Blockchain-based electronic archive intelligent retrieval method and system

Abstract

The application discloses a kind of based on blockchain electronic archives intelligent retrieval method and system, it is related to the technical field of archives retrieval, including: extracting the text features of electronic archives, generating metadata;Electronic archives original text generates content hash value;Metadata, content hash value and ABE access policy are written into blockchain smart contract;Based on metadata semantic label construction inverted index, index item is associated with blockchain storage address;Root hash is calculated and anchored to blockchain;Resolve keyword and digital identity credentials in user search request;Call smart contract to verify whether user attributes meet the ABE access policy of target archives;Retrieve the encrypted hash list of matching archives in distributed index;From distributed storage system, obtain encrypted archives fragment;Verify data integrity;Combine fragment, generate final search result.The application has the advantages that: through the deep coupling of blockchain and attribute encryption, an electronic archives management system that takes into account security and intelligent retrieval is constructed.

Description

Technical Field

[0001] This invention relates to the field of archival retrieval technology, specifically to a blockchain-based intelligent retrieval method and system for electronic archives. Background Technology

[0002] Current electronic record management systems generally rely on centralized storage architectures and static access control mechanisms, which have systemic flaws. Centralized storage deploys the original archives and retrieval indexes on a single server cluster, leading to a high concentration of security risks. Attackers can easily gain access to massive amounts of sensitive data once they breach the system's defenses, posing a serious threat, especially to government or financial records containing classified information. Traditional access control uses role-based predefined policies; when user attributes change dynamically, administrators must manually update the policies, and the response delay often leads to unauthorized access incidents. Furthermore, data trust assurance mechanisms are weak; existing solutions rely on third-party auditing institutions to verify the integrity of archives, making it difficult to track data tampering in real time in a distributed storage environment.

[0003] Existing intelligent retrieval technologies for electronic records face bottlenecks in dynamic update efficiency and cross-domain collaboration. While semantic retrieval systems have introduced keyword expansion technology, they lack deep analysis of contextual semantics, resulting in a persistently high rate of missed detections of high-value records, such as the loss of semantic association between "stroke" and "apoplexy" in medical records. Inflexible index update mechanisms require a complete rebuild of the inverted index when access policies are adjusted or metadata is updated, causing minute-level interruptions to retrieval services for petabyte-scale archives. The encrypted retrieval field still widely employs symmetric key pre-distribution schemes, which cannot support the immediate application of complex attribute policies. Furthermore, in multi-institutional collaborative scenarios, the lack of trusted audit links between independent storage systems means that existing cross-domain authentication requires multiple public key verification operations, significantly increasing retrieval latency to the hundreds of milliseconds level, making it difficult to meet real-time access requirements. Summary of the Invention

[0004] To address the aforementioned technical problems, a blockchain-based intelligent retrieval method and system for electronic archives is provided. This technical solution resolves at least one of the technical problems mentioned in the background section.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A blockchain-based intelligent retrieval method for electronic archives includes:

[0007] Extract textual features from electronic archives to generate metadata containing subject keywords, semantic tags, and security classification identifiers;

[0008] The original electronic archive is segmented, encrypted, and stored in a distributed storage system, generating a content hash value.

[0009] Write metadata, content hash value and ABE access policy into blockchain smart contract;

[0010] Build inverted index based on metadata semantic tags, index item associated with blockchain storage address;

[0011] Organize index with Merkle tree structure, calculate root hash and anchor to blockchain;

[0012] Set index update trigger, automatically reconstruct index when smart contract captures permission changes;

[0013] Parse keywords and digital identity credentials in user search request;

[0014] Call smart contract to verify whether user attributes meet the ABE access policy of target profile;

[0015] After verification, retrieve the encrypted hash list of matching profiles in distributed index based on keywords in user search request;

[0016] User terminal obtains encrypted profile fragments from distributed storage system according to hash list;

[0017] Compare profile fragment hash with blockchain storage value to verify data integrity;

[0018] Combine fragments and decrypt using attribute private key to generate final search result.

[0019] Preferably, the ABE access policy is specifically:

[0020] Define profile access rules as Boolean logic expressions, bind user attribute certificates;

[0021] Compile access policy into on-chain executable code through smart contract;

[0022] When user attributes change, automatically trigger policy update and index reconstruction.

