WO2020259635A1

WO2020259635A1 - Method and apparatus for sharing blockchain data

Info

Publication number: WO2020259635A1
Application number: PCT/CN2020/098289
Authority: WO
Inventors: 毛嘉宇; 范瑞彬; 张开翔; 张龙
Original assignee: 深圳前海微众银行股份有限公司
Priority date: 2019-06-27
Filing date: 2020-06-24
Publication date: 2020-12-30
Also published as: CN110224814A; CN110224814B

Abstract

The present invention relates to the field of fintech, and discloses a method and an apparatus for sharing blockchain data, the method comprising: a sharing mechanism acquires a first file and determines a hash value of the first file, determines an exchange public key corresponding to the first file, acquires an exchange public key of a plurality of first sharing mechanisms, determines an encryption key on the basis of the exchange public key corresponding to the first file and the exchange public key of the plurality of first sharing mechanisms, uses the encryption key to encrypt the first file to obtain an encrypted ciphertext of the first file, and sends the encrypted ciphertext to a data sharing smart contract of the blockchain. As the exchange public key corresponding to the first file is obtained by means of a private key of the sharing mechanism and an index number, different exchange public keys can be produced for different files without changing the private key of the sharing mechanism, thereby flexibly, conveniently, securely, and efficiently protecting the privacy of the user. Sending the encrypted file to the blockchain implements real placement of the encrypted file on the blockchain and implements real data sharing.

Description

Block chain data sharing method and device

Cross references to related applications

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on June 27, 2019, the application number is 201910569907.2, and the application name is "a blockchain data sharing method and device", the entire content of which is incorporated by reference In this application.

Technical field

The embodiment of the present invention relates to the field of financial technology (Fintech), and in particular to a method and device for sharing data on a blockchain (BlockChain).

Background technique

With the development of computer technology, more and more technologies are applied in the financial field. The traditional financial industry is gradually changing to Finteh. Blockchain technology is no exception, but due to the security and real-time requirements of the financial industry , But also higher requirements for technology.

The existing blockchain system does not directly send encrypted data to the blockchain, but only uploads the Hash (hash) result of the plaintext data to the chain to achieve a certain degree of tamper-proof and verifiable effects; the specific process is as follows : Use Hash algorithm (commonly used but not limited to SHA-2 algorithm) to encrypt the plaintext data, store the plaintext Hash result on the blockchain, and store the plaintext data off-chain. When other users need the plaintext of the data to be obtained, they request the plaintext data from the data owner through the off-chain or on-chain point-to-point secure communication channel; at the same time, download the Hash ciphertext pre-stored in the data from the blockchain. Perform verification.

However, the data in the above scheme is not really stored on the blockchain, and it is impossible to truly share data on the blockchain and control the data sharing authority, but only stores the verification data; it is impossible to restore the ciphertext to plaintext from the blockchain . The data stored on the blockchain is only used for verification, not for sharing.

Summary of the invention

The embodiment of the present invention provides a blockchain data sharing method and device, which are used to store shared data on the blockchain, realize that data sharing cannot be tampered with, and control the scope of data sharing.

In the first aspect, a blockchain data sharing method provided by an embodiment of the present invention includes:

The sharing institution obtains the first file and determines the hash value of the first file, where the first file is a file to be shared;

The sharing organization determines the exchange public key corresponding to the first file according to the hash value, the index number of the first file, and the private key of the sharing organization;

The sharing organization obtains the exchange public keys of a plurality of first sharing organizations, and the first sharing organization is an organization that jointly owns the common authority of the first file with the sharing organization; the exchange public keys of the plurality of first sharing organizations The keys are respectively determined by the plurality of first sharing institutions according to the hash value, the index number of the first file, and the private keys of the plurality of first sharing institutions;

Determining, by the sharing organization, the encryption key of the first file according to the exchange public key corresponding to the first file and the exchange public keys of the multiple first sharing organizations;

The sharing mechanism encrypts the first file using the encryption key of the first file, obtains the encrypted ciphertext of the first file, and sends the encrypted ciphertext to the data sharing of the blockchain In the smart contract, a second sharing organization requests to download the first file, and the second sharing organization is an organization other than the sharing organization and the plurality of first sharing organizations.

In the above technical solution, since the public exchange key corresponding to the first file is obtained through the private key and the index number of the shared institution, it is possible to generate different exchange keys for different files under the condition that the private key of the shared institution remains unchanged. It reduces the storage pressure of massive secret keys, and can protect user privacy flexibly, conveniently and effectively. Sending the encrypted file to the blockchain realizes the real winding of the encrypted file and real data sharing.

Optionally, the sharing organization determining the exchange public key corresponding to the first file according to the hash value, index number of the first file and the private key of the sharing organization includes:

Generating the prime numbers and primitive roots of the first file by the sharing mechanism;

The sharing organization determines the exchange private key of the first file according to the private key of the sharing organization and the index number of the first file;

The sharing agency determines the exchange public key of the first file according to the exchange private key, prime number, and original root of the first file.

