CN118214614B - Method, device and system for access control of data on blockchain system - Google Patents

Abstract

The present invention discloses a method, device and system for access control of data on a blockchain system, the method comprising: receiving a hash value of a message ciphertext sent by a blockchain client, a key ciphertext and an access control list of a data owner, the message ciphertext is obtained by encrypting a message plaintext using a first encryption algorithm, and the key ciphertext is obtained by encrypting a key of the first encryption algorithm using a second encryption algorithm; the distributed decryption share corresponding to the key ciphertext is generated using the second encryption algorithm; the distributed decryption share is encrypted using the access control list of the data owner to obtain the decrypted ciphertext; the decrypted ciphertext is sent to a database, and the database asynchronously waits for a first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then stores them asynchronously; the hash value of the message ciphertext is shared with all data accessors. The present invention can realize fine-grained access control while ensuring the security of user privacy data.

Description

Method, device and system for access control of data on blockchain system

Technical Field

The present invention relates to the fields of software development, distributed systems, and blockchain technology, and in particular to a method, device, and system for controlling access to data on a blockchain system.

Background technique

This section is intended to provide a background or context to the embodiments of the invention recited in the claims. No description herein is admitted to be prior art by inclusion in this section.

Blockchain is a new generation of information technology that combines distributed systems and cryptography. The secure data storage and processing mode of blockchain technology makes it likely to become a driving force for information technology reform. From a technical perspective, blockchain can be roughly divided into non-permissioned chains and permissioned chains. Non-permissioned chains should generally run on open networks, mostly public chains, and participants can participate in consensus and transactions without going through the access approval process. Permissioned chains require that nodes (servers) participating in system operations must be authorized and authenticated by administrators or management agencies. Permissioned chains can be divided into private chains maintained by a single organization and consortium chains maintained by organizations with mutually known identities.

BFT (Byzantine fault tolerance, consensus) is a recognized model of permissioned chains. With the rise of blockchain, the BFT consensus system, as the operating system and key core of blockchain, has been widely used.

BFT is a "user-server" working mode based on state machine replication. BFT should meet security and activity. Security requires that the states of each server remain consistent, and activity requires that the service achieves availability. The consensus protocol is a crucial component of blockchain technology. It ensures that all nodes in the distributed system can reach a consensus on the shared data, so that there is no centralized organization or organization in the blockchain network that can control the entire network, ensuring the decentralized nature of the blockchain, and it directly determines the performance of the blockchain. Distributed storage based on consensus protocol is a technology that stores data on multiple nodes. Each node stores part of the data, and all nodes work together to provide data storage and access services. Unlike traditional centralized storage, distributed storage has the advantages of high availability, high performance, and strong scalability. Because data is stored on multiple nodes, distributed storage has high availability and fault tolerance. Even if one or more nodes fail, it will not affect the operation of the entire system.

Blockchain has high reliability, fault tolerance, integrity, availability, traceability, and evidence storage. However, the existing blockchain system has the following problems:

(1) Only a small amount of data is stored on the chain. The core data cannot be stored on the chain and operated on the chain, which limits the real circulation of data. The phenomenon of data islands has not been eliminated due to the existence of blockchain.

(2) Traditional blockchain systems cannot guarantee the confidentiality of data, and data backup storage actually reduces data confidentiality.

(3) Existing blockchain systems cannot securely and fine-grainedly control the reading and writing of data, increasing the security risks of data access.

Summary of the invention

The embodiment of the present invention provides a method for access control of data on a blockchain system, which is used to implement fine-grained access control while ensuring the security of user privacy data. The method is applied to any node on the blockchain system, and includes:

Receive the hash value of the message ciphertext, the key ciphertext, and the access control list of the data owner sent by the blockchain client, wherein the message ciphertext is obtained by the blockchain client encrypting the message plaintext using the first encryption algorithm, the key ciphertext is obtained by the blockchain client encrypting the key of the first encryption algorithm using the second encryption algorithm, and the message plaintext and the access control list of the data owner are sent by the data owner to the blockchain client;

Using the second encryption algorithm, generating a distributed decryption share corresponding to the key ciphertext;

The distributed decryption shares are encrypted using the access control list of the data owner to obtain the decrypted ciphertext;

Sending the decrypted ciphertext to a database, the database asynchronously waiting for a first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then asynchronously storing the decrypted ciphertexts;

The hash value of the message ciphertext is shared with all data accessors, and the data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, and then decrypt the message plaintext.

The embodiment of the present invention also provides another method for access control of data on a blockchain system, which is used to implement fine-grained access control while ensuring the security of user privacy data. The method is applied to a blockchain client, and includes:

Receiving a message plain text input by a data owner and an access control list of the data owner;

Encrypting the message plaintext using a first encryption algorithm to obtain a message ciphertext;

Using the second encryption algorithm to encrypt the key of the first encryption algorithm to obtain a key ciphertext;

Generate a hash value of the message ciphertext, wherein the hash value is used by a data accessor to obtain the message plaintext;

The hash value of the message ciphertext, the key ciphertext and the access control list are sent to the blockchain system, wherein after the key ciphertext obtains the distributed decryption share through the node private key, the node on the blockchain system uses the access control list of the data owner to encrypt the decryption share to obtain the decrypted ciphertext, and sends it to the database, and the database asynchronously waits for the first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then asynchronously stores them.

