WO2022206439A1

WO2022206439A1 - Method and apparatus for providing cross-chain message

Info

Publication number: WO2022206439A1
Application number: PCT/CN2022/081760
Authority: WO
Inventors: 余逸荣
Original assignee: 支付宝(杭州)信息技术有限公司; 蚂蚁区块链科技(上海)有限公司
Priority date: 2021-03-30
Filing date: 2022-03-18
Publication date: 2022-10-06
Also published as: CN112732800B; CN112732800A

Abstract

A method and apparatus for providing a cross-chain message. The method is executed by node devices in a blockchain, and comprises: obtaining a first transaction, the first transaction calling a first contract and providing a first cross-chain message for the first contract; performing the first transaction to record the first cross-chain message in a message queue in an account state of the first contract; obtaining a second transaction, the second transaction calling a query function in the first contract; performing the second transaction to read the first cross-chain message from the message queue; generating first data corresponding to the second transaction, the first data comprising the first cross-chain message; and storing the first data into the blockchain.

Description

Method and apparatus for providing cross-chain messages

technical field

The embodiments of this specification relate to the field of blockchain technology, and more particularly, to a method and apparatus for providing cross-chain messages, and a method and apparatus for obtaining cross-chain messages.

Background technique

Blockchain technology, also known as distributed ledger technology, is a decentralized distributed database technology characterized by decentralization, openness, transparency, immutability, and trustworthiness. Each data of the blockchain will be broadcast to the blockchain nodes of the entire network, and each full node has a full amount of consistent data. With the popularity of blockchain technology, many different types of chains have emerged, which are applied in the fields of finance, health care, supply chain, asset management and traceability. At present, how to make different types of chains cooperate and realize the circulation of value is an important exploration direction. In the existing cross-chain technology, the cross-chain messages sent by the account in the blockchain to the outside of the chain are usually obtained by reading the block data in the blockchain ledger.

Therefore, a more efficient scheme for delivering messages across chains is needed.

SUMMARY OF THE INVENTION

The embodiments of this specification aim to provide a more efficient solution for transmitting cross-chain messages, so as to solve the deficiencies in the prior art.

In order to achieve the above object, one aspect of this specification provides a method for providing cross-chain messages, the method being executed by a node device of a blockchain, including: acquiring a first transaction, in which the first contract is invoked , and provide the first cross-chain message to the first contract; execute the first transaction to record the first cross-chain message in the message queue in the account state of the first contract; obtain the second transaction, the first In the second transaction, the query function in the first contract is called; the second transaction is executed to read the first cross-chain message from the message queue; the first data corresponding to the second transaction is generated, and the The first data includes the first cross-chain message; and the first data is stored in the blockchain.

In one embodiment, executing the second transaction further includes, after reading the first cross-chain message from the message queue, deleting the first cross-chain message from the message queue.

In one embodiment, executing the second transaction further includes verifying whether the sending account of the second transaction is a predetermined account, and in the case that the sending account of the second transaction is a predetermined account, extracting from the message queue Read the first cross-chain message.

In one embodiment, the first data is a receipt for the second transaction.

In one embodiment, the blockchain is a Fabric chain, and the first data is a read-write set of the second transaction.

Another aspect of this specification provides a method for obtaining a cross-chain message, the method is executed by an off-chain device, and includes: sending a second transaction to the blockchain, in which the query function in the first contract is invoked in the second transaction, The account state of the first contract includes a message queue of cross-chain messages, and the query function is used to read the cross-chain messages in the message queue; obtain from the blockchain corresponding to the second transaction The first data of the first data includes the first cross-chain message in the message queue.

In one embodiment, the method further includes, after obtaining the first data of the second transaction from the blockchain, obtaining certification data of the first data from the blockchain.

In an implementation manner, the query function in the first contract is called with a query parameter as an incoming parameter in the second transaction, and the query parameter is used to indicate the first cross-chain message.

