A blockchain-based method for cross-border circulation of personal data

Abstract

A kind of personal data cross-border circulation method based on blockchain, through data acquisition and local storage, third party neutral agency witness and data fingerprint chain, data transmission and use authorization declaration, receiver on-chain fingerprint verification and data verification, whole-link traceability and dynamic audit.The present application is directed to the trust guarantee of personal data cross-border circulation, which relies on single technical means such as centralized agency authentication or encrypted transmission or static legal agreement, and there are problems of long trust transmission chain and weak cross-border legal mutual recognition, a data fingerprint anchoring system based on blockchain is designed;In view of the fact that traditional data cross-border authorization relies on manual signing of agreement or static strategy configuration, there are problems such as response lag, rule execution deviation, and privacy protection and compliance audit difficult to balance, a dynamic constraint data use rule through smart contract is designed, the user defines data use range, time limit and operation white list through declarative smart contract, and the contract code is automatically executed after being verified by on-chain node consensus.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of computers and relates to a blockchain technology, and particularly relates to a personal data cross-border circulation method based on a blockchain. BACKGROUND

[0002] In a traditional personal data cross-border circulation method, one method is based on a legal compliance framework, establishes mutual recognition mechanisms between countries or regions, and forcibly requires data receivers to meet specific security standards, relying on the approval and supervision mechanisms of centralized agencies to promote personal data cross-border circulation. However, the centralized approval process of this method is time-consuming and lengthy, and is difficult to adapt to high-frequency and fragmented cross-border business scenarios. In addition, legal conflicts in different jurisdictions lead to the vulnerability of mutual recognition mechanisms. One method adds noise to a data set using differential privacy technology to obscure individual information, but differential privacy needs to balance data availability and privacy protection strength, and excessive noise injection may reduce data value. One method uses secure multi-party computation (SMPC) to realize multi-party data collaborative computing without exposing original data, but SMPC and other technologies rely on complex cryptographic protocols, and face network latency and computing power bottlenecks when communicating across domains, making it difficult to support large-scale real-time data circulation needs. In view of the above problems and the technical characteristics of the blockchain, the application provides a personal cross-border data circulation method based on a blockchain. SUMMARY

[0003] The application aims to provide a personal data cross-border circulation method based on a blockchain, to solve the problems of lack of trust, data tampering and loss of control in the authorization of personal data cross-border circulation, and to realize safe, compliant and efficient multi-party data cross-border collaboration.

[0004] The technical problem to be solved by the application is how to build a decentralized trust mechanism and dynamic compliance constraint to support safe and controllable circulation of personal data across the entire cross-border chain and multi-jurisdictional collaborative audit.

[0005] The purpose of the application can be achieved by the following technical solutions: a personal data cross-border circulation method based on a blockchain, comprising the following steps:

[0006] Step 1: Data acquisition and local storage: the user securely downloads personal data from the data provider and stores it in a designated location, generating a storage path index.

[0007] Step 2: Third-party neutral agency witnessing and data fingerprint on-chain: upon user authorization, the third-party agency verifies the storage process and generates a data file hash value, and writes the fingerprint and user identity to the blockchain for storage.

[0008] Step 3: Data Transmission and Usage Authorization Statement: Users transmit data to the recipient through a secure channel, synchronizing the usage authorization statement based on the smart contract to the blockchain.

[0009] Step 4: On-chain fingerprint verification and data verification for the recipient: The recipient calculates the data hash and verifies it with the on-chain fingerprint. If a match is found, the verification is completed. If an anomaly is found, the process is terminated.

[0010] Step 5: End-to-end traceability and dynamic auditing: Data usage behavior is stored on the blockchain in real time, allowing users or regulators to trace the entire lifecycle of operations and trigger compliance controls.

[0011] In step one, the user downloads a personal information data package from the data provider, including but not limited to CSV / JSON format, ensures secure transmission through an encrypted transmission protocol, and stores the data in a location specified by the user, including but not limited to local disk, private cloud storage, or distributed storage network, while generating a storage path index file.

[0012] In step two, with user authorization, a neutral third-party institution intervenes to verify the storage process. First, the institution verifies the user's identity and the integrity of the data packet using digital signatures. Second, it calculates the hash value of the data file using the SHA-256 algorithm, generating a unique "data fingerprint." Finally, the fingerprint is bound to the user's identity identifier and timestamp, and written into a public or consortium blockchain to form an immutable evidence record. Given the architectural differences between public and consortium blockchains in cross-border data flow scenarios—where overseas data processing nodes are primarily deployed on public blockchain networks, while domestic data processing nodes mainly rely on consortium blockchain networks—current cross-border data transmission protocols must fully consider the heterogeneous technical characteristics of these two types of distributed ledgers.

