CN117577248B - Medical data sharing method and system integrating blockchain and privacy protection technology - Google Patents

Abstract

The invention discloses a medical data sharing method and a system for fusing a blockchain and a privacy intersection technology. The invention realizes the unified searching and screening functions of multi-center data on the blockchain and the matching and aligning functions of the multi-center data by introducing the searchable encryption technology and the privacy set intersection technology, enriches the functionality of medical data sharing, and truly realizes the data communication and intercommunication among the multi-centers under the security privacy condition.

Description

Medical data sharing method and system integrating blockchain and privacy protection technology

Technical Field

The present invention belongs to the field of medical information technology, and in particular to a medical data sharing method and system that integrates blockchain and privacy protection technology.

Background technique

Medical data refers to all data sets related to medical and health activities, involving medical services, disease prevention and control, health protection, and health care. It has the characteristics of large data volume, multiple data types, high value, and fast generation. However, in reality, medical data is often not effectively utilized, so the value contained cannot be fully developed. The main reasons are as follows: First, key medical data is often created and maintained by different medical institutions or departments, and is scattered among multiple centers, which makes it inconvenient and inefficient to share medical data between medical institutions. In addition, medical data itself is highly sensitive and contains a large amount of patient privacy information. Its leakage may lead to serious consequences, making most medical institutions reluctant to share their data, hindering the improvement of medical service quality and the development of high-precision research. Therefore, for medical institutions and relevant departments, how to achieve the collection, sharing and effective use of multi-center medical data in a safe and private environment is still a huge challenge.

As a secure distributed ledger and platform, blockchain technology has been gradually applied to the medical field, providing a potential solution for multi-center medical data sharing. For large-scale medical data, blockchain can be combined with emerging security technologies such as privacy computing to provide a new way to store and exchange medical data elements, ensure the trusted sharing and safe use of medical data, and solve the problem of cross-institutional medical data not being able to be used.

At present, the technical solutions closest to this application are: ① Medical blockchain based on data transmission. This type of blockchain stores encrypted medical data ciphertext on the blockchain. Only users with corresponding decryption means can receive the data. The blockchain is mainly used as a medium for secure data transmission. Li Patrick et al. designed a decentralized drug management system called DMMS for the management of patient medication history. The Hyperledger Fabric network is used to upload detailed information about the prescriber, the patient receiving the prescription, and the drug to the blockchain, and asymmetric encryption is used to achieve privacy protection and permission control, which solves the difficulty of transmitting medical data and the insecurity of centralized networks. ② Medical blockchain based on permission verification. This type of blockchain stores specific medical data locally and stores the hash value of medical data on the chain, using the tamper-proof characteristics of the blockchain to achieve secure data storage. Zhang J et al. designed a blockchain sharing solution for electronic rehabilitation medical records, using hybrid P2P networks, asymmetric encryption algorithms, Raft consensus algorithms and other technologies to achieve distributed storage and privacy protection in the sharing process, and store summary information on the alliance blockchain in a blockchain data structure to achieve point-to-point query of medical data between different hospitals.

The existing medical blockchain models all have corresponding shortcomings. ① In the traditional medical blockchain based on data transmission, medical institutions need to upload all data to the blockchain, but in fact the storage capacity of the blockchain is limited. At the same time, for different recipients, the sender needs to re-encrypt the data and upload it again. With the increase in the amount of data uploaded, the performance and efficiency of the blockchain will drop significantly, so the storage capacity of the blockchain is a very big test. ② In the traditional medical blockchain based on permission verification, medical data needs to be stored locally and the data hash value is stored on the blockchain. Although this method reduces the storage overhead on the chain, it also leads to the problem of insufficient functionality of the medical blockchain in the process of sharing medical data. The simple data hash value can only realize simple data exchange, and some studies have also performed simple search functions on the data by storing summaries on the blockchain. However, in actual applications, the medical data itself is complex and changeable, so it is crucial to break the information island of a single medical institution and use the blockchain to achieve unified search, alignment and matching of multi-center medical data in a true sense.

