Credit certificate issuing method and device, computer storage medium and electronic equipment

Abstract

The application discloses a credit certificate issuing method and device, a computer storage medium and an electronic device. It relates to the technical field of blockchains. The method comprises the following steps: receiving a credit certificate issuing application from a target credit certificate receiver; based on the credit certificate issuing application, calling a target blockchain node to determine a floating quota certificate and a fixed quota certificate of the target credit certificate receiver, wherein the floating quota certificate is used to issue credit certificates to N credit certificate receivers, and the fixed quota certificate is used to issue credit certificates to the target credit certificate receiver, wherein N is a positive integer greater than 1; determining a target credit certificate from the floating quota and the fixed quota; and issuing the target credit certificate to the target credit certificate receiver. Through the application, the problem that the issuing of credit certificates is not flexible and the collaborative process is complex in the prior art is solved.

Description

Technical Field

[0001] This application relates to the field of blockchain technology, and more specifically, to a method, apparatus, computer storage medium, and electronic device for issuing credit certificates. Background Technology

[0002] In related technologies, the issuance of credit certificates requires verification of the currently used credit limit. However, due to the multi-level transfer of credit certificates, the verification process requires higher-level institutions to collect the actual issued credit limits from lower-level institutions layer by layer. Only after the data is aggregated can the credit limit be judged and approved. Furthermore, when allocating credit limits among institutions at the same level, the original credit certificate must be invalidated before a new one is issued. This collaborative process is complex. Therefore, related technologies suffer from technical problems such as inflexible issuance of credit certificates and complex collaborative processes.

[0003] There is currently no effective solution to the problems of inflexible issuance of credit certificates and complex collaborative processes in related technologies. Summary of the Invention

[0004] This application provides a method, apparatus, computer storage medium, and electronic device for issuing credit documents, in order to solve the problems of insufficient flexibility and complex collaborative processes in the issuance of credit documents in related technologies.

[0005] According to one aspect of this application, a method for issuing credit certificates is provided. The method includes: receiving a credit certificate issuance application from a target credit certificate recipient; based on the credit certificate issuance application, invoking a target blockchain node to determine a floating credit limit certificate and a fixed credit limit certificate for the target credit certificate recipient, wherein the floating credit limit certificate is used to issue credit certificates to N credit certificate recipients, and the fixed credit limit certificate is used to issue a credit certificate to the target credit certificate recipient, where N is a positive integer greater than 1; determining a target credit certificate from the floating credit limit certificate and the fixed credit limit certificate; and issuing the target credit certificate to the target credit certificate recipient.

[0006] Optionally, before receiving the credit certificate issuance application from the target credit certificate recipient, the above method further includes: building a business chain network based on the credit certificate issuer and the credit certificate recipient, wherein the business chain network includes multiple business chains, and M blockchain nodes are set on the business chains, the M blockchain nodes including the target blockchain, where M is a positive integer greater than 1.

[0007] Optionally, the above method also includes: calling the target blockchain to register digital identities for the issuer and recipient of the credit certificate, wherein the digital identities are used to verify the issuance result of the credit certificate.

[0008] Optionally, the target credit certificate can be determined from the floating credit certificate and the fixed credit certificate, including: obtaining the credit assessment rating of the recipient of the target credit certificate; if the credit assessment rating is higher than the predetermined rating, the target credit certificate can be determined from the floating credit certificate based on the credit certificate issuance application, otherwise the target credit certificate can be determined from the fixed credit certificate.

[0009] Optionally, the target credit certificate is determined from the floating credit certificate, including: obtaining the issuance limit of the floating credit certificate; calling a secure multi-party computation node to calculate the used floating credit certificates of N credit certificate recipients; determining the target floating credit certificate from the floating credit certificates based on the issuance limit and the used floating credit certificates; and determining the target credit certificate based on the target floating credit certificate.

[0010] Optionally, a secure multi-party computation node is invoked to calculate the used floating credit limit certificates of N credit certificate recipients, including: controlling the N credit certificate recipients to randomly divide their respective used floating credit limit certificates into N shares; controlling the N credit certificate recipients to retain one share of the share and randomly send the other N-1 shares of the share to the other N-1 credit certificate recipients; controlling the N credit certificate recipients to sum the retained share of the share and the received N-1 shares of the share, obtaining N sums; and statistically analyzing the N sums to obtain the used floating credit limit certificates.

[0011] Optionally, the above method further includes: obtaining the issuance result of the target credit certificate; verifying the issuance result; and updating the credit assessment rating of the recipient of the target credit certificate based on the verification result.

[0012] According to another aspect of this application, a credit certificate issuance apparatus is provided. The apparatus includes: a receiving module for receiving a credit certificate issuance application from a target credit certificate recipient; an invoking module for invoking a target blockchain node based on the credit certificate issuance application to determine a floating credit limit certificate and a fixed credit limit certificate for the target credit certificate recipient, wherein the floating credit limit certificate is used to issue credit certificates to N credit certificate recipients, and the fixed credit limit certificate is used to issue a credit certificate to the target credit certificate recipient, where N is a positive integer greater than 1; a determining module for determining the target credit certificate from the floating credit limit certificate and the fixed credit limit certificate; and an issuing module for issuing the target credit certificate to the target credit certificate recipient.

