A blockchain-based data transaction system

Abstract

The application discloses a kind of data transaction systems based on block chain, belong to data transaction technical field, solve the problem that existing data transaction mode is difficult to take into account privacy, efficiency and credibility.The system includes several data trader nodes and consumer nodes, blockchain network and cloud server;Among them, each data trader node is also respectively accessed to cloud server, and uploads respective encryption data based on keyword to cloud server;Blockchain network is used to receive the data query request based on keyword submitted by consumer node and transaction deposit, the re-encryption key that data trader node responds to current data query request, the re-encryption data that the encryption data that cloud server responds to current data query request and re-encryption key is obtained by re-encryption processing;Also used to verify re-encryption data, send re-encryption data that pass verification to consumer node, send transaction deposit to cloud server, end this transaction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data transaction, and particularly relates to a data transaction system based on a block chain. BACKGROUND

[0002] With the rapid development of big data and cloud computing technology, data transaction has become one of the core scenarios in the digital economy. However, the traditional centralized data transaction platform has the following key pain points:

[0003] (1) Data privacy leakage risk: data is easy to be stolen by the platform or the third party in the process of transmission and storage, and lacks an end-to-end security protection mechanism.

[0004] (2) Lack of transaction trust: the centralized platform may tamper with transaction records or misuse data, leading to a trust crisis between data providers and consumers.

[0005] (3) Insufficient fine-grained access control: existing solutions are difficult to achieve precise data retrieval and permission management based on keywords (such as medical diagnosis, financial risk control, and other sensitive tags), and cannot meet the needs of complex business scenarios.

[0006] (3) Insufficient transaction transparency and auditability: the transaction process lacks tamper-proof on-chain records, making it difficult to trace responsibility in disputes.

[0007] The decentralized and tamper-proof characteristics of the block chain technology provide a new solution for data transaction, but the existing block chain data transaction scheme still has the following technical bottlenecks:

[0008] (1) Contradiction between encrypted data and keyword retrieval: direct on-chain storage of encrypted data will result in low retrieval efficiency, while off-chain storage faces the problems of data integrity and access control verification.

[0009] (2) Complex re-encryption key management: data owners need to generate independent keys for each consumer, which is costly in key distribution and update, and is prone to single point failure.

[0010] Therefore, how to provide a new solution for data transaction that takes into account privacy, efficiency and credibility is a technical problem to be solved at present. SUMMARY

[0011] In view of the above analysis, the embodiments of the present application aim to provide a data transaction system based on a block chain to solve the problem that the existing data transaction method is difficult to take into account privacy, efficiency and credibility.

[0012] The present application provides a data transaction system based on a block chain, which comprises: a plurality of data transactor nodes and consumer nodes, a block chain network and a cloud server; wherein,

[0013] Each data trader node, consumer node, and cloud server connects to the blockchain network and uses the blockchain network for identity verification, monitoring services, and event capture.

[0014] Each data trader node also connects to a cloud server and uploads its own keyword-based encrypted data to the cloud server;

[0015] The blockchain network is used to receive data query requests and transaction deposits submitted by consumer nodes based on keywords, re-encryption keys from data transaction node responses to the current data query requests, and re-encrypted data obtained by re-encrypting encrypted data from cloud server responses to the current data query requests and re-encryption keys. It is also used to verify the re-encrypted data, send the verified re-encrypted data to the consumer node, send the transaction deposit to the cloud server, and end the transaction.

[0016] Based on the above solution, the present invention also makes the following improvements:

[0017] Furthermore, each data trader node, consumer node, and cloud server serves as a node in the blockchain network, and the blockchain network uses the following method to verify the identity of each node:

[0018] Each node generates its own public-private key pair and uses the public key to send a registration request to the blockchain network.

[0019] In a blockchain network, a validator node receives a node's registration request, encrypts the node's identity information using the node's public key, and generates a unique identity ID for the corresponding node using a hash algorithm, which is then stored in the blockchain ledger.

[0020] When any node initiates an authentication request, it uses its own private key to sign the message containing the current nonce value and sends the signature and public key to the blockchain network.