Optionally, after generating the prime numbers and primitive roots of the first file, the sharing mechanism further includes:

The sharing mechanism composes the prime number and the primitive root into a string according to a preset separator;

The sharing organization encrypts the character string according to the hash value of the first file to obtain the exchange public number of the first file;

The sharing institution sends the exchange public number to the data sharing smart contract of the blockchain, so that the second sharing institution determines the exchange public number and the hash value of the first file. State the prime numbers and primitive roots of the first file.

Optionally, before the sharing agency obtains the first file, the method further includes:

The sharing organization generates the private key of the sharing organization;

The sharing agency creates the data sharing smart contract on the blockchain.

Optionally, the method further includes:

The sharing agency obtains the encrypted ciphertext of the second file from the data sharing smart contract of the blockchain, exchanges public data, authority information, and manager information;

The sharing institution requests the manager of the second file for the hash value of the second file and the exchange public key of the manager of the second file according to the manager information of the second file;

According to the authority information of the second file, the sharing organization requests the exchange public key of the organization having the common authority of the second file from the organization having the common authority of the second file;

The sharing organization is based on the exchange public number of the second file, the hash value of the second file, the exchange public key of the administrator of the second file, and the shared authority of the second file The exchange public key of the institution, which determines the encryption key of the second file;

The sharing agency decrypts the encrypted ciphertext of the second file according to the encryption key of the second file to obtain the second file.

Optionally, the sharing institution is based on the exchange public number of the second file, the hash value of the second file, the exchange public key of the manager of the second file, and the share of the second file To determine the encryption key of the second file by the exchange public key of the organization with the common authority, including:

The sharing mechanism determines the prime number and primitive root of the second file according to the interactive common number of the second file and the hash value of the second file;

The sharing institution determines the second file based on the original root of the second file, the exchange public key of the administrator of the second file, and the exchange public key of the institution with the common authority of the second file. The encryption key of the file.

In the second aspect, an embodiment of the present invention provides a blockchain data sharing device, including:

An obtaining unit, configured to obtain a first file and determine a hash value of the first file, where the first file is a file to be shared;

A processing unit, configured to determine the exchange public key corresponding to the first file according to the hash value, the index number and the private key of the sharing organization of the first file;

The obtaining unit is further configured to obtain the exchange public keys of a plurality of first sharing institutions, the first sharing institution being an institution that jointly owns the common authority of the first file with the sharing institution; the multiple first sharing institutions The exchange public keys of the institutions are respectively determined by the multiple first sharing institutions according to the hash value, the index number of the first file, and the private keys of the multiple first sharing institutions;

The processing unit is further configured to determine the encryption key of the first file according to the exchange public key corresponding to the first file and the exchange public keys of the plurality of first sharing institutions; use the first file Encrypt the first file with the encryption key to obtain the encrypted ciphertext of the first file, and send the encrypted ciphertext to the data sharing smart contract of the blockchain, so that the second sharing organization The download of the first file is requested, and the second sharing organization is an organization other than the sharing organization and the plurality of first sharing organizations.

In the third aspect, an embodiment of the present invention also provides a computing device, including:

Memory, used to store program instructions;

The processor is configured to call the program instructions stored in the memory, and execute the above blockchain data sharing method according to the obtained program.

In a fourth aspect, embodiments of the present invention also provide a computer-readable non-volatile storage medium, including computer-readable instructions, which when the computer reads and executes the computer-readable instructions, cause the computer to execute the aforementioned blockchain Data sharing method.

In a fifth aspect, the embodiments of the present invention also provide a computer program product, the computer program product includes a calculation program stored on a non-transitory computer-readable storage medium, the computer program includes program instructions, when the program instructions When executed by a computer, the computer is caused to execute the blockchain data sharing method as described above.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings needed in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative work, other drawings can be obtained from these drawings.

FIG. 1 is a schematic diagram of a system architecture provided by an embodiment of the present invention;

2 is a schematic flowchart of a blockchain data sharing method provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of another data encryption process provided by an embodiment of the present invention;

4 is a schematic diagram of a data decryption process provided by an embodiment of the present invention;

Figure 5 is a schematic diagram of a digital envelope provided by an embodiment of the present invention;

6 is a schematic structural diagram of a block chain data sharing device provided by an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

FIG. 1 exemplarily shows a system architecture to which an embodiment of the present invention is applicable. The system architecture may include multiple sharing institutions 100 and a blockchain system 200. The blockchain system 200 is a consortium chain built by multiple sharing institutions 100, and the consortium chain may include one or more blockchain nodes 210, so as to achieve more data activities in the institution.

Among them, the sharing organization 100 communicates with the blockchain system 200, and manages data sharing smart contracts in the blockchain system 200.

The blockchain system 200 is composed of multiple blockchain nodes 210, which respectively communicate with multiple sharing institutions 100, and are used to store data sent by the sharing institution 100, and to accept the sharing institutions 100 to deploy on the blockchain node 210. Data sharing smart contract for management. The multiple blockchain nodes 210 can be connected to each other for communication. Each blockchain node 210 includes multiple blocks, and the blocks are used for transaction data.