[0013] According to another aspect of the present invention, a computer storage medium is also provided for storing a program, wherein the program, when running, controls the device where the computer storage medium is located to execute a credit certificate issuance method.

[0014] According to another aspect of the present invention, an electronic device is also provided, comprising one or more processors and a memory; the memory stores computer-readable instructions, and the processor is configured to execute the computer-readable instructions, wherein the computer-readable instructions execute a credit certificate issuance method.

[0015] This application employs the following steps: receiving a credit certificate issuance application from the target credit certificate recipient; based on the credit certificate issuance application, invoking the target blockchain node to determine the target credit certificate recipient's floating credit limit certificate and fixed credit limit certificate, wherein the floating credit limit certificate is used to issue credit certificates to N credit certificate recipients, and the fixed credit limit certificate is used to issue credit certificates to the target credit certificate recipient, where N is a positive integer greater than 1; determining the target credit certificate from the floating and fixed credit limits; and issuing the target credit certificate to the target credit certificate recipient. This solves the problems of insufficient flexibility in credit certificate issuance and complex collaborative processes in related technologies. It achieves flexible control over the credit limit and realizes flexible and verifiable issuance of credit certificates. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0017] Figure 1 This is a flowchart of a credit certificate issuance method provided according to embodiments of this application; and

[0018] Figure 2 This is a schematic diagram of a blockchain-based flexible signature system for credit credentials provided according to an optional implementation of this application;

[0019] Figure 3 This is an internal structure diagram of the secure multi-party computation node 4 provided according to an optional implementation of this application;

[0020] Figure 4 This is a flowchart of a flexible signing method for blockchain-based credit credentials provided according to an optional implementation of this application;

[0021] Figure 5 This is a schematic diagram of a credit certificate issuing device provided according to an embodiment of this application. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] It should be noted that all information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for display, data used for analysis, etc.) involved in this disclosure are information and data authorized by the user or fully authorized by all parties. For example, this system has an interface with relevant users or organizations. Before obtaining relevant information, it is necessary to send an acquisition request to the aforementioned user or organization through the interface, and obtain the relevant information after receiving consent information from the aforementioned user or organization.

[0026] It should be noted that the credit certificate issuance method, device, computer storage medium and electronic device determined in this disclosure can be used in the field of blockchain technology, or in any field other than blockchain technology. The application field of the credit certificate issuance method, device, computer storage medium and electronic device determined in this disclosure is not limited.

[0027] In existing business scenarios, the tiered transmission of credit certificates among participating institutions is often used for comprehensive control of credit limits. The current solution involves the root credit institution issuing credit certificates to primary institutions, which then issue these certificates to secondary institutions. Verification requires a step-by-step back process: primary institutions verify the secondary institutions' credit certificates, and the core enterprise verifies the secondary institutions' credit certificates based on the primary institutions' certificates. If the core enterprise issues credit certificates to multiple primary institutions, the sum of these certificates represents the total credit limit. Similarly, the credit limit for secondary institutions is the sum of all secondary institution credit certificates issued by the primary institutions. During issuance, the applicant typically fills in the requested credit limit, and the higher-level institution verifies the total used credit limit.

[0028] However, existing letters of credit require verification of the currently used credit limit when they are issued. Because credit involves multiple levels of transfer, the upper-level institution needs to collect the actual credit limits issued by the lower-level institutions layer by layer, and then summarize them before the credit limit can be judged and reviewed. Furthermore, when flexibly allocating credit limits among institutions at the same level, the original letters of credit need to be voided and new letters of credit need to be issued, making the coordination process complex.

[0029] Therefore, existing technologies suffer from problems such as insufficient flexibility in issuing credit certificates and complex collaborative processes.

[0030] Therefore, this application aims to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in subsequent embodiments.

[0031] For ease of description, the following explains some of the nouns or terms used in the embodiments of this application:

[0032] Consortium blockchain: Business partners form a blockchain consortium network based on business needs, extract business rules into business smart contracts, and deploy them on the blockchain consortium network to endorse specific business data.

[0033] Blockchain digital identity technology is a technology based on blockchain technology that verifies the digital identity identifiers of entities and their associated digital attribute claims. Through a cryptographic system linked to these entity digital identity identifiers, it supports the secure and efficient transfer of verifiable credentials among consortium institutions. It mainly includes distributed digital identity (DID) and verifiable digital credentials.

[0034] Digital Identity (DID): A unique identifier for a distributed digital identity. Its uses include two main aspects: first, identifying a specific instance of a DID subject (person, organization, device, key, service, and general thing); and second, facilitating the exchange and verification of user credentials between entities through persistent, encrypted private channels without any centralized registration mechanism.

[0035] Verifiable digital credentials: Credentials refer to the attribute descriptions of an entity. Verifiable credentials are tamper-proof credentials that are signed and encrypted by the issuer, possessing cryptographic security and privacy protection features. They typically consist of at least two sets of information: first, the verifiable credential itself, containing credential metadata and claims; and second, the digital signature of the verifiable credential.

[0036] Secure multi-party computation: A multi-party collaborative privacy-preserving computation technology that divides data from each party into multiple parts and distributes them to different participants, each holding one part, to collaboratively complete the computation task. Because each participant cannot see the full amount of data, the data is "usable but not visible," thus achieving privacy protection.

