Four-dimensional dynamic label and manufacturing method and using method thereof

Abstract

The invention relates to a four-dimensional dynamic label and a manufacturing method and a using method thereof, and the four-dimensional dynamic label is manufactured by combining a quantum dot film with organic glass; the application method comprises the following steps: S1, collecting position distribution data of all fluorescent points in a film, capturing position information of all particles on multiple groups of xy planes along a z axis to obtain a fluorescent image, converting the fluorescent image into a fluorescent key, and storing the fluorescent key; s2, performing first verification: reading any single-layer instantaneous fluorescence image in real time, converting the image into a fluorescence key, and comparing the fluorescence key with a label key in a database to judge whether the image is true or false; s3, non-first verification: marking the used fluorescent key as expired data; any single-layer fluorescence image is read again in real time and converted into a fluorescence secret key; and comparing with the tag key in the database to judge whether the tag is true or false. According to the method, the inherent random flicker behavior of the quantum dots is utilized, so that the four-dimensional dynamic PUF password primitive is almost impossible to predict or copy, and the security of an encryption system is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of encrypted tags, and in particular to a tag with four-dimensional dynamic physical unclonable functionality and its identification method. Background Technology

[0002] With the rise of the global digital economy, the number of devices storing data connected via wireless networks is constantly increasing, leading to a growing demand for secure authentication and identification methods. Encryption keys are the cornerstone of ensuring the secure transmission and reception of encrypted information, as well as verifying the authenticity of products, data, information, and identities. However, these keys are traditionally embedded in non-volatile read-only memory (ROM) or static random access memory (SRAM), making them vulnerable to side-channel attacks. These vulnerabilities can lead to key decryption and ultimately the collapse of the entire security infrastructure. A promising and emerging solution involves developing secure tags that incorporate physically unclonable (PUF) functionality.

[0003] Physically unclonable functions (PUFs) are devices that generate unique keys based on unpredictable and highly random variations occurring during manufacturing. These unique characteristics provide a physical object with a unique "fingerprint" or anchor of trust. PUFs have potential applications in various fields, including anti-counterfeiting, identification, authentication, key generation, and advanced protocols such as forgetting transmission, key exchange, key updates, and virtual reality authentication. Different PUF designs have been developed using different physical principles. For example: radio frequency (RF) PUFs utilize manufacturing-induced variations, such as local oscillator frequency shifts, in-phase or quadrature phase mismatches, or DC offsets, to generate unique identifiers; electronic PUFs utilize the inherent irregularities of electronic signals from components such as carbon nanotubes or graphene field-effect transistors, or the randomness of halide perovskite memristor switching physics; magnetic PUFs utilize unintentional magnetic emission, interfacial magnetic anisotropy, or the apparent randomness of configuration; nanoscale magnetic tunnel junction arrays; and optical PUFs include artificial fingerprinting techniques based on optical scattering, spontaneously generated fluorescence patterns, randomly stimulated Raman scattering patterns, and chaotic behavior in nonlinear silicon photonic devices. However, these PUFs are typically static, meaning their cryptographic primitives remain unchanged regardless of when they are accessed. Advances in machine learning and artificial intelligence now enable increasingly sophisticated forgery techniques, raising concerns about the replication of static PUF code, especially since many such devices rely on a single, fixed PUF code.

[0004] In summary, Physically Unclonable Functions (PUFs) utilize random defects in physical entities to generate cryptographic primitives. With the emergence of advanced technologies such as machine learning and artificial intelligence, the threat of copying these cryptographic elements is escalating, especially considering that traditional static PUF devices typically rely on a single, permanent PUF code. Summary of the Invention

[0005] The purpose of this invention is to provide a four-dimensional dynamic tag, its manufacturing method, and its usage method, which utilizes Na... h K i Rb j Cs k PbI3 quantum dots (where 0≤h, i, j, k≤1, h+i+j+k=1, and the molar ratio of Pb to I is 1:3) combined with plexiglass, utilizing Na h K i Rb j Cs k The PbI3 (where 0≤h, i, j, k≤1, h+i+j+k=1, and the molar ratio of Pb to I is 1:3) "on" and "off" emission states can be directly mapped to binary bits "1" and "0". At the same time, the inherent random flickering behavior of quantum dots makes it almost impossible to predict or copy four-dimensional dynamic cryptographic primitives, thereby significantly improving the security of the encryption system.