Another aspect of this specification provides an apparatus for providing cross-chain messages, the apparatus is deployed on a node device of a blockchain, and includes: a first obtaining unit configured to obtain a first transaction, in which the first transaction calls the the first contract and provide the first cross-chain message to the first contract; the first execution unit is configured to execute the first transaction to record the first transaction in the message queue in the account state of the first contract a cross-chain message; a second acquisition unit, configured to acquire a second transaction, in which the query function in the first contract is invoked; and a second execution unit, configured to execute the second transaction to obtain the reading the first cross-chain message in the message queue; a generating unit configured to generate first data corresponding to the second transaction, where the first data includes the first cross-chain message; a storage unit , configured to store the first data in the blockchain.

In one embodiment, the second execution unit is further configured to delete the first cross-chain message from the message queue after reading the first cross-chain message from the message queue.

In one embodiment, the second execution unit is further configured to verify whether the sending account of the second transaction is a predetermined account, and in the case that the sending account of the second transaction is a predetermined account, from the The first cross-chain message is read from the message queue.

In one embodiment, the first data is a receipt for the second transaction.

Another aspect of this specification provides an apparatus for obtaining cross-chain messages, the apparatus is deployed on off-chain devices, and includes: a sending unit configured to send a second transaction to the blockchain, in which the second transaction calls the first transaction A query function in the contract, the account status of the first contract includes a message queue of cross-chain messages, and the query function is used to read the cross-chain messages in the message queue; the first acquisition unit is configured to: The first data corresponding to the second transaction is obtained from the blockchain, and the first data includes the first cross-chain message in the message queue.

In one embodiment, the apparatus further includes a second obtaining unit configured to obtain the first data of the second transaction from the blockchain after obtaining the first data of the second transaction from the blockchain Proof data of the first data.

Another aspect of the present specification provides a computer-readable storage medium on which a computer program is stored, when the computer program is executed in a computer, the computer is made to execute any one of the above-mentioned methods executed by a blockchain node device.

Another aspect of this specification provides a computing device, including a memory and a processor, where a computer program is stored in the memory, and when the processor executes the computer program, the processor implements any one of the above-mentioned execution by the blockchain node device. a method.

Another aspect of the present specification provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed in a computer, causes the computer to execute any one of the above-mentioned methods executed by an off-chain device.

Another aspect of the present specification provides a computing device, including a memory and a processor, where a computer program is stored in the memory, and when the processor executes the computer program, the processor implements any one of the above-mentioned methods executed by an off-chain device .

In the solution for providing cross-chain messages according to the embodiments of this specification, the cross-chain messages are stored in the account state of the message sending contract, and the cross-chain messages in the account state are queried by calling the query function of the message sending contract, providing a A novel method for querying the blockchain ledger, through which a verification procedure can be set in the query function, and it can also be verified whether the query account is an allowed preset account, thereby improving security.

Description of drawings

By describing the embodiments of the present specification in conjunction with the accompanying drawings, the embodiments of the present specification can be made clearer:

FIG. 1 shows a schematic diagram of a cross-chain system according to an embodiment of the present specification;

2 shows a flowchart of a method for providing a cross-chain message according to an embodiment of the present specification;

Figure 3 shows a schematic diagram of transaction m;

Figure 4 shows a schematic diagram of a log included in receipt m;

FIG. 5 shows an apparatus 500 for providing a cross-chain message according to an embodiment of the present specification;

FIG. 6 shows an apparatus 600 for acquiring a cross-chain message according to an embodiment of the present specification.

Detailed ways

The embodiments of the present specification will be described below with reference to the accompanying drawings.