[0023] Preferably, the inverted index is specifically:

[0024] Use NLP model to analyze profile content, expand synonym library and standardize subject heading list;

[0025] Build hierarchical Merkle Patricia Trie index, leaf nodes store profile hash pointers;

[0026] Periodically batch write index root hash to blockchain to generate timestamp proof.

[0027] Preferably, verifying whether user attributes meet the ABE access policy of target profile specifically includes:

[0028] User submits zero-knowledge proof of attribute proof commitment;

[0029] Smart contract verifies the validity of the zero-knowledge proof and outputs the permission determination result without exposing the attribute details;

[0030] Generate a dynamic access token, and the validity period of the token is controlled by the countdown of the smart contract.

[0031] Preferably, the encrypted hash list of the matching profile retrieved in the distributed index specifically includes:

[0032] Based on the keywords in the user search request, a sharding search mechanism is used to divide the user search request into a plurality of search request shards, each search shard including at least one keyword;

[0033] Each search request shard is stored in a different blockchain shard network;

[0034] Each search request shard is routed to the target shard network for parallel execution, and the results are aggregated and returned.

[0035] Preferably, the routing of each search request shard to the target shard network for parallel execution specifically includes:

[0036] Based on the keywords corresponding to each search shard, the BERT model is used to analyze the context semantics;

[0037] An extended query vector is generated by associating the semantic tag library in the metadata;

[0038] The search results are sorted by semantic similarity, and the top K associated profiles are output as the search results for the keywords.

[0039] Preferably, the comparison of the profile shard hash and the blockchain stored value to verify data integrity specifically includes:

[0040] The terminal calculates the SHA-256 hash value of the profile shard;

[0041] The smart contract is called to compare the original hash stored on the chain;

[0042] If there is a difference, trigger the audit contract to perform consistency verification on the distributed storage nodes.

[0043] Preferably, the search method further includes an edge cache acceleration mechanism, and the edge cache acceleration mechanism specifically includes:

[0044] Monitor high-frequency access profiles and cache encrypted copies of them to edge CDN nodes;

[0045] Verify the latest state of the blockchain before activating the cache to ensure data validity;

[0046] The edge node is accessed preferentially when a user searches.

[0047] Further, a blockchain-based electronic archive intelligent retrieval system is proposed for implementing the blockchain-based electronic archive intelligent retrieval method as described above, comprising:

[0048] A metadata generation module configured to extract electronic archive text features and generate metadata containing topic keywords, semantic labels and classification labels;

[0049] A distributed storage module configured to split and encrypt the original text of the electronic archive and store it in a distributed storage system, and generate a content hash value;

[0050] A blockchain contract module configured to write the metadata, content hash value and ABE access policy into a blockchain smart contract;

[0051] An index construction module configured to construct an inverted index based on the semantic labels of the metadata, associate the index items with the blockchain storage addresses, and organize the index using a Merkle tree structure and anchor the root hash to the blockchain;

[0052] A trigger module configured to automatically trigger index reconstruction in response to a permission change event captured by the smart contract;

[0053] An identity verification module configured to parse the keywords and digital identity credentials in the user search request, and call the smart contract to verify whether the user attributes meet the ABE access policy of the target archive;

[0054] A retrieval execution module configured to retrieve the encrypted hash list of the matching archives in the distributed index based on the keywords in the user search request;

[0055] A data acquisition and verification module configured to acquire encrypted archive fragments from the distributed storage system according to the hash list, and compare the fragment hash values with the blockchain storage values to verify the data integrity;

[0056] A result generation module configured to combine the fragments and use the attribute private key to decrypt and generate the final search result.

[0057] Optionally, the system further comprises an edge cache acceleration module for implementing the edge cache acceleration mechanism as described above.