[0021] In the blockchain network, the verification node uses the public key in the authentication request to decrypt the signature and compares it with the nonce value cached locally. If the decryption result is equal to the nonce value + 1, the verification is successful, the nonce value is updated, and the verification result is broadcast.

[0022] Once more than a preset percentage of nodes in the blockchain network have successfully verified the identity, a message indicating successful identity verification is returned to the requesting node.

[0023] Furthermore, each data trader node, consumer node, and cloud server captures events through the blockchain network listening service and executes:

[0024] Consumer nodes are used to initiate keyword-based data query requests and generate digital signatures;

[0025] The data owner node is configured to subscribe to a data transaction event, store a data query request related to the data owner node in a smart contract of a blockchain network, generate a re-encryption key in response to the current data query request, and send the re-encryption key to the smart contract.

[0026] The cloud server is configured to deploy a blockchain network listening service, and when the current data query request and the re-encryption key are listened to, search for encrypted data according to the current data query request and the re-encryption key, re-encrypt the searched encrypted data to obtain re-encrypted data, and send the re-encrypted data to the smart contract.

[0027] Further, the smart contract in the blockchain network is configured to verify whether the keyword in the keyword-based data query request is consistent with the keyword in the re-encrypted data, and if the keywords are consistent, the re-encrypted data is verified.

[0028] Further, the consumer node is configured to generate a keyword trapdoor based on a keyword of required data and a private key of the consumer node, form a keyword-based data query request, and upload the keyword-based data query request to the blockchain network; and receive the re-encrypted data verified by the blockchain network, and decrypt the re-encrypted data to obtain the matched required data.

[0029] Further, for the jth consumer node, in order to request the required data with the keyword w', the keyword trapdoor is generated by using the trapdoor generation algorithm based on the private key b j,2 and the keyword w' of the required data. H is a hash function.

[0030] Further, in the data query request, in addition to the keyword trapdoor, the public key and address information of the consumer node and the address information of the target data owner node are included.

[0031] Further, the data owner node is configured to encrypt the data itself based on a keyword of the data, generate encrypted data, and upload the encrypted data to a server; and after the data owner node listens to a data query request related to the data owner node through a blockchain network, generate a re-encryption key in response to the current data query request using a private key of the data owner node and a public key of the consumer, and send the re-encryption key to the blockchain network.

[0032] Further, the cloud server is configured to verify the access permission of the encrypted data of the target data owner node by using the re-encryption key when the current data query request and the re-encryption key are listened to, and locate the encrypted data with the same keyword as the keyword of the required data in the cloud server by using the keyword trapdoor.

[0033] Further, the cloud server is configured to re-encrypt the searched matching encrypted data according to the re-encryption key to generate re-encrypted data.

[0034] Compared with the prior art, the application can achieve at least one of the following beneficial effects.

[0035] The blockchain-based data transaction system provided by the application aims to solve the following core problems:

[0036] 1) Balance between privacy protection and verifiability: By storing encrypted data through an off-chain cloud server and verifying re-encrypted data on-chain, both data privacy and the credibility of transaction results are ensured.

[0037] 2) Fine-grained keyword search and permission control: By using a keyword trapdoor and a re-encryption key mechanism, the data owner can accurately authorize consumer access rights, supporting complex query scenarios.

[0038] 3) Decentralized trust building: Through identity verification on the blockchain network, automatic execution of smart contracts, and a transaction deposit mechanism, the centralized trust risk is eliminated, and the transaction transparency is improved.

[0039] 4) Efficient on-chain verification: Lightweight verification logic (such as keyword consistency checking) is designed to reduce on-chain computing load and improve transaction processing efficiency.

[0040] In summary, the blockchain-based data transaction system provided by the application integrates blockchain, re-encryption, and cloud storage technologies to provide a new solution for data transactions that balances privacy, efficiency, and credibility.