It should be noted that the structure shown in FIG. 1 is only an example, which is not limited in the embodiment of the present invention.

Based on the foregoing description, FIG. 2 exemplarily shows the flow of a blockchain data sharing method provided by an embodiment of the present invention, and the flow can be executed by a blockchain data sharing device.

As shown in Figure 2, the process specifically includes:

Step 201: The sharing institution obtains the first file and determines the hash value of the first file.

When the sharing organization needs to share the first file, it may first obtain the shared first file, and then use a hash algorithm to calculate the hash value of the first file. The hash value of the first file may be stored in the local database for later use when requested by the second sharing organization.

It should be noted that, before obtaining the first file, the sharing organization needs to generate its own private key, which is the use of the sharing organization, and create a data sharing smart contract for data sharing on the blockchain. Before data sharing, each sharing organization in the consortium chain needs to generate its own private key. When generating the private key, it can automatically generate a random number with a fixed bit length (for example, 256 bits), or be based on BIP -32 protocol/BIP-44 protocol standard generates mnemonic words, generates seeds through mnemonic words, and generates master key and main chain code through seeds.

In the embodiment of the present invention, the aforementioned data sharing smart contract may include basic file information (name, size, creation date, etc.) of the file, file authority information, and file manager information. The permission information of the file can reflect the information of the co-owner of the file, that is, which sharing organization jointly owns the file, and the shared permissions. The file manager information can reflect which organization is responsible for uploading and managing the file.

Step 202: The sharing organization determines the exchange public key corresponding to the first file according to the hash value, the index number of the first file, and the private key of the sharing organization.

Specifically, the sharing organization may first generate the prime number and original root of the first file, and then determine the exchange private key of the first file according to the private key of the sharing organization and the index number of the first file, and finally according to the exchange private key of the first file. The key, prime number and primitive root determine the exchange public key of the first file. Optionally, after obtaining the prime number and the original root of the first file, the prime number and the original root can also be formed into a string according to a preset separator, and then the string is encrypted according to the hash value of the first file to obtain the first file. The exchange public number of a file, and finally the exchange public number is sent to the data sharing smart contract of the blockchain, so that the second sharing institution can determine the prime number and original number of the first file based on the exchange public number and the hash value of the first file. root. Among them, the preset separator can be set based on experience, for example, it can be a separator such as a comma, a semicolon, and a comma.

That is, the sharing organization generates the prime number and primitive root of the first file. The prime number can usually be 2 or 5, and the prime number can be a number greater than 200 digits long. Separate the prime number and the original root with a comma to form a string, and then use a symmetric encryption algorithm to encrypt the string to obtain the exchange public number, and the encryption key is the hash value of the first file. The sharing organization can send the exchange public number to the blockchain for storage.

The sharing organization calculates and obtains the exchange private key of the first file by using the MAC (Message Authentication Codes) algorithm or other hash algorithms based on the above-mentioned private key of the first file in combination with the index number of the first file. According to the prime number and primitive root of the first file, the exchange public key of the first file can be calculated. For example, the exchange public key of the first file can be obtained by formula (1).

g ^Msa mod p=Mpa…………………………(1)

Among them, g is the prime number of the first file, Msa is the exchange private key of the first file, p is the original root of the first file, and Mpa is the exchange public key of the first file.

Optionally, the sharing organization may store the exchange public key of the first file in a local database, and it does not need to be saved. In this case, the exchange private key and the prime number and original root of the first file can be obtained at any time. Exchange public keys. The exchange public key of the first file is also the exchange public key of the sharing organization.

Since the private key of each sharing organization is fixed, but the index number of each file is unique, the embodiment of the present invention can generate different exchange secrets for different files without the private key of the sharing organization. key.

It should be noted that, depending on the privacy level of the shared files, the sharing organization can choose to store the interactive exchange public key in the aforementioned data sharing smart contract for some relatively insensitive data or data that does not require authorization.

Step 203: The sharing organization obtains the exchange public keys of multiple first sharing organizations.

In the embodiment of the present invention, the first sharing organization is an organization that shares the common authority of the first file with the sharing organization, that is, an organization that has the common authority of the first file together with the sharing organization.

The exchange public keys of the plurality of first sharing institutions are respectively determined by the plurality of first sharing institutions according to the hash value, index number and respective private keys of the first file and then sent to the sharing institution. The method for each first sharing organization to determine its own exchange of public keys can be found in the steps described in step 202 above. The hash value of the first file can be sent to each first sharing organization through a secure data channel or off-chain by the sharing organization. mechanism. Among them, the exchange public key of each first sharing institution can also be stored in the aforementioned data sharing smart contract.

Step 204: The sharing organization determines the encryption key of the first file according to the exchange public key corresponding to the first file and the exchange public keys of the multiple first sharing organizations.

After the sharing organization obtains the exchange public key of each first sharing organization, the encryption key of the first file can be calculated through the encryption algorithm. For example, the encryption key can be obtained by formula (2).