[0058] Compared with the prior art, the beneficial effects of the present application are:

[0059] The application builds an electronic archive management system considering security and intelligent retrieval by deep coupling of blockchain and attribute encryption. In the security and credibility level, the dual-track mechanism of archive fragmentation encryption storage and blockchain hash anchoring is adopted to ensure the data tamper resistance in the distributed environment. Any abnormal tampering behavior can be exposed in real time through the on-chain self-checking mechanism, which significantly improves the archive credibility level. In the dynamic level of permission control, the on-chain compilation and automatic triggering mechanism of ABE access policy are adopted to realize the instant effect of policy and the synchronous update of index when the user attributes change, which fundamentally solves the over-reach access risk caused by the lag of permission update. In the retrieval performance level, the inverted index based on semantic expansion combined with edge cache acceleration greatly reduces the retrieval delay of high-frequency access archives, and effectively copes with the concurrent pressure of massive data cross-domain access through parallel processing of the fragmentation network. In the privacy protection level, the application of zero-knowledge proof technology makes the attribute verification process without revealing the user's sensitive information, providing access control without privacy exposure risk for high-security scenarios. The system has broken through the technical contradiction in the field of electronic archive management that security control, retrieval efficiency and privacy protection are difficult to be optimized simultaneously. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 The method flow chart for intelligent retrieval of electronic archives based on blockchain is proposed for example one;

[0061] Figure 2 The method flow chart of ABE access policy is proposed for example one;

[0062] Figure 3 The method flow chart for constructing inverted index is proposed for example one;

[0063] Figure 4 The method flow chart for verifying whether the user attributes meet the ABE access policy of the target archive is proposed for example one;

[0064] Figure 5 The method flow chart for retrieving the encrypted hash list of matching archives in the distributed index is proposed for example one;

[0065] Figure 6 The method flow chart for routing each retrieval request to the target fragmentation network for parallel execution is proposed for example one;

[0066] Figure 7 The method flow chart for verifying data integrity is proposed for example one;

[0067] Figure 8 The method flow chart of edge cache acceleration mechanism is proposed for example two. DETAILED DESCRIPTION

[0068] The following description is made to disclose the present application so that those skilled in the art can implement the present application. The preferred embodiments in the following description are only as examples, and other obvious modifications can be conceived by those skilled in the art.

[0069] Embodiment one:

[0070] Referring to Figure 1 As shown in the figure, a blockchain-based electronic archive intelligent retrieval method includes:

[0071] Extracting the text features of the electronic archive to generate metadata containing topic keywords, semantic labels and classified labels;

[0072] Through the automatic extraction of multi-dimensional metadata, topic keywords + semantic labels + classified labels, a machine-understandable archive semantic graph is constructed, breaking through the limitations of traditional file name-based retrieval, significantly improving the capture accuracy of high-value information, and significantly improving the correlation retrieval effect of cross-domain professional archives;

[0073] The original text of the electronic archive is segmented and encrypted and stored in a distributed storage system to generate a content hash value;

[0074] The sharding encryption technology is used to break the single point failure risk of centralized storage, and the cryptographic hash is used to generate a unique data fingerprint, laying a foundation for subsequent distributed trust verification, eliminating the risk of whole archive leakage from the root and ensuring data traceability;

[0075] The metadata, content hash value and ABE access policy are written into a blockchain smart contract;

[0076] The immutable characteristics of the blockchain are used to solidify the access control logic, realize the on-chain trusted storage of ABE policy and metadata, solve the vulnerability of malicious tampering of policy files in traditional systems, and provide a decentralized trust anchor for cross-agency collaboration;

[0077] An inverted index is constructed based on the semantic labels of the metadata, and the index items are associated with the blockchain storage addresses;

[0078] Unstructured semantic labels are converted into machine-readable codes that can be indexed, which significantly improves the recall rate of fuzzy semantic retrieval, such as "cardiovascular disease" associated with "heart attack", and the binding of index items and blockchain addresses realizes the verifiability of retrieval results

[0079] The index is organized using a Merkle tree structure, the root hash is calculated and anchored to the blockchain;

[0080] An index self-validation system is established through the Merkle tree structure, and any tampering of index nodes will cause the root hash value to change abnormally, which makes the verification efficiency of index consistency in a distributed environment two orders of magnitude higher than traditional replica comparison;

[0081] Set index update trigger, automatically reconstruct the index when the smart contract captures the permission change;

[0082] Break the strong coupling problem of permission update and index maintenance, realize the instant synchronization of index during the dynamic adjustment of permission policy, and completely eliminate the service interruption window period caused by manual reconstruction of index;

