Privacy protection method and system in multimedia data transmission

Abstract

The invention provides a privacy protection method and system in multimedia data transmission, and belongs to the technical field of data transmission encryption. Multimedia data is finely divided into privacy layers of different levels according to importance through a multi-level privacy protection strategy, it is ensured that high-sensitivity data is better protected, and the privacy protection effect is improved. Meanwhile, the availability and access efficiency of low-sensitivity data are kept; besides, through generation and distributed storage of key fragments, construction of a cross-level key association system, setting of an independent core key for a core-level privacy layer, and combination of the cross-level key association system for dual key verification, additional security guarantee is provided for most sensitive data; in addition, a protection strategy can be automatically adjusted according to the change of the importance degree of the data so as to adapt to a new security requirement, and then the reliability and efficiency of data transmission are effectively improved through refined privacy layer division and a key management strategy.

Description

Technical Field

[0001] The present invention relates to the technical field of data transmission encryption, and in particular to a privacy protection method and system in multimedia data transmission. Background Art

[0002] In today's digital age, the transmission of multimedia data (including text, images, audio and video, etc.) has become an important way to exchange and share information. However, with the surge in data volume and the diversification of transmission channels, the issue of privacy protection in multimedia data transmission has become increasingly prominent.

[0003] With the rapid development of technologies such as cloud computing, big data, and the Internet of Things, multimedia data often needs to be frequently transmitted between different devices, networks, and services. In this process, the risk of data privacy leakage increases significantly. Attackers may obtain sensitive information by intercepting, tampering with, or stealing data in transit, thus posing a serious threat to personal privacy.

[0004] In multimedia data transmission, key management is a key link to achieve privacy protection. However, the traditional key management method has a contradiction between complexity and security. On the one hand, in order to enhance security, it is necessary to adopt a complex key generation, storage and distribution mechanism; on the other hand, the complex key management process may increase system overhead and reduce data transmission efficiency. Therefore, how to simplify and improve key management while ensuring security has become an urgent problem to be solved.

[0005] In multimedia data transmission scenarios, data often needs to be accessed and controlled at different levels. However, existing data access control mechanisms often fail to achieve flexible access and fine control across levels. This results in some sensitive data being accessed by unauthorized users, thus causing privacy leakage risks.

[0006] With the change of data importance and the emergence of new security threats, the privacy protection strategy in multimedia data transmission needs to be constantly adjusted and optimized. However, existing privacy protection methods often lack dynamic adjustment and adaptability, and it is difficult to respond to new security requirements in a timely manner.

[0007] Therefore, it is necessary to provide a privacy protection method and system in multimedia data transmission to solve the above technical problems. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a privacy protection method and system in multimedia data transmission to solve the following problems: the traditional key management method is too complicated to affect the data transmission efficiency; the existing data access control mechanism is often difficult to achieve flexible access and fine control across levels; the existing privacy protection methods often lack dynamic adjustment and adaptability.

[0009] The present invention provides a privacy protection method in multimedia data transmission, the privacy protection method comprising the following steps: Collect and identify multimedia data to be transmitted, evaluate the importance of the multimedia data, and assign a weight value corresponding to the importance to each piece of data, wherein the multimedia data includes text, images, audio or video; Based on the weight value assigned to each piece of data, each piece of data is divided into a corresponding privacy layer through a preset weight threshold segment, wherein the privacy layer includes a primary, secondary, tertiary and core privacy layer in ascending order of weight value; For each data category of the privacy layer, several key fragments are generated, and the key fragments are used to encrypt the data of the corresponding privacy layer; By combining several key fragments into a complete key, a cross-level key association system is constructed; Set up an independent core key for the core privacy layer, and configure double key verification in combination with the constructed cross-level key association system; During the data transmission process, the importance of multimedia data is periodically re-evaluated. Based on the results of the periodic evaluation, the multimedia data is re-divided into privacy layers, key fragments are encrypted, a cross-level key association system is built, and dual key verification is configured.

