A blockchain-based method and system for tracing a used car detection and evaluation report

Abstract

The application provides a kind of based on blockchain's second-hand car detection evaluation report traceability method and system, it is related to traceability detection technical field, including the following steps: the second-hand car is detected to obtain structured report data, structured report data includes multiple traceability information and multiple characteristic information;Structured data is encrypted, generates first verification code and characteristic information set integrity check code, generates a second verification code for each traceability information;Structured report data is stored in distributed storage system, obtains the global content addressing identifier of structured report data in distributed storage system;Multiple key data is organized according to predefined order and format, calculate abstract fingerprint, abstract fingerprint, structured report abstract and multiple verification codes are written into the block of blockchain;In second-hand car export transaction, traceability verification is carried out.The application has the advantages of high reliability and can ensure that detection report data is real, complete, traceable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of traceability detection, in particular to a blockchain-based traceability method and system for used car detection and evaluation reports. BACKGROUND

[0002] In the used car trade, the trust problem in cross-border transactions has become a major obstacle.

[0003] Different countries have different detection standards, evaluation systems, and regulatory requirements for used cars, which results in that an authoritative detection and evaluation report issued in one country may not be accepted or needs to be re-detected in another country. This not only increases the trade cost and time cycle, but also provides space for information fraud (such as adjusting the table and concealing accident history). Traditional paper reports or centralized electronic report systems cannot guarantee the originality, tamper resistance, and trusted circulation between agencies of the data, which seriously restricts the large-scale development of used car export business.

[0004] Therefore, there is an urgent need for a solution that can establish cross-country and cross-agency trust, and achieve a high-reliability authentication solution that can ensure the authenticity, integrity, and traceability of detection report data. SUMMARY

[0005] The purpose of the present application is to provide a blockchain-based traceability method and system for used car detection and evaluation reports, which has high reliability and can ensure the authenticity, integrity, and traceability of detection report data.

[0006] The present application is achieved by the following technical solutions:

[0007] A blockchain-based traceability method for used car detection and evaluation reports, comprising the following steps:

[0008] Step S1: detecting a used car to obtain structured report data, the structured report data including multiple traceability information and multiple characteristic information, the traceability information being fixed identification information of the vehicle, and the characteristic information being results of detection items;

[0009] Step S2: encrypting the structured data, generating a first verification code for each type of characteristic information, generating a characteristic information set integrity check code based on the first verification code, generating a second verification code for each type of traceability information, and forming multiple verification codes;

[0010] Step S3: storing the structured report data in a distributed storage system and obtaining a global content addressing identifier of the structured report data in the distributed storage system;

[0011] The plurality of key data is organized in a predefined order and format to form a structured report abstract, a hash calculation is performed on the structured report abstract to obtain an abstract fingerprint, and the abstract fingerprint, the structured report abstract and the multiple verifications are written into a block of a blockchain;

[0012] Step S4: In each link of the used car export transaction, the traceability record formed based on the structured report data, the multiple verifications, the structured report abstract and the abstract fingerprint is used for traceability verification.

[0013] Preferably, the plurality of traceability information includes a vehicle identification code, an engine number and a first registration date; and one piece of feature information corresponds to the result of one detection item.

[0014] Preferably, the method for generating the second verification code for the traceability information is:

[0015] The parameter name and value of the traceability information are spliced to form a traceability string;

[0016] A hash algorithm is applied to encrypt the traceability string, and a second verification code is output.

[0017] Preferably, the method for generating the first verification code for the feature information is:

[0018] Each piece of feature information is subjected to the following operations:

[0019] The item detection name, detection result and detection method of the feature information are spliced to form a feature string;

[0020] A hash algorithm is applied to encrypt the feature string, and the first verification code is output.

[0021] Preferably, the method for generating the feature information set integrity check code is:

[0022] After obtaining all the first verification codes, all the feature verification codes are deterministically sorted, and all the feature verification codes are spliced in the order of deterministic sorting to form a spliced first verification code;

[0023] The spliced first verification code is encrypted by a hash algorithm to obtain the feature information set integrity check code.