Summary of the invention

The purpose of the present invention is to address the deficiencies of the prior art and provide a medical data sharing method and system that integrates blockchain and privacy protection technology.

The objective of the present invention is achieved through the following technical solutions:

According to a first aspect of this specification, a medical data sharing method integrating blockchain and privacy protection technology is provided, the method comprising:

Establishing a medical blockchain system, the medical blockchain system comprising two independent and parallel blockchains: a summary search chain and a data transmission chain;

Extract the medical data stored locally by medical institutions into summary form, and upload the medical data summary to the summary search chain through a consensus mechanism;

Search the medical data abstracts in the abstract search chain, filter the medical data abstracts according to the search conditions provided by the search party, and return the filter structure to the medical institution to which the medical data belongs;

The screened medical data summaries are matched and aligned with multiple medical institutions based on privacy intersection technology, and the alignment results are returned to the medical institution to which the medical data belongs;

If the medical institution that receives the screening or alignment results agrees to share the medical data, the medical data to be shared will be uploaded to the data transmission chain through an attribute encryption method based on a ciphertext strategy, and will be decrypted and obtained by the search party that meets the attribute conditions.

Furthermore, the summary search chain is composed of nodes of medical institutions and regulatory agencies, storing medical data summaries uploaded by medical institutions, and the regulatory platform serves as an external client for the search function;

The data transmission chain is composed of nodes of medical institutions, regulatory agencies and third-party agencies, and stores medical data uploaded after screening and alignment by medical institutions. The regulatory agency is responsible for the authority management of third-party agencies and completes data sharing between medical institutions and between medical institutions and third-party agencies.

Furthermore, the upload of the medical data summary is specifically as follows:

The medical data stored locally by medical institutions are extracted into an agreed summary form. The medical institutions regularly create blocks and connect them in chronological order. The created blocks complete the upload of the medical data summary to the chain through consensus among the nodes of each medical institution.

Furthermore, the search and screening of the medical data summary is specifically as follows:

Medical institutions determine security parameters based on security levels and generate their own public and private keys;

Medical institutions use their own public keys to encrypt the medical data summaries to be uploaded to the chain to generate ciphertext, and upload the ciphertext of all medical data summaries to the chain;

When the searcher searches for medical data summaries through the intermediary platform provided by the regulatory agency, the regulatory agency sends the searcher's search conditions to all medical institutions participating in the consensus on the summary search chain;

Each medical institution generates a trapdoor using its own private key based on the search criteria;

The smart contract searches all encrypted summaries of medical institutions stored on the chain according to the trapdoors uploaded by the medical institutions, compares the trapdoors with each encrypted summary, and selects the encrypted summaries that meet the search criteria;

The smart contract will notify the medical institution to which it belongs of the screened encrypted summary. The medical institution will decrypt the encrypted summary using its own private key to obtain the decrypted medical data summary.

Furthermore, the matching and alignment of the medical data summaries adopts the privacy intersection technology based on the Diffie-Hellman key exchange algorithm, and implements the encryption operation of exchanging the encryption order twice through the exchangeable encryption function, so that the participating parties obtain exactly the same irreversible ciphertext for the intersection data.

Furthermore, for any two medical institutions to be matched and aligned with medical data summaries, denoted as A and B, the matching and alignment process is as follows:

For medical institution A, a random number α is selected as the private key, a hash operation is performed on each screened medical data summary, and the hash value is encrypted using the private key α to generate a ciphertext. On the chain, the ciphertext/> Sent to medical institution B through the regulatory agency node;

For medical institution B, a random number β is selected as the private key, a hash operation is performed on each screened medical data summary, and the hash value is encrypted using the private key β to generate a ciphertext. On the chain, the ciphertext/> Sent to medical institution A through the regulatory agency node;

Medical institution B receives the ciphertext Use the private key β to perform secondary encryption to generate ciphertext/> And upload it to the chain again; Medical institution A receives the ciphertext/> Use private key α to perform secondary encryption to generate ciphertext/> And wind it up again;

Compare ciphertexts through smart contracts deployed on the summary search chain and/> ,/> and/> The consistent medical data summary is the intersection data/> .