[0010] Preferably, the steps of collecting and identifying multimedia data to be transmitted, evaluating the importance of the multimedia data, and assigning a weight value corresponding to the importance to each piece of data, wherein the multimedia data includes text, images, audio or video, include: Acquire and collect multimedia data to be transmitted from device storage or the network, including text, images, audio or video; Use media type identification technology to distinguish the type of each piece of data; Use a multi-dimensional evaluation method to evaluate the importance of each piece of data and obtain the evaluation results; According to the evaluation results, a weight value corresponding to the importance is assigned to each piece of data.

[0011] Preferably, based on the weight value assigned to each piece of data, each piece of data is divided into a corresponding privacy layer through a preset weight threshold segment, wherein the privacy layer includes primary, secondary, tertiary and core privacy layers sorted in ascending order according to the weight value, and the specific steps include: Four weight threshold segments are pre-set, corresponding to the primary, secondary, tertiary and core privacy layers; The weight value of each piece of data is compared with the four preset weight threshold segments, and the privacy layer to which each piece of data belongs is determined based on the comparison result.

[0012] Preferably, for each data category of the privacy layer, a plurality of key fragments are generated, and the key fragments are used to encrypt the data of the corresponding privacy layer, and the specific steps include: For each privacy layer, generate several key fragments; The generated key fragment is used to encrypt the data of the corresponding privacy layer, and the encryption method is symmetric encryption or asymmetric encryption.

[0013] Preferably, the cross-level key association system is specifically as follows: after each privacy layer generates n key fragments, when it is necessary to access the target privacy layer data, it is necessary to combine at least m key fragments pre-stored in the next level privacy layer to generate a complete key, and preliminarily decrypt the target privacy layer based on the generated complete key, where n≥2, 1≤m≤n.

[0014] Preferably, the key fragments are stored in a distributed manner, and key fragments of different privacy layers are managed by independent nodes.

[0015] Preferably, the core-level privacy layer is provided with an independent core key, and double key verification is configured in combination with the constructed cross-level key association system, and the specific steps include: Generate an independent core key for the core-level privacy layer, wherein the core key is generated based on biometric recognition or dynamic password; Based on the core key combined with the cross-level key association system, a dual key verification mechanism is configured for the data of the core-level privacy layer. That is, in the process of decrypting the core-level privacy layer, it is necessary to verify the core key and the complete key obtained through the cross-level key association system at the same time.

[0016] A privacy protection system in multimedia data transmission, the privacy protection system comprising: A weight assignment module, used to collect and identify multimedia data to be transmitted, evaluate the importance of the multimedia data, and assign a weight value corresponding to the importance to each piece of data, wherein the multimedia data includes text, image, audio or video; A data partitioning module, for partitioning each piece of data into a corresponding privacy layer through a preset weight threshold segment based on a weight value assigned to each piece of data, wherein the privacy layer includes a primary, secondary, tertiary and core privacy layer in ascending order of weight value; A primary encryption module, for generating a number of key fragments for each data category of each privacy layer, and using the key fragments to encrypt the data of the corresponding privacy layer; A key association module, used to construct a cross-level key association system by combining several key fragments into a complete key; The secondary encryption module is used to set an independent core key for the core-level privacy layer and configure double key verification in combination with the constructed cross-level key association system; The monitoring feedback execution module is used to periodically re-evaluate the importance of multimedia data during data transmission. Based on the results of periodic evaluation, the multimedia data is re-divided into privacy layers, key fragments are encrypted, a cross-level key association system is constructed, and dual key verification is configured.