[0024] Preferably, the format of the structured report abstract is a JSON object or a binary structure of a specific byte sequence.

[0025] The key data includes the traceability information, the set of second verification codes, the feature information set integrity check code, the global content addressing identifier, the identification of the detection agency and the timestamp of the generation of the detection report.

[0026] Preferably, the method of performing hash calculation on the structured report summary is:

[0027] deterministically serializing the structured report summary into a continuous byte stream;

[0028] performing hash calculation on the continuous byte stream.

[0029] Preferably, when the structured report summary is in the format of JSON object, the method of deterministically serializing the structured report summary into a continuous byte stream is:

[0030] using JSON serialization method to ensure that the order of keys, spaces and numerical representation are fixed.

[0031] Preferably, the method of traceability verification is:

[0032] the verifier enters the VIN code, retrieves the traceability record of the used car from the blockchain, and downloads the structured report data and the structured report summary;

[0033] processing the plurality of pieces of traceability information and the plurality of pieces of feature information of the structured report data in the same manner as in step S2 to obtain a feature information set integrity check code and a second verification code for verification;

[0034] comparing the first verification code and the feature information set integrity check code for verification with the first verification code and the feature information set integrity check code stored in the block of the blockchain, and if they are consistent, passing the overall tamper detection verification, otherwise failing;

[0035] comparing the second verification code for verification with the second verification code stored in the block of the blockchain, and if they are consistent, passing the vehicle identity information verification, otherwise failing;

[0036] performing hash calculation on the structured report summary in the manner of step S3 to obtain a summary fingerprint for verification;

[0037] comparing the summary fingerprint for verification with the summary fingerprint in the block of the blockchain, and if they are consistent, passing the authenticity check, otherwise failing;

[0038] If the overall tamper detection verification, the vehicle identity information verification and the authenticity check all pass, the verifier uses a private key to digitally sign, thereby adding a new transaction record on the blockchain.

[0039] The application also provides an authentication system for a used car detection and evaluation report.

[0040] A data acquisition terminal is configured to detect a used car and obtain the structured report data.

[0041] The blockchain is a permissioned chain including a plurality of nodes, each of which is run by an agency, including an export country detection agency, an export country customs / inspection, an import country certification agency, an import country customs and a trader.

[0042] The authentication system server includes:

[0043] An information acquisition module is configured to receive the structured report data.

[0044] A verification code generation module is configured to generate the first verification code, the second verification code and the integrity check code of the feature information set.

[0045] An on-chain storage module is configured to generate the structured report abstract and the abstract fingerprint, package the structured report abstract, the abstract fingerprint and the multiple verification codes, and write them into a block of the blockchain.

[0046] The technical scheme of the application has at least the following advantages and beneficial effects:

[0047] The application generates a verification code for each feature information and traceability information, and further generates a check code that can express data integrity, effectively preventing data from being tampered with, even if a single detection data is modified, the abnormality can be found through the verification code check, and the credibility of the detection and evaluation report is improved.

[0048] The application stores the structured report data into a distributed storage system and generates a global content addressing identifier, which not only guarantees data security and backup, but also improves access efficiency and fault tolerance, avoiding the single point failure problem caused by centralized data storage.

[0049] The blockchain used in the application allows multiple agencies to jointly maintain the blockchain ledger, connects different cross-border agencies into a consensus network, and the authenticity of the report is no longer dependent on the reputation of a single agency, but is witnessed and endorsed by all participants on the entire chain, fundamentally solving the trust problem of international mutual recognition.

[0050] The application stores the structured report data off-chain and distributes it, and only the abstract fingerprint, the structured report abstract and the multiple verification codes are on-chain, which balances data security, privacy and blockchain performance, and the verification process of each link is automated, greatly improving the clearance and authentication efficiency.