Among them, Mpb is the exchange public key of the first shared institution b, Mpa is the exchange public key of the shared institution a, p is the original root of the first file, Mpab is the intermediate exchange public key, and Mpc is the exchange public key of the first shared institution c. Key, Ms is the encryption key of the first file.

Step 205: The sharing organization encrypts the first file using the encryption key of the first file, obtains the encrypted ciphertext of the first file, and sends the encrypted ciphertext to the blockchain Data sharing smart contract.

After the sharing organization calculates the encryption key of the first file, it can use the encryption key of the first file to encrypt the first file to obtain the encrypted ciphertext of the first file, and send the encrypted ciphertext to the district Block chain data sharing smart contract. In order to enable the second sharing organization to request the download of the first file to complete the sharing of the first file, the second sharing organization is an organization other than the foregoing sharing organization and the multiple first sharing organizations.

So far, the data sharing smart contract of the blockchain can include but is not limited to the following:

The basic information of the file, the index number of the file, the owner of the file (the authority information of the file), the administrator of the file; the exchange of public numbers, encrypted ciphertext, and the data signature that the owner of the file agrees to share. Optionally, it may also include the exchange public key of the sharing organization and the exchange public key of each first sharing organization.

Further, the sharing organization can also download files shared by other second organizations in the data sharing smart contract in the blockchain, specifically:

The sharing organization can obtain the encrypted ciphertext of the second file from the data sharing smart contract of the blockchain, exchange public data, authority information and manager information. Then, according to the manager information of the second file, request the manager of the second file for the hash value of the second file and the exchange public key of the manager of the second file. The organization with the common authority requests the exchange public key of the organization with the common authority of the second file. According to the exchange public number of the second file, the hash value of the second file, the exchange public key of the administrator of the second file, and the exchange public key of the organization with the common authority of the second file, the encryption secret of the second file is determined. key. Finally, the encrypted ciphertext of the second file is decrypted according to the encryption key of the second file to obtain the second file.

It should be noted that if the exchange public key of the institution with the common authority of the second file is stored in the data sharing smart contract, the data sharing smart contract can also be directly called for downloading and obtaining.

The sharing organization can send request information to each organization with the common authority of the second file through the secure data channel to request the exchange public key of each organization with the common authority of the second file, and each organization with the common authority of the second file After the sharing organization is approved, the exchange public key can be sent to the sharing organization. The sharing organization can then determine the second file based on the exchange public number of the second file, the hash value of the second file, the exchange public key of the administrator of the second file, and the exchange public key of the organization with the common authority of the second file. 2. The encryption key of the file. Specifically, the prime number and original root of the second file can be determined based on the interactive public number of the second file and the hash value of the second file, and then based on the original root of the second file and the exchange public key of the administrator of the second file Exchange the public key with the organization that has the common authority of the second file to determine the encryption key of the second file.

After the encryption key of the second file is obtained, the encrypted ciphertext of the second file can be decrypted to obtain the second file.

In order to better explain the embodiments of the present invention, the above data sharing process will be described below in a specific implementation scenario.

In the embodiment of the present invention, it is assumed that in a consortium chain, there are four peer institutions A, B, C, and D, each having a blockchain node of the consortium chain. Suppose there is a file M (the file M can also be any text in plain text information or other format information), the file belongs to organization A, in organization A, the index number of file M is n, and organization B and C has common permissions to the file. Now institution A needs to initiate a request for data on the chain. This operation will also trigger a smart contract to call the function function of the related smart contract for file storage; it needs to obtain the file exchange public key of institutions B and C, and encrypt the file M to the block. On the chain.

When organization D needs to download file M, it can request organizations A, B, and C to obtain the corresponding keys; combined with the encrypted ciphertext stored on the blockchain, file M can be re-decrypted by executing a preset calculation method The plaintext.

The following are the detailed steps for implementing the embodiment of the present invention: the data encryption process and the data decryption process respectively. The process of data encryption can be shown in Figure 3, and the process of data decryption can be shown in Figure 4.

It should be noted that the algorithms and algorithm parameters (such as key length) involved in the embodiments of the present invention are only exemplary and are not limited to the above. In the specific implementation process, they can also be extended to other similar application algorithms.

As shown in Figure 3, the process specifically includes:

Step 301: Each participating organization on the blockchain generates its own private key.

The blockchain nodes of each participating organization of the blockchain generate a fixed-bit length (for example, 256-bit) number as the private key S. For organization A, organization B, and organization C, Sa, Sb, and Sc will be generated respectively.

The generation of the private key can be to automatically generate a random number; it can also be based on the BIP-32/BIP-44 standard to generate mnemonic words, generate seeds from mnemonics, and generate master keys and main chain codes from seeds.

Step 302: The data uploader creates a data sharing smart contract.

The data uploader is institution A, and institution A creates a file sharing data sharing smart contract Cm. The data sharing smart contract Cm contains basic file information (file name, size, creation date, etc.), and file authority management information , File co-owner information and other information.

