoding method with the best performance.

2. The position-related security information transmission method based on visible polarization light interferometry according to claim 1, characterized in that, Establishing a mapping from position / incident spectrum to exit spectrum includes: The sampling location information is obtained when sampling is performed at different spatial locations; at different locations, the color of the light emitted by the transmitting device is adjusted and the spectral characteristics used are recorded; the receiving end collects the output spectrum under different emission spectra at each location and records the spectral characteristics of the output light; the output of the sampling process is a mapping from position / incident spectrum to output spectrum.

3. The position-related security information transmission method based on visible polarized light interferometry according to claim 1, characterized in that, The sampling process obtains a mapping from the position / incident spectrum to the output spectrum. The encoding process obtains a mapping from the 0 / 1 sequence to the incident spectrum. The decoding process takes the obtained mapping from the output spectrum / position to the 0 / 1 sequence, the position of the receiving device, and the received output spectrum as inputs.

4. The position-related security information transmission method based on visible polarized light interferometry according to claim 3, characterized in that, The decoding process is as follows: The mapping from the output spectrum to the 0 / 1 sequence is obtained: the sampling process obtains the mapping from the position / incident spectrum to the output spectrum, the encoding process obtains the mapping from the 0 / 1 sequence to the incident spectrum, and finally the mapping from the output spectrum / position to the 0 / 1 sequence is obtained. Determine the location and collect the emitted spectrum; Based on the mapping from the emitted spectrum / position to the 0 / 1 sequence and the position of the receiver, the received spectrum is used to obtain the 0 / 1 sequence, which means successful decoding and obtaining the information that the transmitter wants to transmit.

5. The position-related security information transmission method based on visible polarized light interferometry according to claim 4, characterized in that, After an authorized device enters space, it sends its location to the transmitting device. The transmitting device maintains the mapping relationship between device IDs and locations. The transmitting end determines the incident spectrum sequence of the transmitting end based on the location of the authorized device and the 0 / 1 sequence sent.

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