[0006] This invention is achieved through the following technical solution: a four-dimensional dynamic label, the main body of which is an organic glass block, with Na formed by recrystallization in a solvent embedded within the transparent glass block. h K i Rb j Cs k PbI3 quantum dot thin film (where 0≤h, i, j, k≤1, h+i+j+k=1, and the molar ratio of Pb to I is 1:3); this film can produce time-varying fluorescence scintillation under ultraviolet light excitation.

[0007] A method for creating a four-dimensional dynamic label, characterized by the following steps:

[0008] Step 1, Na h K i Rb j Cs k The synthesis of PbI3 (0≤h, i, j, k≤1, and h+i+j+k=1) quantum dots employed an antisolvent precipitation method, in which a dimethyl sulfoxide solution rich in YI and PbI2 was gradually introduced into methyl methacrylate as a solvent. Y represents one or more of Na, K, Rb, and Cs. + Pb 2+ and I- The solubility of Na+ ions in methyl methacrylate decreases sharply, creating a supersaturated environment. Stirring further reduces the solubility of Na+ ions. h K i Rb j Cs k Rapid recrystallization of PbI3 quantum dots; followed by irradiation of the solution with ultraviolet light, the presence of a specific color of fluorescence confirms the presence of Na. h K i Rb j Cs k Successful synthesis of PbI3 quantum dots;

[0009] Step 2: Place the solution from Step 1 into a patterned mold, add 0.1%-1% of the monomer mass as initiator azobisisobutyronitrile (AIBN), and let it stand at 50-80 ℃ for 1-6 hours to cure, forming a film with a thickness of 50-100 μm.

[0010] Step 3: Transfer the film pattern to a PMMA solution. After the solvent evaporates, the film is completely embedded in the PMMA, forming a transparent patterned acrylic label.

[0011] A method for using four-dimensional dynamic tags; including the following steps:

[0012] Step 1: Collect the position distribution data of all fluorescent spots in all thin film layers in the plexiglass. This allows for capturing the position information of all particles on the outermost xy plane of a single film over a continuous period of time to obtain a fluorescence image. Then, by changing the focal plane, position data along the z-axis is obtained, thereby obtaining fluorescence images of different thin film layers. The fluorescence images with fluorescent spots are converted into fluorescence keys and stored in the computer vision engine to build a secure tag database.

[0013] Step 2, Initial Verification: During verification, the position distribution data of fluorescent spots on their respective xy planes corresponding to any single-layer instantaneous fluorescence image are read in real time, converted into fluorescence keys, and then compared with the tag keys in the database. If they match the tag keys in the database, a true result is reported; otherwise, a false result is reported.

[0014] Step 3, Non-first-time verification: The real-time fluorescence keys that have been compared are stored in another database and marked as expired data; a new verification is performed, and the position distribution data of the fluorescence spots on their respective xy planes corresponding to any single-layer instantaneous fluorescence image are read in real time again and converted into fluorescence keys; then this key is first matched with the keys in the expired database. If it matches the keys in the expired database, the expired key is returned; if it does not match the keys in the expired database, it is matched with the keys in the security tag database; if it matches the keys in the security tag database, it is returned as true; if it does not match the keys in the security tag database, it is returned as false.

[0015] Compared with previous technologies, the beneficial effects of the present invention are as follows:

[0016] 1. High safety factor, utilizing Na h K i Rb j Cs k The "on" and "off" emission states of PbI3, specifically using CsPbI3 as an example, can be directly mapped to binary bits "1" and "0". Due to the inherent random flickering behavior of quantum dots, four-dimensional dynamic PUF cryptographic primitives are almost impossible to predict or copy, thus significantly improving the security of the encryption system.