[0017] Compared with the related art, the privacy protection method and system in multimedia data transmission provided by the present invention have the following beneficial effects: The present invention uses a multi-level privacy protection strategy to finely divide multimedia data into privacy layers of different levels according to their importance, ensuring that highly sensitive data is more strongly protected while maintaining the availability and access efficiency of less sensitive data. In addition, the generation and distributed storage of key fragments, as well as the construction of a cross-level key association system, not only enhance the flexibility and security of key management, but also further improve the security threshold for data access. An independent core key is set for the core-level privacy layer, and double key verification is performed in combination with a cross-level key association system, providing additional security for the most sensitive data. The present invention can also automatically adjust the protection strategy according to changes in the importance of the data to adapt to new security requirements, thereby effectively improving the reliability and efficiency of data transmission through refined privacy layer division and key management strategies. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of a privacy protection method in multimedia data transmission in Embodiment 1 of the present invention; Figure 2 This is a system block diagram of a privacy protection system in multimedia data transmission in Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0020] Embodiment 1 like Figure 1 As shown, a privacy protection method in multimedia data transmission includes the following steps: S1. Collect and identify multimedia data to be transmitted, evaluate the importance of the multimedia data, and assign a weight value corresponding to the importance to each piece of data, wherein the multimedia data includes text, image, audio or video; S2. Based on the weight value assigned to each piece of data, each piece of data is divided into a corresponding privacy layer through a preset weight threshold segment, wherein the privacy layer includes a primary, secondary, tertiary and core privacy layer in ascending order according to the weight value; S3. Generate several key fragments for each data category of each privacy layer, and use the key fragments to encrypt the data of the corresponding privacy layer; S4. Construct a cross-level key association system by combining several key fragments into a complete key; S5. Set an independent core key for the core privacy layer, and configure double key verification in combination with the constructed cross-level key association system; S6. During the data transmission process, the importance of multimedia data is periodically re-evaluated. Based on the results of the periodic evaluation, the multimedia data is re-divided into privacy layers, key fragments are encrypted, a cross-level key association system is constructed, and dual key verification is configured.

[0021] In the specific implementation process, the specific steps of step S1 are: S101. Acquire and collect multimedia data to be transmitted from device storage or a network, including text, images, audio, or video.

[0022] Specifically, first determine the source of the multimedia data to be transmitted, which can be local storage of the device, such as data in a mobile phone, computer or camera, or data obtained from the Internet or other networks; obtain and collect the multimedia data to be transmitted by accessing the network database or API interface. The collected data types include text (such as documents, emails), images (such as photos, screenshots), audio (such as recordings, voice messages) and video (such as surveillance videos, meeting minutes).

[0023] S102: Use media type identification technology to distinguish the type of each piece of data.

[0024] Specifically, the type of each piece of data is determined by analyzing the file header, extension or content features of the data using the media type identification technology.

[0025] For example, an image file usually has a specific file header identifier (such as FFD8FFE0 of JPEG), while an audio file may have a different identifier (such as ID3 tag of MP3), and the type of each data is determined by identifying these identifiers.

[0026] S103. Use a multi-dimensional evaluation method to evaluate the importance of each piece of data and obtain an evaluation result.

[0027] Specifically, a multi-dimensional evaluation is used to evaluate the importance of each piece of data, specifically through the three dimensions of data sensitivity assessment, data value assessment and data timeliness assessment. The machine learning algorithm is trained by obtaining historical data of transmitted multimedia data, and an evaluation model is obtained after training. The currently collected multimedia data to be transmitted is input into the evaluation model, and analysis is performed to finally obtain specific evaluation results.

[0028] S104: According to the evaluation result, a weight value corresponding to the importance is assigned to each piece of data.

[0029] Specifically, a weight value corresponding to the importance is assigned to each piece of data based on the evaluation results. The weight value can be a number or a letter, which is used to indicate the priority of the data in the privacy protection system. In this embodiment, the specific weight value is a number, and the numerical value of the importance in the evaluation result can be the corresponding weight value.

[0030] In this embodiment, the "project plan.docx" in the multimedia data is evaluated as being highly sensitive and of high value, and its evaluation result is 10, and a corresponding weight value of 10 will be assigned to it. On the contrary, the user uploaded an ordinary landscape photo "sunset beauty.jpg" in the multimedia data, and its evaluation result is 2, and a corresponding weight value of 2 will be assigned to it.

[0031] In the specific implementation process, the specific steps of step S2 are: S201. Preset four weight threshold segments, corresponding to the primary, secondary, tertiary and core privacy layers respectively.

[0032] Specifically, four different weight threshold segments are pre-set, and these segments will be used to divide the collected multimedia data into different levels of privacy layers, wherein the four different weight threshold segments are defined in ascending order from low to high.

[0033] In this embodiment, the weight threshold segment corresponding to the first-level privacy layer is specifically: the weight value segment of 1-3, the weight threshold segment corresponding to the second-level privacy layer is specifically: the weight value segment of 4-6, the weight threshold segment corresponding to the third-level privacy layer is specifically: the weight value segment of 7-9, and the weight threshold segment corresponding to the core-level privacy layer is specifically: the segment with a weight value above 10.

