Multi-department digital identity verification-oriented block chain solving method

Abstract

The invention provides a multi-department digital identity verification-oriented block chain solving method, which comprises the following steps that: a key generation and distribution center initializes a global system, and distributes system public parameters and public and private key pairs to each participant; the user initiates a digital identity authorization application to an authentication department; encrypting the digital identity certificate, calculating a signature and an on-chain index, and completing on-chain and off-chain storage of the digital identity certificate of the user; the user digital identity certificate authorization operation record is uploaded to the log chain for synchronous recording; when a user needs to carry out certain identity verification, generating a query trap door to execute on-chain data retrieval, obtaining digital certificate authority on-chain information of a corresponding department, and decrypting to obtain a digital identity certificate; the identity verification service provider performs signature verification operation on the digital identity certificate; the user digital identity certificate verification request record is uploaded to the log chain for synchronous recording; and an auditing unit performs authorization of an authoritative authentication department and user identity verification operation traceability auditing on records on the log chain.

Description

Technical Field

[0001] The present invention belongs to the technical field of network security and relates to a blockchain solution for multi-department digital identity authentication. Background Art

[0002] With the development of digitization and networking, digital identity authentication plays an increasingly critical role in sensitive resource management and various online services. Government agencies and authoritative departments are gradually transitioning the traditional paper-based process of identity authentication to digitalization, which is widely used in digital government services, social security management, public security systems, medical and health record management, and entry and exit management. While digital certificates bring many conveniences to the identity authentication process, they also face a series of new challenges. The traditional centralized identity authentication architecture relies heavily on a single trust institution, and the system has problems such as single point failure, tampering risk, data leakage, and high trust cost. In addition, due to the decentralized nature of authority management, the current identity authentication system usually relies on independent authentication processes of various departments, resulting in repeated authentication, user privacy exposure, and complex cross-departmental verification processes. With the increasing issuance and management of various digital certificates, how to effectively integrate and verify these digital identity certificates has become a major problem. Due to the lack of a unified data sharing platform, a "data island" effect is formed between departments, which not only increases management complexity, but also raises challenges in trust and security. How to achieve efficient and secure identity authentication and ensure data integrity, authenticity, and privacy in the context of multiple digital identity certificates has become a key issue that needs to be solved in digital identity management. Summary of the invention

[0003] To solve the above problems, the purpose of the present invention is to provide a blockchain solution for multi-department digital identity authentication. By designing a complete multi-department digital identity certificate blockchain storage and verification architecture, efficient, reliable and secure management of multi-domain digital identity certificates is achieved; an aggregated signature verification mechanism is designed to support the legal and efficient verification of multi-user digital certificates in cross-department and cross-authority scenarios; a log chain is introduced to ensure the synchronization of digital certificate authorization and verification records, and an aggregated Byzantine optimization consensus mechanism is designed to improve the efficiency of the log chain consensus, solve the bottleneck of dual-chain structure synchronization performance, and promote efficient audit tracing.

[0004] The present invention provides a blockchain solution for multi-department digital identity authentication, comprising the following steps:

[0005] Step 1: The key generation and distribution center initializes the global system and distributes system public parameters and public and private key pairs to all participants;

[0006] Step 2: The user initiates a digital identity authorization application to the authentication department;

[0007] Step 3: Encrypt the digital identity certificate, calculate the signature and on-chain index, and complete the on-chain and off-chain storage of the user's digital identity certificate;

[0008] Step 4: The user's digital identity certificate authorization operation record is uploaded to the log chain for synchronization recording;

[0009] Step 5: When a user needs to perform a certain identity authentication to access a specific service, a query trap is generated to perform on-chain data retrieval, obtain the digital certificate authority on-chain information of the corresponding department and decrypt it to obtain the digital identity certificate;

[0010] Step 6: The identity verification service provider performs signature verification on the digital identity certificate;

[0011] Step 7: The user digital identity certificate verification request record is uploaded to the log chain for synchronization recording;

[0012] Step 8: The audit unit conducts a traceability audit of the authorization by the authoritative certification department and the user identity authentication operations recorded on the log chain.