[0051] The present scheme takes the single vehicle VIN code as the core for traceability, establishes a unique and tamper-proof "digital identity" for each independent report, and is completely applicable to non-standard and unique asset traceability scenarios.

[0052] The present application effectively eliminates the information asymmetry problem in the process of used car transaction by the characteristics of blockchain, such as openness, traceability and tamper-proof, and enhances the trust of consumers and regulatory agencies in vehicle detection results. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 A flowchart of a traceability method of a used car detection and evaluation report based on a blockchain provided for embodiment 1 of the present application;

[0054] Figure 2 A principle schematic diagram of an authentication system of a used car detection and evaluation report provided for embodiment 2 of the present application. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0056] Embodiment 1

[0057] The present embodiment provides a traceability method of a used car detection and evaluation report based on a blockchain, referring to Figure 1 , comprising the following steps:

[0058] Step S1: detecting a used car to obtain structured report data, the structured report data including a plurality of traceability information and a plurality of characteristic information, the traceability information being fixed identification information of the vehicle, and the characteristic information being results of detection items.

[0059] Specifically, the plurality of traceability information refers to the unique fixed identification information of the vehicle, which mainly serves as the primary key of the report, and can include the vehicle identification code, the engine number and the first registration date. One characteristic information corresponds to the result of one detection item, such as engine working condition, left front door paint thickness, OBD fault code, chassis rust photo, etc. In actual application scenarios, a structured report data can include hundreds of characteristic information.

[0060] In particular, the blockchain preferably adopts a consortium chain (such as Hyperledger Fabric), and can also adopt a public chain (such as Ethereum) and use its side chain or Layer2 solution to obtain higher transparency and public credibility, but the transaction cost and privacy protection problem needs to be considered.

[0061] Step S2: encrypting the structured data, generating a first verification code for each feature information, generating a feature information set integrity check code based on the first verification code, generating a second verification code for each traceability information, and forming multiple verification codes.

[0062] This step can realize precise processing of structured data and generate multiple verification codes with high security and verification capability.

[0063] In this embodiment, the method for generating the second verification code for the traceability information is:

[0064] The parameter name and value of the traceability information are spliced to form a traceability string. The purpose of this step is to standardize the parameter pairs. For example:

[0065] The parameter name (such as "vehicle identification code") and its corresponding value (such as "LSVXXXXXX") are standardized and spliced, for example, to form a string of "vehicle identification code: LSVXXXXXX".

[0066] The traceability string is encrypted by applying a hash algorithm, and the second verification code is output. The hash algorithm here is a pre-set, high-strength one-way encryption hash algorithm, which can use SHA-256, SHA-3 or national standard SM3 algorithm.

[0067] The above scheme ensures that the second verification code of each traceability parameter not only uniquely reflects its content, but also causes the verification code to change in an avalanche effect style due to any minor changes to the parameter name or value, thereby effectively ensuring the authenticity and integrity of the vehicle basic identity information and having anti-collision property.

[0068] On the other hand, the method for generating the first verification code for the feature information is:

[0069] For each feature information, the following operations are performed:

[0070] The item detection name, detection result and detection method of the feature information are spliced to form a feature string. For example, the detection item name (such as "left front door paint thickness"), the detection result (such as "120μm" or a hash value / CID pointing to an image / video file), and the optional detection method / standard code are standardized and spliced to form a unique feature information description string.

[0071] The feature string is encrypted by applying a hash algorithm, and the first verification code is output. Similarly, the hash algorithm here is a preset, high-strength one-way encryption hash algorithm, which can use the same or different algorithm as the hash algorithm for generating the second verification code, such as SHA-256. The first verification code ensures the authenticity and integrity of the content of a single test item,

[0072] In order to verify the integrity of the total number, type and order (if order is important) of feature information (test items) in the entire test report, prevent malicious addition, deletion or exchange of test items, the embodiment introduces a feature information set integrity verification code. Based on the above method of obtaining the first verification code, the generation method of the feature information set integrity verification code is:

[0073] After obtaining all the first verification codes, all the feature verification codes are determined to be sorted, and all the feature verification codes are spliced to form a spliced first verification code in the order of the determined sorting, for example, the first verification code is sorted according to the lexicographical order of the feature item name, or sorted according to the preset test item order in the test report template.

