Block chain-based outsourcing hierarchical searchable attribute-based encryption method

Abstract

The invention relates to a block chain-based outsourcing hierarchical searchable attribute-based encryption method, which comprises the following steps that: a data owner encrypts an original message by using a symmetric key and constructs an access tree, blinds a secret value by using a blinding factor, and sends an intermediate ciphertext to an edge node; executing final encryption to obtain a hierarchical node ciphertext, and uploading the hierarchical node ciphertext to an interstellar file system to obtain a ciphertext address; and finally, generating an index, and uploading the index, the symmetric key hash and the ciphertext address to the block chain. The data user sends a search trap door to the block chain, and the block chain executes an intelligent contract search algorithm to return a ciphertext address to the data user; and then sending the ciphertext address to an interstellar file system, and decrypting the ciphertext by using a symmetric key to obtain an original message. According to the invention, the hierarchical access control tree structure is improved, and child nodes are allowed to have a plurality of father nodes. The node multiplexing mechanism eliminates attribute redundancy, and minimizes calculation and storage cost on the premise of ensuring safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of encryption technology, in particular to a layered outsourcing searchable attribute-based encryption method based on a blockchain. BACKGROUND

[0002] The existing cloud storage, searchable encryption and attribute-based encryption technical solutions based on the blockchain have the following main problems in practical application: 1. Lack of third-party trust and single point failure: cloud storage is highly dependent on trusted third parties, and server downtime can cause data loss or leakage; centralized architecture is prone to single point failure, and it is difficult to trace data and identify responsibility; existing layered solutions mostly rely on centralized cloud servers, and once the cloud server is attacked or fails, the privacy is at risk of being leaked.

[0003] 2. Huge computing and storage overhead: standard attribute-based encryption schemes require generating complete ciphertext components for each file's independent access policy when processing multiple file encryption, resulting in huge computing and storage overhead; decryption relies on complex bilinear pair operations, which puts a heavy computing burden on resource-constrained user terminals; existing layered attribute-based encryption schemes often ignore the attribute redundancy problem in the access structure, resulting in unnecessary storage consumption and computing bottlenecks.

[0004] 3. Search efficiency and functional defects: in existing attribute-based searchable encryption schemes, the search complexity is usually linearly related to the number of keywords or attributes, which is extremely inefficient in massive data scenarios; most schemes rely on centralized servers to perform searches, and once the server returns false results maliciously, users cannot detect them; existing outsourcing attribute-based encryption schemes mostly fail to effectively integrate ciphertext retrieval functions, and users cannot judge data relevance before downloading, resulting in bandwidth waste caused by blind downloading. SUMMARY

[0005] To solve the above problems, the purpose of the embodiments of the present application is to provide a layered outsourcing searchable attribute-based encryption method based on a blockchain.

[0006] A layered outsourcing searchable attribute-based encryption method based on a blockchain, comprising: Step 1: the data user sends a request to the trusted agency, the trusted agency generates a key according to the attribute set of the data user, and issues a public key and a private key to the data user, and issues an index key to the data owner; Step 2: the trusted agency generates a conversion key in combination with the private key of the data user, and sends it to the interstellar file system; Step 3: the data owner encrypts the original message using a symmetric key and constructs an access tree, then takes a blinding factor for each level node in the tree to blind the secret value, and sends the intermediate ciphertext to the edge node; Step 4: The edge node performs pre-encryption, calculates the pre-encryption ciphertext for each hierarchical node and sends it to the data owner; the data owner performs final encryption to obtain the hierarchical node ciphertext, and then uploads the hierarchical node ciphertext to the Interplanetary File System to obtain the ciphertext address; Step 5: The data owner extracts the keyword set from the file to perform index generation, and then uploads the index, hash of the symmetric key and the ciphertext address to the blockchain; Step 6: The data user inputs the query keyword set to perform trapdoor generation, and then uploads the trapdoor to the blockchain; Step 7: The smart contract receives the index and the trapdoor, verifies the matching equation, and outputs the ciphertext address if the matching is successful; Step 8: The data user sends the ciphertext address to the Interplanetary File System, which performs pre-decryption to obtain the pre-decryption ciphertext and sends it to the data user; Step 9: The data user performs key recovery to obtain the symmetric key, then performs hash operation on the symmetric key and sends it to the blockchain for verification. After successful verification, the symmetric key is used to decrypt the ciphertext to obtain the original message.