[0013] In step three, the user transmits the original data file to the data recipient through a secure channel such as IPFS or end-to-end encryption, and attaches an authorization statement based on a smart contract, including but not limited to restrictions on the scope of use, validity period and purpose description; the contract automatically synchronizes the authorization terms to the blockchain.

[0014] In step four, after the data recipient downloads the file, they calculate the hash value of the data file locally and retrieve the original fingerprint from the evidence storage record through a blockchain explorer or API interface; they compare the two for consistency, and if they match, a verification certificate is generated; if they do not match, an alarm is triggered and the data usage process is terminated.

[0015] In step five, all data usage activities, including but not limited to recipient access records and data processing operations, are recorded on the blockchain in real time via event logs and stored using a Merkle tree structure for compression. Users or regulators can query on-chain records by time range, operation type, and other criteria to achieve full lifecycle traceability. If any violations are detected, the smart contract automatically freezes data access permissions and notifies the user.

[0016] The present invention has the following beneficial effects:

[0017] 1. Currently, trust assurance for cross-border personal data flows primarily relies on centralized institutional authentication or encrypted transmission—single technical means or static legal agreements. This presents challenges such as lengthy trust transfer chains and fragile cross-border legal recognition. To address this, a data fingerprint anchoring system based on blockchain technology is designed. This system binds the data file hash value, user digital identity, and timestamp to a permissioned blockchain, leveraging the blockchain's immutability to permanently store data status. This method overcomes the limitations of traditional hash verification, which is only used in the transmission stage, extending data trustworthiness verification to the storage source, forming a full-cycle anchoring chain from "generation-storage-transmission-use." Data recipients no longer need to rely on repeated verification from the original data provider; they only need to verify the fingerprint on the blockchain to confirm data integrity and legality of origin, thus improving verification efficiency.

[0018] 2. To address the issues of traditional cross-border data authorization relying on manual agreement signing or static policy configuration, which suffers from delayed response, rule execution deviations, and difficulties in balancing privacy protection and compliance auditing, a system was designed to dynamically constrain data usage rules through smart contracts. During the data transmission phase, users define the scope, timeliness, and operation whitelist of data usage through declarative smart contracts. The contract code is automatically executed after being verified by consensus among on-chain nodes. Simultaneously, data usage behavior is encrypted and digested and uploaded to the blockchain in real time, enabling end-to-end traceability of cross-border data behavior while ensuring privacy and reducing the risk of privacy leaks. Attached Figure Description

[0019] Figure 1 This is a flowchart of a blockchain-based method for cross-border circulation of personal data, as described in this invention.

[0020] Figure 2 This is a schematic diagram illustrating an example of a blockchain-based method for cross-border circulation of personal data, as described in this invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Example 1

[0022] A blockchain-based method for cross-border flow of personal data includes the following steps:

[0023] Step 1: Data Acquisition and Local Storage: Users securely download personal data from the data provider and store it in a designated location, generating a storage path index.

[0024] Users download personal information data packages from data providers, including but not limited to CSV / JSON formats. The transmission is secured through encrypted transmission protocols, and the data is stored in locations specified by the user, including but not limited to local disks, private cloud storage, or distributed storage networks. At the same time, a storage path index file is generated.

[0025] Regarding encrypted transmission protocols: the transmission between users and data providers adopts the TLS 1.3 protocol or quantum-resistant encryption protocol (such as NTRU) to ensure transport layer security and prevent man-in-the-middle attacks; for large-scale data packets, the IPFS protocol is used to implement distributed transmission, and decentralized addressing is achieved through content identifier (CIDv1) to avoid single points of failure. After data is segmented, BLS signature aggregation technology is used to verify transmission integrity.

[0026] In terms of enhanced storage security: local storage supports hardware security modules (HSM) to perform XTS-AES full-disk encryption, key management follows the FIPS 140-3 standard, and storage keys and authentication are decoupled through key layering derivation (HKDF-SHA512); distributed storage networks (such as IPFS) use fragmented encryption technology, and data fragments are stored on different nodes, and the complete file can be reconstructed only through the user's private key.

[0027] After a user downloads data, it completes local storage through an encryption protocol and a storage security module (labeled "HSM"), generates a UUID index, and records it to the on-chain metadata table.