[0041] The above technical solutions can be combined with each other to achieve more preferred combination solutions. Other features and advantages of the application will be described in the subsequent specification, and some advantages will become apparent from the specification or through implementation of the application. The purpose and other advantages of the application can be achieved and obtained from the specific content indicated in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0042] The accompanying drawings are provided for the purpose of illustrating specific embodiments and are not considered limiting of the application, in which the same reference numerals indicate the same components throughout the drawings;

[0043] Figure 1 The structure diagram of the blockchain-based data transaction system provided by the embodiment of the application.

[0044] Figure 2 The data transaction flow diagram of the blockchain-based data transaction system provided by the embodiment of the application. DETAILED DESCRIPTION

[0045] Preferred embodiments of the present application will be described in detail below with reference to the drawings, wherein the drawings constitute a part of this application, and are used to explain the principles of the present application, and are not intended to limit the scope of the present application.

[0046] A specific embodiment of the present application discloses a blockchain-based data transaction system, a structural schematic diagram of which is shown in the figure. Figure 1 As shown in the figure, the system comprises a plurality of data trader nodes and consumer nodes, a blockchain network and a cloud server; wherein each data trader node, consumer node and cloud server is connected to the blockchain network, and performs identity authentication, listens to service and captures events through the blockchain network; each data trader node is also connected to the cloud server, and uploads its own encrypted data based on a keyword to the cloud server; the blockchain network is used for receiving a data query request based on a keyword and a transaction deposit submitted by a consumer node, a re-encryption key in response to a current data query request submitted by a data trader node, and re-encrypted data obtained by re-encryption processing of encrypted data in response to a current data query request and a re-encryption key submitted by a cloud server; and is also used for verifying the re-encrypted data, sending the re-encrypted data that passes the verification to the consumer node, sending the transaction deposit to the cloud server, and ending the transaction.

[0047] The blockchain-based data transaction system proposed in the embodiment is a decentralized data transaction system, which aims to realize safe and efficient transaction of data through an interaction protocol without the intervention of a trusted third party. Participants in the data transaction system involve the following four key entities: consumers, data owners, cloud service providers and blockchains (embedded smart contracts). Except for the smart contract, it is assumed that the other entities are semi-honest entities, that is, they will follow the protocol, but may try to obtain additional benefits from the protocol. Next, the roles and responsibilities of each entity are described as follows.

[0048] (1) Consumer

[0049] Role positioning: the consumer is the demand side of data transaction, and obtains the required data by paying fees.

[0050] Main responsibilities:

[0051] 1) Initiate data request: submit a data query request based on a keyword to the system, and specify the characteristics and range of the required data;

[0052] 2) Pay transaction fees: pay the corresponding data purchase fees to the data owner according to the protocol;

[0053] 3) Obtain the required data: receive the re-encrypted data verified by the smart contract, and decrypt to obtain the required data.

[0054] (2) Data owner

[0055] Role positioning: Data owner is the provider of data, owns the ownership of data, and obtains remuneration by selling data to consumers.

[0056] Main responsibilities:

[0057] 1) Data storage delegation: entrust encrypted data to cloud service providers for storage, ensuring data security and privacy;

[0058] 2) Respond to data requests: retrieve and provide matching re-encryption keys according to consumer keyword requests;

[0059] 3 Collect transaction remuneration: obtain remuneration for data sales from consumers through the execution of smart contracts.

[0060] (3) Cloud service provider

[0061] Role positioning: Cloud service provider is the infrastructure support of data storage and delivery, providing encrypted data storage services for data owners, and assisting in completing data delivery in the data transaction process, and is the participant of data transaction and data download.

[0062] Main responsibilities:

[0063] 1) Data storage management: receive encrypted data entrusted by data owners, responsible for data storage, backup and management, ensure data persistence and availability;

[0064] 2) Data delivery support: in the process of data transaction, according to the instructions of smart contract, assist in completing the operation of data download and delivery, ensure that data can be safely and efficiently transmitted to consumers.

[0065] (4) Blockchain (embedded smart contract)

[0066] Role positioning: Blockchain as the central de-centralized trust infrastructure, embedded smart contract for automatic execution of transaction protocol, ensure the fairness, transparency and non-tamperability of data transaction process.