[0074] The spliced first verification code is encrypted by a hash algorithm to obtain the feature information set integrity verification code.

[0075] In this way, the first verification code ensures that each test item content is not tampered with, and the feature information set integrity verification code ensures the integrity of the total number, type and relative order (if defined) of test items that should be included in the test report through the ordered aggregation hash of all first verification codes. Any increase, deletion, tampering or order change (if the order is included in the sorting rule) of the test item will cause the feature information set integrity verification code to change.

[0076] Step S3: Store the structured report data in the distributed storage system, and obtain the global content addressing identifier of the structured report data in the distributed storage system.

[0077] The purpose of this step is to store the complete used car test evaluation report (including all traceability information parameters and their values, all feature information entries and detailed results, and associated large media files such as photos / videos) in a preset distributed storage system (for example: IPFS - InterPlanetary File System). Other cloud storage solutions can also be used, but the neutrality of the storage service provider and the accessibility of the data must be ensured.

[0078] In addition, the plurality of key data needs to be organized in a predefined order and format to form a structured report summary, hash the structured report summary to obtain a summary fingerprint, and write the summary fingerprint, the structured report summary and the multiple verification codes into a block of the blockchain.

[0079] As a preferred solution, the format of the structured report summary is a JSON object or a binary structure of a specific byte sequence. The purpose is to organize key data items in a predefined order and format to form a structured data object as a "report summary".

[0080] The key data includes the traceability information, the set of second verification codes, the feature information set integrity check code, the global content addressing identifier, the identification of the detection agency and the timestamp of the generation of the detection report. For example:

[0081] Traceability information (plaintext) <code>source_information< / code> ):

[0082] Vehicle identification number (VIN) <code>vin< / code> : [value of VIN code]

[0083] Engine number <code>engine_number< / code> : [value of engine number]

[0084] First registration date <code>first_registration_date< / code> : [value of first registration date, unified format such as YYYY-MM-DD]

[0085] (Other necessary traceability information parameters and their values, arranged in a fixed order)

[0086] Feature information set integrity check code <code>feature_set_integrity_checksum< / code> : [value of feature information set integrity check code generated in step S2, usually a hexadecimal string]

[0087] Second verification code set <code>second_vericodes_set< / code> :

[0088] [value of second verification code generated for VIN code]

[0089] [value of second verification code generated for engine number]

[0090] [value of second verification code generated for first registration date]

[0091] (Second verification codes corresponding to other traceability parameters, consistent with the order of traceability information parameters or sorted according to a predetermined rule)

[0092] (Special note: Alternatively, in order to reduce the amount of data on the chain, here it can also be the hash value calculated after splicing all the second verification codes in a fixed order, but this will sacrifice the directness of checking a certain second verification code alone. If space permits, it is recommended to keep the original set.)

[0093] Full report storage address ( <code>full_report_cid< / code> ): [The value of the global content addressing identifier IPFS CID of the structured report data in the distributed storage system obtained in step S3]

[0094] Detection agency identifier ( <code>inspection_agency_id< / code> ): [The unique digital identity ID of the detection agency or its public key fingerprint]

[0095] Report generation timestamp ( <code>timestamp< / code> ): [Unix timestamp or time string in ISO8601 format of report generation]

[0096] On this basis, the method for calculating the hash of the structured report summary is:

[0097] Deterministically serialize the structured report summary and then convert it into a continuous byte stream;

[0098] Hash the continuous byte stream.