Furthermore, the medical data is specifically shared as follows:

Medical institutions participating in data sharing generate public keys and master keys based on security parameters;

For the medical data to be shared, the medical institution generates an access structure according to the requirements specified by the search party to be shared, and encrypts the medical data to be shared with the public key to generate ciphertext. The medical institution uploads the generated ciphertext to the data transmission chain through consensus;

Each search party combines its own attributes and the master key to generate a private key for decryption. For search parties that meet the attribute conditions, the generated private key is used to decrypt the encrypted medical data to obtain medical data that meets the search conditions, thereby completing the secure sharing of medical data.

According to a second aspect of this specification, a medical data sharing system integrating blockchain and privacy protection technology is provided, the system comprising:

Blockchain framework module: establish a medical blockchain system, which includes two independent and parallel blockchains: a summary search chain and a data transmission chain;

Data summary upload module: extracts the medical data stored locally by medical institutions into summary form, and uploads the medical data summary to the summary search chain through a consensus mechanism;

Data summary search and screening module: Search the medical data summaries in the summary search chain, screen the medical data summaries according to the search conditions provided by the searcher, and return the screening structure to the medical institution to which the medical data belongs;

Data summary matching and alignment module: matches and aligns the selected medical data summaries across multiple medical institutions based on privacy intersection technology, and returns the alignment results to the medical institution to which the medical data belongs;

Data transmission and sharing module: If the medical institution that receives the screening or alignment results agrees to share the medical data, the medical data to be shared will be uploaded to the data transmission chain through an attribute encryption method based on the ciphertext strategy, and will be decrypted and obtained by the search party that meets the attribute conditions.

According to the third aspect of this specification, a medical data sharing device integrating blockchain and privacy intersection technology is provided, comprising a memory and one or more processors, wherein the memory stores executable code, and when the processor executes the executable code, the medical data sharing method integrating blockchain and privacy intersection technology as described in the first aspect is implemented.

According to a fourth aspect of this specification, a computer-readable storage medium is provided, on which a program is stored. When the program is executed by a processor, the medical data sharing method that integrates blockchain and privacy protection technology as described in the first aspect is implemented.

The beneficial effects of the present invention are:

1. The present invention designs a dual-chain parallel blockchain system structure. First, through two independent and parallel medical blockchains, on-chain search of medical data summaries and on-chain sharing of corresponding medical data are realized, and only necessary and key data are stored, which solves the problems of insufficient storage space and bloated blockchain volume in medical blockchains based on data transmission; second, blockchain is combined with attribute encryption technology, and summary retrieval is separated from data transmission, so as to realize one-time upload and multiple sharing and many-to-many data sharing modes, avoiding the problems of multiple requests and repeated sharing of data sharing in medical blockchains based on authority verification, and solving the problem of low efficiency of multi-center data sharing.

2. This invention introduces searchable encryption technology and privacy set intersection technology, and organically combines the two to achieve unified search and screening functions of multi-center data on the blockchain, as well as matching and alignment functions of multi-center data. It solves the problem of insufficient functionality of traditional medical blockchains and the certain closedness and fragmentation of each center in the data sharing process, and truly realizes data exchange and intercommunication between multiple centers under the condition of ensuring security and privacy.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic diagram showing a medical data sharing method integrating blockchain and privacy protection technology according to an exemplary embodiment;

FIG2 is a diagram showing the architecture of a medical blockchain system based on dual chains according to an exemplary embodiment;

FIG3 is a structural diagram of a medical data sharing system integrating blockchain and privacy protection technology, shown in an exemplary embodiment;

FIG4 is a structural diagram of a medical data sharing device that integrates blockchain and privacy-enforcing technologies, shown as an exemplary embodiment.