[0013] The blockchain solution for multi-department digital identity authentication of the present invention has at least the following beneficial effects:

[0014] 1) The existing digital certificate storage method has high collaboration complexity in complex scenarios of multi-department collaboration, which easily forms information barriers and data islands. This invention provides a complete on-chain encrypted index verification design, uses aggregate signatures to improve the efficiency of multi-certificate verification, and realizes the unified integration of digital identity certificates of various institutions and departments under the premise of ensuring data integrity, privacy and legitimacy.

[0015] 2) There are still deficiencies in the efficient recording and auditing of digital certificate storage and verification in the existing blockchain context. The present invention introduces a log chain structure to synchronously record the authorization and verification process, thereby reducing the pressure on the main chain and improving the auditing efficiency. At the same time, in view of the potential synchronization lag problem of the dual-chain structure, an Aggregated Optimized Byzantine Consensus (AOB-Consensus) is designed to optimize the efficiency of the log chain consensus. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a system architecture diagram of a blockchain solution for multi-department digital identity authentication of the present invention;

[0017] Figure 2 It is a flow chart of a blockchain solution for multi-sector digital identity authentication of the present invention;

[0018] Figure 3aIt is a comparison chart of the time cost of calculation in the trapdoor generation stage using the method of the present invention and the existing method;

[0019] Figure 3b It is a comparison chart of the time cost of computing in the search and matching stage using the method of the present invention and the existing method;

[0020] Figure 3c It is a comparison chart of the total computation time cost in the trapdoor generation phase and the search and matching phase using the method of the present invention and the existing method;

[0021] Figure 4 It is a comparison chart of the computation time overhead of aggregate authentication and single-user authentication in the implementation of the present invention;

[0022] Figure 5 This is the overall flow chart of the aggregated Byzantine optimization consensus mechanism designed by the present invention. DETAILED DESCRIPTION

[0023] The principles and features of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific examples cited here are only used to explain the present invention and are not used to limit the scope of the present invention.

[0024] Blockchain is a decentralized distributed ledger technology. All participants do not need to rely on a central agency for data storage and verification, but instead use a consensus algorithm to achieve distributed recording and verification of data. Once the data contained in each block is recorded, it cannot be tampered with. All participants hold the same copy of the data, ensuring the integrity and immutability of the data. The introduction of blockchain effectively addresses the problems of single point failure, tampering risk, data leakage, etc. in centralized systems, reduces the cost of trust, and provides effective solutions in areas such as privacy data protection and data sharing. However, the application of existing blockchain mechanisms in digital identity storage and verification scenarios for multi-department collaboration is not yet mature, and the efficiency requirements for encrypted retrieval and verification of on-chain data have not yet been fully met. At the same time, the efficient recording and auditing issues in the storage and verification process of digital certificates under the blockchain background are still insufficient and need to be optimized urgently.

[0025] The present invention provides a blockchain solution for multi-department digital identity authentication. The overall system architecture is as follows: Figure 1 As shown, it is mainly composed of users, identity certificate chains, authentication departments, identity authentication service providers and other units. The detailed functions of each part are introduced as follows. The relevant symbols of the present invention are shown in Table 1.

[0026] 1) Users: The main participants of the system, who have public and private key pairs issued by KGC and identity authority certificates issued by the certification department.

[0027] 2) Key Generation Center (KGC): responsible for generating and managing users' public and private key pairs for initial key distribution.

[0028] 3) InterPlanetary File System (IPFS): used to store encrypted identity authority certificates, ensure high data availability and distributed storage security, and bind with the signature on the identity certificate chain to ensure complete and trusted storage of data.

[0029] 4) Authorization Departments (AD): including various government agencies and authoritative departments, responsible for issuing and managing user identity authority digital certificates.

[0030] 5) Identity Verification Service Providers (IVSP): Service providers that need to verify user identities, such as customs, banks, e-government platforms, online service providers, etc.