[0083] Parse the keywords and digital identity credentials in the user search request;

[0084] Separate the processing flow of identity verification and search operation, avoid the overall service stagnation of traditional system when a single module is stuck, and provide flexible processing capability for high concurrency scenarios;

[0085] Call the smart contract to verify whether the user attributes meet the ABE access policy of the target archive;

[0086] Based on the attribute matching mechanism of on-chain verifiable computation, realize the dynamic judgment of fine-grained permission, and solve the complex attribute combination scene that traditional RBAC model cannot handle;

[0087] After verification, search for the encrypted hash list of the matching archive in the distributed index based on the keywords in the user search request;

[0088] Disperse the search load through the distributed architecture, so that the query delay of the billion-level archive library no longer increases linearly with the data volume, and solve the performance bottleneck problem of centralized index server in large-scale search;

[0089] The user terminal obtains the encrypted archive fragments from the distributed storage system according to the hash list;

[0090] Based on the point-to-point data acquisition mechanism of the hash list, avoid the archive content flowing through the third-party server, and cut off the man-in-the-middle attack path of the transmission link;

[0091] Compare the archive fragment hash with the blockchain storage value to verify data integrity;

[0092] Establish an end-to-end data integrity closed-loop verification chain, any fragment-level tampering is immediately identified, and meet the rigid requirement of the judicial evidence chain for the "unmodified" electronic archive;

[0093] Combine the fragments and decrypt using the attribute private key to generate the final search result.

[0094] Adopt the dynamic decryption mechanism of attribute private key to ensure that sensitive information only lands on authorized terminals, and break the secondary disclosure risk caused by centralized decryption of traditional system.

[0095] Referring to Figure 2 The ABE access policy in this embodiment is specifically:

[0096] Define the access rule of the archive as a Boolean logic expression, bind the user attribute certificate;

[0097] Compile the access strategy into chain-executable code through the smart contract;

[0098] When the user attribute changes, automatically trigger the strategy update and index reconstruction.

[0099] By compiling the access strategy into a chain-executable smart contract, a dynamic permission control paradigm that unifies the flexibility of the strategy and the rigidity of the execution is constructed. The access rule is defined by a Boolean logic expression, breaking through the static limit of the traditional role binding model, supporting fine-grained control of arbitrary attribute combinations, and realizing precise authorization of high-sensitive archives; Based on the strategy code solidified by the tamper-proof characteristics of the blockchain, the risk of malicious tampering of the access control list in centralized storage is completely eradicated, establishing a mandatory trusted mechanism for strategy execution; When the user attribute changes, the response loop formed by the automatic triggering of index reconstruction and strategy update makes the revocation of permissions and the termination of data access capabilities achieve instantaneous synchronization, and the super-privilege leakage hidden danger caused by the inherent time window period of the traditional manual synchronization mechanism is broken down. This design first realizes the deep unification of flexible strategy definition and real-time control of permissions in high-dynamic scenarios such as medical data sharing and cross-agency investigation.

[0100] Refer to Figure 3 In the embodiment, the inverted index is constructed as follows:

[0101] An NLP model is used to analyze the content of the archive, expand the synonym library and standardize the subject heading table;

[0102] A hierarchical Merkle Patricia Trie index is constructed, and the leaf node stores the archive hash pointer;

[0103] Periodically write the index root hash in batches to the blockchain to generate a timestamp proof.

[0104] A dual protection mechanism of retrieval accuracy and data credibility is built through a semantic-enhanced hierarchical index architecture. A NLP model is used to deeply analyze the semantic of the archive content and expand the synonym network, so that the coverage of the subject word table breaks through the limitations of traditional keyword matching. For example, "myocardial infarction" and "ST segment elevation myocardial infarction" are automatically associated, and the problem of missed detection caused by professional term variants is completely solved. The hierarchical Merkle Patricia Trie index structure forms an anti-tampering data link by binding the leaf nodes to the archive hash pointers. Any local index tampering behavior will be captured in real time due to the failure of hierarchical hash verification, which improves the sensitivity of data anomaly detection compared to traditional B+ tree index. Periodic anchoring to the index root hash of the blockchain provides verifiable timestamp proof and establishes a lightweight evidence mechanism for the full index, which improves the verification efficiency of index integrity in a distributed environment by several orders of magnitude, providing technical support for the judicial traceability of large-scale archive retrieval. This design fundamentally unifies the dual core capabilities of high-precision semantic retrieval and verifiable data credibility.