Detailed ways

In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

The present invention provides a medical data sharing method that integrates blockchain and privacy-enhancing technology. As shown in FIG1 , the method includes establishing a medical blockchain system based on a dual chain, uploading data summaries, searching and screening data summaries, matching and aligning data summaries, and transmitting and sharing data. The specific implementation process of each part is described in detail below.

1. Establish a dual-chain medical blockchain system

Different from the traditional medical blockchain, as shown in Figure 2, the medical blockchain system of the present invention consists of two independent parallel blockchains, each with different functions, and the functions, status and number of nodes involved are also different. There are three types of nodes participating in the medical blockchain system of the present invention:

① Medical institutions, such as hospitals. This type of node is a full node with data upload and consensus functions. It is mainly responsible for uploading and downloading medical data summaries and required data. It is fully trusted by default in the system;

② Third-party institutions, such as universities, research centers, pharmaceutical companies, insurance companies, private clinics, etc. The main purpose of the system is to obtain the required medical data and participate in some consensus functions under certain conditions. Such nodes are semi-trusted nodes by default;

③ Regulatory agencies: Regulatory agencies are responsible for the management and approval of the authority and access of third-party agencies in the blockchain, and serve as an intermediate functional platform for data search and alignment matching, but do not participate in the consensus mechanism.

The above three types of nodes will jointly constitute two blockchains: summary search chain and data transmission chain.

① The summary search chain is composed of medical institution nodes and regulatory agency nodes. It will store the medical data summaries uploaded by various medical institutions, and the regulatory platform will serve as the external client of the search function. Third-party agency nodes do not participate in the work of the chain.

②The data transmission chain is composed of all three types of nodes, which store the data uploaded by medical institutions after screening and alignment according to corresponding requirements, and complete data sharing between medical institutions and between medical institutions and third-party institutions. The nodes of third-party institutions will participate in the consensus in this part.

2. Data summary upload

In order to ensure the security of data on the blockchain and overcome the storage space limitations and performance bottlenecks of the blockchain, the present invention uses a storage mode that combines on-chain and off-chain. Specific and detailed medical data will be stored in the local server of the medical institution, and the summary search chain will store the medical data in the form of an agreed summary on the chain. The medical institution will create blocks regularly and connect them in chronological order. Each block consists of two parts: a block header and a block body. The block header contains necessary information such as block hash, timestamp, and Merkle root; the Merkle tree of the block body is the key to the summary, mainly including information such as medical institution ID, patient ID, disease type, medical data format, and medical treatment time, so as to achieve refined search and screening of medical data, and can further achieve data alignment of different conditions such as patient samples or disease types. For example, data alignment can be performed at the patient level. Specifically, if a patient has medical records in multiple medical institutions, the screening and alignment mechanism can be used to obtain all the medical information of the patient in multiple medical institutions within a fixed time interval at one time; or data alignment can be performed at the disease type level. Specifically, if a scientific research institute needs to study the potential relationship between disease A and disease B, the screening and alignment mechanism can be used to find patients with both disease A and disease B in each medical institution and their medical information.

The blocks created by the medical institution complete the upload of summary data to the chain through the consensus between the nodes. In this step, only the nodes of the medical institution participate in the consensus because they are completely trustworthy by default. The consensus here will use the Raft consensus algorithm to improve the efficiency of the consensus. The maximum number of fault-tolerant nodes it supports is (N-1)/2, where N is the total number of nodes in the cluster. The general process of the Raft consensus algorithm is as follows: First, a "leader" is elected, and then the "leader" is given full power to manage the writing of the block. After receiving the write request of the block, the "leader" completes the write operation, generates the block, and copies it to other nodes.

3. Data summary search and screening

In order to ensure the security and privacy of data during the search and screening process, this paper adopts the Public Key Encryption With Searching (PEKS) method to implement the search function. The complete data summary search and screening process is as follows:

(1) Medical institutions determine safety parameters based on their respective safety levels , and generate its own public key/> and private key/> ;

in is the key generation function.