[0017] 2. Large encoding capacity: The encoding capability of the tag of this invention depends on the number of film layers and the number of scintillation points of CsPbI3 quantum dots. In a 1000-pixel image, all bright spots exhibit scintillation characteristics, theoretically resulting in an encoding capacity exceeding 10. 100 The encoding capacity of traditional two-dimensional static security tags is approximately 10. 70 . Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the label of the present invention;

[0019] Figure 2 This is a schematic diagram of the invention read by a mobile phone;

[0020] Figure 3 This is a schematic diagram comparing the coding capabilities of existing two-dimensional static PFUs and the present invention.

[0021] Figure 4 This is a comparison chart of the performance differences between the four-dimensional dynamic pseudo-random function and the static pseudo-random function of this invention;

[0022] Figure 5 This is a schematic diagram of the verification scheme during the anti-counterfeiting application of the present invention;

[0023] Figure 6The true / false verification rate is plotted as a function of similarity.

[0024] Figure 7 This is a diagram illustrating the steps of using the present invention. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings:

[0026] like Figure 1 As shown: A four-dimensional dynamic label, the main body of which is an acrylic glass block, with Na formed by recrystallization in a solvent embedded within the transparent glass block. h K i Rb j Cs k PbI3 (0≤h, i, j, k≤1, and h+i+j+k=1) quantum dot thin film; this film can produce time-varying fluorescence scintillation under ultraviolet light excitation.

[0027] Wherein, Na h K i Rb j Cs k PbI3 (0≤h, i, j, k≤1, and h+i+j+k=1); specifically, it is CsPbI3 and one of the single or combined doped phases of Na, K, and Rb at the cesium site.

[0028] Photoluminescence scintillation is a ubiquitous phenomenon observed in single colloidal quantum dots, characterized by random transitions between bright (on) and dark (off) emission states over time. This behavior provides a suitable basis for binary data storage, with bright states representing "1" and dark states representing "0". Lead halide perovskite quantum dots (PUFs) are promising candidates for optically dynamic PUF tagging due to their unique optical properties, including high photoluminescence quantum yield, significant fluorescence scintillation, and robustness to structural defects and surface states. Lead halide perovskite quantum dots are known for their excellent stability and transparency when combined with polymeric materials. Polymethyl methacrylate (PMMA), a thermoplastic known for its light transmittance, durability, and chemical resistance, is often used as an alternative to glass. Constructing a four-dimensional dynamic PUF cryptographic primitive is feasible by randomly embedding fluorescently scintillated lead halide perovskite quantum dots into the three-dimensional volume of a PMMA matrix. Traditionally, the fluorescence images required for this application have been obtained using expensive fluorescence microscopy systems, which increases the overall cost of authentication. However, advancements in the integration and computing power of modern mobile and embedded devices have transformed smartphones into a viable platform for capturing and processing fluorescence data; this development has the potential to significantly simplify and reduce the costs associated with the certification process.

[0029] Taking CsPbI3 as an example, this invention randomly embeds scintillation-inducing CsPbI3 quantum dots into a PMMA matrix. The spatially confined quantum dots exhibit strong photoluminescence with pronounced scintillation characteristics, serving as the fundamental elements for generating transient binary codes. Each quantum dot represents a "1" in the bright state or a "0" in the dark state, distributed across multiple focal planes within a four-dimensional spacetime framework. The proposed encryption strategy ensures a massive coding capacity, theoretically exceeding 10^65. 100 Simultaneously, it maintains a low density of approximately 6% scintillation dots within a 1000-pixel pattern on a single PUF device. The nanoscale randomness of the spatial distribution of the scintillation quantum dots, coupled with their time-varying fluorescence patterns, makes the tag itself unclonable. Furthermore, the PMMA-encapsulated four-dimensional dynamic PUF tag exhibits excellent stability, retaining its anti-counterfeiting functionality after exposure to air for up to 12 months. We demonstrate the practicality of using a smartphone-based system to verify these four-dimensional dynamic PUF cryptographic primitives. This design marks a significant advancement from traditional static PUF encryption to a dynamic four-dimensional encryption paradigm, overcoming the limitations of spatial and temporal dimensions.