Step 303: Generate the exchange public number and related keys of the data uploader.

The data uploader A calculates the Hash value h of the file M and stores it in the local database.

The data uploader A generates the prime number P and the primitive root g of the file M. Usually g is 2 or 5, and the prime number P is at least 200 bits long.

Separate P and g with a separator (such as,) to form a string of P, g; then use a symmetric encryption algorithm (such as AES (Advanced Encryption Standard, Advanced Encryption Standard)), and the encryption key is h to obtain the exchange public number Mn .

The organization A uses the MAC algorithm (such as HMAC-SHA512) to calculate and obtain the organization A's exchange private key Msa for the file M according to the organization private key Sa generated in step 1, combined with the index number n of the file M.

Institution A obtains the exchange public key Mpa through the above formula (1).

Since the organization private key Sa is fixed, but the index number of each piece of data is unique, this mechanism can generate different exchange keys for different data without changing the organization private key Sa.

Institution A initiates an on-chain request and saves the exchange public number Mn into the previously created data sharing smart contract Cm.

Institution A can save the exchange public key Mpa in a local database or file; it does not need to be stored locally. If it is not stored, institution A can calculate and restore the value of Mpa at any time based on Msa and g, p. At the same time, institution A can also consider the encryption level of data privacy. For some relatively insensitive data or data that does not require authorization, it can choose to store the exchange public key Mpa in the data sharing smart contract Cm.

Step 304: Request to obtain the exchange public keys of other data owners.

Institution A can automatically send messages to the data owners B and C through the event notification function mechanism of the data sharing smart contract Cm; it can also initiate to the data owners through the secure data transmission channel on the chain or off-chain Key application.

Institutions B and C can use the data sharing smart contract Cm to download the key exchange public number Mn and basic information of the file. Institutions B and C can respectively retrieve file M based on the existing file information to calculate the hash value of file M; if M is not saved, they can apply to institution A to obtain the hash value h through the secure data transmission channel.

Referring to step 303, institutions B and C can generate exchange public keys Mpb and Mpc corresponding to file M. Under the premise of approving the encryption and sharing of data, the above-mentioned institutions can send corresponding Mpb and Mpc information to institution A. Institutions B and C can save the specific data of Mpb and Mpc locally, so that they can be retransmitted when institution A fails to receive it or sent when other participants initiate a decryption request; they can also not be stored locally. If not, institution B And C can repeat the process of calculating Mpb or Mpc in this step when receiving the request.

At the same time, institutions A, B, and C can also consider the encryption level of data privacy. For some relatively insensitive data or data that does not require authorization, they can choose to store all or part of the exchange public keys Mpa, Mpb, and Mpc in the data sharing intelligence. Contract Cm.

Step 305: Calculate the encryption key and encrypt the file.

Based on the above information, organization A can calculate the final encryption key Ms of the file by formula (2).

Then, the organization A uses the above-mentioned key Ms to encrypt the file M using a symmetric encryption algorithm (such as AES), and finally obtains the ciphertext S.

In step 306, the encrypted ciphertext of the file is sent to the blockchain.

Institution A calls the interface of the blockchain smart contract and sends the encrypted ciphertext to the data sharing smart contract Cm corresponding to the blockchain. The data sharing smart contract Cm also stores the encrypted ciphertext of the file M.

In summary, the content of file M that is finally saved on the data sharing smart contract includes but is not limited to the following main content:

Organization A: the basic information of the file, the index number of the file, the owner of the file, the manager of the file; the public number Mn in the key exchange protocol, the interactive public key Mpa of the organization A (optional). The final ciphertext.

Institutions B and C: data signatures agreed to be shared; public keys of each institution in the key exchange agreement (optional).

As shown in Figure 4, the data decryption process specifically includes:

Step 401: Apply to the data manager to obtain file information.

Organization D can obtain the basic information, authority information and manager information of file M through the data sharing smart contract Cm. If the public keys Mpa, Mpb, and Mpc have been saved on the chain, you can directly call the data sharing smart contract to download and obtain.

Organization D first applies to data manager A to obtain file M through the secure data channel. If organization A passes the review, it returns the hash value h and exchange public key Mpa of the file to organization D.

Institution D downloads the exchange public number Mn corresponding to the file through the data sharing smart contract of the blockchain, and uses h to decrypt it to obtain the corresponding values of g and p.

Step 402: Apply to other data owners to obtain file information.

Institution D first applies to other data holder institutions B and C to obtain file M through the secure data channel. If institutions B and C pass the review, they will return their respective interactive public keys Mpb and Mpc to institution D (if Mpb and Mpc have been stored in the chain Above, you can get it directly through the chain, you can skip this step).

Step 403: Decrypt the file.

After the organization D has completed the above two steps, it can refer to step 305 of the encryption scheme to obtain the encryption key Ms of the file M.

Institution D can download the final file cipher text S through the data sharing smart contract Cm, and can decrypt the final plain text M by using the same symmetric encryption algorithm (such as AES) used in the encryption process.