(2) Summary of data to be uploaded to the chain , the medical institution encrypts it with its own public key to generate ciphertext ;

in It is an encryption function; the ciphertext of all data summaries are uploaded to the chain.

(3) When a searcher searches for medical data summaries through the regulator’s intermediate functional platform, the regulator will Sent to all medical institutions participating in the consensus on the summary search chain, such as search conditions/> For: all the medical information of a patient ID within a fixed time interval;

Medical institutions according to search conditions Through your own private key /> Generate the corresponding trapdoor/> ;

in is a trapdoor function.

(4) The smart contract deployed on the summary search chain is based on the trapdoors on the chain of each medical institution. , all encrypted summaries of the medical institution stored on the chain/> Search and compare trapdoors/> and each encrypted digest/> , determine the search conditions/> and data summary/> Whether it matches, return each encrypted summary/> Comparison results of /> If it does not match, , if it matches then/> ;

in is the matching function.

(5) After the search is completed, the smart contract will send an encrypted summary that meets the screening requirements Notify the medical institution and search party to which the medical institution belongs, and the medical institution will send the encrypted summary/> Decrypted with its own private key to obtain the decrypted data summary , used for subsequent matching and alignment;

in is the decryption function.

4. Data Summary Matching and Alignment

After completing the preliminary data screening, the screened data is further matched and aligned to obtain medical data that meets common requirements from multiple centers, i.e. multiple medical institutions. The present invention introduces the Private Set Intersection (PSI) technology to obtain the intersection of multi-center medical data without exposing data outside the intersection. This step will be completed through the regulatory agency node used for communication and the smart contract deployed on the summary search chain. In order to facilitate the combination with searchable encryption to achieve privacy intersection on the blockchain, the present invention adopts the PSI scheme based on the Diffie-Hellman key exchange algorithm. The scheme is based on the idea of the Diffie-Hellman key exchange protocol and implements two encryption operations of exchanging encryption orders through an exchangeable encryption function, so that the participating parties can obtain exactly the same irreversible ciphertext for the intersection data. For the present invention, taking the privacy intersection between medical institution A and medical institution B as an example, the data summary matching and alignment process is as follows:

Assume that after the initial search and screening of data summaries, the data summaries that meet the requirements in medical institution A are as follows: , the summary of data that meets the requirements in medical institution B is/> , where the commutative encryption function is defined as follows:

in, For data that needs to be encrypted, /> This is two encryption operations.

For medical institution A, select a random number As a private key. For each data digest/> , medical institution A performs hash operation on it/> , and then encrypt it with the private key based on its hash value to generate ciphertext/> On the chain, and this ciphertext/> Sent to medical institution B through the regulatory agency node.

For medical institution B, select a random number As a private key. For each data digest/> , medical institution B performs hash operation on it/> , and then encrypt it with the private key based on its hash value to generate ciphertext/> On the chain, and this ciphertext/> Sent to medical institution A through the regulatory agency node.

Medical institution B receives the ciphertext from medical institution A. , using its private key/> It is encrypted twice to generate ciphertext/> And wind it up again.

Medical institution A receives the ciphertext from medical institution B , using its private key/> It is encrypted twice to generate ciphertext/> And wind it up again.

Compare the encrypted ciphertexts of medical institutions A and B after double encryption through the smart contract deployed on the summary search chain and/> If medical institutions A and B have the same data summary, the ciphertexts obtained by the two encryptions are the same, so/> and The consistent data summary in is the intersection data U of the two.

in Represents a set intersection operation.

If multi-center data summary matching and alignment is required, the data summary matching and alignment of two medical institutions shall be performed multiple times according to the above steps. Specifically, in the case where more than two medical institutions are screened out, for example, medical institutions A, B, and C are screened out, the data of medical institutions A and B can be aligned first, and the alignment results can be aligned with the data of medical institution C, so as to obtain medical data summaries that meet the screening requirements in all three medical institutions.