FIG. 1 shows a schematic diagram of a cross-chain system according to an embodiment of the present specification. As shown in FIG. 1 , the cross-chain system includes a blockchain 11 and an off-chain device 12 . A business contract and a message sending contract are deployed in the blockchain 11. The business contract is, for example, a cross-chain transfer contract, and the business contract includes a call of a message sending contract, and the message sending contract is used to send cross-chain messages. When a user in the blockchain 11 wishes to perform a cross-chain transfer, he can send transaction 1 to the blockchain 11 through his device. The transaction 1 calls the business contract, and transfers the parameters related to the transfer to the business contract. Such as the blockchain identification of the receiving transfer, the account receiving the transfer, the transfer amount, the receiving contract account, etc. When each node device in the blockchain 11 executes the transaction 1, the account balance that initiates the transaction 1 is reduced by the transfer amount, and a cross-chain message to be sent (message 1 in FIG. 1 ) is generated. For example, the message 1 includes The message 1 contains the sending block chain identifier, receiving block chain identifier, sending account, receiving account, receiving contract account, and adding the amount to the balance of the receiving account, and then executes the message sending contract and provides message 1 to the message sending contract. By executing the message sending contract in transaction 1, the message 1 is recorded in the message queue in the account status of the message sending contract, that is, the message 1 is recorded in the ledger of the blockchain 11. In Figure 1, the messages 1- Message 5 schematically shows the message queue in the account state of the message sending contract.

The off-chain device 12 is used to pass messages between the blockchain 11 and other blockchains. The off-chain device 12 can obtain cross-chain messages by sending a transaction (eg, transaction m in FIG. 1 , where m is a transaction number) to the blockchain 11 . The query function of the message sending contract is called in transaction m to query the above message queue. Assuming that the blockchain 11 is the Ethereum chain, when the node device in the blockchain 11 executes the transaction m, it reads the message 1 from the message queue and deletes the message 1 in the message queue (as shown in the dotted box in Figure 1). shown). After the node device executes and completes the transaction m, it stores the receipt m in the blockchain 11, and the receipt m includes the message 1 obtained by querying the message queue. After that, the off-chain device 12 can read the receipt m and its Spv proof from the blockchain 11, so that the receipt m can be verified through the Spv proof, and the message 1 in it can be obtained. After acquiring the message 1, the off-chain device 12 can provide the message 1 to the receiving account and the receiving contract in the receiving blockchain in the message 1, so that the receiving blockchain can complete the transfer process based on the message 1.

It can be understood that the above description with reference to FIG. 1 is only illustrative, and is not used to limit the embodiments of the present specification. For example, the blockchain 11 is not limited to the Ethereum chain, therefore, when executing the transaction m, it is not limited to depositing the receipt m including the message 1 in the blockchain 11, but can be implemented in other forms according to the specific blockchain type The storage of message 1 is performed. The method for providing messages across chains according to embodiments of the present specification will be described in detail below.

FIG. 2 shows a flowchart of a method for providing a cross-chain message according to an embodiment of the present specification. As shown in FIG. 2 , the blockchain 11 includes, for example, node 1 and node 2. The ledger data of the blockchain 11 is stored in the node devices of node 1 and node 2 of the blockchain, which are described in FIG. 2 and below. In , in order to simplify the description, node 1 represents the node device of node 1, node 2 represents the node device of node 2, and the corresponding steps are performed by the corresponding node device. The method can be executed jointly by node 1, node 2 and off-chain device 12 of the blockchain 11.

First, in step S201, node 1 sends transaction 1 to node 2.

For example, a user corresponding to node 1 in blockchain 11 wishes to perform a cross-chain transfer business. Therefore, the user can send transaction 1 to any node in blockchain 11 (for example, node 2 here) through node 1 to Broadcast transaction 1 to the blockchain. The transaction 1 includes a call to the business contract in FIG. 1 for cross-chain transfer business. The business contract calls the sending function included in the message sending contract with message 1 as the incoming parameter, so as to send message 1 to the outside of the chain as a cross-chain message. It can be understood that, here, it is not limited to send transaction 1 from node 1 to node 2. For example, the user of blockchain 11 can also send transaction 1 to node 2 through their user equipment.

In step S202, node 2 executes transaction 1 and stores message 1 in blockchain 11.