[0067] Main responsibilities:

[0068] 1) Transaction protocol execution: automatically execute data transaction protocol through smart contract, ensure that both parties operate according to the preset rules, prevent fraud;

[0069] 2) Transaction record storage: record each link and result of data transaction on the blockchain, provide tamper-proof transaction evidence, enhance the credibility and traceability of transaction;

[0070] 3) Fairness guarantee: through the consensus mechanism of blockchain and the logic of smart contract, ensure the fairness of data transaction process, protect the legitimate rights and interests of participants;

[0071] 4) Data verification: Verify the integrity and accuracy of the re-encrypted data to ensure that the obtained data meets expectations.

[0072] In the data transaction system as shown in Figure 1 Each entity works together through the interaction protocol to complete the entire process of data transaction. Consumers request data through keywords, data owners provide data according to requests, cloud service providers are responsible for storing and delivering data, and blockchain and smart contracts run through the entire transaction process to ensure fairness and security of transactions. The design of this data transaction model fully utilizes the technical advantages of blockchain and smart contracts, combines the division of responsibilities of each entity, and realizes secure data transactions in a decentralized environment, providing a feasible technical solution for the healthy development of the data factor market. Next, the specific composition of the system and the functions of each entity are described as follows.

[0073] (1) Blockchain network

[0074] 1) Identity verification

[0075] Each data trader node, consumer node, and cloud server as a node in the blockchain network, the blockchain network uses the following methods to verify the identity of each node:

[0076] Each node generates its own public and private key pair, and uses the public key to send a registration request to the blockchain network;

[0077] The verification node in the blockchain network receives the node's registration request, encrypts the node's identity information using the node's public key, and generates a unique identity ID for the node through a hash algorithm and stores it in the blockchain ledger;

[0078] When any node initiates an identity verification request, use the private key to sign the message containing the current nonce value, and send the signature and public key to the blockchain network;

[0079] The verification node in the blockchain network uses the public key in the identity verification request to decrypt the signature and compares it with the local cached nonce value. If the decryption result is equal to nonce value + 1, the verification is successful, the nonce value is updated, and the verification result is broadcast;

[0080] When more than a preset proportion of nodes in the blockchain network confirm that the verification is successful, the request node returns a message indicating that the identity verification is successful.

[0081] 2) Capture events through the blockchain network listening service

[0082] Each data trader node, consumer node, and cloud server captures events through the blockchain network listening service, which performs:

[0083] a consumer node for initiating a keyword-based data query request and generating a digital signature;

[0084] a data owner node for subscribing to a data transaction event, storing a data query request related to itself through a smart contract of a blockchain network, generating a re-encryption key responding to the current data query request, and sending to the smart contract;

[0085] a cloud server for deploying a blockchain network listening service, when listening to the current data query request and the re-encryption key, retrieving encrypted data according to the current data query request and the re-encryption key, and re-encrypting the retrieved encrypted data to obtain re-encrypted data, and sending the re-encrypted data to the smart contract.

[0086] 3) re-encrypted data verification

[0087] a smart contract in the blockchain network, verifying whether the keyword in the keyword-based data query request is consistent with the keyword in the re-encrypted data, if consistent, the re-encrypted data verification is passed.

[0088] Specifically, in the embodiment, each node can generate a public-private key pair based on a key generation algorithm of a bilinear mapping.

[0089] For the i-th data owner node, a random number a i,1 and a i,2 generate a private key sk i = (a i,1 , a i,2 ), calculate the public key and generate encrypted data C i,w according to the private key sk i of the data owner node, the data m and the keyword w of the data.

[0090] For the j-th consumer node, a random number b j,1 and b j,2 generate a private key sk j = (b j,1 , b j,2 ), calculate the public key

[0091] (2) consumer node

[0092] The consumer node is used to generate a keyword trapdoor according to the keyword of the required data and its own private key, form a keyword-based data query request, and upload to the blockchain network; and is also used to receive the re-encrypted data verified by the blockchain network, and obtain the matched required data after decryption.