The embodiment of the present invention provides an access control device for data on a blockchain system, which is used to implement fine-grained access control while ensuring the security of user privacy data, and is applied to any node on the blockchain system. The device includes:

A first receiving module is used to receive a hash value of a message ciphertext, a key ciphertext, and an access control list of a data owner sent by a blockchain client, wherein the message ciphertext is obtained by the blockchain client encrypting the message plaintext using a first encryption algorithm, the key ciphertext is obtained by the blockchain client encrypting the key of the first encryption algorithm using a second encryption algorithm, and the message plaintext and the access control list of the data owner are sent by the data owner to the blockchain client;

A distributed decryption share generation module, used to generate a distributed decryption share corresponding to the key ciphertext by using a second encryption algorithm;

A decrypted ciphertext obtaining module is used to encrypt the distributed decryption shares using the access control list of the data owner to obtain the decrypted ciphertext;

A sending module, used for sending the decrypted ciphertext to a database, and the database asynchronously stores the decrypted ciphertexts corresponding to the access control list of the first number of matching data owners after asynchronously waiting;

The hash value sharing module is used to share the hash value of the message ciphertext with all data accessors. After the data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, they decrypt the message plaintext.

The embodiment of the present invention provides an access control device for data on a blockchain system, which is used to implement fine-grained access control while ensuring the security of user privacy data, and is applied to a blockchain client. The device includes:

A second receiving module, used for receiving a message plain text input by a data owner and a data owner access control list;

A first encryption module, used to encrypt the message plaintext using a first encryption algorithm to obtain a message ciphertext;

A second encryption module, used to encrypt the key of the first encryption algorithm using a second encryption algorithm to obtain a key ciphertext;

A hash value generation module, used to generate a hash value of a message ciphertext, wherein the hash value is used by a data accessor to obtain a message plaintext;

The second sending module is used to send the hash value of the message ciphertext, the key ciphertext and the access control list to the blockchain system, wherein after the key ciphertext obtains the distributed decryption share through the node private key, the node on the blockchain system uses the access control list of the data owner to encrypt the decryption share to obtain the decrypted ciphertext, and sends it to the database, and the database asynchronously waits for the first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then asynchronously stores them.

The embodiment of the present invention provides an access control system for data on a blockchain system, which is used to achieve fine-grained access control while ensuring the security of user privacy data. The system includes: a blockchain system, a blockchain client and a database, wherein:

The blockchain client is used to: receive a message plaintext and an access control list input by a data owner; encrypt the message plaintext using a first encryption algorithm to obtain a message ciphertext, encrypt the key of the first encryption algorithm using a second encryption algorithm to obtain a key ciphertext, and generate a hash value of the message ciphertext; send the hash value of the message ciphertext, the key ciphertext and the access control list to the blockchain system;

The node on the blockchain system is used to: receive the hash value of the message ciphertext sent by the blockchain client, the key ciphertext and the access control list of the data owner; use the second encryption algorithm to generate the distributed decryption share corresponding to the key ciphertext, and use the access control list of the data owner to encrypt the distributed decryption share to obtain the decrypted ciphertext; send the decrypted ciphertext to the database; share the hash value of the message ciphertext with all data accessors, and the data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, and then decrypt to obtain the message plaintext;

The database is used to asynchronously store the decrypted ciphertexts corresponding to the first number of matching access control lists after asynchronously waiting.

An embodiment of the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the access control method for data on the above-mentioned blockchain system when executing the computer program.

An embodiment of the present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the access control method for data on the above-mentioned blockchain system.

An embodiment of the present invention also provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, it implements the access control method for data on the above-mentioned blockchain system.

In an embodiment of the present invention, a blockchain client can receive a message plaintext and an access control list input by a data owner; encrypt the message plaintext using a first encryption algorithm to obtain a message ciphertext, encrypt the key of the first encryption algorithm using a second encryption algorithm to obtain a key ciphertext, and generate a hash value of the message ciphertext; send the hash value of the message ciphertext, the key ciphertext and the access control list to the blockchain system; a node on the blockchain system can receive the hash value of the message ciphertext, the key ciphertext and the access control list of the data owner sent by the blockchain client; use the second encryption algorithm to generate a distributed decryption share corresponding to the key ciphertext, and use the access control list of the data owner to encrypt the distributed decryption share to obtain a decrypted ciphertext; send the decrypted ciphertext to a database; share the hash value of the message ciphertext with all data accessors, and the data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, and then decrypt to obtain the message plaintext; the database can asynchronously wait for the first number of decrypted ciphertexts corresponding to the matching access control lists, and then perform asynchronous storage. Compared with the traditional blockchain system with low performance, the method and system proposed in the embodiment of the present invention do not rely on open source software or existing blockchain platforms, can be quickly updated and iterated, and can store a large amount of core data on the chain and support on-chain operations through the database, breaking through the barriers of data islands, truly realizing the collaborative sharing and efficient use of data resources, ensuring the activity of the system, reducing the difficulty and pressure of data maintenance, reducing the cost of system storage and call processes, and improving the security and reliability of the system; through the access control list of the data owner, the access control can be fine-grained and accurately controllable, and can determine which data, at what time, and by whom to read or use, and can also dynamically determine and modify access control permissions, which can ensure that there is no single point of error in the whole process, without the need for a trusted third party, and ensure the reliability, activity and integrity of the blockchain system.

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 following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. 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 creative work. In the drawings:

FIG1 is a flow chart of a method for controlling access to data on a blockchain system according to an embodiment of the present invention;

FIG2 is a schematic diagram of a write operation in an embodiment of the present invention;

FIG3 is a flow chart of another method for controlling access to data on a blockchain system according to an embodiment of the present invention;

FIG4 is a schematic diagram of a read operation in an embodiment of the present invention;

FIG5 is a schematic diagram of a device for controlling access to data on a blockchain system according to an embodiment of the present invention;

FIG6 is a schematic diagram of another device for controlling access to data on a blockchain system according to an embodiment of the present invention;

FIG7 is a schematic diagram of an access control system for data on a blockchain system according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a computer device according to an embodiment of the present invention.