[0007] Preferably, in the step 1, it comprises: Step 1.1: The trusted authority TA inputs security parameters , constructs a bilinear group and , selects a generator , defines a bilinear mapping , and sets hash functions and ; Step 1.2: The trusted authority TA randomly selects , calculates , outputs public parameters and master key ; Step 1.3: The data user DU registers with the trusted authority TA and submits an attribute set ; Step 1.4: The trusted authority TA performs a key generation algorithm, randomly selects , and generates a public-private key pair and an index key .

[0008] Preferably, in the step 2, it comprises: The trusted authority TA performs a conversion key generation algorithm to generate a conversion key according to the attribute set and the unique identifier of the data user DU.Send to Interplanetary File System IPFS for outsourcing pre-decryption.

[0009] Preferably, in the step 3, comprising: Step 3.1: Data owner DO randomly selects symmetric key ;

[0010] plaintext ; Step 3.2: Data owner DO constructs access tree , for each level node in the tree, randomly selects private number and auxiliary factor and blinding factor , outputs intermediate ciphertext to edge node EN.

[0011] Preferably, in the step 4, comprising: Step 4.1: Edge node EN calculates level ciphertext component, for each node , calculates and sends to data owner DO; Step 4.2: After data owner DO receives , eliminate auxiliary factor , get level node ciphertext , then send to Interplanetary File System IPFS; Step 4.3: After Interplanetary File System IPFS receives , send ciphertext storage address to data owner DO.

[0012] Preferably, in the step 5, comprising: Step 5.1: Data owner DO selects a multi-key set W containing d keywords from plaintext, generates multi-key index ; Step 5.2: Data owner DO performs hash operation on symmetric key to get ; Step 5.3: Data owner DO sends , and ciphertext address to blockchain.

[0013] Preferably, in the step 6, comprising: Step 6.1: Data user DU selects a keyword set containing keywords , generate search trapdoor .

[0014] Step 6.2: Data user DU sends to the blockchain.

[0015] Preferably, in the step 7, it includes: Step 7.1: The smart contract receives the index and the trapdoor .

[0016] Step 7.2: The smart contract matches the index and the trapdoor , and if the matching is successful, outputs the ciphertext address .

[0017] Preferably, in the step 8, it includes: Step 8.1: After the data user DU gets the ciphertext address , it sends it to the IPFS; Step 8.2: After the IPFS receives the ciphertext address , it performs pre-decryption using the conversion key , and calculates the pre-decryption ciphertext . Step 8.3: The IPFS sends the pre-decryption ciphertext to the data user DU.

[0018] Preferably, in the step 9, it includes: Step 9.1: The data user DU decrypts the ciphertext using the private key to get the symmetric key .

[0019] Step 9.2: The data user DU performs hash operation on the symmetric key to get . Step 9.3: The data user DU sends to the blockchain.

[0020] Step 9.4: After the blockchain receives the sent by the data user DU, it automatically executes the smart contract for matching, and if , it indicates that the symmetric key is restored correctly and the outsourcing calculation process is not tampered with. Step 9.5: The data user DU decrypts to get the plaintext using the restored symmetric key .

[0021] According to the specific embodiments provided by the present application, the following technical effects are disclosed: The present application relates to a kind of outsourcing hierarchical searchable attribute-based encryption method based on block chain, compared with prior art, the present application introduces edge node to bear part of encryption load, and outsourcing complex decryption bilinear operation to interstellar file system, significantly reduce the user end load, realizes lightweight decryption;Improved hierarchical access control tree structure allows child node to have multiple parent nodes.This node reuse mechanism eliminates attribute redundancy, minimizes the cost of calculation and storage under the premise of guaranteeing security;For different files sharing the same access policy, user only needs to perform decryption operation once to obtain the key, avoid the redundant overhead caused by repeated decryption.