5. Data transmission and sharing module

After completing the search and screening of data summaries, matching and alignment of data summaries, it is necessary to share specific data that meets the requirements between medical institutions and third-party institutions, and between medical institutions. This step is achieved through a second blockchain-data transmission chain that is parallel and independent to the summary search chain. In order to ensure the efficiency and privacy of the data sharing process, the present invention introduces the attribute encryption (KP-ABE) method based on the ciphertext strategy to achieve secure many-to-many sharing. The sharing process is as follows:

(1) Medical institutions participating in data sharing shall share data according to security parameters. Generate public key/> and the master key/> ;

in is the key generation function.

(2) For the medical data to be shared, the medical institution will generate the access structure T according to the requirements specified by the search party to be shared, and combine it with the public key Encrypt and protect the shared medical data D to generate ciphertext/> ;

in is an encryption function; the medical institution generates the ciphertext through consensus/> Upload to the data transfer chain.

(3) For attribute encryption, different access structures correspond to different attributes. Only when attribute S satisfies access structure T can decryption be performed. For the ciphertext generated by access structure T , each search party will own the attribute S and the master key/> Combined to generate a private key for decryption/> ;

in is the key generation function.

(4) For search parties that meet the attribute conditions, the generated private key can be used to decrypt the encrypted medical data, obtain the medical data that meets the search conditions, and complete the secure sharing of medical data. When there are multiple search parties, as long as they have the attributes that meet the access structure, they can decrypt the ciphertext, avoiding the space occupation and efficiency reduction caused by multiple encryption;

in is the decryption function.

The search party can be a third-party organization or other medical institution. The third-party organization is a semi-trusted node in the medical blockchain system. Considering its instability, the consensus algorithm of the data transmission chain adopts the Practical Byzantine Fault Tolerance (PBFT). The PBFT algorithm provides (n-1)/3 fault tolerance while ensuring availability and security. That is, in a blockchain system with n nodes, no more than (n-1)/3 nodes can be tolerated as malicious nodes, which greatly improves the fault tolerance rate of the consensus algorithm, resists malicious attacks, and protects system consistency.

The present invention also provides a medical data sharing system integrating blockchain and privacy protection technology, as shown in FIG3 , the system mainly includes the following five modules:

Blockchain framework module: Establish a medical blockchain system, provide underlying support, allocate and confirm the functions and status of each node in the blockchain, and provide a trusted security environment and privacy protection for the exchange of medical data; specifically, the established medical blockchain system includes two independent and parallel blockchains: summary search chain and data transmission chain;

Data summary upload module: extracts the medical data stored locally by medical institutions into summary form, and uploads the medical data summary to the summary search chain through a consensus mechanism;

Data summary search and screening module: Search the medical data summaries in the summary search chain, screen the medical data summaries according to the search conditions provided by the searcher, and return the screening structure to the medical institution to which the medical data belongs;

Data summary matching and alignment module: matches and aligns the screened medical data summaries across multiple medical institutions based on privacy intersection technology, and returns the alignment results to the medical institution to which the medical data belongs;

Data transmission and sharing module: If the medical institution that receives the screening or alignment results agrees to share the medical data, the medical data to be shared will be uploaded to the data transmission chain through an attribute encryption method based on the ciphertext strategy, and will be decrypted and obtained by the search party that meets the attribute conditions.

All relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, and will not be repeated here.

Corresponding to the aforementioned embodiment of the medical data sharing method integrating blockchain and privacy intersection technology, the present invention also provides an embodiment of a medical data sharing device integrating blockchain and privacy intersection technology.

Referring to FIG. 4 , an embodiment of the present invention provides a medical data sharing device that integrates blockchain and privacy intersection technology, including a memory and one or more processors. The memory stores executable code. When the processor executes the executable code, it is used to implement a medical data sharing method that integrates blockchain and privacy intersection technology in the above embodiment.