Detailed ways

To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

FIG1 is a flow chart of a fine-grained access control method for a blockchain system in an embodiment of the present invention. The method is applied to any node on the blockchain system. The method includes:

Step 101, receiving a hash value of a message ciphertext, a key ciphertext, and an access control list of a data owner sent by a blockchain client, wherein the message ciphertext is obtained by encrypting a message plaintext by the blockchain client using a first encryption algorithm, the key ciphertext is obtained by encrypting a key of the first encryption algorithm by the blockchain client using a second encryption algorithm, and the message plaintext and the access control list of the data owner are sent by the data owner to the blockchain client;

Step 102, using a second encryption algorithm to generate a distributed decryption share corresponding to the key ciphertext;

Step 103, using the access control list of the data owner to encrypt the distributed decryption share to obtain a decrypted ciphertext;

Step 104, sending the decrypted ciphertext to a database, and the database asynchronously waits for a first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then asynchronously stores them;

Step 105, sharing the hash value of the message ciphertext with all data accessors, and the data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, and then decrypt the message plaintext.

In the embodiment of the present invention, the plain text of the message includes user privacy data: the user privacy data includes user personal information (for example, age, gender, etc.) and also includes data generated by personal electronic devices.

The blockchain system proposed in the embodiment of the present invention includes a blockchain consensus module, a blockchain storage module, an access control module, a network communication protocol module and a cryptographic component.

Blockchain consensus module: A consensus algorithm refers to a distributed algorithm that multiple nodes run in a distributed scenario to achieve the same data state. In a distributed scenario, network packet loss, clock drift, node downtime, node malicious behavior, and other faults may occur. The consensus algorithm needs to be able to tolerate these errors to ensure that multiple nodes obtain the same data state. According to the different types of tolerable faults, consensus algorithms can be divided into two categories: crash fault tolerant consensus algorithms, which can tolerate benign errors such as network packet loss, clock drift, and partial node downtime. Common algorithms include Paxos and Raft. Byzantine fault tolerant consensus algorithms, which can tolerate any type of errors in some nodes, including node malicious behavior. Common algorithms include PBFT, PoW, PoS, etc.

According to different usage scenarios, consensus algorithms can be divided into two categories: public chain consensus and consortium chain consensus. In distributed technology, consensus has become synonymous with a specific algorithm within a single function. However, consensus includes more than simply agreeing on the order of information. This distinction is highlighted by its basic role in the entire information process, from proposal and endorsement to sorting, verification and submission. In short, consensus is defined as a closed-loop verification of the correctness of a set of information that makes up a block. The characteristics of the consortium chain are that the network between nodes is relatively stable and there are access requirements for nodes. Raft and PBFT algorithms can be selected according to the type of errors that need to be tolerated. The advantages of this type of algorithm are high TPS and transactions can be confirmed at the millisecond level. The disadvantage is that the number of supported nodes is limited, usually not more than 100 nodes.

Blockchain storage module: The storage module is responsible for persistent storage of ledger data such as blocks, transactions, status, historical read-write sets, etc. on the chain, and provides external query functions for the above data. The blockchain submits data in batches in units of blocks. One block submission involves the submission of multiple ledger data, such as transaction submission, status data modification, etc., so the storage module needs to maintain the atomicity of the ledger data. The embodiment of the present invention intends to support commonly used databases to store ledger data, such as LevelDB, BadgerDB, TikvDB, MySQL and other databases. The business can choose any of these databases to deploy the blockchain. In the embodiment of the present invention, the hash value of the message ciphertext, the key ciphertext and the access control list of the data owner may exist in the blockchain storage module.

Access control module: Access control is used to define how decisions are made and specific results are achieved. To this end, access control generally describes who and what, such as a person's access or permissions to private data. In the embodiment of the present invention, access control is a management mechanism for the infrastructure. Access control indicates how members agree to or reject the network, etc. Access control is unanimously agreed upon by alliance members when the network is initially configured, but can be modified during the evolution of the network. For example, they define criteria for adding or removing members, changing the block format, or specifying the number of organizations that need endorsements. All of these behaviors that define who can do what are described in access control. Simply put, everything you want to do in the blockchain platform is subject to access control. In existing blockchain systems, it is impossible to achieve secure and fine-grained control of data reading and writing, which increases the security risks of data access. The access control scheme for data on the blockchain system proposed in the embodiment of the present invention can solve this problem.

Network communication protocol module: All nodes in the blockchain system use national secret TLS+gRPC for communication. TLS is a transport layer protocol based on the TCP protocol, and the TCP protocol has the feature of data retransmission, ensuring the reliability and efficiency of data transmission; at the same time, components such as gRPC's name resolver and load balancer ensure the activity, health and availability of the connection.

Cryptographic component: provides software implementation of signature and verification, hash calculation, encryption and decryption functions, and cryptographic protocols based on SM2 and SM3 algorithms.

FIG2 is a schematic diagram of a write operation in an embodiment of the present invention, corresponding to the write operation of step 101 to step 105. Symmetric encryption cannot be innovated. However, an embodiment of the present invention adopts a hybrid encryption mode consisting of a first encryption algorithm and a second encryption algorithm, wherein the first encryption algorithm is a symmetric encryption algorithm and the second encryption algorithm is a distributed encryption algorithm. Since symmetric encryption cannot encrypt large data, distributed encryption is used to encrypt messages. However, in order to ensure confidentiality, symmetric encryption is used to encrypt keys.

