Government affair approval data credibility method and system based on block chain technology

Abstract

The invention relates to the field of block chains, and discloses a government affair approval data credibility method and system based on a block chain technology, and the method comprises the steps: S11, receiving an application; s12, dividing the data; s13, performing hierarchical encryption; s14, under the data storage chain, generating a root hash; s15, the first block is linked in a consensus mode; in the examination and approval stage, S21, data are verified, and operation is received; s22, updating the data, and generating a new root hash; s23, a second block is linked in a consensus mode; the system comprises a data interface module, a data processing module, a composite tree construction module and a consensus writing module. By adopting an on-chain and off-chain collaborative architecture and constructing an MRBT composite tree data structure to aggregate and identify off-chain data, the technical effects of efficiently verifying data integrity and effectively preventing data from being tampered are achieved, non-tampering and traceability of government affair approval full-process data are realized, the authenticity and credibility of approval data are ensured, and the method and the device have the advantages of being high in practicability and easy to popularize and use. And the final credibility of the approval result is improved.

Description

Technical Field

[0001] This invention relates to the field of blockchain technology, specifically to a trusted method and system for government approval data based on blockchain technology. Background Technology

[0002] With the deepening of "Internet Plus Government Services," government approval systems are accelerating their transformation towards digitalization and intelligence. Against this backdrop, blockchain technology, due to its decentralized, immutable, and fully traceable characteristics, has become an important technological path for solving the problem of trustworthy government data. Currently, some government systems have begun to apply blockchain technology, for example, by using distributed ledgers and smart contract mechanisms to solidify approval records and ensure process transparency. Preliminary explorations have been conducted in areas such as digital identity and electronic certificates, aiming to improve data transparency and credibility, thereby enhancing the government's credibility.

[0003] However, applying existing blockchain solutions to large-scale, high-concurrency government approval scenarios still faces several technical challenges. First, government approvals involve massive amounts of application data; storing all this data directly on the blockchain would place enormous storage pressure on the blockchain and cause slow system response. Second, complex approval processes require highly flexible access control mechanisms to meet the collaborative approval needs of multiple roles and departments, but current solutions do not adequately support this. Third, as the node scale increases, the communication overhead of traditional consensus algorithms such as PBFT increases significantly, reducing consensus efficiency and making it difficult to support high-concurrency approval scenarios. Therefore, designing a new technical solution that balances data trustworthiness, security, and system efficiency has become an urgent research direction in this field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a trusted method and system for government approval data based on blockchain technology. It solves the problem of how to ensure the security and trustworthiness of massive amounts of off-chain data and achieve refined access control while maintaining overall system efficiency in government approval applications, by utilizing an on-chain and off-chain collaborative architecture.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a trusted method for government approval data based on blockchain technology, comprising an application stage and an approval stage; The application stage includes the following steps: S11. Receive the approval application submitted by the applicant, which contains government approval data; S12. Perform sensitivity analysis on the government approval data, and divide the government approval data into public layer data, internal layer data and sensitive layer data according to the analysis results. The internal layer data and sensitive layer data need to be encrypted. S13. Based on the division results, a differentiated encryption strategy is adopted to process the government approval data. For the internal layer data, the attribute encryption algorithm based on the ciphertext strategy, namely the CP-ABE algorithm, is used for encryption. For the sensitive layer data, the symmetric encryption algorithm AES-256 is first used to encrypt the data to generate ciphertext. Then, the CP-ABE algorithm is used to encrypt the key of the AES-256 algorithm used to encrypt the sensitive layer data to generate key ciphertext. S14. Store the encrypted government approval data in an off-chain database, and generate the first root hash based on the encrypted government approval data using a Merkle-Radix-Bloom Filter composite tree structure; S15. An improved PBFT algorithm is used to reach consensus on the first block containing the first root hash and the initial approval status, and the first block that has reached consensus is written into the blockchain. The approval stage includes the following steps: S21. Receive the approval operation submitted by the approver for the approval application and compare it; S22. Update the approval status and result of the government approval data in the off-chain database according to the approval operation submitted by the approval application, and generate a second root hash through the Merkle-Radix-BloomFilter composite tree structure according to the updated government approval data; S23. The improved PBFT algorithm is used to reach a consensus on the second block containing the second root hash and the updated approval status, and the consensus-reached second block is written into the blockchain.