[0030] The temporal evolution of the fluorescence image represents the private binary key sequence distributed across different thin film layers, establishing a complete four-dimensional dynamic PUF cryptographic structure. This configuration significantly improves the system's encoding capability and security level. This encryption method transcends the constraints of a two-dimensional plane, pioneering the development of dynamic PUF cryptographic primitives within a four-dimensional framework for the first time.

[0031] The encoding capability of the fabricated four-dimensional dynamic PUF security tag depends on the number of film layers and the scintillation of CsPbI3 quantum dots. To evaluate the actual encoding capability, the proportion of bright green fluorescent dots in all pixels was calculated. Fluorescence images obtained from the same layer in different regions, at different time intervals in the same region, and between different layers showed that bright spots accounted for approximately 6% of all pixels. The theoretical encoding capability of the four-dimensional dynamic tag can be expressed as follows:

[0032] C = nC p 0.06p × 2 0.06p ;

[0033] Where C represents the coding capacity, n represents the total number of layers, p represents the total number of pixels, and 0.06p represents the number of blinking points. For example, in a 1000-pixel image, if all bright spots exhibit blinking characteristics, the theoretical coding capacity exceeds 10. 100 This is significantly higher than the 10% of traditional two-dimensional static PUF security tags. 70 To further demonstrate the advantages of d-puf, Figure 3A comparison of the encoding capabilities of existing two-dimensional static PUFs and d-PUFs is presented. In a two-dimensional static PUF, the position of the bright spot remains fixed, limiting the number of static cryptographic variations to less than 1. Conversely, a deterministic d-PUF, with its inherent dynamic cryptographic information, achieves more than 10... 17 Its mutation capability highlights its superior coding potential and enhanced security.

[0034] A method for creating a four-dimensional dynamic label includes the following steps:

[0035] Step 1, Na h K i Rb j Cs k The synthesis of PbI3 (0≤h, i, j, k≤1, and h+i+j+k=1) quantum dots employed an antisolvent precipitation method, in which a dimethyl sulfoxide solution rich in YI and PbI2 was gradually introduced into methyl methacrylate as a solvent. Y represents one or more of Na, K, Rb, and Cs. + Pb 2+ and I - The solubility of Na+ ions in methyl methacrylate decreases sharply, creating a supersaturated environment. Stirring further reduces the solubility of Na+ ions. h K i Rb j Cs k Rapid recrystallization of PbI3 quantum dots; followed by irradiation of the solution with ultraviolet light, the presence of a specific color of fluorescence confirms the presence of Na. h K i Rb j Cs k Successful synthesis of PbI3 quantum dots;

[0036] Step 2: Place the solution from Step 1 into a patterned mold, add 0.5% of the monomer mass of initiator azobisisobutyronitrile, and let it stand at 66 °C for 5 hours to cure, forming a film with a thickness of about 80 micrometers.

[0037] Step 3: Transfer the film pattern to a PMMA solution. After the solvent evaporates, the film is completely embedded in the PMMA, forming a transparent patterned acrylic label.

[0038] To better illustrate the process, this invention provides a specific workflow. First, lead-citrate cesium quantum dots (CsPbI3) are synthesized using a mature antisolvent precipitation method. Specifically, a dimethyl sulfoxide (DMSO) solution rich in CsI and PbI2 is gradually added to methyl methacrylate (MMA), which acts as a poor solvent. This results in the concentration of CsI in the MMA... + Pb 2+ and I ⁻The solubility of the ions decreased sharply, creating a supersaturated environment that promoted rapid recrystallization of CsPbI3 quantum dots during stirring. Upon irradiation with ultraviolet light, the resulting solution exhibited strong green fluorescence, confirming the successful synthesis of CsPbI3 quantum dots. Subsequently, by adding the initiator azobisisobutyronitrile (AIBN), the mixture was injected into a pre-designed gravure mold, and a 65-micrometer-thick "FZU" pattern was formed through polymerization (see...). Figure 6 The pattern was then transferred to a PMMA solution. After the solvent evaporated, the "FZU" pattern was completely embedded in the PMMA, forming a transparent and flexible security tag. The encapsulated security tag emitted a green light under ultraviolet light.