(1) The blockchain client receives the plaintext message m sent by the data owner and the data owner's access control list ACL, where the data owner's access control list includes the public key of the data accessor. The blockchain client can be a client browser and can communicate with the data owner through an interface.

(2) The blockchain client uses the first encryption algorithm to encrypt the message plaintext m to obtain the message ciphertext C. In the embodiment of the present invention, the first encryption algorithm is a symmetric encryption algorithm. Then the blockchain client uses the key key _sm4 of the first encryption algorithm to encrypt the message plaintext m to obtain the message ciphertext C.

Symmetric encryption algorithms use the same key (or private key) to encrypt and decrypt data. In symmetric encryption, the sender and receiver must share the same key in advance, which means that the same key is used for both encryption and decryption, so it is also called "shared key encryption."

The steps of the symmetric encryption algorithm (which may adopt the national encryption SM4) include:

In the symmetric encryption key generation phase, the key key _sm4 required by the symmetric encryption algorithm is determined according to the security parameter l;

In the encryption phase, the plaintext message m and the key key _sm4 are obtained, and the plaintext message m is encrypted by a symmetric encryption algorithm to obtain the ciphertext message C;

In the decryption stage, the message ciphertext C and key key _sm4 are obtained, and the message plaintext m is decrypted through the symmetric encryption algorithm.

(3) The blockchain client uses the second encryption algorithm to encrypt the key key _sm4 of the first encryption algorithm to obtain the key ciphertext c;

Distributed encryption algorithms can prevent a single node from obtaining a key, causing a single point of error. Distributed encryption algorithms are used to protect confidential information from being leaked or abused by a single key holder. It is based on the concept of distributed key generation and sharing, divides the key into multiple parts, and distributes it to multiple participants, so that these participants can only cooperate in decryption when predetermined conditions are met. The embodiment of the present invention adopts a robust label-based distributed encryption scheme. Among them, the label lb, that is, the data owner can specify "how, when, and where" the data accessor accesses the data. The label here is the following access control list ACL. The embodiment of the present invention innovatively combines the distributed encryption algorithm with the fine-grained access control method. In the traditional distributed encryption scheme, only the label of the message is input in the encryption stage. The embodiment of the present invention replaces the label in the distributed encryption algorithm with a fine-grained access control list for data by transforming the distributed encryption algorithm, thereby forming a fine-grained access control method for messages.

In one embodiment, the second encryption algorithm is a distributed encryption algorithm (which may be referred to as TDH2);

The steps of the distributed encryption algorithm include:

In the distributed encryption key generation stage, the public key pk of the blockchain system and the private key (sk ₁ ,...,sk _n ) of each node and the verification key vk are obtained according to the security parameters, the number n of nodes in the blockchain system and the number t of faulty nodes that can be tolerated in the blockchain system;

In the encryption phase, the key key _sm4 of the first encryption algorithm, the access control list of the data owner (including the public key of the data accessor) and the blockchain system public key pk are obtained, and the key key _sm4 of the first encryption algorithm is output as the key ciphertext c through the encryption algorithm;

In the decryption share generation phase, the node inputs the key ciphertext c, the node's private key sk _i and the data owner's access control list, and outputs the corresponding node's distributed decryption share σ _i ;

In the decryption share verification phase, the decryption ciphertext E _pkSM2i (σ _i ) is verified according to the decryption ciphertext E _pkSM2i (σ _i ) input by the data accessor, the verification key vk, the access control list of the data owner and a decryption share σ _i . When the verification result is 1, the verification is determined to be successful, and when the verification result is 0, the verification is determined to be failed.

In the recovery phase, the message plaintext m or an illegal mark is output based on the verification key vk, (t) decryption shares σ _i and the access control list of the data owner input by the data accessor.

(4) The blockchain client generates a message ciphertext hash value h for C;

(5) The blockchain client sends the hash value of the message ciphertext, the key ciphertext, and the access control list of the data owner to the node on the blockchain system, and sends the hash value of the message ciphertext and the access control list of the message ciphertext data owner to the database.

(6) The node uses the second encryption algorithm to generate a distributed decryption share corresponding to the key ciphertext, which corresponds to the decryption share generation stage of the distributed encryption algorithm.

(7) The access control list of the data accessor includes the public key pk _SM2i of the data accessor; the node uses the access control list pk _SM2i of the data owner to encrypt the distributed decryption share σ _i to obtain the decrypted ciphertext Epk _SM2i (σ _i ); the decrypted ciphertext is sent to the database, and the database asynchronously waits for the first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then asynchronously stores them;

In order to avoid the problem that in the traditional blockchain system, when reading information, it is necessary to obtain information from the chain, which causes the performance of the entire system to decline. The embodiment of the present invention can directly operate the database, greatly improving the performance of the blockchain system. The entire read operation is based on the write operation, that is, when writing to the database in the embodiment of the present invention, a new process is adopted to avoid single point errors that may exist in the database. The operation of writing to the database is innovatively integrated with the distributed encryption algorithm.

In one embodiment, the database is a SQL database;

The primary key of the SQL database during storage is the hash value of the message ciphertext, and the key value is the message ciphertext;

The first number is the number of fault-tolerant error nodes in the blockchain system plus 1;

The first number of decrypted ciphertexts corresponding to the access control lists ACL of matching data owners are obtained according to the access control lists of the same data owner.

The first quantity can be expressed as t+1; for example, there are 4 blockchain nodes (one of which is an error node), that is, the database receives 2 Epk _SM2i (σ _i ) and they have the same ACL before writing Epk _SM2i (σ _i ) to the database.