After node 1 sends transaction 1 to blockchain 11, each node of blockchain 11 will obtain transaction 1 and execute transaction 1 to store the data related to transaction 1 in the ledger of blockchain 11 .

Specifically, when the node device of each node in the blockchain 11 executes the message sending contract in transaction 1, it generates message 1 based on the incoming parameters, and records message 1 in the message queue in the account status of the message sending contract, As shown in Figure 1. The message queue may be a first-in, first-out message queue. For example, as shown in FIG. 1 , message 1 is a cross-chain message corresponding to transaction 1, message 2 is a cross-chain message corresponding to transaction 2, and transaction 2 is executing The transaction is executed after transaction 1. Therefore, message 2 enters the message queue after message 1. When the off-chain device 12 reads the message queue, message 1 can be read first, and then message 2 can be read.

In step S203, the off-chain device 12 sends the transaction m to the node 2.

The off-chain device 12 may be the device of the user of the blockchain 11, the node device of other blockchains, or the relay device used to transfer messages between multiple blockchains, etc., which is not limited here. , the ledger data of the blockchain 11 is not stored in the off-chain device 12 . The off-chain device 12 obtains cross-chain messages from the blockchain 11 by sending a specific transaction to the blockchain 11 . Specifically, for example, as shown in FIG. 1 , the off-chain device 12 can send a transaction m to any node of the blockchain 11 (eg, node 2 ), and the transaction m calls the query function included in the message sending contract. Figure 3 shows a schematic diagram of transaction m. As shown in Figure 3, in transaction m, "0x215e..." in the "From" field is the account used by the off-chain device 12 to send the transaction m to the blockchain 11, indicating that the transaction m is sent by the off-chain device 12 Send, "SendMessage(0x29a0...)" in the "To" field is the contract name of the message sending contract, "0x29a0..." is the contract account of the message sending contract, indicating that the transaction m calls the message sending contract, and the "Data" field "Query()" is the query function in the message sending contract, which means that transaction m calls the query function in the message sending contract. Here, no parameters are passed to Query(), as described below, under different settings for the Query() function, the parameters for querying can also be passed to the Query() function.

In step S204, node 2 executes transaction m and reads message 1.

Assuming that the blockchain 11 is an Ethereum chain, after the off-chain device 12 sends the transaction m to any node in the blockchain 11, the node broadcasts the transaction m to the blockchain 11, and the The accounting node of 1 executes transaction m, updates the world state and incorporates the block, after which the accounting node sends the block including transaction m to blockchain 11, so that each node in blockchain 11 executes transaction m , update the world state and update the block, so that finally the ledger data of each node in the blockchain 11 is consistent. That is, this step performed by the node 2 of the blockchain 11 shown in FIG. 2 is performed in each node device in the blockchain 11 .

When the node 2 of the blockchain 11 executes the transaction m, the query function in the message sending contract in the transaction m is executed. The query function can be preset to allow the query account to verify whether the sending account of the transaction m is an allowed query account. . Therefore, when executing the query function, the sending account of the transaction m is first verified. If the verification fails, the query failure is returned. If the verification succeeds, the cross-chain message is read from the message queue in the account status of the message sending contract. It can be understood that in the case where the query account does not need to be verified, when the query function is executed, the cross-chain message can be directly read from the message queue in the account state of the message sending contract.

In the case where the blockchain 11 is the Hyperledger Fabric blockchain, in one embodiment, the query function includes, for example, the GetProposer interface. When executing the query function, the certificate of the proposer is first obtained by calling GetProposer. It includes the proposer's account, public key and other information, so that it can be verified whether the proposer is allowed to query based on the account or public key preset in the query function. In one embodiment, the query function includes, for example, the GetCreator interface. When the query function is executed, the proposer's account is first obtained by calling GetCreator, and then whether the proposer's account is verified based on the allowable account preset in the query function for allowed accounts.