[0037] According to an embodiment of this application, a method for issuing credit certificates is provided.

[0038] Figure 1 This is a flowchart of a credit certificate issuance method provided according to an embodiment of this application. For example... Figure 1 As shown, the method includes the following steps:

[0039] Step S102: Receive a credit document issuance application from the target credit document recipient;

[0040] Step S104: Based on the credit certificate issuance application, call the target blockchain node to determine the floating credit certificate and fixed credit certificate of the target credit certificate recipient. The floating credit certificate is used to issue credit certificates to N credit certificate recipients, and the fixed credit certificate is used to issue credit certificates to the target credit certificate recipient. N is a positive integer greater than 1.

[0041] Step S106: Determine the target credit certificate from the floating credit certificate and the fixed credit certificate;

[0042] Step S108: Issue the target credit certificate to the recipient of the target credit certificate.

[0043] Through the above steps, after receiving a credit certificate issuance application from the target credit certificate recipient, the system calls the target blockchain node corresponding to the target credit certificate recipient based on the application to determine the floating and fixed credit limit certificates that can be issued to the target credit certificate recipient. Then, according to the number of credit certificates applied for by the target credit certificate recipient, the target credit certificate is determined from the floating and fixed credit limit certificates. After that, the target credit certificate can be issued to the target credit certificate recipient. In this embodiment, the target blockchain node acts as an intermediary in the process of issuing credit certificates to the target credit certificate recipient. The credit certificate is issued directly to the target credit certificate recipient based on the floating and fixed credit limit certificates, without having to verify the currently used credit limit layer by layer among multiple credit certificate recipients and multiple credit certificate issuers. Therefore, it greatly improves the flexibility of credit certificate issuance and reduces the complexity of collaboration in the credit certificate issuance process. It solves the problems of insufficient flexibility in credit certificate issuance and complex collaboration processes in related technologies, thereby achieving flexible control over the credit limit and realizing the technical effect of flexible and verifiable issuance of credit certificates.

[0044] It should be noted that, in this embodiment of the application, floating credit limit certificates and fixed credit limit certificates are set for the target credit certificate recipients respectively. The floating credit limit certificate corresponding to the target credit certificate recipient is issued by the credit certificate issuer within a limited range based on the current empty balance. It can be used to issue credit certificates to multiple credit certificate recipients simultaneously. The fixed credit limit certificate corresponding to the target credit certificate recipient is a fixed usage credit limit certificate allocated by the credit certificate issuer to the target credit certificate recipient. It can only be used to issue credit certificates to that target credit certificate. Therefore, when determining the target credit certificate based on the credit certificate issuance application, various methods can be adopted. For example, the target credit certificate can be determined only from the floating credit limit certificate or the fixed credit limit certificate, or a combination of floating credit limit certificates and fixed credit limit certificates can be used to determine the target credit certificate.

[0045] Optionally, in the credit certificate issuance method provided in this application embodiment, before receiving the credit certificate issuance application from the target credit certificate recipient, the method further includes: establishing a business chain network based on the credit certificate issuer and the credit certificate recipient. The business chain network includes multiple business chains, each with M blockchain nodes, including the target blockchain, where M is a positive integer greater than 1. Each blockchain node has a consistent structure, and the blockchain nodes can achieve consensus and consistent ledger recording through a consensus algorithm. That is, each blockchain can directly record the credit certificate issuance results between the credit certificate issuer and the credit certificate recipient, and update the issuance limits of each credit certificate recipient and each credit certificate issuer in a timely manner based on the issuance results.

[0046] It should be noted that the issuer and recipient of credit documents in this application embodiment are relative terms. If multiple layers of institutions are involved in the issuance of credit documents, such as a root-level institution, a primary institution, and a secondary institution, and the root-level institution can issue credit documents to the primary institution, then the root-level institution is the issuer of credit documents relative to the primary institution, and the primary institution is the recipient of credit documents relative to the root-level institution. If the primary institution can issue credit documents to the secondary institution, then the primary institution is the issuer of credit documents relative to the secondary institution, and the secondary institution is the recipient of credit documents relative to the primary institution, and so on.

[0047] Optionally, in the credit certificate issuance method provided in the embodiments of this application, the method further includes: calling the target blockchain to register digital identities for the credit certificate issuer and the credit certificate recipient, wherein the digital identities are used to verify the credit certificate issuance result.

[0048] On the one hand, the blockchain node in this application embodiment can register digital identities (DIDs) for the issuer and recipient of credit certificates, generate an identifier that uniquely corresponds to the issuer or recipient of the credit certificate, bind the public and private key pair corresponding to the digital identity, and upload the digital identity and public key information to the blockchain.

[0049] On the other hand, based on the registration of digital identity, the blockchain node can respond to credit certificate issuance applications, approve and issue corresponding verifiable credit certificates according to the credit certificate limit requirements. That is, the blockchain node can disclose credit authorization information in the issued credit certificate, and the credit certificate issuer can use its private key to sign and endorse the issued credit certificate, thereby realizing the issuance of verifiable credit certificates.