The embodiment of a medical data sharing device that integrates blockchain and privacy intersection technology provided by the present invention can be applied to any device with data processing capabilities, and the device with data processing capabilities can be a device or apparatus such as a computer. The device embodiment can be implemented by software, or by hardware or a combination of software and hardware. Taking software implementation as an example, as a device in a logical sense, it is formed by the processor of any device with data processing capabilities in which it is located to read the corresponding computer program instructions in the non-volatile memory into the memory and run it. From the hardware level, as shown in Figure 4, it is a hardware structure diagram of any device with data processing capabilities where a medical data sharing device that integrates blockchain and privacy intersection technology provided by the present invention is located. In addition to the processor, memory, network interface, and non-volatile memory shown in Figure 4, any device with data processing capabilities where the device in the embodiment is located can also include other hardware according to the actual function of the device with data processing capabilities, which will not be repeated.

The implementation process of the functions and effects of each unit in the above-mentioned device is specifically described in the implementation process of the corresponding steps in the above-mentioned method, and will not be repeated here.

As for the device embodiment, since it basically corresponds to the method embodiment, the relevant parts can refer to the partial description of the method embodiment. The device embodiment described above is only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of the present invention. A person of ordinary skill in the art can understand and implement it without paying creative labor.

An embodiment of the present invention also provides a computer-readable storage medium on which a program is stored. When the program is executed by a processor, a medical data sharing method that integrates blockchain and privacy-enhancing technology in the above embodiment is implemented.

The computer-readable storage medium may be an internal storage unit of any device with data processing capability described in any of the aforementioned embodiments, such as a hard disk or a memory. The computer-readable storage medium may also be an external storage device of any device with data processing capability, such as a plug-in hard disk, a smart media card (SMC), an SD card, a flash card, etc. equipped on the device. Furthermore, the computer-readable storage medium may also include both an internal storage unit and an external storage device of any device with data processing capability. The computer-readable storage medium is used to store the computer program and other programs and data required by any device with data processing capability, and may also be used to temporarily store data that has been output or is to be output.

The above embodiments are used to illustrate the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims (4)