[0105] Referring to Figure 4 In the embodiment shown, verifying whether the user attributes meet the ABE access policy of the target archive specifically includes:

[0106] Zero-knowledge proof commitment of the user submitting attribute proof;

[0107] The smart contract verifies the validity of the zero-knowledge proof and outputs the permission determination result without exposing the attribute details;

[0108] A dynamic access token is generated, and the token validity period is controlled by the smart contract countdown.

[0109] Through the cooperation mechanism of zero-knowledge proof and on-chain dynamic token, an access verification paradigm that prioritizes privacy security and fine-grained control is built. The zero-knowledge commitment of the user submitting attribute proof allows the smart contract to verify the validity of the attributes without needing to obtain specific certificate numbers or agency names, completely eliminating the risk of sensitive identity information leakage in medical data cross-institution retrieval scenarios; based on the dynamic access token generated through on-chain verification, the smart contract countdown controls the precise limitation of permission time, breaking through the security defects of traditional static tokens that are long-term effective, and realizing the time-boxed safety isolation of high-sensitivity operations such as emergency archive retrieval in the operating room. This design reconstructs the attribute verification logic with cryptography, eliminating privacy exposure risks while establishing a dynamic security boundary with time dimension precise control for electronic archive access.

[0110] Referring to Figure 5 In the embodiment shown, the encrypted hash list of the matching archive in the distributed index specifically includes:

[0111] Based on the keywords in the user search request, a sharding search mechanism is used to divide the user search request into a plurality of search request shards, each search shard including at least one keyword;

[0112] Each search request shard is stored in a different blockchain shard network;

[0113] Each search request shard is routed to a target shard network for parallel execution, and the results are aggregated and returned.

[0114] Through the parallel search architecture of the blockchain shard network, a search paradigm is constructed in which the throughput and response speed simultaneously jump in a massive data environment. The user search request is decoupled into independent keyword subsets using a sharding mechanism, such as separating "electrocardiogram" and "ventricular premature beat" in medical record search as different shards, allowing each search shard to be executed in parallel in a dedicated blockchain shard network, completely eliminating the single-point performance bottleneck of traditional centralized indexing; Based on the precise routing strategy of the target shard network, the concurrent computing resources of multiple chains are fully utilized, such as the hospital internal chain processing professional term shards and the public chain processing general word shards, which significantly reduces the cross-domain search delay of PB-level archives; The verifiable merging mechanism of the search results in the aggregation layer not only guarantees the integrity of distributed execution, but also avoids the risk of network congestion caused by the transmission of full data sets in traditional schemes. This design first realizes the paradigm-level reconstruction of distributed index search in medical big data platforms, cross-border financial archives, and other scenarios with high concurrency, low latency, and verifiability.

[0115] Referring to Figure 6 In the embodiment, routing each search request shard to a target shard network for parallel execution specifically includes:

[0116] Using a BERT model to analyze the context semantics based on the keywords corresponding to each search shard;

[0117] Generating an extended query vector by associating with the semantic tag library in the metadata;

[0118] Sorting the search results by semantic similarity and outputting the top K associated archives as the search results of the keywords, K being a set search output value used to control the number of archives output by the search, and in some embodiments, the value of K is set to 5.

[0119] A high-precision intelligent retrieval paradigm in a complex professional scenario is constructed through a BERT-driven context semantic analysis and a multi-modal association mechanism. Based on the BERT model, the context semantics of a keyword (such as the automatic association of “atrioventricular conduction delay” and “bundle branch block” in the medical scenario) are deeply analyzed, and the drawbacks of the traditional keyword matching in the homogenization processing of term variants and synonymous expressions are solved. An extended query vector is generated through dynamic association with a metadata semantic tag library, so that the retrieval range breaks through the literal limitations of the original user query, and the structured capture of implicit knowledge in the professional field is realized. The mechanism of intelligent sorting of retrieval results according to semantic similarity and output of high correlation archives can improve the first-screen hit rate of target data to a practical level in the scenarios of judicial archive investigation and cross-disciplinary scientific research retrieval. This design fundamentally reconstructs the semantic understanding depth of electronic archive retrieval and provides an intelligent interpretation ability similar to expert thinking for professional knowledge discovery.