As can be seen from the above, each blockchain node will generate decrypted ciphertext. However, if the decrypted ciphertext is only stored locally in the blockchain, the performance of users reading the blockchain will be reduced; therefore, the blockchain node will send the decrypted ciphertext to the SQL database. However, the decrypted ciphertext may be lost when sending information; the SQL database needs to wait asynchronously, which is very important because the decrypted ciphertext may not arrive at the database at the same time due to network factors and other issues. Therefore, the SQL database waits asynchronously for the decrypted ciphertext to arrive; SQL not only needs to wait asynchronously for the decrypted ciphertext, but also needs to wait for t+1 decrypted ciphertexts before writing them to the SQL database. This approach not only avoids single point errors, but also is the number of decrypted ciphertexts required in the subsequent recovery phase. Only with the database write operation can the data accessor directly read t+1 decrypted ciphertexts in the read phase.

(8) The hash value of the message ciphertext is shared with all data accessors. The data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, and then decrypt the message plaintext.

FIG3 is a flow chart of another method for controlling access to data on a blockchain system according to an embodiment of the present invention, which is applied to a blockchain client and includes:

Step 301, receiving a plain text message input by a data owner and a data owner access control list;

Step 302, encrypt the message plaintext using a first encryption algorithm to obtain a message ciphertext;

Step 303, using the second encryption algorithm to encrypt the key of the first encryption algorithm to obtain a key ciphertext;

Step 304, generating a hash value of the message ciphertext, wherein the hash value is used by the data accessor to obtain the message plaintext;

Step 305: Send the hash value of the message ciphertext, the key ciphertext and the access control list to the blockchain system, wherein after the key ciphertext obtains the distributed decryption share through the node private key, the node on the blockchain system uses the data owner's access control list to encrypt the decryption share to obtain the decrypted ciphertext, and sends it to the database, and the database asynchronously waits for the first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then asynchronously stores them.

FIG3 is a write operation described from the perspective of a blockchain client. In one embodiment, the method further includes:

Using a third encryption algorithm, generating a private key and a public key of the data accessor, and sending the public key of the data accessor to the blockchain system;

The third encryption algorithm is adopted to encrypt the distributed decryption share using the access control list of the data owner to obtain the decrypted ciphertext, wherein the access control list of the data accessor includes the public key of the data accessor.

In one embodiment, the third encryption algorithm is a public key encryption algorithm;

The steps of the public key encryption algorithm include:

In the key generation phase of the public key confidentiality algorithm, the private key sk _SM2 and the public key pk _SM2 of the data accessor are obtained according to the security parameters;

In the encryption phase, the distributed decryption shares and the public key of the data accessor are obtained, and the distributed decryption shares are encrypted to output the decrypted ciphertext.

In the decryption phase, the decrypted ciphertext and the private key of the data accessor are obtained, and the distributed decryption share is obtained by decryption.

The embodiment of the present invention uses a public key encryption algorithm and innovatively proposes that the blockchain uses the public key of the data accessor in the access control to encrypt the decrypted ciphertext, which further protects the confidentiality of the decrypted ciphertext.

The process by which a data accessor obtains the plaintext of a message is called a read operation. The following describes the steps of a read operation.

FIG. 4 is a schematic diagram of a read operation in an embodiment of the present invention.

(1) Send the hash value h of the message ciphertext, the message ciphertext C, and the access control list ACL of the data owner to the database;

(2) Receive a read request sent by a data accessor through a blockchain client and send it to the database. The read request includes the hash value h of the message ciphertext and the access control list ACL of the data accessor. When the database compares the access database list of the data accessor to be within the range of the access control list of the data owner, it feedbacks the message ciphertext C and the decrypted ciphertext Epk _SM2i (σ _i );

(3) Decrypt the decrypted ciphertext Epk _SM2i (σ _i ) to obtain the message plaintext m, which specifically includes:

(3.1) Decrypt the decrypted ciphertext Epk _SM2i (σ _i ) according to the data accessor’s private key sk _SM2 to obtain the distributed decryption share σ _i ;

(3.2) Using the second encryption algorithm to verify whether the distributed decryption share σ _i is legal;

(3.3) If yes, add the distributed decryption share σ _i to the queue;

(3.4) When there are a first number of legal distributed decryption shares σ _i in the queue, the second encryption algorithm is used to obtain the key of the first encryption algorithm;

(3.5) Use the key of the first encryption algorithm to decrypt the message ciphertext C to obtain the message plaintext m.

Referring to FIG. 5 , an embodiment of the present invention further provides an access control device for data on a blockchain system, which is applied to any node on the blockchain system, and includes:

The first receiving module 501 is used to receive the hash value of the message ciphertext, the key ciphertext and the access control list of the data owner sent by the blockchain client, wherein the message ciphertext is obtained by the blockchain client encrypting the message plaintext using the first encryption algorithm, the key ciphertext is obtained by the blockchain client encrypting the key of the first encryption algorithm using the second encryption algorithm, and the message plaintext and the access control list of the data owner are sent by the data owner to the blockchain client;

A distributed decryption share generation module 502, configured to generate a distributed decryption share corresponding to a key ciphertext by using a second encryption algorithm;

A decrypted ciphertext obtaining module 503 is used to encrypt the distributed decryption shares using the access control list of the data owner to obtain the decrypted ciphertext;

A sending module 504 is used to send the decrypted ciphertext to a database, and the database asynchronously waits for a first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then asynchronously stores them;

The hash value sharing module 505 is used to share the hash value of the message ciphertext with all data accessors. After the data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, they decrypt the message plaintext.