The data sharing method provided by the embodiments of the present invention can be extended to scenarios where the owner of the data sharing is one or more institutions, and in conjunction with the blockchain smart contract, the authorization scope, flow and authority of the data sharing can be accurately controlled.

Compared with the existing data sharing method, the data sharing method provided by the embodiment of the present invention has the following specific points:

1. Compared with the digital envelope scheme, there is no need to store massive symmetric keys off-chain.

2. The encrypted data is actually on the chain, and the plaintext data can be restored through decryption.

3. As long as the user's private key is properly stored, the data will not be lost.

4. A flexible and convenient data sharing mechanism can be realized.

5. Conducive to effective protection of user privacy.

6. Flexible permission control mechanism ensures that the sharing of data on the chain is fully authorized.

7. The encryption and decryption calculation of data sharing is small and the efficiency is high.

The embodiment of the present invention shows that the sharing organization obtains the first file and determines the hash value of the first file. The first file is the file to be shared. According to the hash value, index number, and private key of the sharing organization, Determine the exchange public key corresponding to the first file, obtain the exchange public keys of multiple first sharing institutions, and determine the encryption secret of the first file based on the exchange public keys corresponding to the first file and the exchange public keys of the multiple first sharing institutions Key, use the encryption key of the first file to encrypt the first file to obtain the encrypted ciphertext of the first file, and send the encrypted ciphertext to the data sharing smart contract of the blockchain, so that the second sharing organization can A file is requested to download. Since the exchange public key corresponding to the first file is obtained through the private key and index number of the shared organization, different exchange keys can be generated for different files under the condition that the private key of the shared organization remains unchanged, which can be flexible, convenient, Effectively protect user privacy. Sending the encrypted file to the blockchain realizes the real winding of the encrypted file and real data sharing.

It should be noted that in the above scheme, the private key of the key exchange algorithm (such as Msa) can not only be generated by the HMAC (Hash-based Message Authentication Code) algorithm by using the master private key + index, but also The CKD (child key derivation) equation can be used in the BIP32 protocol to derive the child key from the parent key. The subkey derivation equation is based on a single hash equation.

The above data sharing method can also use the digital envelope scheme, as shown in Figure 5:

1. The sender A uses the symmetric key K to encrypt the plaintext M to generate ciphertext information S.

2. The sender A puts the ciphertext information S on the chain, uses B's public key to encrypt the symmetric key K, and sends it to the receiver B through a secure data transmission channel.

3. After receiving the encrypted information of the sender A, the receiver B uses its own private key to decrypt it to obtain the symmetric key K.

4. The receiver B obtains the ciphertext information on the chain, uses the symmetric key K to decrypt the ciphertext information, and obtains the original plaintext M.

Based on the same technical concept, FIG. 6 exemplarily shows the structure of a blockchain data sharing device provided by an embodiment of the present invention, and the device can execute a blockchain data sharing process.

As shown in Figure 6, the device specifically includes:

The obtaining unit 601 is configured to obtain a first file and determine a hash value of the first file, where the first file is a file to be shared;

The processing unit 602 is configured to determine the exchange public key corresponding to the first file according to the hash value, the index number and the private key of the sharing organization of the first file;

The obtaining unit 601 is further configured to obtain the exchange public keys of multiple first sharing institutions, the first sharing institutions being institutions that jointly own the common authority of the first file with the sharing institutions; The exchange public keys of the shared institutions are respectively determined by the multiple first shared institutions according to the hash value, the index number of the first file, and the private keys of the multiple first shared institutions;

The processing unit 602 is further configured to determine the encryption key of the first file according to the public exchange key corresponding to the first file and the public exchange keys of the multiple first sharing institutions; The encryption key of the file encrypts the first file to obtain the encrypted ciphertext of the first file, and sends the encrypted ciphertext to the data sharing smart contract of the blockchain, so that the second sharing An organization requests to download the first file, and the second sharing organization is an organization other than the sharing organization and the multiple first sharing organizations.

Based on the same principle, the present invention also provides an electronic device, as shown in FIG. 7, including:

It includes a processor 701, a memory 702, a transceiver 703, and a bus interface 704, wherein the processor 701, the memory 702 and the transceiver 703 are connected through the bus interface 704;

The processor 701 is configured to read a program in the memory 702 and execute the blockchain data sharing method described above, and the method includes:

Control the transceiver 703 to obtain the first file and determine the hash value of the first file, where the first file is a file to be shared;

Determine the exchange public key corresponding to the first file according to the hash value, the index number of the first file, and the private key of the sharing organization;

The control transceiver 703 obtains the exchange public keys of a plurality of first sharing institutions, the first sharing institution being an institution that jointly owns the common authority of the first file with the sharing institution; the exchange public keys of the multiple first sharing institutions The keys are respectively determined by the plurality of first sharing institutions according to the hash value, the index number of the first file, and the private keys of the plurality of first sharing institutions;

Determine the encryption key of the first file according to the public exchange key corresponding to the first file and the public exchange keys of the multiple first sharing institutions; use the encryption key of the first file to pair the first file A file is encrypted, the encrypted ciphertext of the first file is obtained, and the encrypted ciphertext is sent to the data sharing smart contract of the blockchain, so that the second sharing agency requests to download the first file , The second sharing organization is an organization other than the sharing organization and the plurality of first sharing organizations.