[0093] For the jth consumer node, for the required data with the keyword w' of the request, according to the private key b j,2 and the keyword w' of the required data, the keyword trapdoor is generated by using the trapdoor generation algorithm H is a hash function.

[0094] In the data query request, in addition to including the keyword trapdoor, the public key and address information of the consumer node, and the address information of the target data owner node of the request are also included.

[0095] (3) Data owner node

[0096] The data owner node is used to encrypt the data itself based on the keyword of the data, generate encrypted data, and upload the encrypted data to the server; and is also used to, after listening to a data query request related to itself through the blockchain network, generate a re-encryption key for responding to the current data query request using the private key of itself and the public key of the consumer, and send it to the blockchain network.

[0097] Suppose the jth consumer requests data from the ith data owner, at this time, the ith data owner generates a re-encryption key i and the public key pk j of the jth consumer based on the private key sk

[0098] (4) Cloud server

[0099] 1) Data retrieval

[0100] When the current data query request and the re-encryption key are listened to, the access permission of the encrypted data of the target data owner node is verified by using the re-encryption key, and the encrypted data stored in the cloud server with the same keyword as the keyword of the required data is located by using the keyword trapdoor.

[0101] After inputting the encrypted data C i,w , the keyword trapdoor T j,w' and the re-encryption key rk i→j , if w = w', then the search algorithm outputs 1, representing that the related message is matched, otherwise 0 is output.

[0102] 2) Data re-encryption

[0103] The cloud server re-encrypts the matched encrypted data retrieved to generate re-encrypted data.

[0104] The cloud storage provider re-encrypts the matched encrypted data C i,w retrieved using the re-encryption key rk i→j to obtain re-encrypted data C j,w .

[0105] Further, the blockchain network receives the C j,w and the keyword trapdoor T j,w' After that, if w = w', the test algorithm outputs 1, representing that the ciphertext and the trapdoor are matched, i.e. the keyword generating the trapdoor and the message being tested are matched, otherwise 0 is output.

[0106] The consumer node decrypts the re-encrypted data by inputting the consumer's private key sk j and the ciphertext C j,w After that, the decrypted message m is output. Further, the data owner node can also decrypt its own data by inputting the data owner's private key sk i and the ciphertext C i,w After that, the decrypted message m is output.

[0107] According to the data transaction flowchart of the above-mentioned blockchain-based data transaction system as shown in Figure 2 , the following processes are included:

[0108] 1. The data owner uploads the encrypted data to the cloud server.

[0109] 2) The consumer generates a keyword trapdoor according to the keyword of the required data, submits a keyword-based data query request to the blockchain network, and pays the transaction deposit.

[0110] 3) The data owner generates a re-encryption key in response to the data query request and sends it to the smart contract.

[0111] 4) The cloud server retrieves the encrypted data according to the current data query request and the re-encryption key, and performs re-encryption processing on the retrieved encrypted data to generate re-encrypted data.

[0112] 5) The smart contract verifies the re-encrypted data and sends the verified re-encrypted data to the consumer and the transaction deposit to the cloud server.

[0113] 6) The consumer node decrypts the re-encrypted data to obtain the required data.

[0114] In addition, the data owner can also obtain the transaction deposit and data transaction status by interacting with the cloud service.

[0115] Those skilled in the art can understand that all or part of the processes of the above-mentioned embodiments can be completed by a computer program instructing related hardware, and the program can be stored in a computer readable storage medium. Among them, the computer readable storage medium is a disk, an optical disk, a read-only memory or a random access memory, etc.