[0050] In addition, the blockchain node in this application embodiment can also be used to verify credit certificates. That is, it uses the public key information corresponding to the digital identity of the credit certificate issuer to verify the authenticity of the endorsement of the issued credit certificate. Since the private key of the credit certificate issuer is used when endorsing the issued credit certificate, if the endorsement information can be successfully decrypted using the public key of the credit certificate issuer, it can be verified that the credit certificate was indeed issued by the credit certificate issuer. Otherwise, it proves that the credit certificate was not issued by the credit certificate issuer.

[0051] Optionally, in the credit certificate issuance method provided in this application embodiment, determining the target credit certificate from floating credit line certificates and fixed credit line certificates includes: obtaining the credit assessment level of the target credit certificate recipient; if the credit assessment level is higher than a predetermined level, determining the target credit certificate from floating credit line certificates based on the credit certificate issuance application; otherwise, determining the target credit certificate from fixed credit line certificates. In this application embodiment, the determination method of the target credit certificate can be determined according to the credit assessment level of the target credit certificate recipient. For example, if the credit assessment level is divided into poor, average, good, and excellent, and the predetermined level is average, then when the credit assessment level of the target credit certificate recipient is higher than average, i.e., the credit assessment level is good or excellent, the target credit certificate can be determined first from floating credit line certificates without occupying fixed credit line certificates.

[0052] Optionally, in the credit certificate issuance method provided in this application embodiment, determining the target credit certificate from the floating credit certificate includes: obtaining the issuance limit of the floating credit certificate; calling a secure multi-party computation node to calculate the used floating credit certificates of N credit certificate recipients; determining the target floating credit certificate among the floating credit certificates based on the issuance limit and the used floating credit certificates; and determining the target credit certificate based on the target floating credit certificate.

[0053] Since floating credit line certificates are used by multiple credit certificate issuers, when determining the target certificate from the floating credit line certificates, it is necessary to first determine the current usage of the floating credit line and identify the currently available floating credit line certificates, i.e., the target floating credit line certificates. For example, assuming the initial issuance limit of floating credit line certificates is set to 1000, and the used floating credit line certificates of N credit certificate recipients are calculated to be 300 after calling the secure multi-party computation node, then the target floating credit line certificate is 1000-300=700. Then, the target credit certificate actually used for issuance can be determined based on the target floating credit line certificate of 700.

[0054] Optionally, in the credit certificate issuance method provided in this application embodiment, a secure multi-party computation node is invoked to calculate the used floating credit limit certificates of N credit certificate recipients, including: controlling the N credit certificate recipients to randomly divide their respective used floating credit limit certificates into N shares of credit limit certificates; controlling the N credit certificate recipients to retain one share of credit limit certificates and randomly send the other N-1 shares of credit limit certificates to the other N-1 credit certificate recipients; controlling the N credit certificate recipients to sum the retained share of credit limit certificates and the received N-1 shares of credit limit certificates to obtain N summed results; and statistically analyzing the N summed results to obtain the used floating credit limit certificates.

[0055] This application embodiment can complete the collaborative calculation of the credit limit that can be issued among multiple credit certificate issuers by calling a secure multi-party computation node. Since each credit certificate issuer only needs to expose a portion of the credit limit certificate to another credit certificate issuer separately during the calculation process, each credit certificate issuer cannot infer the current available credit limit certificate of any other credit certificate issuer based solely on the portion of the credit limit certificate it receives. In this way, the information security of each credit certificate issuer can be guaranteed while calculating the target floating credit limit certificate.

[0056] Optionally, in the credit certificate issuance method provided in this application embodiment, the method further includes: obtaining the issuance result of the target credit certificate; verifying the issuance result; and updating the credit assessment level of the target credit certificate recipient based on the verification result. After issuance, the issuance result can be verified based on the endorsement records of each credit certificate issuer when issuing the credit certificate or the usage records corresponding to the target credit certificate, and the verification result can be used as the basis for credit assessment level evaluation to update the credit assessment level of the credit certificate issuer or the credit certificate recipient, thereby achieving the effect of adjusting the usage rights of floating credit certificates. Taking the root-level institution, first-level institution, and second-level institution as an example, if the root-level institution provides floating credit certificates to multiple first-level institutions, and a certain first-level institution uses the floating credit certificate to issue credit certificates to second-level institutions, the root-level institution can verify the credit of the first-level institution based on the on-chain first-level institution's credit limit security multi-party calculation endorsement record, as the basis for first-level institution credit analysis and evaluation, and as an incentive mechanism for the credit of floating credit institutions.

[0057] The credit certificate issuance method provided in this application embodiment receives a credit certificate issuance application from the target credit certificate recipient; based on the credit certificate issuance application, it calls the target blockchain node to determine the target credit certificate recipient's floating credit limit certificate and fixed credit limit certificate, wherein the floating credit limit certificate is used to issue credit certificates to N credit certificate recipients, and the fixed credit limit certificate is used to issue credit certificates to the target credit certificate recipient, where N is a positive integer greater than 1; the target credit certificate is determined from the floating credit limit and the fixed credit limit; and the target credit certificate is issued to the target credit certificate recipient. This solves the problems of insufficient flexibility in credit certificate issuance and complex collaborative processes in related technologies. It thus achieves flexible control over the credit limit and realizes the effect of flexible and verifiable issuance of credit certificates.

[0058] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0059] Based on the above embodiments and optional embodiments, this application also provides an optional implementation method, which will be described below.