[0031] 6) Identity Certificate Chain (ICC): used to store key information of digital identity authority certificates and authorization certificates to ensure data integrity and security during the identity authentication process.

[0032] 7) Log Chain (LC): Synchronously record authorization and authentication operations to ensure the traceability and transparency of all processes, provide reliable historical records for audits, and ensure the overall security of the system. By storing these records independently on the log chain, the main chain only needs to process core information, reducing the storage burden. The log chain is synchronized with the main chain to achieve efficient recording and operation verification.

[0033] 8) Audit Unit (AU): Responsible for tracing and reviewing all authorization and authentication operations recorded on the log chain and evaluating the compliance of main chain operations.

[0034] Table 1 Symbols and meanings

[0035]

[0036] like Figure 2 As shown, a blockchain solution for multi-department digital identity authentication of the present invention includes the following steps:

[0037] Step 1: The key generation and distribution center initializes the global system and distributes system public parameters and public-private key pairs to all participants.

[0038] The key generation and distribution mechanism adopted by the present invention is based on the mathematical basis of bilinear mapping to ensure the security and efficiency of the system. Furthermore, the step 1 specifically includes the following steps:

[0039] Step 1.1: Given a security parameter λ, choose a large prime number p and select the prime field F from the prime field p = {0,1,2,…,p-1} Select two cyclic groups G1 and G2 on the elliptic curve, both of which have order p, where the generator of G1 is g; on this basis, define the bilinear map e(P,R) = Q where P,R∈G1,Q∈G2, select a finite field The key generation and distribution center randomly selects the system private key And calculate the corresponding system public key To ensure collision resistance, five hash functions are defined as follows:

[0040]

[0041] H3(Q)=HashFunction(Bytes(Q)) Q∈G2

[0042]

[0043] Among them, Bytes(P) is the byte representation of P, that is, the value of P is converted into hexadecimal representation, and then every two hexadecimal characters are combined into 1 byte, || means concatenating the bit string b with Bytes(P), HashFunction(z) is a hash algorithm used to map the variable z to a fixed-length summary. HashFunction() can use SHA256 or SHA512. As the mapping function, the hash operation result of HashFunction() is modulo p-1 plus 1 to ensure that the hash value is converted to Elements of a group; is the mapping function. The hash operation result of HashFunction() is modulo p-1 and then added 1 to calculate the x-axis coordinate on the elliptic curve group G1. The equation on the elliptic curve is solved according to the x-coordinate to obtain the y-coordinate, and finally a legal point (x, y)∈G1 on the elliptic curve is obtained as the mapping result.

[0044] The final system public parameters are SP = {p, g, e, S pk ,H1,H2,H3,H4,H5}, the system public parameters are released to all participants in the system through secure channels.

[0045] Step 1.2: For any user i, the key generation and distribution center randomly selects the identity coefficient And based on the user's unique ID i ∈{0,1} * Calculate the relevant part of the public and private key pair of user i Calculate partial public key of user i Part of the private key of user i The user independently selects Part of the private key Calculate partial public key of user i Jointly generate the public key of user i and the private key of user i Other nodes in the system, including the certification department, audit unit and log chain consensus node, all use the above method to generate public and private key pairs.

[0046] Step 2: The user initiates a digital identity authorization application to the certification department.

[0047] When a user applies for a service and needs to authenticate their identity, they must first complete the cross-departmental identity certificate authorization process to ensure that the storage and verification of identity information are legal and secure. i Submit an identity verification application to the system, and after verification and approval by the certification department, issue the corresponding digital identity certificate AuthCert i .

[0048] Step 3: Encrypt the digital identity certificate, calculate the signature and on-chain index to complete the on-chain and off-chain storage of the user's digital identity certificate.