The reading method of cross-chain messages in the query function can be set according to requirements. For example, it can be preset that each time the query function is executed, the oldest message is read from the message queue. Referring to Figure 1, assuming the current message 1 is the earliest recorded message, and message 2-message 5 are all messages recorded after message 1. Therefore, when the query function is executed this time, message 1 in the message queue is read. It can be understood that the query function is not limited to reading the oldest message, but can be preset to read the oldest predetermined number (for example, 5, etc.) messages in the message queue, or can be preset to read The latest predetermined number of messages in the message queue, or it can be preset to read the message with the specified sequence number, and the specified sequence number can be passed to the query function as an incoming parameter when calling the query function, or it can be preset to read the specified sequence number. The content of the message, the specified content is the content included in the message, such as accepting the contract account number, receiving the blockchain identifier, etc. The specified content can also be passed to the query function as an incoming parameter when calling the query function. .

The query function can also be preset to modify the state of the message sending contract (that is, modify the world state) after reading the cross-chain message. Specifically, in one embodiment, after reading the message 1 in the message queue, for example, the message 1 can be deleted in the message queue, so that the message 1 will not be read repeatedly when the query function is executed next time. In one embodiment, after reading message 1, message 1 may be marked to indicate that off-chain device 12 has read message 1, and in this embodiment, off-chain device 12 may read message 1 repeatedly, Alternatively, in the case where more than one off-chain device reads the cross-chain message from the blockchain 11, after the off-chain device 12 reads the message 1, other off-chain devices can also read the message 1.

In step S205, node 2 generates and stores receipt m.

After node 2 executes the above query function, it uses the read cross-chain message (for example, message 1) as the return data for executing the query function, so that after executing transaction m, node 2 generates a receipt m for transaction m, and displays it in the area. The receipt m of the transaction m is stored in the blockchain, and the receipt m includes the return data (ie, message 1) of executing the query function.

It can be understood that although the blockchain 11 is described as an example of the Ethereum chain, the blockchain 11 is not limited to the Ethereum chain, but can be any other type of blockchain. For example, the blockchain 11 can also be a Hyperledger Fabric blockchain. In this case, when the node device of the endorsing node in the blockchain 11 pre-executes the transaction m, after reading the message 1, it writes the message 1 into In the read-write set corresponding to the transaction m, the submitting node in the blockchain 11 stores the read-write set in the blockchain 11 after verifying the read-write set of the transaction m.

In step S206, the off-chain device 12 obtains the receipt m from the node 2.

In one embodiment, the off-chain device 12 can connect to any node in the blockchain 11 and remotely read the receipt m from that node. In one embodiment, after reading the receipt m, the off-chain device 12 may also read the Spv proof of the receipt m from the node of the blockchain 11 .

In one embodiment, any node in the blockchain 11 can actively push the receipt m to the off-chain device 12 after depositing the receipt m.

In step S207, the off-chain device 12 obtains the message 1 from the receipt m.

In one embodiment, when the off-chain device 12 is a relay device, the off-chain device 12 can obtain the message 1 by parsing the receipt m after obtaining the receipt m and its Spv proof. Message 1 is recorded in receipt m, for example, in the form of a log (Log). The log is a log recorded after executing the message sending contract, and is used to record the return data when the function of the message sending contract is executed, that is, message 1. FIG. 4 shows a schematic diagram of the log included in the receipt m. As shown in Fig. 4, the log has, for example, a preset specific identifier (as shown in "Message" in Fig. 4), and the "From" field in the log records the contract that calls the message sending contract (such as the transfer contract Transfer) The account of the message sending contract is recorded in the "To" field. Therefore, in receipt m, the log for recording message 1 can be determined based on the specific identifier "Message" or the account of the message sending contract, and the content of the "Data" field of the log can be obtained, which is message 1 .

After acquiring the message 1, the off-chain device 12 can determine the receiving chain identification from the message 1 based on the predetermined data structure of the message 1, and thus can provide the receipt m and its Spv proof to the corresponding receiving chain.