[0034] S202: Compare the weight value of each piece of data with four preset weight threshold segments respectively, and determine the privacy layer to which each piece of data belongs based on the comparison result.

[0035] Specifically, according to the weight value of each piece of data, by determining the specific weight threshold segment in which its weight value falls among the four weight threshold segments, it is automatically divided into the privacy layer corresponding to the specific weight threshold segment.

[0036] In the specific implementation process, the specific steps of step S3 are: S301. Generate several key fragments for each privacy layer.

[0037] Specifically, a suitable encryption algorithm is selected to generate key fragments, which can be based on symmetric encryption (such as AES, DES, etc.) or asymmetric encryption (such as RSA, ECC, etc.); a certain number of key fragments are generated for each privacy layer (level one, level two, level three and core level), wherein the higher the level of the privacy layer, the more key fragments are generated to increase data security; after determining the encryption algorithm and the number of key fragments, the key fragments are generated. It should be noted that the generated key fragments need to be securely stored and managed for use in subsequent processes.

[0038] In this embodiment, key fragments are generated for the data of the first-level privacy layer. The AES symmetric encryption algorithm is selected, and it is decided to generate three key fragments to generate an original AES key (for example, a 128-bit key). Then, the original key is divided into three parts (each part may be 43 bits or 42 bits, 42 bits, and 43 bits). Each part is used as a key fragment, and these key fragments are stored on three different security nodes respectively to ensure the security of the data.

[0039] S302: Use the generated key fragment to encrypt the data of the corresponding privacy layer, using a symmetric encryption or asymmetric encryption method.

[0040] In this embodiment, three key fragments are generated for the data of the first privacy layer and encrypted using the AES algorithm. Before encryption, the three key fragments are combined into a complete AES key, specifically a key recovery algorithm is used to reassemble the split key fragments into a complete key. Once the complete key is obtained, the AES algorithm can be used to encrypt the data. Secondly, the encrypted data is securely stored in the encrypted storage area of ​​the device and is ready to be transmitted to the target location through a secure channel.

[0041] In the specific implementation process, the specific steps of step S4 are: The cross-level key association system is as follows: after each privacy layer generates n key fragments, when the target privacy layer data needs to be accessed, at least m key fragments pre-stored in the next privacy layer need to be combined to generate a complete key, and the target privacy layer is preliminarily decrypted based on the generated complete key, where n≥2, 1≤m≤n; and the key fragments are distributedly stored, and the key fragments of different privacy layers are managed by independent nodes.

[0042] Specifically, first, define the key fragment combination logic between each privacy level (primary, secondary, tertiary, core level). For example, core-level complete key = core key + 1 key fragment of the third-level privacy layer + 1 key fragment of the second-level privacy layer; third-level privacy layer complete key = third-level key fragment + second-level key fragment + first-level key fragment; generate multiple key fragments for each privacy layer (such as K1-1 and K1-2 for the first-level layer, and K2-1 and K2-2 for the second-level layer); the core layer independently generates a core key (K-core), and selects a fragment from the third and second layers (such as K3-1 and K2-1) as the associated fragment, and the storage association relationship is: core layer complete key = K-core + K3-1 + K2-1; when decrypting, the required key fragments of other levels are automatically retrieved according to the level to which the data belongs. For example, when decrypting core layer data, it is necessary to call the core key (K-core) and verify the fragments of the third layer (K3-1) and the second layer (K2-1).

[0043] In the specific implementation process, the specific steps of step S5 are: S501. Generate an independent core key for the core-level privacy layer, wherein the core key is generated based on biometric recognition or a dynamic password.

[0044] Specifically, the key is generated using the individual's biometric features (such as fingerprints, irises, facial recognition, etc.). In specific operations, the user is required to authenticate through a biometric recognition device (such as a fingerprint reader, iris scanner, etc.), and then a key related to the biometric feature is generated based on the verification result; alternatively, additional security is provided by generating a dynamic password that changes over time. Dynamic passwords are usually used in conjunction with hardware tokens or mobile phone applications, which generate new passwords periodically.