[0049] In order to ensure the security, privacy and non-forgeability of multi-department digital identity certificate storage verification, while reducing the on-chain storage burden and improving the on-chain storage flexibility, the present invention designs an encryption and signature mechanism to store the encrypted digital certificate in the off-chain interplanetary file system, and upload the off-chain storage index, digital certificate signature, digital certificate summary and digital certificate authorization department information to the identity certificate chain. Furthermore, the step 3 specifically includes the following steps:

[0050] Step 3.1: For the issued digital identity certificate AuthCert i , the system encrypts the authorization information by randomly selecting the ciphertext coefficient Compute encryption components and The specific calculation method is as follows:

[0051]

[0052] The final encryption result is expressed as

[0053] Step 3.2: For the issued digital identity certificate AuthCert i , the certification authority signs the certificate. The signing process first randomly selects the digest coefficient According to the permission applicant's identity ID i Calculate the message digest of the digital identity certificate The specific calculation method is as follows:

[0054]

[0055] Then use the certification department private key and the certification authority public key Calculate the signature component and The specific calculation method is as follows:

[0056]

[0057] By introducing the message digest, all parts of the signature are ensured to be associated with the corresponding user identity. The final signature form is

[0058] Step 3.3: On AuthCert i After encryption, the encryption result C i Will be stored in the distributed interstellar file system, with off-chain storage index and digital certificate signatureσ i , the digital certificate summary and the digital certificate authority information are uploaded to the identity certificate chain, where the chain storage index is constructed as follows:

[0059]

[0060] This stage is described in Algorithm 1, where the ExtractCertType() function extracts AuthCert i Department to which the certificate belongs.

[0061]

[0062] Step 4: The user digital identity certificate authorization operation record is uploaded to the log chain for synchronization recording.

[0063] In order to further improve the audit efficiency of the system and reduce the performance burden of high-frequency operations in the main chain, this invention introduces an independent log chain structure. When a user applies for an identity certificate from the certification department, all related operations will be uploaded to the log chain synchronously through the smart contract, forming a detailed historical record chain, providing an efficient and reliable solution for subsequent audit queries and data tracing.

[0064] The specific step 4 is as follows: the digital identity certificate authorization log record is encrypted by the symmetric encryption algorithm AESEncrypt(), and the log encryption result is represented as encryptedLog. The on-chain index is represented by {ID i , CertType, actionType} triples are composed, and the log information summary Loghash is stored on the chain to verify the integrity of the log data; i represents the unique identifier of user i, CertType represents the department to which the digital identity certificate belongs, and actionType represents the type of identity certificate chain operation. The log chain synchronization record description is shown in Algorithm 2.

[0065]

[0066] Step 5: When a user needs to perform an identity authentication to access a specific service, a query trap is generated to perform on-chain data retrieval, obtain the digital certificate authority on-chain information of the corresponding department, and decrypt it to obtain the digital identity certificate.

[0067] When user i needs to perform a certain identity authentication to access a specific service, such as applying for a cross-border entry and exit permit, handling online government services, or applying for access rights to medical records, the system will perform on-chain data retrieval based on the search trap submitted by the user. Further, step 5 specifically includes the following steps:

[0068] Step 5.1: User randomly selects trapdoor generation coefficient Calculate and provide query trapdoor i =(τ1,τ2) and the department to which the digital certificate belongs, CertType, the query trap calculation method is as follows:

[0069]

[0070] Step 5.2: The identity certificate chain performs on-chain matching query based on CertType and query trapdoor. First, the on-chain storage index is calculated through the query trapdoor to obtain the on-chain information of all department digital certificate permissions associated with the user identity. The on-chain storage index calculation method is as follows:

[0071]

[0072] Then, the CertType attribute is used to further filter and extract the digital certificate authority chain information of the corresponding department from the digital certificate authority chain information of all departments, so as to realize the accurate filtering and positioning of the target data under the digital certificate storage of multiple departments.