Referring to FIG. 6 , an embodiment of the present invention further provides another device for controlling access to data on a blockchain system, which is applied to a blockchain client and includes:

The second receiving module 601 is used to receive a message plain text and a data owner access control list input by a data owner;

A first encryption module 602, configured to encrypt a message plaintext using a first encryption algorithm to obtain a message ciphertext;

The second encryption module 603 is used to encrypt the key of the first encryption algorithm using the second encryption algorithm to obtain a key ciphertext;

A hash value generation module 604 is used to generate a hash value of a message ciphertext, and the hash value is used by a data accessor to obtain a message plaintext;

The second sending module 605 is used to send the hash value of the message ciphertext, the key ciphertext and the access control list to the blockchain system, wherein after the key ciphertext obtains the distributed decryption share through the node private key, the node on the blockchain system uses the access control list of the data owner to encrypt the decryption share to obtain the decrypted ciphertext, and sends it to the database, and the database asynchronously waits for the first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then asynchronously stores them.

Referring to FIG. 7 , an embodiment of the present invention further proposes an access control system for data on a blockchain system, including a blockchain system 702 , a blockchain client 701 , and a database 703 , wherein:

The blockchain client is used to: receive a message plaintext and an access control list input by a data owner; encrypt the message plaintext using a first encryption algorithm to obtain a message ciphertext, encrypt the key of the first encryption algorithm using a second encryption algorithm to obtain a key ciphertext, and generate a hash value of the message ciphertext; send the hash value of the message ciphertext, the key ciphertext and the access control list to the blockchain system;

The node on the blockchain system is used to: receive the hash value of the message ciphertext sent by the blockchain client, the key ciphertext and the access control list of the data owner; use the second encryption algorithm to generate the distributed decryption share corresponding to the key ciphertext, and use the access control list of the data owner to encrypt the distributed decryption share to obtain the decrypted ciphertext; send the decrypted ciphertext to the database; share the hash value of the message ciphertext with all data accessors, and the data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, and then decrypt to obtain the message plaintext;

The database is used to asynchronously store the decrypted ciphertexts corresponding to the first number of matching access control lists after asynchronously waiting.

The method and system proposed in the embodiments of the present invention can be used for a personal digital health record system, covering the medical data full life cycle security system standards for medical data collection security, medical data transmission security, medical data storage security, medical data exchange security, medical data processing security, and medical data destruction security. The personal digital health record system is based on the personal electronic health code as the unique identifier of the resident's health identity, dynamically perceives the resident's medical behavior, records the medical service trajectory, accurately aggregates diagnosis and treatment service information, and combines the input and upload of residents' daily health monitoring data to form a standardized, credible, authoritative, and resident-manageable full-life cycle personal digital health record.

The method and system proposed in the embodiment of the present invention can be used for data recording systems in the field of public services, and can improve the efficiency and transparency of public services by establishing a decentralized, transparent, and tamper-proof data recording system, improve data sharing and security between public service departments and between public service departments and citizens, and simplify administrative procedures and the provision of public services. By storing key information and transaction records on the blockchain, public service departments can achieve a higher level of data traceability and compliance, strengthen supervision and governance capabilities, and thus provide the public with more fair, efficient, and reliable services.

The beneficial effects of the method and system proposed in the embodiments of the present invention are:

Compared with the traditional blockchain system with low performance, the method and system proposed in the embodiment of the present invention do not rely on open source software or existing blockchain platforms, can be updated and iterated quickly, and can store a large amount of core data on the chain and support on-chain operations through the database, break through the barriers of data islands, truly realize the collaborative sharing and efficient use of data resources, ensure the activity of the system, reduce the difficulty and pressure of data maintenance, reduce the cost of system storage and call processes, and improve the security and reliability of the system; through the access control list of the data owner, the access control can be fine-grained and accurately controllable, and can determine which data, at what time, and by whom to read or use, and can also dynamically determine and modify access control permissions, which can ensure that there is no single point error in the whole process, no trusted third party is required, and the reliability, activity and integrity of the blockchain system are guaranteed. In the fine-grained access control of this scheme, in addition to adding the attributes of the data accessor, the attributes of the regulator can also be added. This can ensure the legitimacy of the data and allow the regulator to trace the information.

An embodiment of the present invention further provides a computer device. FIG8 is a schematic diagram of a computer device in an embodiment of the present invention. The computer device 800 includes a memory 810, a processor 820, and a computer program 830 stored in the memory 810 and executable on the processor 820. When the processor 820 executes the computer program 830, the access control method for data on the above-mentioned blockchain system is implemented.

An embodiment of the present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the access control method for data on the above-mentioned blockchain system.

An embodiment of the present invention also provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, it implements the access control method for data on the above-mentioned blockchain system.

It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

The present invention is described with reference to the flowchart and/or block diagram of the method, device (system), and computer program product according to the embodiment of the present invention. It should be understood that each process and/or box in the flowchart and/or block diagram, as well as the combination of the processes and/or boxes in the flowchart and/or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device for implementing the functions specified in one process or multiple processes in the flowchart and/or one box or multiple boxes in the block diagram.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims (16)