[0006] Preferably, the step of performing sensitivity analysis on government approval data during the application stage specifically includes: Based on preset field types, content keywords, or business rules, the government approval data is divided into a public layer, an internal layer, or a sensitive layer; wherein, the public layer data is not encrypted.

[0007] Preferably, the construction steps of the Merkle-Radix-Bloom Filter composite tree structure include: The keys of the government approval data are processed by multiple hash functions and mapped to a bit array of a Bloom filter; The key-value pairs of the government approval data are stored in a Radix tree, and redundant nodes are reduced through path compression. The hash value of the encrypted government approval data is inserted as a leaf node into the Merkle tree, and the first root hash or the second root hash is generated by calculating layer by layer.

[0008] Preferably, the improved PBFT algorithm is a PoS-based Layered PBFT algorithm, which divides consensus nodes into a master node layer, a validator node layer, and a normal node layer.

[0009] Preferably, the master node of the master node layer is elected by the node's stake weight, and the stake weight is calculated using the following formula: ; In the formula, For nodes equity weight, For nodes initial rights, For nodes Behavioral rating The sum of adjusted equity for all nodes; The verification nodes are responsible for verifying and voting to confirm the master node's proposal, thus assisting in the consensus process. The ordinary nodes are used to make final confirmation of the consensus result after the verification nodes have confirmed it, and then write it into the blockchain.

[0010] Preferably, the behavior score The calculation formula is: ; In the formula, For nodes Behavioral rating Frequency of node participation For response time, Due to information transmission delay, Recording malicious behavior These are the preset weighting coefficients.

[0011] Preferably, the second block generated during the approval stage also includes the identity identifier of the approver who performed the approval operation and the operation timestamp.

[0012] Preferably, the method further includes data query and decryption steps, specifically: Upon receiving a user query request, the query key is pre-checked using the Bloom filter in the Merkle-Radix-BloomFilter composite tree structure; If the check passes, locate the data in the Radix tree; Verify whether the set of attributes of the user's private key satisfies the access policy set during encryption using the CP-ABE algorithm; If the verification passes, the internal layer data can be directly decrypted using the user's private key; For the sensitive layer data, the user's private key is first used to decrypt the data to obtain the key for the symmetric encryption algorithm, and then the key is used to decrypt the data.

[0013] Preferably, the method further includes an on-chain and off-chain data consistency verification step, specifically: Recalculate the root hash of the Merkle-Radix-Bloom Filter composite tree structure of all government approval data in the off-chain database to obtain the off-chain root hash; The off-chain root hash is compared with the latest root hash stored on the blockchain; If the two are inconsistent, the path verification of the Merkle-Radix-BloomFilter composite tree structure is used to locate the tampered data.

[0014] A trusted government approval data system based on blockchain technology includes: The data interface module is used to receive approval applications submitted by applicants and approval operations submitted by approvers. The data processing module, connected to the data interface module, is used to perform sensitivity analysis on the government approval data in the approval application and process it using a differentiated encryption strategy to generate encrypted data; A composite tree construction module, connected to the data processing module and the data interface module, is used to store the encrypted data into an off-chain database and generate a first hash or a second hash through a Merkle-Radix-Bloom Filter composite tree structure based on the encrypted data or data updates triggered by the approval operation. The consensus writing module, connected to the composite tree construction module, is used to use an improved PBFT algorithm to reach consensus on blocks containing the first root hash or the second root hash and the corresponding approval status, and to write the consensus-reaching blocks into the blockchain.

[0015] This invention provides a trusted method and system for government approval data based on blockchain technology. It has the following beneficial effects: 1. This invention adopts an on-chain and off-chain collaborative architecture and constructs an MRBT composite tree data structure to aggregate and identify off-chain data. This achieves the technical effect of efficiently verifying data integrity and effectively preventing data tampering. It solves the problems of low credibility caused by the difficulty in efficiently verifying the authenticity and integrity of data and the ease with which data can be tampered with in the existing technology. It realizes the immutability and traceability of data in the entire process of government approval, ensures the authenticity and credibility of approval data, and enhances the final credibility of approval results.

[0016] 2. This invention combines a layered encryption strategy with an attribute-based encryption algorithm based on a ciphertext strategy, achieving a refined and dynamic access control for data of different sensitivity levels. It solves the problems of privacy leakage and high risk of unauthorized access caused by the use of coarse-grained permission management or a single encryption strategy in existing technologies. It realizes the secure hierarchical control of core sensitive government information, ensuring that data can only be accessed by legally authorized personnel within the prescribed permissions, and significantly improves the overall data security of the system.