[0028] Step Two: Third-Party Neutral Institution Witnessing and Data Fingerprint Uploading: With user authorization, a third-party institution verifies the storage process and generates a data file hash value. After binding the fingerprint with the user's identity, it is written into the blockchain for evidence storage.

[0029] With user authorization, a neutral third-party institution intervenes to verify the storage process. First, the institution verifies the user's identity and the integrity of the data packets using digital signatures. Second, it calculates the hash value of the data file using the SHA-256 algorithm, generating a unique "data fingerprint." Finally, the fingerprint is bound to the user's identity identifier and timestamp, and written into a public or consortium blockchain to form an immutable evidence record. Given the architectural differences between public and consortium blockchains in cross-border data flow scenarios—with overseas data processing nodes primarily deployed on public blockchain networks and domestic data processing nodes mainly relying on consortium blockchain networks—current cross-border data transmission protocols must fully consider the heterogeneous technical characteristics of these two types of distributed ledgers.

[0030] Third-party institution qualification requirements: Institutions must pass the timestamp certification of the National Time Service Center to ensure that the storage time cannot be tampered with; they must have the TEE (Trusted Execution Environment) compliance certification of the Ministry of Industry and Information Technology to verify the physical security of storage nodes (such as anti-tampering hardware).

[0031] Hash algorithm compatibility design: Domestic data processing nodes use the national cryptographic SM3 algorithm to generate data fingerprints, which meets the requirements of China's Cybersecurity Law; overseas nodes use the SHA-3 algorithm, and cross-chain smart contracts are used to realize the mapping and verification of the hash values ​​of the two algorithms.

[0032] Evidence storage chain selection strategy: Domestic data evidence storage is written into a consortium blockchain (such as FISCO BCOS) to support real-time auditing by regulatory agencies; overseas data evidence storage is written into a public blockchain (such as Ethereum) to leverage its decentralized nature to ensure cross-border mutual trust.

[0033] A third-party organization verifies the storage nodes (labeled as "secure containers") in the TEE environment, generates hashes, and writes them to the domestic consortium blockchain and the overseas public blockchain respectively. The hash values ​​of the two chains are synchronized through a cross-chain oracle, and threshold signature (TSS) technology is used to ensure the security of cross-chain operations.

[0034] Step 3: Data Transmission and Usage Authorization Statement: Users transmit data to the recipient through a secure channel, synchronizing the usage authorization statement based on the smart contract to the blockchain.

[0035] Users transmit raw data files to data recipients through secure channels such as IPFS or end-to-end encryption, along with a smart contract-based authorization statement, including but not limited to usage restrictions, validity period, and purpose description; the contract automatically synchronizes the authorization terms to the blockchain.

[0036] Secure channel technologies include: employing end-to-end encryption (such as the Signal protocol) to ensure that only the sender and receiver can decrypt the data; and adding homomorphic encryption for sensitive data, allowing the receiver to perform calculations in encrypted form.

[0037] Dynamic authorization for smart contracts: The authorization statement follows the OAuth 2.1 standard extension, including geo-fencing constraints, differential privacy parameters (ε≤1), and federated learning model access permissions. The statement file is compressed and stored in CBOR-encoded format. The authorization statement supports nested logic with multiple conditions (e.g., "only European IP addresses are allowed to access, and the number of uses is ≤5"). The contract code is verified using formal verification tools (such as CertiK) to ensure it is vulnerability-free and prevents authorization rules from being bypassed.

[0038] When a smart contract is deployed, it triggers on-chain consensus verification (marked as "node verification"). The contract logic takes effect after formal verification, and the authorization rules are bound to the data file for transmission.

[0039] Step 4: On-chain fingerprint verification and data verification for the recipient: The recipient calculates the data hash and verifies it with the on-chain fingerprint. If a match is found, the verification is completed. If an anomaly is found, the process is terminated.

[0040] After downloading the file, the data recipient calculates the hash value of the data file locally and retrieves the original fingerprint from the evidence record through a blockchain explorer or API interface; the two are compared for consistency. If they match, a verification certificate is generated; if they do not match, an alarm is triggered and the data usage process is terminated.

[0041] Zero-Knowledge Proof (ZKP) Implementation: The receiver generates a proof using the zk-SNARKs protocol to verify the consistency between the local hash and the on-chain fingerprint without exposing the original data; a pre-built verification key on the chain is used to quickly verify the validity of the proof through lightweight computation.