In one embodiment, in the case where the off-chain device 12 is a trusted relay device, after obtaining the receipt m and its Spv certificate, the off-chain device 12 can first use the Spv certificate to verify the receipt m, and after the verification passes In the case of , by parsing the receipt m, the message 1 can be obtained, the receiving chain identifier can be determined from the message 1, and the message 1 can be directly provided to the corresponding receiving chain.

In one embodiment, where the off-chain device 12 only obtains receipt m, receipt m or message 1 in receipt m may be provided to the corresponding receiving chain.

FIG. 5 shows an apparatus 500 for providing a cross-chain message according to an embodiment of the present specification. The apparatus 500 is deployed on a node device of a blockchain, and includes: a first obtaining unit 51 configured to obtain a first transaction, where the In the first transaction, the first contract is invoked, and the first cross-chain message is provided to the first contract; the first execution unit 52 is configured to execute the first transaction to the account status of the first contract. The first cross-chain message is recorded in the message queue; the second acquisition unit 53 is configured to acquire a second transaction, and the query function in the first contract is called in the second transaction; the second execution unit 54 is configured to in order to execute the second transaction to read the first cross-chain message from the message queue; the generating unit 55 is configured to generate first data corresponding to the second transaction, wherein the first data contains Including the first cross-chain message; the storage unit 56 is configured to store the first data in the blockchain.

In an embodiment, the second execution unit 54 is further configured to delete the first cross-chain message from the message queue after reading the first cross-chain message from the message queue .

In one embodiment, the second execution unit 54 is further configured to verify whether the sending account of the second transaction is a predetermined account, and in the case that the sending account of the second transaction is a predetermined account, from the Read the first cross-chain message from the message queue.

In one embodiment, the first data is a receipt for the second transaction.

FIG. 6 shows an apparatus 600 for obtaining a cross-chain message according to an embodiment of the present specification. The apparatus 600 is deployed on an off-chain device, and includes a sending unit 61 configured to send a second transaction to the blockchain, the The second transaction calls the query function in the first contract, the account status of the first contract includes a message queue of cross-chain messages, and the query function is used to read the cross-chain messages in the message queue; the first The obtaining unit 62 is configured to obtain first data corresponding to the second transaction from the blockchain, where the first data includes the first cross-chain message in the message queue.

In one embodiment, the apparatus 600 further includes a second obtaining unit 63, configured to obtain the first data of the second transaction from the blockchain after obtaining the first data of the second transaction from the blockchain Proof data of the first data.

Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, as for the system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and for related parts, please refer to the partial descriptions of the method embodiments.

The foregoing describes specific embodiments of the present specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different from that in the embodiments and still achieve desirable results. Additionally, the processes depicted in the figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Those of ordinary skill in the art should further realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software or a combination of the two, in order to clearly illustrate the hardware and software interchangeability, the components and steps of each example have been generally described in terms of functions in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Persons of ordinary skill in the art may use different methods of implementing the described functionality for each particular application, but such implementations should not be considered beyond the scope of this application. Wherein, the software module can be placed in random access memory (RAM), internal memory, read only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or technical fields in any other form of storage medium known in the art.

The specific embodiments described above further describe the purposes, technical solutions and beneficial effects of the embodiments of the present specification in detail. It should be understood that the above descriptions are only specific implementations of the embodiments of the present specification, and are not intended to be used for The protection scope of the embodiments of this specification is limited, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the embodiments of this specification shall be included within the protection scope of the embodiments of this specification.