[0017] 3. This invention achieves high throughput and low response latency in high-concurrency, high-data-volume scenarios by storing only key root hash information on the blockchain and combining an improved PoS-based Layered PBFT consensus algorithm with an efficient indexing mechanism in the MRBT structure. This solves the problems of existing technologies that put large amounts of data on the blockchain or use inefficient consensus mechanisms, which can easily lead to network congestion, low processing efficiency, and high response latency in high-concurrency scenarios. It enables the system to operate efficiently and stably under high load, ensuring the response speed of government approval services, and making this technical solution have excellent overall performance in actual business scenarios. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method steps of the present invention; Figure 2 This is a schematic diagram of the Merkle-Radix-Bloom Filter Tree structure of the present invention; Figure 3 This is a flowchart of the PoS-based Layered PBFT algorithm of the present invention; Figure 4 This is a flowchart of the application process for this invention; Figure 5 This is a flowchart of the approval process for this invention; Figure 6 This is the overall system flowchart of the present invention; Figure 7 This is a system module architecture diagram of the present invention. Detailed Implementation

[0019] Please see the appendix Figure 1 -Appendix Figure 5 This invention provides a trusted method for government approval data based on blockchain technology. This method can operate in a distributed network system composed of multiple computing device nodes. The system includes an application server, a storage server configured with an off-chain database, and a server acting as a blockchain consensus node.

[0020] In a specific implementation example, the method provided by this invention includes an application stage and an approval stage.

[0021] The specific processing procedure for the application stage is as follows: First, in step S11, the system's data interface module receives the approval application submitted by the applicant through the client device. This approval application contains structured or unstructured government approval data, such as the applicant's basic information, details of the application, and relevant supporting documentation.

[0022] Next, in step S12, after receiving the government approval data, the system's data processing module performs a sensitivity analysis. This analysis is based on a preset business rule base, which defines the correspondence between different field types, content keywords, and data sensitivity levels. For example, the data can be divided into three levels: public layer data (such as the public number of the application item), internal layer data (such as the applicant's regular contact information), and sensitive layer data (such as ID card numbers or biometric information). Public layer data is not encrypted.

[0023] Subsequently, in step S13, the data processing module performs differentiated encryption processing on data at different levels based on the analysis results of step S12. For internal layer data, the Attribute Encryption Based on Ciphertext Policy (CP-ABE) algorithm is used for encryption. For sensitive layer data, a symmetric encryption algorithm (such as the AES-256 algorithm) is first used to encrypt the data, generating ciphertext; then, the CP-ABE algorithm is used to encrypt the AES-256 algorithm key used to encrypt the sensitive layer data, generating key ciphertext.

[0024] In step S14, the system's composite tree construction module stores the encrypted government approval data (including the ciphertext of the internal layer data, the ciphertext of the sensitive layer data, and the ciphertext of the key) into an off-chain database. Simultaneously, based on all the encrypted government approval data stored in the current off-chain database, this module generates a unique root hash, i.e., the first root hash, using a Merkle-Radix-Bloom Filter (MRBT) composite tree structure.

[0025] The construction process of this Merkle-Radix-Bloom Filter composite tree structure consists of three parts. First, the key (e.g., application number) of each piece of government approval data is processed using multiple preset hash functions, and the processing result is mapped into a bit array of a Bloom filter for subsequent fast query pre-checking. Second, the key-value pairs of government approval data are stored in a Radix tree, which reduces redundant nodes through path compression to support fast data location. Finally, the hash value of each encrypted piece of government approval data is used as a leaf node to construct a standard Merkle tree. By performing layer-by-layer hash calculations on the leaf nodes, the first hash is finally generated at the root of the tree.

[0026] Then, in step S15, the system's consensus writing module packages the first root hash generated in step S14 and the initial approval status of the approval application (e.g., "pending approval") into a data body for a first block. Subsequently, the consensus nodes in the system use an improved Practical Byzantine Fault Tolerance (PBFT) algorithm to reach consensus on the first block.