[0022] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0024] Figure 1 A flow chart of the outsourcing hierarchical searchable attribute-based encryption method based on block chain provided by the present application is provided. Figure 2 An access control diagram of the outsourcing hierarchical searchable attribute-based encryption method based on block chain provided by the present application is provided. Figure 3 A workflow diagram of the outsourcing hierarchical searchable attribute-based encryption method based on block chain provided by the present application is provided. Figure 4 An overall diagram of the outsourcing hierarchical searchable attribute-based encryption method based on block chain provided by the present application is provided. DETAILED DESCRIPTION

[0025] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0026] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0027] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0028] Please refer to Figures 1-4 A blockchain-based outsourcing hierarchical searchable attribute-based encryption method, comprising: Step 1: The data user sends a request to the trusted agency, and the trusted agency generates a key according to the attribute set of the data user, and issues a public key and a private key for the data user, and issues an index key for the data owner; In the step 1, it comprises: Step 1.1: The trusted authority TA inputs the security parameters , constructs a bilinear group and , selects a generator , defines a bilinear mapping , and sets a hash function and ; Step 1.2: The trusted authority TA randomly selects , calculates , outputs the public parameters and the master key ; Step 1.3: Data user DU registers with the trusted authority TA and submits a set of attributes ; Step 1.4: The trusted authority TA executes a key generation algorithm, randomly selects , generates a public-private key pair and an index key .

[0029] Step 2: The trusted authority generates a conversion key in combination with the data user's private key; The trusted authority TA executes a conversion key generation algorithm to generate a conversion key based on the data user DU's attribute set and unique identifier send to the InterPlanetary File System IPFS for outsourcing pre-decryption.

[0030] Step 3: The data owner encrypts the original message using a symmetric key and constructs an access tree, then takes a blinding factor for each level node in the tree to blind the secret value, and sends the intermediate ciphertext to the edge node; Wherein, step 3 includes: Step 3.1: The data owner DO randomly selects symmetric key encrypts the plaintext

[0031] into ; Step 3.2: The data owner DO constructs an access tree , randomly selects a secret number for each level node in the tree and auxiliary factor and blinding factor , outputs the intermediate ciphertext to the edge node EN.

[0032] Step 4: The edge node performs pre-encryption and calculates the pre-encryption ciphertext for each level node and sends it to the data owner; the data owner performs final encryption to obtain the level node ciphertext, then uploads the level node ciphertext to the InterPlanetary File System to obtain the ciphertext address; Wherein, step 4 includes: Step 4.1: The edge node EN calculates the level ciphertext component, for each node , calculates send to the data owner DO; Step 4.2: After receiving , the data owner DO eliminates the auxiliary factor to obtain the level node ciphertext , then Send to Interplanetary File System (IPFS); Step 4.3: Interplanetary File System (IPFS) receives After that, the ciphertext storage address is sent to the data owner (DO).

[0033] Step 5: The data owner extracts the keyword set from the file to perform index generation, and then uploads the index, hash of the symmetric key, and ciphertext address to the blockchain; Step 5 includes: Step 5.1: The data owner (DO) selects a multi-keyword set W containing d keywords from the plaintext, and generates a multi-keyword index . Step 5.2: The data owner (DO) performs a hash operation on the symmetric key to obtain . Step 5.3: The data owner (DO) sends to the blockchain along with and the ciphertext address .

[0034] Step 6: The data user inputs a query keyword set to perform trapdoor generation, and then uploads the trapdoor to the blockchain; In step 6, it includes: Step 6.1: The data user (DU) selects a keyword set containing keywords, and generates a search trapdoor .

[0035] Step 6.2: The data user (DU) sends to the blockchain.

[0036] Step 7: After the smart contract receives the index and trapdoor, it verifies the matching equation. If the matching is successful, it outputs the ciphertext address; In step 7, it includes: Step 7.1: The smart contract receives the index and the trapdoor .

[0037] Step 7.2: The smart contract matches the index and the trapdoor . If the matching is successful, it outputs the ciphertext address .