1. A method for controlling access to data on a blockchain system, characterized in that it is applied to any node on the blockchain system and includes: Receive the hash value of the message ciphertext, the key ciphertext, and the access control list of the data owner sent by the blockchain client, wherein the message ciphertext is obtained by the blockchain client encrypting the message plaintext using the first encryption algorithm, the key ciphertext is obtained by the blockchain client encrypting the key of the first encryption algorithm using the second encryption algorithm, and the message plaintext and the access control list of the data owner are sent by the data owner to the blockchain client; Using the second encryption algorithm, generating a distributed decryption share corresponding to the key ciphertext; The distributed decryption shares are encrypted using the access control list of the data owner to obtain the decrypted ciphertext; Sending the decrypted ciphertext to a database, the database asynchronously waiting for a first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then asynchronously storing the decrypted ciphertexts; The hash value of the message ciphertext is shared with all data accessors, and the data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, and then decrypt the message plaintext; When the blockchain client uses the second encryption algorithm to encrypt the key of the first encryption algorithm, in the encryption stage of the second encryption algorithm, the key of the first encryption algorithm, the access control list of the data owner and the public key of the blockchain system are obtained, and the key of the first encryption algorithm is output as a key ciphertext through the encryption algorithm; When using the second encryption algorithm to generate distributed decryption shares corresponding to the key ciphertext, in the decryption share generation phase of the second encryption algorithm, the node inputs the key ciphertext, the node's private key and the access control list of the data owner, and outputs the distributed decryption share of the corresponding node. 2. The method according to claim 1, wherein the first encryption algorithm is a symmetric encryption algorithm; The steps of the symmetric encryption algorithm include: In the symmetric encryption key generation phase, the key required by the symmetric encryption algorithm is determined based on the security parameters; In the encryption stage, the plaintext message and the key are obtained, and the plaintext message is encrypted using a symmetric encryption algorithm to obtain the ciphertext message; In the decryption stage, the message ciphertext and key are obtained, and the message plaintext is decrypted using a symmetric encryption algorithm. 3. The method according to claim 1, wherein the second encryption algorithm is a distributed encryption algorithm; The steps of the distributed encryption algorithm include: In the distributed encryption key generation stage, the public key of the blockchain system and the private key and verification key of each node are obtained according to the security parameters, the number of nodes in the blockchain system, and the number of faulty nodes that can be tolerated in the blockchain system; In the encryption phase, the key of the first encryption algorithm, the access control list of the data owner and the public key of the blockchain system are obtained, and the key of the first encryption algorithm is output as a key ciphertext through the encryption algorithm; In the recovery phase, the plain text of the message or the illegal mark is output according to the verification key, decryption share and access control list of the data owner input by the data accessor. 4. The method according to claim 1, wherein the database is a SQL database; The primary key of the SQL database during storage is the hash value of the message ciphertext, and the key value is the message ciphertext; The first number is the number of fault-tolerant error nodes in the blockchain system plus 1; The decrypted ciphertexts corresponding to the first number of access control lists matching the data owners are obtained according to the access control list of the same data owner. 5. The method of claim 1, wherein the access control list of the data owner includes a public key of a data accessor; The access control list of the data accessor includes the public key of the data accessor. 6. A method for access control of data on a blockchain system, characterized in that it is applied to a blockchain client and includes: Receiving a message plain text input by a data owner and an access control list of the data owner; Encrypting the message plaintext using a first encryption algorithm to obtain a message ciphertext; Using the second encryption algorithm to encrypt the key of the first encryption algorithm to obtain a key ciphertext; Generate a hash value of the message ciphertext, wherein the hash value is used by a data accessor to obtain the message plaintext; Sending the hash value of the message ciphertext, the key ciphertext and the access control list to the blockchain system, wherein after the key ciphertext obtains the distributed decryption share through the node private key, the node on the blockchain system uses the data owner's access control list to encrypt the decryption share to obtain the decrypted ciphertext, and sends it to the database, and the database asynchronously waits for the first number of decrypted ciphertexts corresponding to the access control list that matches the data owner and then asynchronously stores them; When the second encryption algorithm is used to encrypt the key of the first encryption algorithm to obtain the key ciphertext, in the encryption stage of the second encryption algorithm, the key of the first encryption algorithm, the access control list of the data owner and the public key of the blockchain system are obtained, and the key of the first encryption algorithm is outputted through the encryption algorithm to obtain the key ciphertext; When the key ciphertext obtains the distributed decryption share through the node private key, in the decryption share generation phase of the second encryption algorithm, the node inputs the key ciphertext, the node's private key and the access control list of the data owner, and outputs the distributed decryption share of the corresponding node. 7. The method according to claim 6, further comprising: Using a third encryption algorithm, generating a private key and a public key of the data accessor, and sending the public key of the data accessor to the blockchain system; The third encryption algorithm is adopted to encrypt the distributed decryption share using the access control list of the data owner to obtain the decrypted ciphertext, wherein the access control list of the data accessor includes the public key of the data accessor. 8. The method according to claim 7, wherein the third encryption algorithm is a public key encryption algorithm; The steps of the public key encryption algorithm include: In the key generation phase of the public key confidentiality algorithm, the private key and public key of the data accessor are obtained according to the security parameters; In the encryption phase, the distributed decryption shares and the public key of the data accessor are obtained, and the distributed decryption shares are encrypted to output the decrypted ciphertext; In the decryption phase, the decrypted ciphertext and the private key of the data accessor are obtained, and the distributed decryption share is obtained by decryption. 9. The method according to claim 6, further comprising: Sending the hash value of the message ciphertext, the message ciphertext and the access control list of the data owner to the database; Receive a read request sent by a data accessor through a blockchain client and send it to a database, wherein the read request includes a hash value of a message ciphertext and an access control list of the data accessor, and when the database compares the access database list of the data accessor to be within the range of the access control list of the data owner, feedback the message ciphertext and the decrypted ciphertext; Decrypt the decrypted ciphertext to obtain the message plaintext. 