[0073] In order to prove the effectiveness of the solution of the present invention, a proof of derivation of on-chain data retrieval is given as follows:

[0074]

[0075] Step 5.3: The user obtains the encrypted result C stored in the Interstellar File System based on the off-chain storage index in the on-chain information of the digital certificate authority of the corresponding department. i , use the user private key sku i Execute the decryption process, the calculation method is as follows:

[0076]

[0077] In order to prove the effectiveness of the scheme of the present invention, the decryption proof of the ciphertext of the user digital certificate is given here, as follows:

[0078]

[0079]

[0080] FIG3 shows a comparison of the computational time overhead of the blockchain solution for multi-department digital identity authentication of the present invention with other methods in the trapdoor generation phase and the search and matching phase as the number of identity certificate query items increases. Figure 3a It is a comparison chart of the time cost of calculation in the trapdoor generation stage using the method of the present invention and the existing method; Figure 3b It is a comparison chart of the time cost of computing in the search and matching stage using the method of the present invention and the existing method; Figure 3c This is a comparison chart of the total computational time cost of the method of the present invention and the existing method in the trapdoor generation stage and the search and matching stage. As can be seen from the figure, the computational time cost of the scheme of the present invention in the trapdoor generation stage is higher than that of scheme 1 but lower than that of scheme 2; while in the on-chain search and matching stage, the computational efficiency of the scheme of the present invention is higher, and both are better than the comparative schemes. Considering the total time cost of the trapdoor generation and on-chain search stages, the efficiency of the scheme of the present invention is equal to that of scheme 1 and better than that of scheme 2.

[0081] Step 6: The identity verification service provider performs a signature verification operation on the digital identity certificate.

[0082] In order to prevent the forgery of digital identity authority certificates and ensure the legitimacy and authority of the certificates, the system needs to verify the retrieved on-chain storage signatures. For complex digital identity authentication scenarios involving multiple users across departments and authorities, the present invention designs an aggregated verification scheme to meet the verification needs in multi-department collaboration scenarios. Furthermore, step 6 specifically includes the following steps:

[0083] Step 6.1: In single certificate verification, for the on-chain stored signature obtained by the index, the verifier needs to recalculate the digital certificate message digest, and then verify the consistency of both sides of the following equation based on the corresponding public key of the CertType department:

[0084]

[0085] Step 6.2: In multi-certificate verification, first aggregate the multi-certificate signatures. The aggregate signature component is generated as follows, where n represents the number of digital identity certificates to be verified:

[0086]

[0087]

[0088] Step 6.3: Validator receives aggregate signature Then, use the public keys of the certification authorities corresponding to the n digital identity certificates to verify the consistency of both sides of the following equation:

[0089]

[0090] To prove the effectiveness of the solution of the present invention, a digital certificate signature verification derivation proof is given here, as shown in the following formula. For the aggregate signature verification in a multi-user verification scenario, the derivation principle is similar to the following formula, which will not be repeated here:

[0091]

[0092] Figure 4 The blockchain solution for multi-department digital identity authentication of the present invention is demonstrated. As the number of verification items increases during the digital certificate verification phase, the computational overhead comparison between aggregate verification and single-user verification is shown. It can be seen from the figure that the aggregate verification used in the present invention can effectively improve the verification efficiency in multi-user scenarios.

[0093] The overall description of the digital certificate retrieval and verification operation in step 5 and step 6 is shown in Algorithm 3:

[0094]

[0095]

[0096] Step 7: The user digital identity certificate verification request record is uploaded to the log chain for synchronization recording.

[0097] When the user submits the certificate to the identity verification service provider for identity verification, the relevant operations will be uploaded to the log chain synchronously through the smart contract. Further, the step 7 is specifically as follows:

[0098] Log data is stored off-chain using the symmetric encryption algorithm AESEncrypt() for encryption. The on-chain index is represented by {ID i , CertType, actionType} triples, where ID iIt represents the unique identity identifier of user i, CertType represents the department to which the digital certificate belongs, and actionType represents the type of identity certificate chain operation.

[0099] Step 8: The audit unit conducts a traceability audit of the authorization by the authoritative certification department and the user identity authentication operations recorded on the log chain.