[0027] The improved PBFT algorithm is specifically a Proof-of-Stake (PoS) based Layered PBFT algorithm. This algorithm divides all consensus nodes into three role layers: the master node layer, the validator node layer, and the ordinary node layer. The master node layer contains only one master node in each round of consensus, responsible for packaging transactions and generating proposal blocks. The election of the master node is based on the node's dynamic stake weight. The validator node layer consists of a group of nodes with higher stake weights, responsible for validating, signing, and voting on the master node's proposals. The ordinary node layer, after receiving a sufficient number of validator node signatures, provides final confirmation of the consensus result and writes it to the local blockchain ledger.

[0028] The stake weight on which the master node is elected The calculation formula is: ; In the formula, For nodes equity weight, For nodes initial rights, For nodes Behavioral rating It represents the sum of the adjusted equity of all nodes.

[0029] Node behavior scoring Determined by its historical consensus behavior, its calculation formula is as follows: ; In the formula, For nodes Behavioral rating This represents the node participation frequency, initialized to 0. It increases by 10 for each consensus process a node participates in (such as processing approval requests or verification messages), and deducts 5 if a node does not participate in consensus for an extended period. Response time represents the speed at which a node processes request and response messages. A lower response time increases the value by 10, and vice versa. Information transmission latency represents the time it takes for information to be transmitted between nodes; that is, the time it takes for data to travel from one node to another in the network. Lower latency increases by 5, and higher latency decreases by 5. For malicious behavior, such as occasional delays in message delivery (generally malicious), 10 points will be deducted. If a node intentionally tampers with data or engages in a denial-of-service attack (a serious malicious act), it will be removed from the consensus process. These are preset weighting coefficients, and their sum is 1.

[0030] Once consensus is reached on the first block, the block is written into the blockchain, completing the on-chain storage of data from the application phase.

[0031] The specific processing flow during the approval stage is as follows: In step S21, the system's data interface module receives the approval operation submitted by the approver with the corresponding authority, such as approval, rejection, or supplementary materials.

[0032] Next, in step S22, the composite tree construction module updates the approval status and result of the corresponding government approval data for the approval application in the off-chain database based on the received approval operation. Since the data in the off-chain database has changed, the composite tree construction module will re-execute the aforementioned Merkle-Radix-BloomFilter composite tree structure construction process based on the updated full data to generate a new root hash, i.e., the second root hash.

[0033] Finally, in step S23, the consensus writing module packages the second hash, the updated approval status (e.g., approval passed), the identity of the approver who performed the approval operation, and the timestamp of the operation together to form a second block. The consensus nodes in the system again use the aforementioned improved PBFT algorithm to reach consensus on this second block. After consensus is reached, the second block is written to the blockchain, thereby achieving an immutable traceable record of the approval behavior.

[0034] Please see the appendix Figure 2 During the application stage, the method of this invention aims to standardize the reception, secure processing and reliable storage of government approval data submitted by the applicant.

[0035] Specifically, in step S11, the system's data interface module is responsible for receiving the approval application submitted by the applicant. This module provides a standardized data input interface for receiving forms and attachments containing various government approval data.

[0036] In step S12, the data processing module performs sensitivity analysis on the received government approval data. This module categorizes the data into public, internal, or sensitive layers based on a pre-defined rule base. This rule base matches data based on field type (e.g., text, number, date), content keywords (e.g., ID card, contact number), or specific business rules (e.g., all attachments for a particular approval process are defined as sensitive). For example, public layer data may include policy documents or public notices; internal layer data may include intermediate states of the approval process or non-sensitive user information; and sensitive layer data may include personal identification information or financial information.

[0037] In step S13, the data processing module executes a differentiated encryption strategy based on the sensitivity analysis results. This process first requires generating system-level public parameters PK and master key MSK. For data classified as public, no encryption is performed, but access is controlled through authentication and operation logs.

[0038] For data that is divided into inner layers The data processing module uses the CP-ABE algorithm and sets an access strategy for it. Perform encryption operations to generate ciphertext. : ; In the formula, Ciphertext generated for encrypting inner layer data, The data is the inner layer data to be encrypted; An access strategy defined by a set of attributes that is bound to this data; These are common parameters of the system; This is the CP-ABE encryption function.

[0039] For data that is classified into a sensitive layer The data processing module performs two-step encryption. First, it uses the AES-256 symmetric encryption algorithm with a randomly generated key. Data Encryption is performed to obtain ciphertext data. : ; In the formula, Ciphertext generated for encrypting sensitive layer data, This refers to sensitive layer data that needs to be encrypted. This is the symmetric key for the AES-256 algorithm; This is an AES-256 encryption function.