[0039] It should be noted that when synthesizing lead cesium iodide quantum dots using the above method, we also considered replacing iodine with other halogen elements. However, we found that the required recrystallization could not be synthesized. With the currently used antisolvent precipitation process, only iodides can be used to finally achieve lead cesium iodide quantum dots with application value.

[0040] The minimal difference in transmittance curves between the PMMA film and the encapsulated four-dimensional security tag confirms its optical transparency. The excellent transmittance of the acrylic glass ensures that the encapsulated CsPbI3 quantum dots can be excited from any direction. For example, under ultraviolet excitation from above, macroscopic fluorescence patterns such as “FZU” and “CUHKSZ” are clearly visible. Simultaneously, the fluorescence scintillation of randomly dispersed CsPbI3 quantum dots within the PMMA matrix was captured under ultraviolet illumination using a smartphone equipped with a commercial objective lens.

[0041] The inherent fluorescence scintillation properties of a single CsPbI3 quantum dot can generate a series of temporally dynamic, spatially dispersed fluorescence images. For example... Figure 2 As shown in the right panel, these images are characterized by randomly appearing bright spots with varying brightness within the planes of the acrylic glass. These spatially distributed CsPbI3 quantum dots exhibit random "on" (intensity gradient) and "off" emission states on multiple planes parallel to the PMMA matrix surface. This mechanism lays the foundation for constructing four-dimensional d-PUF encryption elements. Unlike simple binary encoding (where "on" and "off" correspond only to "1" and "0"), the bright states of the brightness gradient can be converted into digital grayscale values ​​(1-255), where the "off" state corresponds to the value 0. This allows each pixel to represent 256 possible states, which are embedded in the private key system. The performance difference between the four-dimensional dynamic pseudo-random function and the static pseudo-random function is shown in [the relevant section]. Figure 4 .

[0042] Of course, the above-mentioned thin film does not necessarily have to form a pattern; it can be a regular square or circle. If a pattern is formed, it can serve as the identification area, and the formed pattern becomes the encryption area. This also incorporates customer needs; for example, if a customer needs to display their logo, we can encrypt it within their logo.

[0043] Unlike traditional static PUFs, the keys generated by four-dimensional dynamic PUF cryptographic primitives change with temporal and spatial parameters, making database construction more difficult. Here, computer vision methods are employed for the encryption and decryption of two-dimensional dynamic codes.

[0044] It should be noted that the dense spots inside the plexiglass are only a few nanometers in size and are evenly distributed within the plexiglass. In order to optically distinguish the nanoparticles, the distance between them needs to be >200 nanometers. Assuming that a layer is 500 nanometers thick, a film thickness of 50-100 micrometers can be divided into many layers.

[0045] A method for using four-dimensional dynamic tags includes the following steps:

[0046] Step 1: Collect the position distribution data of all fluorescent spots in all thin films of plexiglass. This allows for capturing the position information of all particles on the outermost xy plane of a single film over a continuous period of time to obtain a fluorescence image. Then, by changing the focal plane, position data along the z-axis is obtained, thereby obtaining fluorescence images of different film layers. The fluorescence images with fluorescent spots are converted into fluorescence keys and stored in the computer vision engine to build a secure tag database.

[0047] Step 2, Initial Verification: During verification, the position distribution data of fluorescent spots on their respective xy planes corresponding to any single-layer instantaneous fluorescence image are read in real time, converted into fluorescence keys, and then compared with the tag keys in the database. If they match the tag keys in the database, a true result is reported; otherwise, a false result is reported.