1. A medical data sharing method integrating blockchain and privacy protection technology, characterized by comprising: Establishing a medical blockchain system, the medical blockchain system comprising two independent and parallel blockchains: a summary search chain and a data transmission chain; The summary search chain is composed of nodes of medical institutions and regulatory agencies, storing medical data summaries uploaded by medical institutions, and the regulatory platform serves as an external client for the search function; The data transmission chain is composed of nodes of medical institutions, regulatory agencies and third-party institutions, storing medical data uploaded after screening and alignment by medical institutions. The regulatory agency is responsible for the authority management of third-party institutions, and completes data sharing between medical institutions and between medical institutions and third-party institutions. Extract the medical data stored locally by the medical institution into a summary form, and upload the medical data summary to the summary search chain through a consensus mechanism; the specific uploading of the medical data summary is: extract the medical data stored locally by the medical institution into an agreed summary form, and the medical institution regularly creates blocks and connects them in chronological order, and the created blocks complete the upload of the medical data summary to the chain through the consensus between the nodes of each medical institution; Search the medical data abstracts in the abstract search chain, filter the medical data abstracts according to the search conditions provided by the search party, and return the filter structure to the medical institution to which the medical data belongs; the search and filter of the medical data abstracts are specifically as follows: Medical institutions determine security parameters based on security levels and generate their own public and private keys; Medical institutions use their own public keys to encrypt the medical data summaries to be uploaded to the chain to generate ciphertext, and upload the ciphertext of all medical data summaries to the chain; When the searcher searches for medical data summaries through the intermediary platform provided by the regulatory agency, the regulatory agency sends the searcher's search conditions to all medical institutions participating in the consensus on the summary search chain; Each medical institution generates a trapdoor using its own private key based on the search criteria; The smart contract searches all encrypted summaries of medical institutions stored on the chain according to the trapdoors uploaded by the medical institutions, compares the trapdoors with each encrypted summary, and selects the encrypted summaries that meet the search criteria; The smart contract notifies the medical institution to which the selected encrypted summary belongs. The medical institution decrypts the encrypted summary using its own private key to obtain the decrypted medical data summary. The selected medical data summaries are matched and aligned with multiple medical institutions based on the privacy intersection technology, and the alignment results are returned to the medical institution to which the medical data belongs; the matching and alignment of the medical data summaries adopts the privacy intersection technology based on the Diffie-Hellman key exchange algorithm, and the encryption operation of exchanging the encryption order twice is realized through the exchangeable encryption function, so that the participating parties obtain exactly the same irreversible ciphertext for the intersection data; If the medical institution that receives the screening or alignment results agrees to share the medical data, the medical data to be shared will be uploaded to the data transmission chain through an attribute encryption method based on a ciphertext strategy, and will be decrypted and obtained by the search party that meets the attribute conditions; the sharing of the medical data is specifically as follows: Medical institutions participating in data sharing generate public keys and master keys based on security parameters; For the medical data to be shared, the medical institution generates an access structure according to the requirements specified by the search party to be shared, and encrypts the medical data to be shared with the public key to generate ciphertext. The medical institution uploads the generated ciphertext to the data transmission chain through consensus; Each search party combines its own attributes and the master key to generate a private key for decryption. For search parties that meet the attribute conditions, the generated private key is used to decrypt the encrypted medical data to obtain medical data that meets the search conditions, thereby completing the secure sharing of medical data. 2. According to the medical data sharing method integrating blockchain and privacy intersection technology as described in claim 1, it is characterized in that for any two medical institutions to be matched and aligned with medical data summaries, they are respectively denoted as A and B, and the matching and alignment process is as follows: For medical institution A, a random number α is selected as the private key, and a hash operation is performed on each screened medical data summary. The private key α is used to encrypt the hash value to generate the ciphertext U _A on the chain, and the ciphertext U _A is sent to medical institution B through the regulatory agency node; For medical institution B, a random number β is selected as the private key, and a hash operation is performed on each screened medical data summary. The private key β is used to encrypt the hash value to generate the ciphertext U _B on the chain, and the ciphertext U _B is sent to medical institution A through the regulatory agency node; Medical institution B uses private key β to re-encrypt the received ciphertext U _A to generate ciphertext U _AB and upload it to the chain again; medical institution A uses private key α to re-encrypt the received ciphertext U _B to generate ciphertext U _BA and upload it to the chain again; The ciphertexts U _BA and U _AB are compared through the smart contract deployed on the summary search chain. The consistent medical data summaries in U _BA and U _AB are the intersection data U = U _BA ∩ U _AB . 3. A medical data sharing system integrating blockchain and privacy-enforcing technology implemented by the method of claim 1 or 2, characterized in that it includes: Blockchain framework module: establish a medical blockchain system, which includes two independent and parallel blockchains: a summary search chain and a data transmission chain; Data summary upload module: extracts the medical data stored locally by medical institutions into summary form, and uploads the medical data summary to the summary search chain through a consensus mechanism; Data summary search and screening module: Search the medical data summaries in the summary search chain, screen the medical data summaries according to the search conditions provided by the searcher, and return the screening structure to the medical institution to which the medical data belongs; Data summary matching and alignment module: matches and aligns the selected medical data summaries across multiple medical institutions based on privacy intersection technology, and returns the alignment results to the medical institution to which the medical data belongs; Data transmission and sharing module: If the medical institution that receives the screening or alignment results agrees to share the medical data, the medical data to be shared will be uploaded to the data transmission chain through an attribute encryption method based on the ciphertext strategy, and will be decrypted and obtained by the search party that meets the attribute conditions. 4. A medical data sharing device that integrates blockchain and privacy intersection technology, comprising a memory and one or more processors, wherein the memory stores executable code, and wherein when the processor executes the executable code, the medical data sharing method that integrates blockchain and privacy intersection technology as described in claim 1 or 2 is implemented.