[0099] At the same time, when the format of the structured report summary is a JSON object, the method for deterministically serializing the structured report summary and then converting it into a continuous byte stream is:

[0100] Use the JSON serialization method for processing, such as RFC 8785 JSON Canonicalization Scheme-JCS, to ensure that the order of keys, spaces, and numerical representations are fixed, and then always generate exactly the same byte stream for logically identical JSON objects.

[0101] Step S5: At each link of the used car export transaction, the traceability record formed based on the structured report data, multiple verification codes, structured report summaries, and summary fingerprints is verified for traceability.

[0102] As a preferred scheme of the present embodiment, the method for traceability verification is:

[0103] The verifier enters the VIN code, retrieves the traceability record of the used car from the blockchain, and downloads the structured report data and the structured report summary;

[0104] The plurality of traceability information and the plurality of characteristic information of the structured report data are processed in the same manner as in step S2 to obtain a characteristic information set integrity check code for verification and a second verification code.

[0105] The first verification code for verification and the characteristic information set integrity check code are compared with the first verification code and the characteristic information set integrity check code stored in the block of the blockchain. If they are consistent, the overall tamper detection item is passed, otherwise it is not passed. The passing of the verification can prove that the overall report (including the type, quantity, content and order) has not been tampered with.

[0106] The second verification code for verification is compared with the second verification code stored in the block of the blockchain. If they are consistent, the vehicle identity information verification is passed, otherwise it is not passed. The purpose of this verification is to verify the vehicle identity information.

[0107] The structured report summary is hashed according to the manner of step S3 to obtain a summary fingerprint for verification;

[0108] The summary fingerprint for verification is compared with the summary fingerprint in the block of the blockchain. If they are consistent, the authenticity verification is passed, otherwise it is not passed. The passing of the verification can prove that the report content has not been changed since being uploaded.

[0109] If the overall tamper detection item verification, vehicle identity information verification and authenticity verification are all passed, the verification party uses a private key to digitally sign, realizing the addition of a new transaction record on the blockchain, indicating its approval of the report. The subsequent link can directly view this signature to realize the transmission of trust.

[0110] Embodiment 2

[0111] The embodiment provides an authentication system for a used car detection and evaluation report, which is applied to the above-mentioned used car detection and evaluation report traceability method based on a blockchain, and refers to Figure 2 , comprising:

[0112] A data acquisition terminal is used to detect a used car to obtain the structured report data;

[0113] The blockchain is a permissioned chain including a plurality of nodes, each institution running a node, the institutions including an export country detection institution, an export country customs / inspection, an import country certification institution, an import country customs and a trader;

[0114] An authentication system server comprises:

[0115] An information acquisition module is used to receive the structured report data;

[0116] The verification code generation module is configured to generate the first verification code, the second verification code, and a feature information set integrity check code.

[0117] The upper chain storage module is configured to generate the structured report abstract and the abstract fingerprint, pack the structured report abstract, the abstract fingerprint, and the multiple verification codes, and write the multiple verification codes into a block of the block chain.

[0118] The above merely describes the preferred embodiments of the present application, but is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A blockchain-based traceability method for used car inspection and evaluation reports, characterized in that, Includes the following steps: Step S1: Inspect the used car to obtain structured report data. The structured report data includes multiple traceability information and multiple feature information. The traceability information is the vehicle's fixed identification information, and the feature information is the result of the inspection items. Step S2: Encrypt the structured data, generate a first verification code for each type of feature information, generate an integrity verification code for the feature information set based on the first verification code, and generate a second verification code for each type of traceability information to form a multi-factor verification code; Step S3: Store the structured report data in a distributed storage system and obtain the global content addressing identifier of the structured report data from the distributed storage system; Multiple key data are organized in a predefined order and format to form a structured report summary. The structured report summary is hashed to obtain a summary fingerprint. The summary fingerprint, the structured report summary, and the multi-factor verification code are then written into a block of the blockchain. Step S4: At each stage of the used car export transaction, traceability verification is carried out based on the traceability records formed by structured report data, multiple verification codes, structured report summaries, and summary fingerprints; The structured report summary is in the format of a JSON object or a binary structure with a specific byte order; The key data includes the traceability information, the set of the second verification codes, the integrity check code of the feature information set, the global content addressing identifier, the identifier of the testing institution, and the timestamp of the testing report generation; The method for hashing the structured report summary is as follows: The structured report summary is deterministically serialized and then converted into a continuous byte stream; Perform hash calculation on the continuous byte stream; When the structured report summary is in the format of a JSON object, the method for deterministically serializing the structured report summary and then converting it into a continuous byte stream is as follows: The process uses JSON serialization to ensure that the order of keys, spaces, and number representations are fixed.