[0048] Step 3, Non-first-time verification: The real-time fluorescence keys that have been compared are stored in another database and marked as expired data; a new verification is performed, and the position distribution data of the fluorescence spots on their respective xy planes corresponding to any single-layer instantaneous fluorescence image are read in real time again and converted into fluorescence keys; then this key is first matched with the keys in the expired database. If it matches the keys in the expired database, the expired key is returned; if it does not match the keys in the expired database, it is matched with the keys in the security tag database; if it matches the keys in the security tag database, it is returned as true; if it does not match the keys in the security tag database, it is returned as false.

[0049] In steps 2 and 3, fluorescent codes from different times and different film layers are collected and compared with computational fluorescence images acquired by an image acquisition device. If the similarity is less than 0.2, the label is determined to be a fake security label; if the similarity is greater than 0.2, it is determined to be a genuine label.

[0050] Step 4 involves collecting and comparing the fluorescence codes of films from different times and different layers, and then comparing their similarity with the calculated fluorescence images acquired using an image acquisition device. If the similarity score is less than 0.2, the label is considered a fake security label; if the similarity score is greater than 0.2, it is considered a genuine label. Specifically, the similarity value for fake security labels is 0-0.1, while the similarity value for genuine security labels is 0.35-0.6.

[0051] like Figure 5-7 As shown: To thoroughly evaluate the stability of the four-dimensional dynamic PUF security tag, we conducted a series of extensive tests during which the tag was exposed to air and its security performance was carefully monitored regularly. Figure 5 As shown, unique keys were extracted from the four-dimensional dynamic PUF anti-counterfeiting tags every two weeks over a year, and similarity assessments were performed against a database. The consistently high similarity observed in data collected from the same PUF tag at multiple time points provides compelling evidence of the significant stability of the four-dimensional dynamic PUF security tag. Furthermore, we conducted detailed analyses of fluorescence emission intensity and XRD patterns to assess the structural and functional robustness of the tag. Despite slight fluctuations in fluorescence and diffraction intensity observed, possibly due to experimental variability, the overall structural integrity and performance stability of the tag remained intact. These findings cumulatively underscore the exceptional stability and reliability of the four-dimensional dynamic PUF security tag for long-term applications.

[0052] In summary, this invention identifies the information (i.e., the key) on the plane where the CsPbI3 quantum dot is located, thus obtaining a key, which is then sent to the backend for verification (matching). If a match is found, the verification is successful (true); otherwise, it fails (false). Once a key has been used, it is stored in a database. If, by chance, the same key is found (with an extremely low probability), an expiration code is reported.

[0053] The temporal evolution process of fluorescence images in this invention constructs a complete four-dimensional dynamic PUF encryption architecture through private binary key sequences distributed across different dimensions. This design significantly improves the system's encoding capability and security level. Specifically, it includes two dimensions corresponding to the xy-plane, three dimensions along the z-axis, and the time dimension, breaking through the limitations of the two-dimensional plane and pioneering the development of d-PUF encryption primitives within a four-dimensional space (including spatial and temporal dimensions) framework.

[0054] The coding capacity of the fabricated four-dimensional dynamic security tag depends on its number of layers and the number of scintillating CsPbI3 quantum dots. To evaluate the actual coding capability, we analyzed it by calculating the proportion of bright green fluorescent spots among all pixels. The theoretical coding capacity of this four-dimensional dynamic tag can be expressed as follows:

[0055]

[0056] Where C represents the coding capacity, n represents the total number of layers, and p represents the total number of pixels. This formula differs from a simple binary system (2^p) because each pixel can exhibit 256 different states (0-256 grayscale values) due to variations in brightness, rather than just two states (on / off). In a 300×300 pixel image, when all bright spots exhibit flickering characteristics, the theoretical coding capacity exceeds 10^25. 216 It is significantly higher than the traditional two-dimensional static physical no-cloning function (PUF) and two-dimensional dynamic physical no-cloning function security labels.