The processor 701 may be a central processing unit (central processing unit, CPU for short), a network processor (NP for short), or a combination of CPU and NP. It can also be a hardware chip. The aforementioned hardware chip may be an application-specific integrated circuit (ASIC for short), a programmable logic device (PLD for short), or a combination thereof. The above-mentioned PLD can be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (generic array logic, GAL), or any of them combination.

The memory 702 is configured to store one or more executable programs, and can store data used by the processor 701 when performing operations.

Specifically, the program may include program code, and the program code includes computer operation instructions. The memory 702 may include a volatile memory (volatile memory), such as random-access memory (random-access memory, RAM for short); the memory 702 may also include a non-volatile memory (non-volatile memory), such as flash memory ( flash memory), hard disk drive (HDD for short) or solid-state drive (SSD for short); the memory 702 may also include a combination of the foregoing types of memories.

The memory 702 stores the following elements, executable modules or data structures, or their subsets, or their extended sets:

Operating instructions: including various operating instructions, used to implement various operations.

Operating system: including various system programs, used to implement various basic services and process hardware-based tasks.

The bus interface 704 may be a wired communication access port, a wireless bus interface or a combination thereof, where the wired bus interface may be, for example, an Ethernet interface. The Ethernet interface can be an optical interface, an electrical interface or a combination thereof. The wireless bus interface may be a WLAN interface.

Based on the same technical concept, an embodiment of the present invention also provides a computing device, including:

Memory, used to store program instructions;

Based on the same technical concept, the embodiments of the present invention also provide a computer-readable non-volatile storage medium, including computer-readable instructions. When the computer reads and executes the computer-readable instructions, the computer executes the above-mentioned areas. Block chain data sharing method.

Based on the same principle, embodiments of the present invention also provide a computer program product, the computer program product includes a calculation program stored on a non-transitory computer-readable storage medium, the computer program includes program instructions, when the program When the instructions are executed by a computer, the computer is caused to execute the above-mentioned blockchain data sharing method.

The present invention is described with reference to flowcharts and/or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and/or block in the flowchart and/or block diagram, and the combination of processes and/or blocks in the flowchart and/or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing equipment to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing equipment are generated It is a device that realizes the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing equipment to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction device. The device implements the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

These computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operation steps are executed on the computer or other programmable equipment to produce computer-implemented processing, so as to execute on the computer or other programmable equipment. The instructions provide steps for implementing functions specified in a flow or multiple flows in the flowchart and/or a block or multiple blocks in the block diagram.

Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

A blockchain data sharing method is characterized in that it includes:

The sharing institution obtains the first file and determines the hash value of the first file, where the first file is a file to be shared;

The sharing organization determines the exchange public key corresponding to the first file according to the hash value, the index number of the first file, and the private key of the sharing organization;

The sharing organization obtains the exchange public keys of a plurality of first sharing organizations, and the first sharing organization is an organization that jointly owns the common authority of the first file with the sharing organization; the exchange public keys of the plurality of first sharing organizations The keys are respectively determined by the plurality of first sharing institutions according to the hash value, the index number of the first file, and the private keys of the plurality of first sharing institutions;

Determining, by the sharing organization, the encryption key of the first file according to the exchange public key corresponding to the first file and the exchange public keys of the multiple first sharing organizations;

The sharing mechanism encrypts the first file using the encryption key of the first file, obtains the encrypted ciphertext of the first file, and sends the encrypted ciphertext to the data sharing of the blockchain In the smart contract, a second sharing organization requests to download the first file, and the second sharing organization is an organization other than the sharing organization and the plurality of first sharing organizations.
The method according to claim 1, wherein the sharing organization determines the exchange public key corresponding to the first file based on the hash value, index number and private key of the sharing organization of the first file ,include:

Generating the prime numbers and primitive roots of the first file by the sharing mechanism;

The sharing organization determines the exchange private key of the first file according to the private key of the sharing organization and the index number of the first file;

The sharing agency determines the exchange public key of the first file according to the exchange private key, prime number, and original root of the first file.
3. The method of claim 2, wherein after the sharing mechanism generates the prime numbers and primitive roots of the first file, the method further comprises:

The sharing mechanism composes the prime number and the primitive root into a string according to a preset separator;

The sharing organization encrypts the character string according to the hash value of the first file to obtain the exchange public number of the first file;

The sharing institution sends the exchange public number to the data sharing smart contract of the blockchain, so that the second sharing institution determines the exchange public number and the hash value of the first file. State the prime numbers and primitive roots of the first file.
The method according to claim 1, characterized in that, before the sharing organization obtains the first file, further comprising:

The sharing organization generates the private key of the sharing organization;