[0060] This application proposes an optional implementation of a blockchain-based flexible signing system and method for credit certificates. Figure 2 This is a schematic diagram of a blockchain-based flexible signature system for credit certificates provided according to an optional implementation of this application, such as... Figure 2 As shown, the system includes: business chain 1, blockchain node 2, business system 3, and secure multi-party computation node 4. The system will be described below.

[0061] (1) Business Chain 1

[0062] Business Chain 1 is an alliance business chain established based on the credit certificate signing requirements of external business system 3. The chain includes multiple blockchain nodes 2, each with a consistent structure, capable of registering structural identity and issuing credit certificates. Blockchain nodes 2 achieve consensus and consistent ledger recording through a consensus algorithm.

[0063] (2) Blockchain Node 2

[0064] Blockchain node 2 is used for transaction requests initiated by business system 3 and for endorsement requests of computation tasks from secure multi-party computation node 4, including digital identity (DID) registration, credit certificate issuance, and verification. All blockchain nodes 2 have identical internal structures, generating new block data based on data processed according to the contract's logic, and triggering relevant business processes after contract execution. Specifically:

[0065] 1) DID Registration: Generate a unique DID identifier for participating institutions, bind the public and private key pair corresponding to the user's identity, and put the user's did and public key information on the blockchain;

[0066] 2) Verifiable digital certificate issuance: Credit authorization information is disclosed in the certificate, and the issuing institution uses its own DID private key to sign and endorse it.

[0067] 3) Verifiable digital certificate verification: The verification authority uses the public key information disclosed by the on-chain ID to endorse and verify the authenticity of the issued verifiable digital certificate.

[0068] (3) Business System 3

[0069] Business system 3 is the business transaction request initiation system. It initiates corresponding credit certificate issuance, credit certificate verification, and credit certificate system calculation requests, and completes the credit certificate-related business process processing. Business system 3 can be the credit certificate issuer or credit certificate recipient in the above embodiments. Specifically:

[0070] 1) Issuance of credit certificates: Call the blockchain node 2 of business chain 1 to approve and issue corresponding verifiable credit certificates according to the institution's credit limit requirements; during issuance, it supports customized issuance of floating limit certificates or fixed limit certificates according to flexible certificate requirements.

[0071] 1. Floating Credit Line Certificate: Issued by the superior institution within a limited range based on the current available credit line, such as ≤10000. In actual use, a secure multi-party calculation is performed with the current level institution to obtain the used credit line result R, and the available credit line is 10000-R;

[0072] 2. Fixed-limit vouchers: Fixed-limit vouchers are allocated by the superior institution to the current level institution. In actual use, the usage limit is calculated directly based on the allocated limit. When receiving used limits from other institutions for multi-party calculation, the usage limit is calculated directly based on the allocated limit.

[0073] 2) Credit certificate verification: Call the blockchain node 2 of business chain 1 to complete the verification of credit certificate based on the shared information on the chain and the disclosed public key information.

[0074] 3) Credit certificate calculation: Call the secure multi-party computation node 4 to complete the collaborative calculation of the credit limit.

[0075] (4) Secure multi-party computation node 4

[0076] Secure multi-party computation node 4 is used to perform secure calculations of inter-institutional credit lines, and calculates the currently available credit line in a secret sharing manner.

[0077] Taking the existing credit lines of three institutions as an example, if institutions A, B, and C hold values ​​a, b, and c respectively, the total value R of the currently allocated credit lines needs to be calculated while maintaining confidentiality among the three parties:

[0078] ①A selects random numbers a1, a2, and a3 that satisfy a = a1 + a2 + a3, and sends two of them, a2 and a3, respectively.

[0079] Give to the other two parties, B and C;

[0080] ② Similarly, B and C select random numbers b1, b2, b3 and c1, c2, c3 and send two of them to the other two parties;

[0081] ③ A, B, and C respectively calculate ra = a1 + b1 + c1, rb = a2 + b2 + c2, and rc = a3 + b3 + c3. The final result receiver receives the summed calculation result: R = ra + rb + rc.

[0082] Figure 3 This is an internal structure diagram of the secure multi-party computation node 4 provided according to an optional implementation of this application, such as... Figure 3 As shown, the node includes a routing processing device 11 and a data security computing device 12.

[0083] 1) Node initialization and routing device 11

[0084] The node initialization and routing device 11 is mainly responsible for the initialization of secure multi-party computation nodes, registering distributed digital identity identifiers (DIDs) on the business chain 1, storing private keys, and uploading public keys to the chain for identity recognition and mutual trust communication between secure multi-party computation nodes. It includes a node registration module 111, a node verification module 112, and a node linking module 113.

[0085] 1. Node Registration Module 111

[0086] The node registration module 111 is the node initialization module. It is responsible for registering the corresponding node identity with business chain 1 when a node is activated. It assigns a unique DID identity identifier to the current secure multi-party computation node and registers its organizational structure, connection address, identity public key, and other attribute information on the chain. The identity private key information is stored by the node itself. The corresponding node identity information is identified through the identity private key.

[0087] 2. Node verification module 112

[0088] Node verification module 112 is the identity verification step before secure multi-party computation nodes establish a computation path. After a node registers and activates its identity, it can discover secure multi-party computation node information on the blockchain according to the computation task, obtain the node connection address from the blockchain, and perform corresponding identity challenges and responses based on the public and private key information corresponding to the node's identity DID identifier to complete node identity verification.