[0057] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A four-dimensional dynamic tag, characterized in that: The main body is an organic glass block, with Na formed by recrystallization in a solvent embedded within the transparent glass block. h K i Rb j Cs k PbI3 quantum dot thin film (where 0≤h, i, j, k≤1, h+i+j+k=1, and the molar ratio of Pb to I is 1:3); this film can produce time-varying fluorescence scintillation under ultraviolet light excitation.

2. A four-dimensional dynamic tag according to claim 1, characterized in that: The Na h K i Rb j Cs k PbI3 (0≤h, i, j, k≤1, and h+i+j+k=1); specifically, it is CsPbI3 and one of the single or combined doped phases of Na, K, and Rb at the cesium site.

3. The method for producing a four-dimensional dynamic label according to claim 1 or 2, characterized in that: Includes the following steps: Step 1, Na h K i Rb j Cs k The synthesis of PbI3 (0≤h, i, j, k≤1, and h+i+j+k=1) quantum dots employed an antisolvent precipitation method. A dimethyl sulfoxide solution rich in YI and PbI2 was gradually introduced into methyl methacrylate as a solvent. Y represents one or more of Na, K, Rb, and Cs. + Pb 2+ and I - The solubility of Na+ ions in methyl methacrylate decreases sharply, creating a supersaturated environment. Stirring further reduces the solubility of Na+ ions. h K i Rb j Cs k Rapid recrystallization of PbI3 quantum dots; followed by irradiation of the solution with ultraviolet light, the presence of a specific color of fluorescence confirms the presence of Na. h K i Rb j Cs k Successful synthesis of PbI3 quantum dots; Step 2: Place the solution from Step 1 into a patterned mold, add 0.1%-1% of the monomer mass of initiator azobisisobutyronitrile, and let it stand at 50-80 ℃ for 1-6 hours to cure, forming a film with a thickness of 50-100 micrometers. Step 3: Transfer the film pattern to a PMMA solution. After the solvent evaporates, the film is completely embedded in the PMMA, forming a transparent patterned acrylic label.

4. A method for using a four-dimensional dynamic tag as described in claim 1 or 2, characterized in that; Includes the following steps: Step 1: Collect the position distribution data of all fluorescent spots in all thin films of plexiglass. This allows for capturing the position information of all particles on the outermost xy plane of a single film over a continuous period of time to obtain a fluorescence image. Then, by changing the focal plane, position data along the z-axis is obtained, thereby obtaining fluorescence images of different film layers. The fluorescence images with fluorescent spots are converted into fluorescence keys and stored in the computer vision engine to build a secure tag database. Step 2, Initial Verification: During verification, the position distribution data of fluorescent spots on their respective xy planes corresponding to any single-layer instantaneous fluorescence image are read in real time, converted into fluorescence keys, and then compared with the tag keys in the database. If they match the tag keys in the database, a true result is reported; otherwise, a false result is reported. Step 3, Non-first-time verification: The real-time fluorescence keys that have been compared are stored in another database and marked as expired data; a new verification is performed, and the position distribution data of the fluorescence spots on their respective xy planes corresponding to any single-layer instantaneous fluorescence image are read in real time again and converted into fluorescence keys; then this key is first matched with the keys in the expired database. If it matches the keys in the expired database, the expired key is returned; if it does not match the keys in the expired database, it is matched with the keys in the security tag database; if it matches the keys in the security tag database, it is returned as true; if it does not match the keys in the security tag database, it is returned as false.

5. The method of using a four-dimensional dynamic tag according to claim 4, characterized in that: In steps 2 and 3, the fluorescence codes of different times and different layers of thin films were collected and compared with the calculated fluorescence images acquired by the image acquisition device. If the similarity threshold is less than 0.2, it is determined to be a fake security label; if the similarity is higher than 0.2, it is determined to be a genuine label.

6. The method of using a four-dimensional dynamic tag according to claim 5, characterized in that; The similarity value of fake security labels is 0~0.1, while the similarity value of genuine security labels is 0.35~0.6.

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