[0100] During the audit process, when the audit unit needs to conduct a compliance review of the authorization behavior of the certification authority, or view the user's identity authentication operation, it will perform precise traceability audit operations through the log chain, as follows:

[0101] Step 8.1: The audit unit shall i , CertType, actionType} as the index and initiate a tracing request to the log chain.

[0102] Step 8.2: The request is audited and authenticated through the smart contract on the chain to ensure the legitimacy and authority control of the audit request. After authentication, the system returns the traceability result {encryptedLog, Loghash}.

[0103] Step 8.3: The audit unit uses the encrypted log result encryptedLog to decrypt the log data D stored off-chain Log , the hash summary of the log data stored off-chain is calculated and recorded as Loghash′.

[0104] Step 8.4: Compare Loghash' with the log information summary Loghash stored on the chain to verify the integrity of the log record.

[0105] In order to improve the consensus efficiency of the log chain and avoid it becoming a performance bottleneck when synchronizing the identity certificate chain operation, the present invention designs the AOB-Consensus consensus mechanism based on the practical Byzantine fault tolerance algorithm and combined with the aggregate verification technology. This mechanism optimizes the consensus process through aggregate verification, accelerates the synchronous verification of the log chain, and realizes the real-time recording of the identity certificate authorization operation. The AOB-Consensus consensus process is as follows: Figure 5 As shown, its description is as follows:

[0106] 1) Proposal phase: The proposing node N0 generates a block M of identity authorization chain synchronization log messages to be agreed upon, and broadcasts M to all other nodes N1, N2, ..., N n-1 .

[0107] 2) Preparation phase: Each backup node N iAfter receiving the message from the proposing node, the correctness of the packaged block M is first verified. If the verification passes, the backup node uses its private key sklog i Sign the message and generate the signature σlog i ,After the signature is completed, each node sends its signature package to the proposing node N0.

[0108] 3) Commit phase: After receiving signatures from at least t nodes, the proposing node N0 aggregates these signatures to generate an aggregate signature σlog agg . Subsequently, the proposing node will aggregate the signature and the signing node public key set {pklog1, pklog2, ..., pklog t}Broadcast to all other nodes N1, N2, ..., N n-1 Each node N i After receiving the aggregate signature and public key set, the aggregate signature is verified. If the verification passes, it is considered that consensus has been reached, and block M is recorded to local storage, marking the consensus has been reached.

[0109] Compared with the traditional PBFT consensus solution, the time complexity of AOB-Consensus consensus is O(N 2 ) is optimized to O(N). In order to verify the improvement of the consensus efficiency of the AOB-Consensus mechanism, the present invention is based on the Python programming language, simulates the network port communication through the socket library to simulate the consensus overhead, uses virtual ports to realize the interaction between multiple nodes, and simulates the overhead of consensus nodes of different scales [4, 8, 16, 32, 48, 64]. After 50 simulation experiments and taking the average, Table 2 shows the consensus overhead comparison between AOB-Consensus and traditional PBFT at different node scales. The results show that with the increase in the number of consensus nodes, the efficiency of AOB-Consensus continues to improve compared with PBFT, verifying that the dual-chain structure of the present invention uses AOB-Consensus for the log chain during node consensus verification and will not cause synchronization lag problems.

[0110] Table 2 Comparison of consensus overhead under different node scales

[0111]