[0045] S502. Based on the core key and the cross-level key association system, a dual key verification mechanism is configured for the data of the core-level privacy layer. That is, in the process of decrypting the core-level privacy layer, it is necessary to verify the core key and the complete key obtained through the cross-level key association system at the same time.

[0046] Specifically, in the process of decrypting the core-level privacy layer, the user needs to provide a core key (which may be obtained through biometric recognition or a dynamic password) to prove his or her identity; he or she also needs to combine at least m key fragments pre-stored in the next-level privacy layer to generate a complete key. This complete key will be used to initially decrypt the data of the target privacy layer. Since the key fragments are stored in a distributed manner, it is difficult for an attacker to simultaneously obtain all the necessary key fragments to generate a complete key.

[0047] For example, the core-level privacy layer stores highly sensitive financial information. In order to access this data, employees not only need to provide the core key obtained through fingerprint recognition, but also need to combine the three key fragments stored in the secondary privacy layer to generate a complete key. This means that attackers need to at least break through the fingerprint recognition system and two key fragment storage nodes in the secondary privacy layer at the same time to access the data in the core-level privacy layer. Its dual key verification mechanism can greatly increase the security of the data.

[0048] The present invention uses a multi-level privacy protection strategy to finely divide multimedia data into privacy layers of different levels according to their importance, ensuring that highly sensitive data is more strongly protected while maintaining the availability and access efficiency of less sensitive data. In addition, the generation and distributed storage of key fragments, as well as the construction of a cross-level key association system, not only enhance the flexibility and security of key management, but also further improve the security threshold for data access. An independent core key is set for the core-level privacy layer, and double key verification is performed in combination with a cross-level key association system, providing additional security for the most sensitive data. The present invention can also automatically adjust the protection strategy according to changes in the importance of the data to adapt to new security requirements, thereby effectively improving the reliability and efficiency of data transmission through refined privacy layer division and key management strategies.

[0049] Embodiment 2 like Figure 2 As shown, a privacy protection system in multimedia data transmission applied to a privacy protection method in multimedia data transmission includes: A weight assignment module, used to collect and identify multimedia data to be transmitted, evaluate the importance of the multimedia data, and assign a weight value corresponding to the importance to each piece of data, wherein the multimedia data includes text, image, audio or video; A data partitioning module, for partitioning each piece of data into a corresponding privacy layer through a preset weight threshold segment based on a weight value assigned to each piece of data, wherein the privacy layer includes a primary, secondary, tertiary and core privacy layer in ascending order of weight value; A primary encryption module, for generating a number of key fragments for each data category of each privacy layer, and using the key fragments to encrypt the data of the corresponding privacy layer; A key association module, used to construct a cross-level key association system by combining several key fragments into a complete key; The secondary encryption module is used to set an independent core key for the core-level privacy layer and configure double key verification in combination with the constructed cross-level key association system; The monitoring feedback execution module is used to periodically re-evaluate the importance of multimedia data during data transmission. Based on the results of periodic evaluation, the multimedia data is re-divided into privacy layers, key fragments are encrypted, a cross-level key association system is constructed, and dual key verification is configured.

[0050] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0051] Those skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage medium includes a read-only memory (ROM), a random access memory (RAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a one-time programmable read-only memory (OTPROM), an electronically erasable rewritable read-only memory (EEPROM), a compact disc (CD-ROM) or other optical disc storage, magnetic disk storage, magnetic tape storage, or any other computer-readable medium that can be used to carry or store data.

[0052] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

Claims

1. A privacy protection method in multimedia data transmission, characterized in that: The privacy protection method comprises the following steps: Collect and identify multimedia data to be transmitted, evaluate the importance of the multimedia data, and assign a weight value corresponding to the importance to each piece of data, wherein the multimedia data includes text, images, audio or video; Based on the weight value assigned to each piece of data, each piece of data is divided into a corresponding privacy layer through a preset weight threshold segment, wherein the privacy layer includes a primary, secondary, tertiary and core privacy layer in ascending order of weight value; For each data category of the privacy layer, several key fragments are generated, and the key fragments are used to encrypt the data of the corresponding privacy layer; By combining several key fragments into a complete key, a cross-level key association system is constructed; Set up an independent core key for the core privacy layer, and configure double key verification in combination with the constructed cross-level key association system; During the data transmission process, the importance of multimedia data is periodically re-evaluated. Based on the results of the periodic evaluation, the multimedia data is re-divided into privacy layers, key fragments are encrypted, a cross-level key association system is built, and dual key verification is configured.