[0116] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A blockchain-based data transaction system, characterized in that, The system comprises a plurality of data trader nodes and consumer nodes, a blockchain network and a cloud server, wherein Each data trader node, consumer node and cloud server accesses the blockchain network respectively, and performs identity authentication, listens to a service and captures an event through the blockchain network; Each data trader node also accesses the cloud server respectively, and uploads respective encrypted data based on a keyword to the cloud server; The blockchain network is configured to receive a data query request based on a keyword and a transaction deposit submitted by a consumer node, a re-encryption key in response to a current data query request submitted by a data trader node, and re-encrypted data obtained by re-encryption processing of encrypted data in response to the current data query request and the re-encryption key submitted by the cloud server, and is further configured to verify the re-encrypted data, send the re-encrypted data that passes the verification to the consumer node, send the transaction deposit to the cloud server, and end the transaction; Each data trader node, consumer node and cloud server serves as a node in the blockchain network, and the blockchain network performs identity authentication on each node in the following manner: Each node generates a public-private key pair of itself, and uses the public key to send a registration request to the blockchain network; A verification node in the blockchain network receives the registration request of the node, encrypts the identity information of the node by using the public key of the node, and generates a unique identity ID of the node by using a hash algorithm and stores the unique identity ID in a blockchain ledger; When any node initiates an identity authentication request, the node uses a private key of itself to sign a message containing a current nonce value, and sends the signature and the public key to the blockchain network; The verification node in the blockchain network uses the public key in the identity authentication request to decrypt the signature, and compares the decrypted result with a locally cached nonce value, if the decrypted result is equal to the nonce value+1, the verification is successful, the nonce value is updated, and a verification result is broadcasted; When more than a preset proportion of nodes in the blockchain network confirm that the verification is successful, the nodes return a message that the identity authentication is successful to the requesting node; Each data trader node, consumer node and cloud server captures an event by listening to a service through the blockchain network, and performs the following operations: The consumer node is configured to initiate a data query request based on a keyword and generate a digital signature; The data trader node is configured to subscribe to a data transaction event, store a data query request related to itself through a smart contract of the blockchain network, generate a re-encryption key in response to a current data query request, and send the re-encryption key to the smart contract; The cloud server is configured to deploy a blockchain network listening service, listen to a current data query request and a re-encryption key, retrieve encrypted data according to the current data query request and the re-encryption key, perform re-encryption processing on the retrieved encrypted data to obtain re-encrypted data, and send the re-encrypted data to the smart contract.

2. The blockchain-based data transaction system according to claim 1, wherein The smart contract in the blockchain network verifies whether the keyword in the data query request based on the keyword is consistent with the keyword in the re-encrypted data, and if the two keywords are consistent, the re-encrypted data passes the verification.

3. The blockchain-based data transaction system according to claim 2, wherein The consumer node is configured to generate a keyword trapdoor based on a keyword of required data and a private key of the consumer node, form a keyword-based data query request, and upload the data query request to a blockchain network; and is further configured to receive re-encrypted data issued by the blockchain network and obtain matched required data after decryption.

4. The blockchain-based data transaction system according to claim 3, characterized in that, For the Each consumer node, for requests containing keywords The required data, based on your own private key Keywords of the required data Keyword trapdoors are generated using a trapdoor generation algorithm. H is a hash function. 5.The blockchain-based data transaction system of claim 4, wherein, In the data query request, in addition to the keyword trapdoor, the data query request further comprises public key and address information of the consumer node and address information of a target data trader node.

6. The blockchain-based data transaction system according to claim 5, characterized in that, The data trader node is configured to encrypt data itself based on a keyword of the data, generate encrypted data, and upload the encrypted data to a server; and is further configured to, after listening to a data query request related to the data trader node through a blockchain network, generate a re-encryption key for responding to the current data query request by using a private key of the data trader node and a public key of the consumer, and send the re-encryption key to the blockchain network.

7. The blockchain-based data transaction system according to claim 6, characterized in that, The cloud server is configured to, when listening to the current data query request and the re-encryption key, verify access permission of encrypted data of the target data trader node by using the re-encryption key, and locate encrypted data stored in the cloud server and having a same keyword as the keyword of the required data by using the keyword trapdoor. 8.The blockchain-based data transaction system of claim 7, wherein, The cloud server is configured to re-encrypt the matched encrypted data retrieved by using the re-encryption key, and generate re-encrypted data.

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