Claims

A method for providing cross-chain messages, the method being executed by a node device of a blockchain, comprising:

Acquire a first transaction, in which the first contract is invoked and a first cross-chain message is provided to the first contract;

executing the first transaction to record the first cross-chain message in the message queue in the account state of the first contract;

Obtain a second transaction, in which the query function in the first contract is called;

executing a second transaction to read the first cross-chain message from the message queue;

generating first data corresponding to the second transaction, where the first data includes the first cross-chain message;

The first data is stored in the blockchain.
The method of claim 1, performing the second transaction further comprising, after reading the first cross-chain message from the message queue, deleting the first cross-chain message in the message queue.
The method according to claim 1, wherein executing the second transaction further comprises verifying whether the sending account of the second transaction is a predetermined account, and in the case that the sending account of the second transaction is a predetermined account, from the Read the first cross-chain message from the message queue.
The method of any one of claims 1 to 3, wherein the first data is a receipt for the second transaction.
The method according to any one of claims 1 to 3, wherein the blockchain is a Fabric chain, and the first data is a read-write set of the second transaction.
A method for obtaining a cross-chain message, the method being executed by an off-chain device, comprising:

Send a second transaction to the blockchain, the query function in the first contract is called in the second transaction, the account status of the first contract includes a message queue of cross-chain messages, and the query function is used to read all Describe the cross-chain messages in the message queue;

Obtain first data corresponding to the second transaction from the blockchain, where the first data includes the first cross-chain message in the message queue.
6. The method of claim 6, further comprising, after obtaining the first data of the second transaction from the blockchain, obtaining attestation data for the first data from the blockchain.
The method according to claim 6, wherein in the second transaction, a query function in the first contract is called with a query parameter as an incoming parameter, and the query parameter is used to indicate the first cross-chain message.
An apparatus for providing cross-chain messages, the apparatus is deployed on a node device of a blockchain, including:

a first obtaining unit, configured to obtain a first transaction in which the first contract is invoked and a first cross-chain message is provided to the first contract;

a first execution unit configured to execute a first transaction to record the first cross-chain message in a message queue in the account state of the first contract;

a second obtaining unit, configured to obtain a second transaction, in which the query function in the first contract is called;

a second execution unit configured to execute a second transaction to read the first cross-chain message from the message queue;

a generating unit, configured to generate first data corresponding to the second transaction, where the first data includes the first cross-chain message;

A storage unit configured to store the first data in the blockchain.
The apparatus according to claim 9, wherein the second execution unit is further configured to delete the first cross-chain message in the message queue after reading the first cross-chain message from the message queue information.
The apparatus according to claim 9, wherein the second execution unit is further configured to verify whether the sending account of the second transaction is a predetermined account, in the case that the sending account of the second transaction is a predetermined account , read the first cross-chain message from the message queue.
11. The apparatus of any one of claims 9 to 11, wherein the first data is a receipt for the second transaction.
The apparatus according to any one of claims 9 to 11, wherein the blockchain is a Fabric chain, and the first data is a read-write set of the second transaction.
A device for acquiring cross-chain messages, the device is deployed on off-chain devices, including:

a sending unit, configured to send a second transaction to the blockchain, the query function in the first contract is called in the second transaction, the account status of the first contract includes a message queue of cross-chain messages, and the query The function is used to read the cross-chain message in the message queue;

A first obtaining unit, configured to obtain first data corresponding to the second transaction from the blockchain, where the first data includes the first cross-chain message in the message queue.
The apparatus of claim 14, further comprising a second obtaining unit configured to obtain the first data from the blockchain after obtaining the first data of the second transaction from the blockchain A proof data of data.
The device according to claim 14, wherein in the second transaction, a query function in the first contract is called with a query parameter as an incoming parameter, and the query parameter is used to indicate the first cross-chain message.
A computer-readable storage medium on which computer programs or instructions are stored, which, when executed in a computer, cause the computer to perform the method of any one of claims 1 to 5.
A computing device, comprising a memory and a processor, wherein a computer program or instruction is stored in the memory, and the processor implements the method according to any one of claims 1 to 5 when executing the computer program or instruction .
A computer-readable storage medium on which computer programs or instructions are stored, which, when executed in a computer, cause the computer to perform the method of any one of claims 6 to 8.
A computing device, comprising a memory and a processor, wherein a computer program or instruction is stored in the memory, and the processor implements the method according to any one of claims 6 to 8 when executing the computer program or instruction .