[0089] 3. Node Link Module 113

[0090] The node connection module 113 is a link establishment module for secure communication between secure multi-party computing nodes. After the node authentication is successful, a short connection for the current task can be established, and secure encrypted data transmission is performed based on the public and private key technology corresponding to the DID. That is, the transmitted data is encrypted with the public key on the target node chain, and only the target node can decrypt it with its private key.

[0091] 2) Data security computing device 12

[0092] The data security computing device 12 is a cryptographic device for performing secure multi-party computations between nodes. Specifically, it includes a data preparation module 121, a data computing module 122, and a security sandbox module 123.

[0093] 1. Data Preparation Module 121

[0094] The data preparation module 121 refers to the collaborative computation data preparation performed by secure multi-party computing nodes according to the computing task, including data fingerprinting on the blockchain, data sharding, encryption and other preparatory work.

[0095] 2. Data Calculation Module 122

[0096] Data computation module 122 refers to the process by which all parties complete privacy computation based on encrypted data according to computation logic and rules. Each node obtains the computation result without being able to see the data of all parties, and puts the computation participants, computation process and encrypted computation result on the blockchain.

[0097] 3. Safety Sandbox Module 123

[0098] The security sandbox module 123 refers to a secure sandbox environment prepared for storing the private key corresponding to the current node's digital identity DID, preparing the current organization's data, and coordinating data computation among all parties, ensuring that the data in the sandbox environment cannot be copied or tampered with.

[0099] Based on the above system, this application proposes an optional implementation method for flexible signing of credit certificates based on blockchain. Figure 4 This is a flowchart of a flexible signing method for blockchain-based credit certificates provided according to an optional implementation of this application, such as... Figure 4 As shown, the method includes the following steps:

[0100] Step S401: The participating parties in the business cooperation jointly establish a consortium blockchain network business chain 1. Partnering institutions deploy blockchain nodes 2 and secure multi-party computation nodes 4 according to the consortium's operational needs. Blockchain nodes 2 communicate with each other to achieve transaction consensus and joint ledger recording on business chain 1. Secure multi-party computation nodes dynamically network according to collaborative computing tasks, dynamically connecting as needed to execute computation tasks. Business system 3 is the business logic processing system that interacts with users to issue and verify credit certificates.

[0101] Step S402: Business system 3 calls blockchain node 2 to register DIDs for all participating structures at all levels involved in the issuance and verification of credit certificates, and issues corresponding credit limit certificates as needed.

[0102] Step S403: The primary institution initiates a credit line certificate issuance application to the root institution. Based on the primary institution's application and its credit assessment, the root institution can selectively issue a floating or fixed credit line certificate. It can choose to issue a more flexible floating credit line certificate to institutions with good credit assessments.

[0103] Step S404A: The primary institution splits the credit limit certificate to the secondary institution based on the maximum floating limit range (MAX) and the secure multi-party calculation result of the used credit limit of the same level institution. Specifically, the splitting process requires obtaining the primary institutions that the current root institution has from business chain 1 and initiating the corresponding secure multi-party credit limit calculation request.

[0104] Step S404B: The primary institution splits the credit limit certificate to the secondary institution according to the fixed limit range.

[0105] Step S405: The primary institution receives the corresponding secure multi-party calculation request for the currently used quota. The floating quota allocation primary institution calculates the actual used quota currently allocated to the tertiary institution and inputs the current actual used quota A into the calculation source data of the secure multi-party calculation node 4. The fixed quota allocation primary institution directly inputs the allocated quota B into the calculation source data of the secure multi-party calculation node 4. Each institution calculates the total currently used quota M through secure multi-party calculation. Under the secure premise that the specific values ​​of the quota allocation and usage quota of the peer institutions are unknown, the available quota T is calculated. The allocable quota = MAX - T.

[0106] Step S406: The root institution can verify the credit of the institution by calculating the endorsement record of the credit limit of the first-level institution on the chain, which serves as the basis for the credit analysis and evaluation of the first-level institution and as an incentive mechanism for the credit of the floating credit limit institution.

[0107] In summary, the optional implementation method of this application achieves flexible management of credit certificate limits through blockchain, distributed digital identity, and secure multi-party computation technology, thereby improving the allocation and utilization rate of credit limits.

[0108] 1. Enhance the flexibility of quota allocation: By issuing floating quota vouchers, the quota can be flexibly adjusted based on the actual amount used when it is actually allocated and used, avoiding complex interactions, calculations and coordination processes between upper and lower level institutions;

[0109] 2. Privacy protection requirements for institutional credit limits: Based on secure multi-party computation technology, collaborative calculation of used credit limits among institutions is performed, and secure multi-party cryptographic computation technology is used to ensure that data is available but not visible, thus protecting the data privacy of institutions.

[0110] 3. End-to-end on-chain endorsement and supervision: The entire process of credit limit calculation and data is controlled on-chain, supporting regulatory audits as credit assessment data for collaborators, and enhancing the trust of participants through the alliance incentive model.

[0111] This application also provides a credit document issuance device. It should be noted that the credit document issuance device of this application can be used to execute the credit document issuance method provided in this application. The following describes the credit document issuance device provided in this application.