[0112] The present invention proposes a blockchain solution for multi-department digital identity authentication, provides a full-process system architecture design for multi-department digital identity certificate storage and verification, breaks down information barriers between departments, and realizes reliable and efficient verification in multi-department collaborative scenarios through an aggregated verification scheme. In response to audit issues, the present invention introduces a log chain to synchronize main chain operation records, improves the efficiency of log chain consensus through an aggregated Byzantine optimization consensus mechanism, and avoids synchronization lag problems in dual-chain structures. Compared with other methods, this solution can effectively reduce computational overhead while ensuring privacy, integrity, and unforgeability, and aggregate signatures realize efficient verification in multi-certificate scenarios. The consensus mechanism avoids potential lag problems in log chain synchronization records.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the concept of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A blockchain solution for multi-sector digital identity authentication, characterized in that: The following steps are involved: Step 1: The key generation and distribution center initializes the global system and distributes system public parameters and public and private key pairs to all participants; Step 2: The user initiates a digital identity authorization application to the authentication department; Step 3: Encrypt the digital identity certificate, calculate the signature and on-chain index, and complete the on-chain and off-chain storage of the user's digital identity certificate; Step 4: The user's digital identity certificate authorization operation record is uploaded to the log chain for synchronization recording; Step 5: When a user needs to perform a certain identity authentication to access a specific service, a query trap is generated to perform on-chain data retrieval, obtain the digital certificate authority on-chain information of the corresponding department and decrypt it to obtain the digital identity certificate; Step 6: The identity verification service provider performs signature verification on the digital identity certificate; Step 7: The user digital identity certificate verification request record is uploaded to the log chain for synchronization recording; Step 8: The audit unit conducts a traceability audit of the authorization by the authoritative certification department and the user identity authentication operations recorded on the log chain.

2. The blockchain solution for multi-sector digital identity authentication as claimed in claim 1, characterized in that: The generation of the system public parameters and the public-private key pair in step 1 is based on the mathematical basis of bilinear mapping, and specifically includes the following steps: Step 1.1: Given a security parameter λ, choose a large prime number p and select the prime field F from the prime field p = {0, 1, 2, ..., p-1} Select two cyclic groups G1 and G2 on the elliptic curve, both of which have order p, where the generator of G1 is g; on this basis, define the bilinear map e(P, R) = Q where P, R∈G1, Q∈G2, select a finite field The key generation and distribution center randomly selects the system private key And calculate the corresponding system public key To ensure collision resistance, five hash functions are defined as follows: H3(Q)=HashFunction(Bytes(Q))Q∈G2 Among them, Bytes(P) is the byte representation of P, that is, the value of P is converted into hexadecimal representation, and then every two hexadecimal characters are combined into 1 byte, || means concatenating the bit string b with Bytes(P), HashFunction(z) is a hash algorithm used to map the variable z to a fixed-length summary, is the mapping function, and the hash operation result of HashFunction{) is modulo p-1 plus 1 to ensure that the hash value is converted to Elements of a group; is the mapping function. The hash operation result of HashFunction() is modulo p-1 and then added 1 to calculate the x-axis coordinate on the elliptic curve group G1. The equation on the elliptic curve is solved according to the x-coordinate to obtain the y-coordinate. Finally, a legal point (x, y)∈G1 on the elliptic curve is obtained as the mapping result. The final system common parameters are SP = (p, g, e, S pk ,H1, H2, H3, H4, H5}, the system public parameters are released to all participants in the system through a secure channel; Step 1.2: For any user i, the key generation and distribution center randomly selects the identity coefficient And based on the user's unique ID i ∈{0, 1} * Calculate the relevant part of the public and private key pair of user i Calculate partial public key of user i Part of the private key of user i The user independently selects Part of the private key Calculate partial public key of user i Jointly generate the public key of user i and the private key of user i Other nodes in the system, including the certification department, audit unit and log chain consensus node, all use the above method to generate public and private key pairs.

3. The blockchain solution for multi-sector digital identity authentication as claimed in claim 2, characterized in that: The step 3 specifically comprises the following steps: Step 3.1: For the issued digital identity certificate AuthCert i , the system encrypts the authorization information by randomly selecting the ciphertext coefficient Compute encryption components and The specific calculation method is as follows: The final encryption result is expressed as Step 3.2: For the issued digital identity certificate AuthCert i , the certification authority signs the certificate. The signing process first randomly selects the digest coefficient According to the permission applicant's identity ID i Calculate the message digest of the digital identity certificate The specific calculation method is as follows: Then use the certification department private key and the certification authority public key Calculate the signature component and The specific calculation method is as follows: By introducing the message digest, all parts of the signature are ensured to be associated with the corresponding user identity. The final signature form is Step 3.3: On AuthCert i After encryption, the encryption result C i Will be stored in the distributed interstellar file system, with off-chain storage index and digital certificate signatureσ i , the digital certificate summary and the digital certificate authority information are uploaded to the identity certificate chain, where the chain storage index is constructed as follows:

4. The blockchain solution for multi-sector digital identity authentication as claimed in claim 1, characterized in that: The synchronization of log chain in step 4 is as follows: the digital identity certificate authorization log record is encrypted by the symmetric encryption algorithm AESEncrypt(), and the log encryption result is represented as encryptedLog. The chain index is represented by {ID i , CertType, actionType} triples are composed, and the log information summary Loghash is stored on the chain to verify the integrity of the log data; i It represents the unique identity identifier of user i, CertType represents the department to which the digital identity certificate belongs, and actionType represents the type of identity certificate chain operation.

5. The blockchain solution for multi-sector digital identity authentication as claimed in claim 1, characterized in that: In step 5, the user generates a query trap to retrieve data on the chain, which specifically includes the following steps: Step 5.1: User randomly selects trapdoor generation coefficient Calculate and provide query trapdoor i =(τ1, τ2) and the department to which the digital certificate belongs, CertType, the query trap calculation method is as follows: Step 5.2: The identity certificate chain performs on-chain matching query based on CertType and query trapdoor. First, the on-chain storage index is calculated through the query trapdoor to obtain the on-chain information of all department digital certificate permissions associated with the user identity. The on-chain storage index calculation method is as follows: Then, the CertType attribute is used to further filter and extract the corresponding department's digital certificate authority chain information from all department digital certificate authority chain information, so as to achieve accurate filtering and positioning of target data under multi-department digital certificate storage; Step 5.3: The user obtains the encrypted result C stored in the Interstellar File System based on the off-chain storage index in the on-chain information of the digital certificate authority of the corresponding department. i , use the user private key sku i Execute the decryption process, the calculation method is as follows:

6. The blockchain solution for multi-sector digital identity authentication as claimed in claim 1, characterized in that: The digital certificate signature verification operation in step 6 supports single certificate verification and multi-certificate verification, including the following steps: Step 6.1: In single certificate verification, for the on-chain stored signature obtained by the index, the verifier needs to recalculate the digital certificate message digest, and then verify the consistency of both sides of the following equation based on the corresponding public key of the CertType department: Step 6.2: In multi-certificate verification, first aggregate the multi-certificate signatures. The aggregate signature component is generated as follows, where n represents the number of digital identity certificates to be verified: Step 6.3: Validator receives aggregate signature Then, use the public keys of the certification authorities corresponding to the n digital identity certificates to verify the consistency of both sides of the following equation:

7. The blockchain solution for multi-sector digital identity authentication as claimed in claim 1, characterized in that: The log chain synchronization record in step 7 is specifically as follows: Log data is stored off-chain using the symmetric encryption algorithm AESEncrypt() for encryption. The on-chain index is represented by {ID i , CertType, actionType} triples, where ID i It represents the unique identity identifier of user i, CertType represents the department to which the digital certificate belongs, and actionType represents the type of identity certificate chain operation.

8. The blockchain solution for multi-sector digital identity authentication as claimed in claim 1, characterized in that: The step 8 is specifically as follows: Step 8.1: The audit unit shall i , CertType, actionType} as the index and initiate a tracing request to the log chain; Step 8.2: The request is audited and authenticated through the on-chain smart contract to ensure the legitimacy and authority control of the audit request. After authentication, the system returns the traceability result {encryptedLog, Loghash}; Step 8.3: The audit unit uses the encrypted log result encryptedLog to decrypt the log data D stored off-chain Log , calculate the hash summary of the log data stored off-chain and record it as Loghash′; Step 8.4: Compare Loghash′ with the log information summary Loghash stored on the chain to verify the integrity of the log record.

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