[0042] Anomaly Handling Mechanism: When hash mismatch occurs, a verifiable audit report is automatically generated, triggering the on-chain reputation penalty mechanism and lowering the reputation score of the receiving node; if consecutive anomalies exceed the threshold, the smart contract automatically adds the receiving party to the cross-border data blacklist, prohibiting subsequent interactions.

[0043] The verification process uses the zk-SNARKs protocol (labeled as "ZKP module") to protect privacy, and the verification results are written to the on-chain event log.

[0044] Step 5: End-to-end traceability and dynamic auditing: Data usage behavior is stored on the blockchain in real time, allowing users or regulators to trace the entire lifecycle of operations and trigger compliance controls.

[0045] All data usage activities, including but not limited to recipient access records and data processing operations, are recorded on the blockchain in real time via event logs and stored using a Merkle tree structure for compression. Users or regulators can query on-chain records by time range, operation type, and other criteria to achieve full lifecycle traceability. If any violations are detected, the smart contract will automatically freeze data access permissions and notify the user.

[0046] Cross-chain traceability technology: Chainlink oracles are used to monitor events on domestic consortium blockchains and overseas public blockchains, and logs are synchronized through standardized interfaces (such as JSON-RPC); the log format follows the W3C Verifiable Credentials specification and supports multi-chain compatible parsing.

[0047] Dynamic compliance management: Violations (such as accessing outside designated regions) trigger automatic penalties in smart contracts, freezing the pledged token assets of the recipient; regulatory agencies can trace the entire operation chain through a cross-chain explorer, supporting one-click generation of audit reports. When advanced persistent threat (APT) characteristics are detected, a trusted execution environment sandbox is activated to isolate suspicious operations, and the permission status of all nodes in the network is updated in real time through the CRL (Certificate Revocation List) broadcast protocol.

[0048] The cross-chain oracle (labeled "Oracle node") synchronizes logs from domestic and foreign chains. Regulators can monitor data flow, operational behavior, and device fingerprint associations in real time through the audit interface (labeled "Regulatory Panel"). It also supports time travel queries to trace back the status at any point in time. Example 2

[0049] See Figure 2 As shown, taking Mr. Wang, a user in location A in China, applying for a loan from a financial institution in location B overseas as an example, requires cross-border flow of personal data between location A in China and location B overseas.

[0050] Step 1: Data Acquisition and Local Storage. Mr. Wang, a user in location A in China, downloads his personal credit report and bank transaction data files through secure interfaces provided by data providers such as the Credit Reference Center of the People's Bank of China and commercial banks. He then encrypts and stores these files on his local encrypted hard drive or private cloud storage node, generating a unique identifier (UUID) containing the storage path and encryption key index, which serves as the logical index for subsequent data retrieval.

[0051] Step Two: Third-Party Neutral Institution Witnessing and Data Fingerprint Uploading. The user authorizes the National Time Service Center and a third-party CA institution certified by the Ministry of Industry and Information Technology to witness the storage process. The third-party institution verifies the physical security of the storage node and the user's biometrics through a Trusted Execution Environment (TEE); performs SHA-3 hashing on the encrypted data file stored by the user to generate a 256-bit data fingerprint, which is then bound to the user's digital identity; the data fingerprint, user identity identifier, timestamp, and third-party digital signature are written into the permissioned blockchain to generate a notarized block, completing the data state solidification.

[0052] Step 3: Data Transfer and Usage Authorization Statement

[0053] When a user submits a loan application to a bank in location B overseas, the user transmits locally stored encrypted data files to the recipient via a TLS 1.3 encrypted channel, simultaneously triggering a smart contract. Data usage authorization rules are declared on the blockchain, including the purpose of use (limited to loan risk assessment), validity period (30 days), and geographical restrictions (access limited to servers in location B). The smart contract binds the recipient's public key (based on the RSA-3072 algorithm) and an access permission whitelist (e.g., prohibiting data forwarding to third parties). The contract code becomes effective after being verified through consensus among on-chain nodes.

[0054] Step Four: Recipient's On-Chain Fingerprint Verification and Data Authenticity Verification. After receiving the data file, the overseas bank in location B calls the blockchain interface to obtain the notarized data fingerprint and smart contract authorization terms; it calculates the SHA-3 hash value of the data file locally and verifies its consistency with the on-chain fingerprint using a zero-knowledge proof protocol to ensure that the data has not been tampered with; if the hash matches and the authorization is compliant, the data is decrypted and enters the loan review process; if any anomalies occur, such as hash value mismatch or exceeding the authorized region, processing is immediately terminated and an on-chain violation alarm event is triggered.