The sharing agency creates the data sharing smart contract on the blockchain.
The method according to any one of claims 1 to 4, wherein the method further comprises:

The sharing agency obtains the encrypted ciphertext of the second file from the data sharing smart contract of the blockchain, exchanges public data, authority information, and manager information;

The sharing institution requests the manager of the second file for the hash value of the second file and the exchange public key of the manager of the second file according to the manager information of the second file;

According to the authority information of the second file, the sharing organization requests the exchange public key of the organization having the common authority of the second file from the organization having the common authority of the second file;

The sharing organization is based on the exchange public number of the second file, the hash value of the second file, the exchange public key of the administrator of the second file, and the shared authority of the second file The exchange public key of the institution, which determines the encryption key of the second file;

The sharing agency decrypts the encrypted ciphertext of the second file according to the encryption key of the second file to obtain the second file.
The method of claim 5, wherein the sharing organization is based on the exchange public number of the second file, the hash value of the second file, and the exchange public key of the manager of the second file. Exchanging the public key with the institution having the shared authority of the second file to determine the encryption key of the second file includes:

The sharing mechanism determines the prime number and primitive root of the second file according to the interactive common number of the second file and the hash value of the second file;

The sharing institution determines the second file based on the original root of the second file, the exchange public key of the administrator of the second file, and the exchange public key of the institution with the common authority of the second file. The encryption key of the file.
A block chain data sharing device is characterized in that it comprises:

An obtaining unit, configured to obtain a first file and determine a hash value of the first file, where the first file is a file to be shared;

A processing unit, configured to determine the exchange public key corresponding to the first file according to the hash value, the index number and the private key of the sharing organization of the first file;

The obtaining unit is further configured to obtain the exchange public keys of a plurality of first sharing institutions, the first sharing institution being an institution that jointly owns the common authority of the first file with the sharing institution; the multiple first sharing institutions The exchange public keys of the institutions are respectively determined by the multiple first sharing institutions according to the hash value, the index number of the first file, and the private keys of the multiple first sharing institutions;

The processing unit is further configured to determine the encryption key of the first file according to the exchange public key corresponding to the first file and the exchange public keys of the plurality of first sharing institutions; use the first file Encrypt the first file with the encryption key to obtain the encrypted ciphertext of the first file, and send the encrypted ciphertext to the data sharing smart contract of the blockchain, so that the second sharing organization The download of the first file is requested, and the second sharing organization is an organization other than the sharing organization and the plurality of first sharing organizations.
The device according to claim 7, wherein the processing unit is specifically configured to:

Generating prime numbers and primitive roots of the first file;

Determine the exchange private key of the first file according to the private key of the sharing organization and the index number of the first file;

Determine the exchange public key of the first file according to the exchange private key, prime number and original root of the first file.
The device according to claim 8, wherein the processing unit is further configured to:

After generating the prime numbers and primitive roots of the first file, compose the prime numbers and primitive roots into a character string according to a preset separator;

Encrypting the character string according to the hash value of the first file to obtain the exchange public number of the first file;

Send the exchange public number to the data sharing smart contract of the blockchain, so that the second sharing agency determines the first file based on the exchange public number and the hash value of the first file The prime numbers and primitive roots of.
The device according to claim 7, wherein the processing unit is further configured to:

Before obtaining the first file, generate the private key of the sharing organization;

Create the data sharing smart contract on the blockchain.
The device according to any one of claims 7 to 10, wherein the processing unit is further configured to:

Obtain the encrypted ciphertext of the second file from the data sharing smart contract of the blockchain, exchange public numbers, authority information and manager information;

Request the hash value of the second file and the exchange public key of the manager of the second file from the manager of the second file according to the manager information of the second file;

According to the authority information of the second file, request the exchange public key of the organization having the common authority of the second file from an organization having the common authority of the second file;

According to the exchange public number of the second file, the hash value of the second file, the exchange public key of the administrator of the second file, and the exchange public of the institution with the common authority of the second file Key, which determines the encryption key of the second file;

Decrypt the encrypted ciphertext of the second file according to the encryption key of the second file to obtain the second file.
The device according to claim 11, wherein the processing unit is specifically configured to:

Determining the prime number and primitive root of the second file according to the interactive common number of the second file and the hash value of the second file;

Determine the encryption secret of the second file according to the original root of the second file, the exchange public key of the administrator of the second file, and the exchange public key of the institution with the common authority of the second file key.
A computing device, characterized by comprising:

Memory, used to store program instructions;

The processor is configured to call the program instructions stored in the memory, and execute the method according to any one of claims 1 to 6 according to the obtained program.
A computer-readable non-volatile storage medium, characterized by comprising computer-readable instructions, when the computer reads and executes the computer-readable instructions, the computer is caused to execute any one of claims 1 to 6 Methods.
A computer program product, characterized in that, the computer program product includes a calculation program stored on a non-transitory computer-readable storage medium, the computer program includes program instructions, when the program instructions are executed by a computer, The computer executes the method described in any one of claims 1 to 6.