[0120] Referring to Figure 7 In the embodiment shown, the comparison of the archive shard hash and the blockchain storage value verifies the data integrity, which specifically includes:

[0121] The terminal calculates the SHA-256 hash value of the archive shard;

[0122] The smart contract is called to compare the original hash stored on the chain;

[0123] If there is a difference, the audit contract triggers consistency verification on the distributed storage nodes.

[0124] Through the closed-loop verification mechanism of on-chain and terminal cooperation, a real-time self-feedback data integrity guarantee paradigm is constructed. The terminal calculates the hash value of the archive shard and compares it with the original value fixed on the blockchain in real time, so that single-shard-level tampering behavior can be accurately located within milliseconds, and the efficiency is improved by two orders of magnitude compared with traditional full archive verification. The smart audit contract triggered automatically when a hash anomaly is detected performs rapid consistency verification on multiple copies through distributed nodes, eliminating manual intervention and forming an automated tracking capability of the tampering source. This design first realizes end-to-end real-time self-certification of data integrity in zero-tolerance scenarios such as real-time file retrieval during surgery and verification of the evidence chain in the judicial field, and upgrades passive auditing to active defense trust infrastructure.

[0125] Embodiment Two:

[0126] Referring to Figure 8 On the basis of Embodiment One, an edge cache acceleration mechanism is proposed to further improve retrieval efficiency. The edge cache acceleration mechanism specifically includes:

[0127] High-frequency access archives are monitored, and their encrypted copies are cached to edge CDN nodes;

[0128] Verify the latest state of the blockchain before cache activation to ensure data validity.

[0129] The edge node is accessed preferentially when the user searches.

[0130] The determination of high-frequency access archives is determined by the access data of archives in the previous access period, combined with the time decay mechanism, and the access coefficient of each archive in the access period is determined by calculating the proportion of the number of searched accesses of each archive in each access period.

[0131] The specific access coefficient calculation formula is:

[0132] ;

[0133] Among them, is the access coefficient of the i-th archive in the access period, is the number of accesses of the i-th archive in the access period, and U is the set of archives accessed in the access period, is the number of accesses of the j-th element in U;

[0134] The access frequency coefficient of the access archive is calculated by combining the access coefficients in all past access periods, and the calculation formula of the access frequency coefficient is:

[0135] ;

[0136] is the access frequency coefficient of the i-th access archive in the t-th period, is the access frequency coefficient of the i-th access archive in the t-1 period, and α and β are time decay coefficients, and α+β=1. If the archive system is highly time-sensitive, increase the value of α to increase the weight of the access data in the recent period.

[0137] If the access frequency coefficient of the access archive in the recent access period is higher than the threshold value, the archive is classified as a high-frequency access archive.

[0138] An edge cache architecture driven by blockchain verification is constructed to build an efficient retrieval paradigm that dynamically unifies acceleration performance and data credibility. Intelligent monitoring of high-frequency access archives and caching of encrypted copies to edge CDN nodes provide near-geographical response capabilities for cross-regional access, such as emergency medical record retrieval response speed improvement, and completely eliminate the cross-network delay bottleneck of centralized storage. Before cache activation, the latest state of the blockchain is verified to ensure that the edge data and the on-chain record are version-synchronized, and the strict on-chain and off-chain data consistency is maintained while the cache acceleration is utilized. The intelligent routing mechanism during user retrieval preferentially accesses the edge node, and in the network congestion scenario, the transmission path of core medical data is shortened to the optimal topology level. This design has broken through the historical contradiction between cache acceleration and data credibility, and has built a core technology base of "acceleration without reducing credibility" for time-sensitive scenarios such as remote consultation and emergency rescue.