[0038] Step 8: The data user sends the ciphertext address to the Interplanetary File System, which performs pre-decryption to obtain the pre-decrypted ciphertext and sends it to the data user; Step 8 includes: Step 8.1: Data user DU gets ciphertext address Then, it is sent to IPFS; Step 8.2: IPFS receives ciphertext address Then, it uses conversion key To perform pre-decryption and calculate pre-decryption ciphertext ; Step 8.3: IPFS sends pre-decryption ciphertext To data user DU.

[0039] Step 9: Data user performs key recovery to get symmetric key, then performs hash operation on the symmetric key and sends it to the blockchain for verification, and after successful verification, uses the symmetric key to decrypt the ciphertext to get the original message.

[0040] Wherein, step 9 comprises: Step 9.1: Data user DU uses private key to decrypt ciphertext To get symmetric key .

[0041] Step 9.2: Data user DU performs hash operation on symmetric key To get ; Step 9.3: Data user DU sends To the blockchain.

[0042] Step 9.4: After the blockchain receives the data user DU sent , it automatically executes the smart contract for matching, if , it indicates that the symmetric key recovery is correct and the outsourcing calculation process is not tampered with; Step 9.5: Data user DU uses the recovered symmetric key To decrypt to get plaintext .

[0043] The principles of the present application are further illustrated in conjunction with specific embodiments as follows: The present application provides a blockchain-based outsourcing hierarchical searchable attribute-based encryption method, comprising steps 1-11, and the specific steps are as follows: Step 1: System initialization .

[0044] TA inputs security parameters , constructs a bilinear group: defines multiplication cyclic groups and on a finite field of prime order , and randomly selects a generator and define a bilinear map . Define a hash function . Randomly select and compute . Randomly select as the file hierarchy identifier, and finally output the public parameters and the master key : .

[0045] Step 2: Key generation .

[0046] TA randomly selects , generates the private key and public key of the DU: , generates the index key of the DO .

[0047] Step 3: Conversion key generation .

[0048] TA randomly selects , where , uid is the unique identifier of the user. For the attribute set , select for each attribute; calculate the conversion key component: For each attribute , calculate: Step 4: Encryption: This process contains the following four sub-stages.

[0049] (1) Data symmetric encryption .

[0050] DO randomly selects symmetric keys to encrypt the plaintext into .

[0051] (2) Key encryption .

[0052] DO constructs an access tree , randomly selects a secret number for each level node in the tree , and auxiliary factors and blinding factors . Calculate: ​ Output intermediate ciphertext and send to the edge node EN.

[0053] (3) Pre-encryption .

[0054] EN computes the hierarchical ciphertext component. For each node , compute: Send to the DO.

[0055] (4) Final encryption .

[0056] After the DO receives , remove the auxiliary factor to generate the final ciphertext component:

[0057] For each symmetric key , compute the ciphertext , using the Shamir threshold sharing scheme, select polynomials , and let

[0058] For attribute , compute: .

[0059]

[0060] Send to the Interplanetary File System.

[0061] Step 5: Keyword ciphertext generation .

[0062] The DO selects a set of d keywords W from the plaintext, and for each , randomly selects , compute the index component: Generate multi-keyword index ciphertext .

[0063] The DO hashes the symmetric key to get , and sends

[0064] Step 6: Trapdoor generation .

[0065] The DU selects a set of A keyword set of keywords For , randomly select , use the private key to calculate: Generate search trapdoor . The DU sends it to the blockchain.

[0066] Step 7: Trapdoor matching .

[0067] Smart contract input , verify if the following equation holds: If the equation holds, the smart contract returns the ciphertext address to the DU; otherwise, output .

[0068] Step 8: Pre-decryption .

[0069] After the trapdoor matches, IPFS uses the conversion key to perform pre-decryption.

[0070] For leaf nodes (if the user attribute matches ), calculate:

[0071] For non-leaf nodes , use the Lagrange interpolation coefficient to recursively calculate:

[0072]

[0073] Finally, calculate the pre-decryption ciphertext : Step 9: Key recovery .

[0074]

[0075] The DU performs a hash operation on the symmetric key to obtain and sends it to the blockchain.

[0076] Step 10: Verification .