[0040] Subsequently, the data processing module processed the key. Set an access policy The CP-ABE algorithm is used to test the key. Encryption is performed to obtain the key ciphertext. : ; In the formula, The key to be encrypted is the AES-256 key. The access policy associated with this key; These are common parameters of the system; This is the CP-ABE encryption function. Ultimately, the data is encrypted. With key ciphertext They are stored together.

[0041] In step S14, the composite tree construction module stores all encrypted data and unencrypted public layer data into the off-chain database. Then, this module constructs a Merkle-Radix-Bloom Filter composite tree for the dataset in the off-chain database and calculates and generates the first root hash. The construction details of this composite tree are as follows: First, for the key of each data item in the dataset ,pass An independent hash function Calculate Each hash value is used to set the corresponding bit in a bit array of the Bloom filter to 1. The false positive rate of this Bloom filter is... satisfy: ; In the formula, The size of the bit array; The number of elements in the dataset; The number of hash functions is specified. Next, the key-value pairs in the dataset are stored in a Radix tree. This Radix tree reduces redundant nodes (the number of nodes) through path compression and merging. ,in, Where L is the character set size and L is the average length. (This refers to the number of key-value pairs) to reduce storage space and query depth.

[0042] Finally, a hash value for each data item is calculated using a hash function (e.g., SHA-256), and these hash values ​​are used as leaf nodes to construct a Merkle tree. The hash value of any non-leaf node in the Merkle tree is... It is obtained by concatenating the hash values ​​of all its child nodes and then hashing them again: ; In the formula, The hash value of the parent node; to This represents the hash values ​​of all child nodes under this node; This indicates a byte string concatenation operation; This is a hash function. Through layer-by-layer calculation, a unique root hash is eventually generated at the top of the tree, which is the first root hash.

[0043] In step S15, the consensus writing module encapsulates the first hash and the initial approval status (e.g., "pending approval") into a block. Subsequently, consensus nodes in the network use the PoS-based Layered PBFT algorithm to reach a consensus on this block. The consensus process of this algorithm is as follows: The master node of the current round sends a Pre-Prepare message containing the new block to all validator nodes. After validating the legality of the block, the validator nodes broadcast the Prepare message to the entire network. When any node collects at least 2f+1 (where f is the maximum number of Byzantine nodes the network can tolerate) valid Prepare messages from different nodes, that node enters the Commit phase and broadcasts a Commit message to the entire network. After collecting a sufficient number of Commit messages, the ordinary node layer writes the block to its local blockchain ledger, thus completing the entire application phase process.

[0044] Please see the appendix Figure 3 After the application stage is completed, the method of this embodiment of the invention enters the approval stage. This stage aims to process the application for approval and to reliably record the processing and results.

[0045] The specific procedures for the approval stage are as follows: First, in step S21, the system's data interface module receives the approval operation submitted by the approver. Prior to this, the user with approval authority must log in to the system. The system will provide the user with a list of applications awaiting approval based on their identity attributes. Before performing an approval operation (e.g., "Approved," "Rejected," or "Request Supplementary Materials"), the approver needs to review the government approval data contained in the application.

[0046] When an approver requests access to data from a specific application, the system executes a data query and decryption process. First, the system pre-checks the key of the requested data using a Bloom filter within the Merkle-Radix-Bloom filter composite tree structure. If the Bloom filter determines the key does not exist, the system directly returns a "data does not exist" response, avoiding invalid access to the off-chain database. If the Bloom filter determines the key may exist, the system quickly locates the data in the off-chain database within the Radix tree.

[0047] After locating the encrypted data, the system performs an access verification. The approver holds the user's private key. It contains a set of attributes. The system verifies whether this set of attributes satisfies the access policy T set when encrypting the data. This verification process is performed using a matching algorithm based on an access control tree.

[0048] If the permission verification passes, the system will perform a mandatory on-chain and off-chain data consistency check. Specifically, the system will read the latest block related to the approval application from the blockchain ledger and obtain the root hash of the record, i.e., the on-chain root hash. Simultaneously, the system retrieves the corresponding Merkle proof path from the data located in the off-chain database and recalculates a root hash accordingly. .