[0139] Embodiment three:

[0140] The embodiment proposes an intelligent retrieval system for electronic archives based on blockchain, which is used to implement the intelligent retrieval method for electronic archives based on blockchain as proposed in embodiment one, and includes:

[0141] A metadata generation module configured to extract electronic archive text features and generate metadata containing theme keywords, semantic labels and secret level identifiers;

[0142] A distributed storage module configured to store the encrypted electronic archive text to a distributed storage system and generate a content hash value;

[0143] A blockchain contract module configured to write the metadata, content hash value and ABE access policy into a smart contract of the blockchain;

[0144] An index construction module configured to construct an inverted index based on the semantic labels of the metadata, associate the index items with the blockchain storage addresses, and organize the index using a Merkle tree structure and anchor the root hash to the blockchain;

[0145] A trigger module configured to automatically trigger index reconstruction in response to a permission change event captured by the smart contract;

[0146] An identity verification module configured to parse the keywords and digital identity credentials in the user retrieval request, and call the smart contract to verify whether the user attributes meet the ABE access policy of the target archive;

[0147] A retrieval execution module configured to retrieve the encrypted hash list of the matching archives in the distributed index based on the keywords in the user retrieval request;

[0148] A data acquisition and verification module configured to acquire the encrypted archive fragments from the distributed storage system according to the hash list, and compare the fragment hash values with the blockchain storage values to verify the data integrity;

[0149] a result generation module configured to combine the fragments and decrypt the final search result using the attribute private key.

[0150] Embodiment Four:

[0151] Further, on the basis of Embodiment Three, in order to further realize the smart search method for electronic archives based on block chain proposed in Embodiment Two, the system further comprises:

[0152] an edge cache acceleration module configured to: monitor high-frequency access archives, cache encrypted copies of the archives to edge CDN nodes; verify the latest state of the block chain before cache activation to confirm data validity; and preferentially route user search requests to edge nodes for search execution.

[0153] In summary, the advantages of the present application are that: through the deep coupling of block chain and attribute encryption, an electronic archive management system that takes into account security and smart search is constructed. In the aspect of security and trust, a dual-track mechanism of archive fragment encryption storage and block chain hash anchoring is adopted to ensure the non-tamperability of data in a distributed environment, and any abnormal tampering behavior can be exposed in real time through the on-chain self-checking mechanism, significantly improving the trust level of archives; in the aspect of dynamicity of permission control, through the on-chain compilation and automatic triggering mechanism of ABE access policy, the policy is instantly effective and the index is synchronously updated when the user attributes change, fundamentally solving the problem of unauthorized access caused by lagging permission updates; in the aspect of search performance, the inverted index based on semantic extension combined with edge cache acceleration greatly reduces the search delay of high-frequency access archives, and through parallel processing of the fragment network, the concurrent pressure of massive data cross-domain access is effectively addressed; in the aspect of privacy protection, the application of zero-knowledge proof technology makes the attribute verification process unnecessary to disclose sensitive information of users, providing access control without privacy exposure risk for high-security scenarios. This system has broken through the technical contradiction in the field of electronic archive management that security control, search efficiency and privacy protection are difficult to be optimized simultaneously.