[0112] Figure 5 This is a schematic diagram of a credit certificate issuing device provided according to an embodiment of this application. Figure 5 As shown, the device includes: a receiving module 51, a calling module 52, a determining module 53, and an issuing module 54. The device will be described below.

[0113] The receiving module 51 is used to receive a credit document issuance application from the target credit document recipient;

[0114] The calling module 52 is connected to the receiving module 51 mentioned above. It is used to call the target blockchain node to determine the floating credit limit certificate and the fixed credit limit certificate of the target credit limit certificate recipient based on the credit certificate issuance application. The floating credit limit certificate is used to issue credit certificates to N credit limit certificate recipients, and the fixed credit limit certificate is used to issue credit certificates to the target credit limit certificate recipient. Here, N is a positive integer greater than 1.

[0115] The determination module 53 is connected to the aforementioned calling module 52 and is used to determine the target credit certificate from the floating credit certificate and the fixed credit certificate;

[0116] The issuing module 54 is connected to the determining module 53 and is used to issue the target credit certificate to the recipient of the target credit certificate.

[0117] Optionally, the credit certificate issuance device provided in this application embodiment further includes: a building unit, used to build a business chain network based on the credit certificate issuer and the credit certificate recipient, wherein the business chain network includes multiple business chains, and M blockchain nodes are set on the business chains, the M blockchain nodes include the target blockchain, wherein M is a positive integer greater than 1.

[0118] Optionally, the credit certificate issuance device provided in this application embodiment further includes: a first invocation unit, used to invoke the target blockchain to register digital identities for the credit certificate issuer and the credit certificate recipient, wherein the digital identities are used to verify the credit certificate issuance result.

[0119] Optionally, in the credit certificate issuance device provided in this application embodiment, the determining module 53 includes: a first obtaining unit, used to obtain the credit assessment level of the target credit certificate recipient; and a first determining unit, used to determine the target credit certificate from floating credit certificates based on the credit certificate issuance application if the credit assessment level is higher than a predetermined level, otherwise determine the target credit certificate from fixed credit certificates.

[0120] Optionally, in the credit certificate issuance device provided in this application embodiment, the first determining unit includes: a second obtaining unit, used to obtain the issuance limit of the floating credit certificate; a second calling unit, used to call a secure multi-party computation node to calculate the used floating credit certificates of N credit certificate recipients; a second determining unit, used to determine the target floating credit certificate among the floating credit certificates based on the issuance limit and the used floating credit certificates; and a third determining unit, used to determine the target credit certificate based on the target floating credit certificate.

[0121] Optionally, in the credit certificate issuance device provided in this application embodiment, the second calling unit includes: a first control unit, used to control N credit certificate recipients to randomly divide their respective used floating credit certificates into N shares of credit certificates; a second control unit, used to control the N credit certificate recipients to retain one share of credit certificates and randomly send the other N-1 shares of credit certificates to the other N-1 credit certificate recipients; a third control unit, used to control the N credit certificate recipients to sum the retained share of credit certificates and the received N-1 shares of credit certificates to obtain N summed results; and a statistics unit, used to perform statistics on the N summed results to obtain the used floating credit certificates.

[0122] Optionally, the credit certificate issuance device provided in this application embodiment further includes: a third acquisition unit, used to acquire the issuance result of the target credit certificate; and an update unit, used to verify the issuance result and update the credit assessment level of the target credit certificate recipient based on the verification result.

[0123] The credit certificate issuance device provided in this application embodiment receives a credit certificate issuance application from a target credit certificate recipient; based on the credit certificate issuance application, it calls a target blockchain node to determine the target credit certificate recipient's floating credit limit certificate and fixed credit limit certificate. The floating credit limit certificate is used to issue credit certificates to N credit certificate recipients, and the fixed credit limit certificate is used to issue credit certificates to the target credit certificate recipient, where N is a positive integer greater than 1; the target credit certificate is determined from the floating and fixed credit limits; and the target credit certificate is issued to the target credit certificate recipient. This solves the problems of insufficient flexibility in credit certificate issuance and complex collaborative processes in related technologies, thereby achieving flexible control over the credit limit and realizing flexible and verifiable issuance of credit certificates.

[0124] The aforementioned credit certificate issuing device includes a processor and a memory. The receiving module 51, calling module 52, determining module 53, and issuing module 54 are all stored as program units in the memory. The processor executes the aforementioned program units stored in the memory to realize the corresponding functions.

[0125] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured. By adjusting kernel parameters, the inflexible issuance of credit documents and the complex collaborative processes in related technologies can be addressed. This allows for flexible control over the credit limit and enables flexible and verifiable issuance of credit documents.

[0126] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0127] This invention provides a computer-readable storage medium storing a program thereon, which, when executed by a processor, implements the credit certificate issuance method.

[0128] This invention provides a processor for running a program, wherein the program executes the credit certificate issuance method during runtime.

[0129] like Figure 3 As shown, this embodiment of the invention provides an electronic device 70, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs the following steps: receiving a credit certificate issuance application from a target credit certificate recipient; based on the credit certificate issuance application, calling a target blockchain node to determine the target credit certificate recipient's floating credit limit certificate and fixed credit limit certificate, wherein the floating credit limit certificate is used to issue credit certificates to N credit certificate recipients, and the fixed credit limit certificate is used to issue credit certificates to the target credit certificate recipient, where N is a positive integer greater than 1; determining the target credit certificate from the floating and fixed credit limits; and issuing the target credit certificate to the target credit certificate recipient. The device in this document can be a server, PC, PAD, mobile phone, etc.