[0055] Step 5: End-to-end traceability and dynamic auditing.

[0056] During data usage, the system executes an on-chain tracking mechanism: all bank operations on the data generate event logs through smart contracts, recording operation timestamps, operation types, and data summaries; users can query the complete data usage records in location B through a blockchain explorer, and if unauthorized use is found, the smart contract can be triggered to automatically freeze data access permissions; regulatory agencies synchronize on-chain logs based on cross-chain protocols to conduct automated compliance audits of cross-border data activities.

[0057] This example demonstrates how blockchain-based methods for cross-border personal data transfer prevent data tampering before and after cross-border transactions through third-party witnessing and on-chain fingerprint anchoring; and how timestamp-based non-repudiation logs support multi-jurisdictional regulatory collaboration, reducing cross-border legal disputes.

[0058] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A blockchain-based method for cross-border flow of personal data, characterized by: Step 1: Data Acquisition and Local Storage: Users securely download their personal data from the data provider and store it in a designated location, generating a storage path index; Users download personal information data packages from data providers, including CSV / JSON formats. The transmission is secured through an encrypted transmission protocol, and the data is stored in locations specified by the user, including local disks, private cloud storage, or distributed storage networks. At the same time, a storage path index file is generated. Regarding encrypted transmission protocols: the transmission between users and data providers adopts the TLS1.3 protocol or quantum-resistant encryption protocol to ensure transport layer security and prevent man-in-the-middle attacks; for large-scale data packets, the IPFS protocol is used to achieve distributed transmission, and decentralized addressing is achieved through content identifiers to avoid single points of failure. After data is segmented, BLS signature aggregation technology is used to verify the integrity of transmission. In terms of enhanced storage security: local storage supports hardware security modules to perform XTS-AES full-disk encryption, key management follows the FIPS140-3 standard, and storage keys and authentication are decoupled through key layering and derivation; the distributed storage network adopts sharding encryption technology, and data is sharded and stored on different nodes, and the complete file can be reconstructed only by the user's private key. After the user downloads the data, it completes local storage through the encryption protocol and storage security module, generates a UUID index and records it to the on-chain metadata table; Step Two: Third-Party Neutral Institution Witnessing and Data Fingerprint Uploading: With user authorization, a third-party institution verifies the storage process and generates a data file hash value. After binding the fingerprint with the user's identity, it is written into the blockchain for evidence storage. With user authorization, a neutral third-party institution intervenes to verify the storage process. First, the institution verifies the user's identity and the integrity of the data packet through digital signature. Second, it uses the SHA-256 algorithm to calculate the hash value of the data file and generate a unique "data fingerprint". Finally, the fingerprint is bound to the user's identity identifier and timestamp and written into a public or consortium blockchain to form an immutable evidence record. Third-party institution qualification requirements: Institutions must pass the timestamp certification of the National Time Service Center to ensure that the storage time cannot be tampered with; they must have the TEE compliance certification of the Ministry of Industry and Information Technology to verify the physical security of the storage nodes; Hash algorithm compatibility design: Domestic data processing nodes use the national cryptographic SM3 algorithm to generate data fingerprints, meeting the requirements of China's Cybersecurity Law; overseas nodes use the SHA-3 algorithm, and cross-chain smart contracts are used to realize the mapping and verification of the hash values ​​of the two algorithms. Evidence storage chain selection strategy: Domestic data is stored on a consortium blockchain to support real-time auditing by regulatory agencies; overseas data is stored on a public blockchain to leverage its decentralized nature to ensure cross-border mutual trust. Third-party institutions verify storage nodes in the TEE environment, generate hashes, and write them to the domestic consortium blockchain and the overseas public blockchain respectively. The hash values ​​of the two chains are synchronized through a cross-chain oracle, and threshold signature technology is used to ensure the security of cross-chain operations. Step 3: Data Transmission and Usage Authorization Statement: Users transmit data to the recipient through a secure channel, simultaneously synchronizing the usage authorization statement based on the smart contract to the blockchain; Users transmit raw data files to data recipients through secure channels such as IPFS or end-to-end encryption, along with a smart contract-based authorization statement, including usage restrictions, validity period, and purpose description; the contract automatically synchronizes the authorization terms to the blockchain; Secure channel technologies include: end-to-end encryption to ensure that only the sender and receiver can decrypt the data; and for sensitive data, homomorphic encryption transmission to allow the receiver to perform calculations in encrypted form. Dynamic authorization for smart contracts: The authorization statement follows the OAuth 2.1 standard extension, including spatiotemporal constraints, differential privacy parameters, and federated learning model access permissions. The statement file is compressed and stored in CBOR encoding format. The authorization statement supports nested logic with multiple conditions. The contract code is verified by formal verification tools to ensure it is free of vulnerabilities and to prevent authorization rules from being bypassed. Smart contract deployment triggers on-chain consensus verification. Contract logic takes effect after formal verification, and authorization rules are bound to data files for transmission. Step 4: On-chain fingerprint verification and data verification for the recipient: The recipient calculates the data hash and verifies it with the on-chain fingerprint. If they match, the verification is completed. If there is an error, the process is terminated. After downloading the file, the data recipient calculates the hash value of the data file locally and retrieves the original fingerprint from the evidence record through a blockchain explorer or API interface; the two are compared for consistency. If they match, a verification certificate is generated; if they do not match, an alarm is triggered and the data usage process is terminated. Zero-knowledge proof ZKP implementation: The receiver uses the zk-SNARKs protocol to generate a proof, verifying the consistency between the local hash and the on-chain fingerprint, without exposing the original data; the on-chain pre-built verification key quickly verifies the validity of the proof through lightweight computation; Anomaly Handling Mechanism: When hash mismatch occurs, a verifiable audit report is automatically generated, triggering the on-chain reputation penalty mechanism and lowering the reputation score of the receiving node; if the anomaly exceeds the threshold continuously, the smart contract will automatically add the receiving party to the cross-border data blacklist, prohibiting subsequent interactions. The verification process uses the zk-SNARKs protocol to protect privacy, and the verification results are written to the on-chain event log. Step 5: End-to-end traceability and dynamic auditing: Data usage behavior is stored on the blockchain in real time, allowing users or regulators to trace the entire lifecycle of operations and trigger compliance controls; All data usage activities, including recipient access records and data processing operations, are recorded on the blockchain in real time through event logs and stored using a Merkle tree structure for compression. Users or regulators can query on-chain records by time range and operation type to achieve full lifecycle traceability. If violations are detected, the smart contract will automatically freeze data access permissions and notify the user. Cross-chain traceability technology: It uses Chainlink oracles to monitor events on domestic consortium blockchains and overseas public blockchains, and synchronizes logs through standardized interfaces; the log format follows the W3C verifiable credential specification and supports multi-chain compatible parsing; Dynamic compliance management: Violations trigger automatic penalties and freezes the pledged token assets of the recipient via smart contracts; regulatory agencies trace the entire chain of operations through cross-chain explorers and support one-click generation of audit reports; when advanced persistent threat characteristics are detected, a trusted execution environment sandbox is enabled to isolate suspicious operations, and the permission status of all nodes in the network is updated in real time through the certificate revocation list broadcast protocol; The cross-chain oracle synchronizes logs from domestic and overseas chains, allowing regulators to monitor data flow, operational behavior, and device fingerprint associations in real time through an audit interface. It also supports time travel queries to trace back to any point in time.