[0049] Subsequently, the system and A comparison is performed. If the two do not match, the system determines that the off-chain data has been tampered with, immediately triggers the tampering alarm mechanism, and terminates the current approval process. If the two match, the system performs decryption according to the different data levels. For internal layer data, the ciphertext is... The system directly uses the user's private key. Decrypt and recover the plaintext data. : ; In the formula, This is the decrypted inner layer data; This is the ciphertext of the inner layer data; For the user's private key; This is the CP-ABE decryption function.

[0050] For sensitive layer data, its encrypted data is: The key ciphertext is The system first uses the user's private key. For key ciphertext Decryption yields the AES-256 symmetric key. : ; In the formula, The AES-256 key obtained for decryption; The ciphertext of the key; For the user's private key; This is the CP-ABE decryption function.

[0051] The system then uses the recovered key. encrypted data Decrypt using AES-256 to obtain plaintext data. : ; In the formula, This is the decrypted sensitive layer data; This is the ciphertext of sensitive layer data; The key obtained for decryption; This is the AES-256 decryption function. After presenting the decrypted data to the approver, the approver can then submit their approval request based on the data content.

[0052] In step S22, the composite tree construction module updates the government approval data stored in the off-chain database in real time based on the approval operation received by the data interface module. The specific update operation includes modifying the approval status field of the application record (for example, updating it from "pending approval" to "approved") and recording the approval result (for example, writing the specific reason for rejection when "rejected").

[0053] Since the data content in the off-chain database has changed, even if it is just a change in a state bit, the composite tree building module will re-execute the same Merkle-Radix-BloomFilter composite tree structure building process as in step S14 based on the updated dataset, thereby generating a brand new root hash that reflects the overall state of the current dataset, namely the second root hash.

[0054] Finally, in step S23, the consensus writing module is responsible for solidifying this approval action onto the blockchain. This module packages the second hash newly generated in step S22, the updated approval status, the unique identifier (ID) of the approver who performed this approval operation, and the precise operation timestamp together to form a data body of the second block.

[0055] The consensus nodes in the system employ the same PoS-based Layered PBFT algorithm as in the application phase to reach consensus on the second block. The consensus process is initiated by the elected master node, followed by verification and voting at the validator node layer. Finally, after collecting a sufficient number of commit messages, the ordinary node layer writes the second block to the blockchain ledger. This process can be automatically triggered by a pre-defined smart contract. The second block written to the blockchain provides an immutable and traceable record of this approval process. Please see the appendix Figure 6 -Appendix Figure 7 This invention includes a trusted system for government approval data based on blockchain technology, comprising: The data interface module is used to receive approval applications submitted by applicants and approval operations submitted by approvers. The data processing module, connected to the data interface module, is used to perform sensitivity analysis on government approval data in the approval application and process it using a differentiated encryption strategy to generate encrypted data. The composite tree construction module, connected to the data processing module and the data interface module, is used to store encrypted data into an off-chain database and generate the first or second hash through a Merkle-Radix-Bloom Filter composite tree structure based on the encrypted data or data updates triggered by approval operations. The consensus writing module, connected to the composite tree construction module, is used to reach consensus on blocks containing the first or second root hash and the corresponding approval status using an improved PBFT algorithm, and write the consensus-reaching blocks into the blockchain.

Claims

1. A trusted method for government approval data based on blockchain technology, characterized in that, This includes the application stage and the approval stage; The application stage includes the following steps: S11. Receive the approval application submitted by the applicant, which contains government approval data; S12. Perform sensitivity analysis on the government approval data, and divide the government approval data into public layer data, internal layer data and sensitive layer data according to the analysis results. The internal layer data and sensitive layer data need to be encrypted. S13. Process the government approval data using a differentiated encryption strategy based on the segmentation results; Specifically, the inner layer data is encrypted using the CP-ABE algorithm, an attribute encryption algorithm based on ciphertext strategy. For the sensitive layer data, the symmetric encryption algorithm AES-256 is first used to encrypt the data to generate ciphertext. Then, the CP-ABE algorithm is used to encrypt the key of the AES-256 algorithm used to encrypt the sensitive layer data to generate key ciphertext. S14. Store the encrypted government approval data in an off-chain database, and generate the first root hash based on the encrypted government approval data using a Merkle-Radix-Bloom Filter composite tree structure; S15. An improved PBFT algorithm is used to reach consensus on the first block containing the first root hash and the initial approval status, and the first block that has reached consensus is written into the blockchain. The approval stage includes the following steps: S21. Receive the approval operation submitted by the approver for the approval application and compare it; S22. Update the approval status and result of the government approval data in the off-chain database according to the approval operation submitted by the approval application, and generate a second root hash through the Merkle-Radix-BloomFilter composite tree structure according to the updated government approval data; S23. The improved PBFT algorithm is used to reach a consensus on the second block containing the second root hash and the updated approval status, and the consensus-reached second block is written into the blockchain.