10. The method according to claim 6, wherein decrypting the decrypted ciphertext to obtain the message plaintext comprises: Decrypt the decrypted ciphertext according to the private key of the data accessor to obtain the distributed decryption share; Using a second encryption algorithm to verify whether the distributed decryption share is legal; If so, add the distributed decryption share to the queue; When a first number of legal distributed decryption shares exist in the queue, a second encryption algorithm is used to obtain a key of the first encryption algorithm; The message ciphertext is decrypted using the key of the first encryption algorithm to obtain the message plaintext. 11. A data access control device on a blockchain system, characterized in that it is applied to any node on the blockchain system, comprising: A first receiving module is used to receive a hash value of a message ciphertext, a key ciphertext, and an access control list of a data owner sent by a blockchain client, wherein the message ciphertext is obtained by the blockchain client encrypting the message plaintext using a first encryption algorithm, the key ciphertext is obtained by the blockchain client encrypting the key of the first encryption algorithm using a second encryption algorithm, and the message plaintext and the access control list of the data owner are sent by the data owner to the blockchain client; A distributed decryption share generation module, used to generate a distributed decryption share corresponding to the key ciphertext by using a second encryption algorithm; A decrypted ciphertext obtaining module is used to encrypt the distributed decryption shares using the access control list of the data owner to obtain the decrypted ciphertext; A sending module, used for sending the decrypted ciphertext to a database, and the database asynchronously stores the decrypted ciphertexts corresponding to the access control list of the first number of matching data owners after asynchronously waiting; A hash value sharing module is used to share the hash value of the message ciphertext with all data accessors. After the data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, they decrypt the message plaintext; When the blockchain client uses the second encryption algorithm to encrypt the key of the first encryption algorithm, in the encryption stage of the second encryption algorithm, the key of the first encryption algorithm, the access control list of the data owner and the public key of the blockchain system are obtained, and the key of the first encryption algorithm is output as a key ciphertext through the encryption algorithm; When using the second encryption algorithm to generate distributed decryption shares corresponding to the key ciphertext, in the decryption share generation phase of the second encryption algorithm, the node inputs the key ciphertext, the node's private key and the access control list of the data owner, and outputs the distributed decryption share of the corresponding node. 12. A data access control device on a blockchain system, characterized in that it is applied to a blockchain client and comprises: A second receiving module, used for receiving a message plain text input by a data owner and a data owner access control list; A first encryption module, used to encrypt the message plaintext using a first encryption algorithm to obtain a message ciphertext; A second encryption module, used to encrypt the key of the first encryption algorithm using a second encryption algorithm to obtain a key ciphertext; A hash value generation module, used to generate a hash value of a message ciphertext, wherein the hash value is used by a data accessor to obtain a message plaintext; A second sending module is used to send the hash value of the message ciphertext, the key ciphertext and the access control list to the blockchain system, wherein after the key ciphertext obtains the distributed decryption share through the node private key, the node on the blockchain system uses the access control list of the data owner to encrypt the decryption share to obtain the decrypted ciphertext, and sends it to the database, and the database asynchronously waits for the first number of decrypted ciphertexts corresponding to the access control list of the matching data owner and then asynchronously stores them; When the second encryption algorithm is used to encrypt the key of the first encryption algorithm to obtain the key ciphertext, in the encryption stage of the second encryption algorithm, the key of the first encryption algorithm, the access control list of the data owner and the public key of the blockchain system are obtained, and the key of the first encryption algorithm is outputted through the encryption algorithm to obtain the key ciphertext; When the key ciphertext obtains the distributed decryption share through the node private key, in the decryption share generation phase of the second encryption algorithm, the node inputs the key ciphertext, the node's private key and the access control list of the data owner, and outputs the distributed decryption share of the corresponding node. 13. An access control system for data on a blockchain system, characterized in that it includes a blockchain system, a blockchain client and a database, wherein: The blockchain client is used to: receive a message plaintext and an access control list input by a data owner; encrypt the message plaintext using a first encryption algorithm to obtain a message ciphertext, encrypt the key of the first encryption algorithm using a second encryption algorithm to obtain a key ciphertext, and generate a hash value of the message ciphertext; send the hash value of the message ciphertext, the key ciphertext and the access control list to the blockchain system; The node on the blockchain system is used to: receive the hash value of the message ciphertext sent by the blockchain client, the key ciphertext and the access control list of the data owner; use the second encryption algorithm to generate the distributed decryption share corresponding to the key ciphertext, and use the access control list of the data owner to encrypt the distributed decryption share to obtain the decrypted ciphertext; send the decrypted ciphertext to the database; share the hash value of the message ciphertext with all data accessors, and the data accessors obtain the decrypted ciphertext from the database through the hash value and the access control list of the data accessors, and then decrypt to obtain the message plaintext; The database is used to: asynchronously wait for the decrypted ciphertexts corresponding to the first number of matching access control lists and then asynchronously store them; When the second encryption algorithm is used to encrypt the key of the first encryption algorithm to obtain the key ciphertext, in the encryption stage of the second encryption algorithm, the key of the first encryption algorithm, the access control list of the data owner and the public key of the blockchain system are obtained, and the key of the first encryption algorithm is outputted through the encryption algorithm to obtain the key ciphertext; When using the second encryption algorithm to generate distributed decryption shares corresponding to the key ciphertext, in the decryption share generation phase of the second encryption algorithm, the node inputs the key ciphertext, the node's private key and the access control list of the data owner, and outputs the distributed decryption share of the corresponding node. 14. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any one of the methods of claims 1 to 10 when executing the computer program. 15. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the method according to any one of claims 1 to 10. 16. A computer program product, characterized in that the computer program product comprises a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 10 is implemented.