2. The traceability method for a blockchain-based used car inspection and evaluation report according to claim 1, characterized in that, The traceability information includes the vehicle identification number, engine number, and first registration date; each piece of feature information corresponds to the result of a detection item.

3. The traceability method for a blockchain-based used car inspection and evaluation report according to claim 1, characterized in that, The method for generating the second verification code based on the traceability information is as follows: The parameter names and values ​​of the traceability information are concatenated to form a traceability string; The source string is encrypted using a hash algorithm, and the second verification code is output.

4. The traceability method for a blockchain-based used car inspection and evaluation report according to claim 1, characterized in that, The method for generating the first verification code based on the aforementioned feature information is as follows: Perform the following operations on each piece of feature information: The project detection name, detection result, and detection method of the aforementioned feature information are concatenated to form a feature string; The feature string is encrypted using a hash algorithm, and the first verification code is output.

5. The traceability method for a blockchain-based used car inspection and evaluation report according to claim 4, characterized in that, The method for generating the integrity check code of the feature information set is as follows: After obtaining all the first verification codes, all feature verification codes are deterministically sorted, and then concatenated in the order of deterministic sorting to form the concatenated first verification code. The first verification code is encrypted using a hash algorithm to obtain the integrity verification code of the feature information set.

6. The traceability method for a blockchain-based used car inspection and evaluation report according to claim 1, characterized in that, The method for tracing and verifying the source is as follows: The verifier enters the VIN code, retrieves the traceability record of the used car from the blockchain, and downloads the structured report data and the structured report summary; The multiple traceability information and multiple feature information of the structured report data are processed in the same way as in step S2 to obtain a feature information set integrity check code and a second verification code for verification. The first verification code and the feature information set integrity check code used for verification are compared with the first verification code and the feature information set integrity check code stored in the block of the blockchain. If they match, the verification that the project as a whole has not been tampered with is passed; otherwise, it is failed. The second verification code used for verification is compared with the second verification code stored in the block of the blockchain. If they match, the vehicle identity information verification is passed; otherwise, it is failed. The structured report digest is hashed according to step S3 to obtain a digest fingerprint for verification. The digest fingerprint used for verification is compared with the digest fingerprint in the block of the blockchain. If they match, the authenticity verification is passed; otherwise, it is failed. If the overall verification of the test items remains unchanged, and the verification of vehicle identity information and authenticity all pass, the verifier uses its private key to digitally sign the transaction, thereby adding a new transaction record to the blockchain.

7. A certification system for used car inspection and evaluation reports, applied to the blockchain-based traceability method for used car inspection and evaluation reports as described in any one of claims 1-6, characterized in that, include: A data acquisition terminal is used to inspect used cars and obtain the structured report data. Blockchain is a permissioned chain that includes multiple nodes, with each institution operating one node. These institutions include the exporting country's testing agency, the exporting country's customs / commodity inspection agency, the importing country's certification agency, the importing country's customs, and traders. The authentication system server includes: The information acquisition module is used to receive the structured report data; The verification code generation module is used to generate the first verification code, the second verification code, and the integrity verification code of the feature information set. The on-chain evidence storage module is used to generate the structured report summary and the summary fingerprint, package the structured report summary, the summary fingerprint and the multi-factor verification code, and write them into the blockchain block.

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