[0077] Blockchain smart contract input DO original key hash value generated in encryption phase Decrypted and recovered by data user . Smart contract compares whether the two are consistent: if , output 1, indicating that the symmetric key recovery is correct and the outsourcing calculation process is not tampered with; otherwise output .

[0078] Step 11: Data symmetric decryption .

[0079] DU uses the recovered symmetric key Decryption Get plaintext .

[0080] Compared with the prior art, the present application has the following beneficial effects: 1. Decentralized and trusted architecture: a collaborative architecture of on-chain index and off-chain storage is constructed. The ciphertext subject is stored by using the Interstellar File System, and the index and trapdoor are stored by the blockchain, effectively balancing the data credibility and storage overhead; the search and verification process is completely automatically executed by the smart contract, eliminating the dependence on trusted third parties and establishing a decentralized and transparent retrieval environment.

[0081] 2. Efficient calculation and storage optimization: edge nodes are introduced to bear part of the encryption load, and complex decryption bilinear operations are outsourced to the Interstellar File System, significantly reducing the user end load and realizing lightweight decryption; the hierarchical access control tree structure is improved to allow child nodes to have multiple parent nodes. This node reuse mechanism eliminates attribute redundancy and minimizes calculation and storage costs while ensuring security; for different files sharing the same access strategy, the user only needs to perform one decryption operation to obtain the key, avoiding the redundant overhead caused by repeated decryption.

[0082] 3. High-performance verifiable search: a search algorithm based on aggregation hash operation is proposed, which can process multiple query keywords as a whole. No matter how many keywords, the calculation overhead of search and index generation is maintained at a constant level, greatly improving the retrieval performance; the smart contract is introduced to verify the key hash value after encryption and decryption, effectively preventing calculation errors caused by lazy or malicious tampering of outsourcing nodes, and ensuring the correctness of the calculation result.

[0083] The application further provides an electronic device, comprising a bus, a transceiver, a memory, a processor and a computer program stored in the memory and executable on the processor, the transceiver, the memory and the processor being connected through the bus, characterized in that the computer program, when executed by the processor, implements the steps of the above-mentioned outsourcing hierarchical searchable attribute-based encryption method based on a block chain.

[0084] The application further provides a computer readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the steps of the above-mentioned outsourcing hierarchical searchable attribute-based encryption method based on a block chain.

[0085] The above is only a specific implementation of the application, but the protection scope of the application is not limited thereto, any person skilled in the art can easily think of changes or alternative technical solutions within the technical range disclosed by the application, which should be covered within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A blockchain-based outsourcing layered searchable attribute-based encryption method, characterized in that, include: Step 1: The data user sends a request to the trusted institution, which generates a key based on the data user's attribute set, and issues a public key and a private key to the data user, and an index key to the data owner; Step 2: The trusted authority generates a conversion key by combining the data user's private key and sends it to the InterPlanetary File System; Step 3: The data owner uses a symmetric key to encrypt the original message and build an access tree. Then, a blinding factor is taken for each level node in the tree to blind the secret value, and the intermediate ciphertext is sent to the edge node. Step 4: Edge nodes perform pre-encryption, calculating pre-encrypted ciphertext for each level of node and sending it to the data owner; The data owner performs final encryption to obtain the hierarchical node ciphertext, and then uploads the hierarchical node ciphertext to the InterPlanetary File System to obtain the ciphertext address; Step 5: The data owner extracts the keyword set from the file, performs index generation, and then uploads the index, the hash of the symmetric key, and the ciphertext address to the blockchain; Step 6: Data users input the set of keywords to be queried to generate a trapdoor, and then upload the trapdoor to the blockchain; Step 7: After receiving the index and trapdoor, the smart contract verifies the matching equation. If the match is successful, the encrypted address is output. Step 8: The data user sends the encrypted address to the InterPlanetary File System (IPS). IPS performs pre-decryption, obtains the pre-decrypted encrypted text, and sends it to the data user. Step 9: The data user performs key recovery to obtain the symmetric key, then performs a hash operation on the symmetric key and sends it to the blockchain for verification. After successful verification, the symmetric key is used to decrypt the ciphertext to obtain the original message.