[0130] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having the following method steps: receiving a credit certificate issuance application from a target credit certificate recipient; based on the credit certificate issuance application, invoking a target blockchain node to determine the target credit certificate recipient's floating credit limit certificate and fixed credit limit certificate, wherein the floating credit limit certificate is used to issue credit certificates to N credit certificate recipients, and the fixed credit limit certificate is used to issue credit certificates to the target credit certificate recipient, where N is a positive integer greater than 1; determining the target credit certificate from the floating credit limit and the fixed credit limit; and issuing the target credit certificate to the target credit certificate recipient.

[0131] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0132] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0133] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0134] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0135] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0136] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0137] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0138] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0139] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for issuing credit instruments, characterized in that, include: Receive credit document issuance applications from the recipient of the target credit document; Based on the credit certificate issuance application, the target blockchain node is invoked to determine the floating credit certificate and fixed credit certificate of the target credit certificate recipient. The floating credit certificate is used to issue credit certificates to N credit certificate recipients, and the fixed credit certificate is used to issue credit certificates to the target credit certificate recipient. N is a positive integer greater than 1. The target credit certificate is determined from the floating credit certificate and the fixed credit certificate; Issue the target credit certificate to the recipient of the target credit certificate; The step of determining the target credit certificate from the floating credit limit certificate and the fixed credit limit certificate includes: obtaining the credit assessment level of the recipient of the target credit certificate; if the credit assessment level is higher than a predetermined level, determining the target credit certificate from the floating credit limit certificate based on the credit certificate issuance application; otherwise, determining the target credit certificate from the fixed credit limit certificate. The step of determining the target credit certificate from the floating credit limit certificates includes: obtaining the issuance limit of the floating credit limit certificates; calling a secure multi-party computation node to calculate the used floating credit limit certificates of the N credit certificate recipients; determining the target floating credit limit certificate among the floating credit limit certificates based on the issuance limit and the used floating credit limit certificates; and determining the target credit certificate based on the target floating credit limit certificate.

2. The method according to claim 1, characterized in that, Prior to receiving the credit document issuance application from the target credit document recipient, the method further includes: A business chain network is established based on the issuer and receiver of credit certificates. The business chain network includes multiple business chains, and each business chain has M blockchain nodes, including the target blockchain, where M is a positive integer greater than 1.

3. The method according to claim 2, characterized in that, The method further includes: The target blockchain is invoked to register digital identities for the issuer and recipient of the credit certificate, wherein the digital identities are used to verify the issuance result of the credit certificate.

4. The method according to claim 1, characterized in that, The invocation of the secure multi-party computation node to calculate the used floating credit limit certificates of the N credit certificate recipients includes: Control the N credit certificate recipients to randomly divide their respective used floating credit limit certificates into N credit limit certificates; Control the N credit certificate recipients to retain one share of the credit limit certificate, and randomly send the other N-1 shares of the credit limit certificate to the other N-1 credit certificate recipients respectively; The N credit certificate recipients are controlled to sum up the one retained credit certificate and the N-1 received credit certificates respectively, to obtain N summation results; The N summation results are statistically analyzed to obtain the used floating quota voucher.

5. The method according to any one of claims 1 to 4, characterized in that, The method further includes: Obtain the issuance result of the target credit certificate; The issuance result is verified, and the credit rating of the recipient of the target credit certificate is updated based on the verification result.

6. A credit certificate issuing device, characterized in that, include: The receiving module is used to receive credit document issuance applications from the target credit document recipient; The calling module is used to call the target blockchain node to determine the floating credit limit certificate and the fixed credit limit certificate of the target credit limit certificate recipient based on the credit certificate issuance application. The floating credit limit certificate is used to issue credit certificates to N credit limit certificate recipients, and the fixed credit limit certificate is used to issue credit certificates to the target credit limit certificate recipient. N is a positive integer greater than 1. The determination module is used to determine the target credit certificate from the floating credit certificate and the fixed credit certificate; The issuance module is used to issue the target credit certificate to the recipient of the target credit certificate; The determining module is further configured to obtain the credit assessment level of the recipient of the target credit certificate; if the credit assessment level is higher than the predetermined level, the target credit certificate is determined from the floating credit certificate based on the credit certificate issuance application; otherwise, the target credit certificate is determined from the fixed credit certificate. The determining module is further configured to obtain the upper limit of the issuance of the floating credit limit certificate; call the secure multi-party computing node to calculate the used floating credit limit certificates of the N credit certificate recipients; determine the target floating credit limit certificate among the floating credit limit certificates based on the upper limit of issuance and the used floating credit limit certificates; and determine the target credit certificate based on the target floating credit limit certificate.

7. A computer storage medium, characterized in that, The computer storage medium is used to store a program, wherein the program, when running, controls the device where the computer storage medium is located to execute the credit certificate issuance method according to any one of claims 1 to 5.

8. An electronic device, characterized in that, It includes one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the credit document issuance method according to any one of claims 1 to 5.

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