2. A privacy protection method in multimedia data transmission according to claim 1, characterized in that: The steps of collecting and identifying multimedia data to be transmitted, evaluating the importance of the multimedia data, and assigning a weight value corresponding to the importance to each piece of data, wherein the multimedia data includes text, images, audio or video, include: Acquire and collect multimedia data to be transmitted from device storage or the network, including text, images, audio or video; Use media type identification technology to distinguish the type of each piece of data; Use a multi-dimensional evaluation method to evaluate the importance of each piece of data and obtain the evaluation results; According to the evaluation results, a weight value corresponding to the importance is assigned to each piece of data.

3. The privacy protection method in multimedia data transmission according to claim 1, characterized in that: Based on the weight value assigned to each piece of data, each piece of data is divided into a corresponding privacy layer through a preset weight threshold segment, wherein the privacy layer includes a primary, secondary, tertiary and core privacy layer in ascending order according to the weight value, and the specific steps include: Four weight threshold segments are pre-set, corresponding to the primary, secondary, tertiary and core privacy layers; The weight value of each piece of data is compared with the four preset weight threshold segments, and the privacy layer to which each piece of data belongs is determined based on the comparison result.

4. The privacy protection method in multimedia data transmission according to claim 1, characterized in that: The specific steps of generating a plurality of key fragments for each data category of each privacy layer and using the key fragments to encrypt the data of the corresponding privacy layer include: For each privacy layer, generate several key fragments; The generated key fragment is used to encrypt the data of the corresponding privacy layer, and the encryption method is symmetric encryption or asymmetric encryption.

5. The privacy protection method in multimedia data transmission according to claim 1, characterized in that: The cross-level key association system is specifically as follows: after each privacy layer generates n key fragments, when it is necessary to access the target privacy layer data, it is necessary to combine at least m key fragments pre-stored in the next-level privacy layer to generate a complete key, and preliminarily decrypt the target privacy layer based on the generated complete key, where n≥2, 1≤m≤n.

6. The privacy protection method in multimedia data transmission according to claim 1, characterized in that: The key fragments are stored in a distributed manner, and key fragments of different privacy layers are managed by independent nodes.

7. The privacy protection method in multimedia data transmission according to claim 1, characterized in that: The core-level privacy layer is provided with an independent core key, and a cross-level key association system is constructed to configure dual key verification, and the specific steps include: Generate an independent core key for the core-level privacy layer, wherein the core key is generated based on biometric recognition or dynamic password; Based on the core key combined with the cross-level key association system, a dual key verification mechanism is configured for the data of the core-level privacy layer. That is, in the process of decrypting the core-level privacy layer, it is necessary to verify the core key and the complete key obtained through the cross-level key association system at the same time.

8. A privacy protection system in multimedia data transmission, applied to a privacy protection method in multimedia data transmission according to any one of claims 1 to 7, characterized in that: The privacy protection system comprises: A weight assignment module, used to collect and identify multimedia data to be transmitted, evaluate the importance of the multimedia data, and assign a weight value corresponding to the importance to each piece of data, wherein the multimedia data includes text, image, audio or video; A data partitioning module, for partitioning each piece of data into a corresponding privacy layer through a preset weight threshold segment based on a weight value assigned to each piece of data, wherein the privacy layer includes a primary, secondary, tertiary and core privacy layer in ascending order of weight value; A primary encryption module, for generating a number of key fragments for each data category of each privacy layer, and using the key fragments to encrypt the data of the corresponding privacy layer; A key association module, used to construct a cross-level key association system by combining several key fragments into a complete key; The secondary encryption module is used to set an independent core key for the core-level privacy layer and configure double key verification in combination with the constructed cross-level key association system; The monitoring feedback execution module is used to periodically re-evaluate the importance of multimedia data during data transmission. Based on the results of periodic evaluation, the multimedia data is re-divided into privacy layers, key fragments are encrypted, a cross-level key association system is constructed, and dual key verification is configured.

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