2. The blockchain-based outsourcing layered searchable attribute-based encryption method according to claim 1, characterized in that, Step 1 includes: Step 1.1: Trusted Authority (TA) inputs security parameters Construct a bilinear group and Select generator Define a bilinear mapping and set the hash function. and ; Step 1.2: A trusted and authoritative organization (TA) is randomly selected. ,calculate Output common parameters With master key ; Step 1.3: Data user DU registers with trusted authority TA and submits attribute sets. ; Step 1.4: The trusted authority (TA) executes the key generation algorithm and randomly selects... Generate public-private key pairs and index key .

3. The blockchain-based outsourcing layered searchable attribute-based encryption method according to claim 2, characterized in that, Step 2 includes: Trusted authority (TA) executes the key generation algorithm based on the attribute set of data user (DU). and unique identifier Generate conversion key Send to the InterPlanetary File System (IPFS) for outsourced pre-decryption.

4. The blockchain-based outsourcing layered searchable attribute-based encryption method according to claim 3, characterized in that, Step 3 includes: Step 3.1: The data owner (DO) is randomly selected. symmetric key plaintext Encryption ; Step 3.2: Data owner (DO) constructs the access tree. , for each level node in the tree Randomly select secret number and cofactors and blinding factor Output intermediate ciphertext Give the edge node EN.

5. A blockchain-based outsourcing layered searchable attribute-based encryption method according to claim 4, characterized in that, Step 4 includes: Step 4.1: Edge node EN calculation of hierarchical ciphertext components, for each node ,calculate Send to the data owner, DO; Step 4.2: Data owner DO receives Afterwards, eliminate the auxiliary factors. Obtain the ciphertext of the hierarchical nodes. Then Send to the InterPlanetary File System (IPFS); Step 4.3: The InterPlanetary File System (IPFS) receives... Then, store the encrypted address. Send to the data owner, DO.

6. The blockchain-based outsourcing layered searchable attribute-based encryption method according to claim 5, characterized in that, Step 5 includes: Step 5.1: The data owner DO selects a multi-keyword set W containing d keywords from the plaintext and generates a multi-keyword index. ; Step 5.2: The data owner DO will transfer the symmetric key. Perform a hash operation to obtain ; Step 5.3: The data owner (DO) will... and and encrypted address Send to the blockchain.

7. A blockchain-based outsourcing layered searchable attribute-based encryption method according to claim 6, characterized in that, Step 6 includes: Step 6.1: Data User DU Selection Includes A collection of keywords. Generate search trapdoor ; Step 6.2: Data user DU will Send to the blockchain.

8. The blockchain-based outsourcing layered searchable attribute-based encryption method according to claim 7, characterized in that, Step 7 includes: Step 7.1: Smart Contract Receives Index and trapdoor ; Step 7.2: Smart Contract Index and trapdoor Perform a match; if a match is successful, output the ciphertext address. .

9. A blockchain-based outsourcing layered searchable attribute-based encryption method according to claim 8, characterized in that, Step 8 includes: Step 8.1: Data user DU obtains the encrypted address. Then, it is sent to the InterPlanetary File System (IPFS); Step 8.2: The InterPlanetary File System (IPFS) receives the encrypted address. Then, using the conversion key Execute the pre-decryption algorithm to calculate the pre-decrypted ciphertext. ; Step 8.3: The InterPlanetary File System (IPFS) will pre-decrypt the ciphertext. Send to data user DU.

10. A blockchain-based outsourcing layered searchable attribute-based encryption method according to claim 9, characterized in that, Step 9 includes: Step 9.1: Data user DU uses their private key to decrypt the ciphertext. To obtain the symmetric key ; Step 9.2: Data user DU will transfer the symmetric key. Perform a hash operation to obtain ; Step 9.3: Data user DU will Send to the blockchain; Step 9.4: The blockchain receives the message sent by data user DU. Then, the smart contract is automatically executed for matching; if... This indicates that the symmetric key was recovered correctly and the outsourced computation process was not tampered with; Step 9.5: Data user DU uses the recovered symmetric key Decryption yields plaintext .

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