[0154] The basic principles, main features and advantages of the present application have been shown and described. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. A blockchain-based electronic archive intelligent retrieval method, characterized in that, The retrieval method comprises the following steps: Extracting text features of electronic archives to generate metadata containing theme keywords, semantic labels and classification labels; Splitting and encrypting the original text of the electronic archives and storing them in a distributed storage system to generate content hash values; Writing the metadata, content hash values and ABE access policy into a smart contract of a blockchain; Building an inverted index based on the semantic labels of the metadata, and associating the index entries with the storage addresses of the blockchain; Organizing the index using a Merkle tree structure, calculating the root hash and anchoring it to the blockchain; Setting an index update trigger, and automatically reconstructing the index when the smart contract detects a change in access rights; Analyzing the keywords and digital identity credentials in the user's retrieval request; Calling the smart contract to verify whether the user's attributes meet the ABE access policy of the target archive; After verification, retrieving the encrypted hash list of matching archives in the distributed index based on the keywords in the user's retrieval request; The user terminal obtains encrypted archive fragments from the distributed storage system according to the hash list; Comparing the archive fragment hash with the storage value of the blockchain to verify data integrity; Combining the fragments and decrypting them using the attribute private key to generate the final retrieval result. Furthermore, the retrieval method also includes an edge cache acceleration mechanism, which specifically comprises: Monitoring high-frequency access archives and caching their encrypted copies to edge CDN nodes; Verifying the latest state of the blockchain before activating the cache to ensure data validity; Prioritize accessing edge nodes when users retrieve. 2.The blockchain-based electronic archive intelligent retrieval method according to claim 1, characterized in that, The ABE access policy specifically comprises: Defining archive access rules as Boolean logic expressions and binding them to user attribute certificates; Compiling the access policy into executable code on the chain through the smart contract; When the user's attributes change, automatically trigger policy update and index reconstruction. 3.The blockchain-based electronic archive intelligent retrieval method according to claim 1, characterized in that, The construction of the inverted index specifically comprises: Using NLP models to analyze archive content, expanding synonym libraries and standardizing theme word tables; Building a hierarchical Merkle Patricia Trie index, and storing archive hash pointers in leaf nodes; Periodically writing the index root hash to the blockchain in batches to generate a timestamp proof. 4.The blockchain-based electronic file intelligent retrieval method according to claim 1, characterized in that, The verification of whether the user's attributes meet the ABE access policy of the target archive specifically comprises: User submits zero-knowledge proof commitment of attribute proof; The smart contract verifies the validity of the zero-knowledge proof and outputs the permission determination result without exposing the attribute details; Generating a dynamic access token, and the token validity period is controlled by the smart contract countdown. 5.The blockchain-based electronic file intelligent retrieval method according to claim 1, characterized in that, The retrieval of the encrypted hash list of matching archives in the distributed index specifically comprises: Based on the keywords in the user's retrieval request, use the shard retrieval mechanism to divide the user's retrieval request into several retrieval request shards, each of which includes at least one keyword; Each retrieval request shard is stored in a different blockchain shard network; Route each retrieval request shard to the target shard network and execute it in parallel, and return the aggregated results.

6. The blockchain-based electronic archive intelligent retrieval method according to claim 5, characterized in that, The routing of each retrieval request shard to the target shard network and the parallel execution specifically comprise: Using the BERT model to analyze the context semantics based on the keywords corresponding to each retrieval shard; Generating an extended query vector by associating the semantic label library in the metadata; Sort the retrieval results by semantic similarity and output the top K associated archives as the retrieval results of the keywords. 7.The blockchain-based electronic file intelligent retrieval method according to claim 1, characterized in that, The comparison of the archive fragment hash and the blockchain storage value verifies data integrity, specifically including: The terminal calculates the SHA-256 hash value of the archive fragment; The smart contract is called to compare the original hash stored on the chain; If there is a difference, trigger the audit contract to verify the consistency of the distributed storage node.

8. A blockchain-based electronic archive intelligent retrieval system, characterized in that, The method for implementing the smart retrieval of electronic archives based on a blockchain according to any one of claims 1-7, comprising: A metadata generation module configured to extract text features of electronic archives and generate metadata containing subject keywords, semantic labels, and classification labels; A distributed storage module configured to store encrypted electronic archive texts in a distributed storage system and generate content hash values; A blockchain contract module configured to write the metadata, content hash values, and ABE access policies into a smart contract of a blockchain; An index construction module configured to construct an inverted index based on semantic labels of metadata, associate index items with blockchain storage addresses, organize the index using a Merkle tree structure, and calculate a root hash to anchor to a blockchain; A trigger module configured to automatically trigger index reconstruction in response to permission change events captured by the smart contract; An identity verification module configured to parse keywords and digital identity credentials in a user retrieval request and call a smart contract to verify whether user attributes meet ABE access policies of target archives; A retrieval execution module configured to retrieve a list of encrypted hash values of matching archives in a distributed index based on keywords in a user retrieval request; A data acquisition and verification module configured to acquire encrypted archive fragments from a distributed storage system according to the hash list and compare fragment hash values with blockchain storage values to verify data integrity; A result generation module configured to combine fragments and use attribute private keys to decrypt and generate a final retrieval result; An edge cache acceleration module for implementing the edge cache acceleration mechanism.

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