2. A blockchain-based device for cross-border circulation of personal data, wherein the device is based on the method described in claim 1, characterized in that: Data Acquisition and Local Storage Module: Users securely download personal data from data providers and store it in a designated location, generating a storage path index; Third-party neutral institution witnessing and data fingerprint on-chain module: With user authorization, a third-party institution verifies the storage process and generates a data file hash value, binds the fingerprint with the user's identity, and writes it into the blockchain for evidence storage; Data transmission and usage authorization statement module: Users transmit data to recipients through a secure channel and synchronize the usage authorization statement based on smart contracts to the blockchain; Receiver on-chain fingerprint verification and data verification module: The receiver calculates the data hash and verifies it with the on-chain stored fingerprint. If the match is found, the verification is completed. If there is an error, the process is terminated. End-to-end traceability and dynamic auditing module: Data usage behavior is stored on the blockchain in real time, allowing users or regulators to trace the entire lifecycle of operations and trigger compliance controls.

3. A non-volatile storage medium, characterized in that, The non-volatile storage medium includes a stored program, wherein the program, when running, controls the device where the non-volatile storage medium is located to execute the method of claim 1.

4. A terminal device, characterized in that, The terminal device includes: a processor, a memory, a communication interface, and a bus; the processor, the memory, and the communication interface are connected through the bus and communicate with each other; the memory stores executable program code; the processor reads the executable program code stored in the memory to run a program corresponding to the executable program code, so as to execute the method described in claim 1 above.

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