2. The trusted method for government approval data based on blockchain technology according to claim 1, characterized in that, The specific steps for conducting sensitivity analysis on government approval data during the application stage are as follows: Based on preset field types, content keywords, or business rules, the government approval data is divided into a public layer, an internal layer, or a sensitive layer; wherein, the public layer data is not encrypted.

3. The trusted method for government approval data based on blockchain technology according to claim 1, characterized in that, The steps for constructing the Merkle-Radix-Bloom Filter composite tree structure include: The keys of the government approval data are processed by multiple hash functions and mapped to a bit array of a Bloom filter; The key-value pairs of the government approval data are stored in a Radix tree, and redundant nodes are reduced through path compression. The hash value of the encrypted government approval data is inserted as a leaf node into the Merkle tree, and the first root hash or the second root hash is generated by calculating layer by layer.

4. The trusted method for government approval data based on blockchain technology according to claim 1, characterized in that, The improved PBFT algorithm is a PoS-based Layered PBFT algorithm that divides consensus nodes into a master node layer, a validator node layer, and a normal node layer.

5. A trusted method for government approval data based on blockchain technology according to claim 4, characterized in that, The master node of the master node layer is elected by the node's stake weight, and the formula for calculating the stake weight is: ； In the formula, For nodes equity weight, For nodes initial rights, For nodes Behavioral rating The sum of adjusted equity for all nodes; The verification nodes are responsible for verifying and voting to confirm the master node's proposal, thus assisting in the consensus process. The ordinary nodes are used to make final confirmation of the consensus result after the verification nodes have confirmed it, and then write it into the blockchain.

6. The trusted method for government approval data based on blockchain technology according to claim 5, characterized in that, The behavioral score The calculation formula is: ； In the formula, For nodes Behavioral rating Frequency of node participation For response time, Due to information transmission delay, Recording malicious behavior These are the preset weighting coefficients.

7. The trusted method for government approval data based on blockchain technology according to claim 1, characterized in that, The second block generated during the approval stage also includes the identity of the approver who performed the approval operation and the operation timestamp.

8. The trusted method for government approval data based on blockchain technology according to claim 1, characterized in that, The method also includes data query and decryption steps, specifically: Upon receiving a user query request, the query key is pre-checked using the Bloom filter in the Merkle-Radix-BloomFilter composite tree structure; If the check passes, locate the data in the Radix tree; Verify whether the set of attributes of the user's private key satisfies the access policy set during encryption using the CP-ABE algorithm; If the verification passes, the internal layer data can be directly decrypted using the user's private key; For the sensitive layer data, the user's private key is first used to decrypt the data to obtain the key for the symmetric encryption algorithm, and then the key is used to decrypt the data.

9. A trusted method for government approval data based on blockchain technology according to claim 1, characterized in that, The method also includes an on-chain and off-chain data consistency verification step, specifically: Recalculate the root hash of the Merkle-Radix-Bloom Filter composite tree structure of all government approval data in the off-chain database to obtain the off-chain root hash; The off-chain root hash is compared with the latest root hash stored on the blockchain; If the two are inconsistent, the path verification of the Merkle-Radix-BloomFilter composite tree structure is used to locate the tampered data.

10. A trusted system for government approval data based on blockchain technology, comprising a trusted method for government approval data based on blockchain technology according to any one of claims 1-9, characterized in that, include: The data interface module is used to receive approval applications submitted by applicants and approval operations submitted by approvers. The data processing module, connected to the data interface module, is used to perform sensitivity analysis on the government approval data in the approval application and process it using a differentiated encryption strategy to generate encrypted data; A composite tree construction module, connected to the data processing module and the data interface module, is used to store the encrypted data into an off-chain database and generate a first hash or a second hash through a Merkle-Radix-Bloom Filter composite tree structure based on the encrypted data or data updates triggered by the approval operation. The consensus writing module, connected to the composite tree construction module, is used to use an improved PBFT algorithm to reach consensus on blocks containing the first root hash or the second root hash and the corresponding approval status, and to write the consensus-reaching blocks into the blockchain.

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