WO2022205956A1

WO2022205956A1 - Method and apparatus for communication between blockchain and off-chain device

Info

Publication number: WO2022205956A1
Application number: PCT/CN2021/133008
Authority: WO
Inventors: 邱鸿霖
Original assignee: 蚂蚁区块链科技(上海)有限公司; 支付宝(杭州)信息技术有限公司
Priority date: 2021-03-30
Filing date: 2021-11-25
Publication date: 2022-10-06
Also published as: CN112738280A; CN112738280B; CN113691633A

Abstract

The embodiments of the present specification provide a method and apparatus for communication between a blockchain and an off-chain device. The method is executed by a blockchain node and comprises: executing a first transaction so as to provide to an off-chain device a pre-enable message of a first session, the first session being a session between a blockchain and the off-chain device; and executing a second transaction sent by the off-chain device so as to provide the off-chain device with an enable message of the first session, the second transaction comprising acknowledgment information for the pre-enable message.

Description

A method and device for communication between blockchain and off-chain devices

technical field

The embodiments of this specification relate to the field of blockchain technology, and more particularly, to a method and apparatus for communication between a blockchain and an off-chain device.

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 transaction of the blockchain will be broadcast to the blockchain nodes of the entire network, and each full node has full and consistent data. Since the blockchain is a closed environment, the blockchain cannot actively initiate network calls, and the smart contracts on the chain can only passively receive data. Therefore, the blockchain cannot actively obtain data or resources outside the chain. In the prior art, in order to overcome the above problems, off-chain trusted devices can log in to the blockchain client and exchange information between the blockchain smart contracts, thereby providing off-chain data or resources to the blockchain, such as It can provide off-chain information, off-chain data processing capabilities, etc. to the blockchain. However, in the existing communication solutions between blockchain and off-chain devices, only one-way communication is realized in which the blockchain receives information from off-chain devices through contracts.

Therefore, there is a need for a more efficient solution for communicating with off-chain devices on the blockchain.

SUMMARY OF THE INVENTION

The embodiments of this specification aim to provide a more effective communication solution between the blockchain and off-chain devices, so as to solve the deficiencies in the prior art.

In order to achieve the above object, one aspect of this specification provides a communication method between a blockchain and an off-chain device, the method being executed by a blockchain node, including: executing a first transaction to provide the off-chain device with A pre-opening message for a first session, wherein the first session is a session between the blockchain and the off-chain device; execute a second transaction sent by the off-chain device to send the off-chain device to the off-chain device An opening message of the first session is provided, and confirmation information for the pre-opening message is included in the second transaction.

In one embodiment, executing the first transaction further includes executing the first transaction to store a pre-opening message of the first session in the blockchain.

In one embodiment, executing the first transaction further includes executing the first transaction to record the state of the first session as a pre-opened state in the blockchain.

In one embodiment, the first contract is invoked in the first transaction, wherein recording the state of the first session as a pre-opened state in the blockchain includes, in the account of the first contract In the state, the state of the first session is recorded as a pre-opened state.

In one embodiment, the first contract is invoked in the second transaction, and the executing the second transaction sent by the off-chain device includes executing the first contract invoked in the second transaction , so that it is determined whether the second transaction is executed within the first predetermined period, and in the case where it is determined that the second transaction is executed within the first predetermined period, an opening message of the first session is provided to the off-chain device.

In one embodiment, executing the first contract invoked in the second transaction further results in ending the first session if the second transaction is determined to be executed after a first predetermined period of time.

In one embodiment, providing the off-chain device with an open message of the first session includes modifying the state of the first session to an open state.

In one embodiment, providing the off-chain device with the opening message of the first session includes storing the opening message of the first session in the blockchain.

In one embodiment, the method further includes, after providing the off-chain device with the opening message of the first session, executing a third transaction invoking the first contract, the third transaction including the pending first session A piece of data, so as to determine whether the state of the first session is an open state, and in the case of determining that the state of the first session is an open state, it is stored in the blockchain in association with the first session the first data.

In one embodiment, the method further includes: executing a fourth transaction sent by the off-chain device, the fourth transaction including pre-closing information, so that it is determined whether the off-chain device has received All messages sent; in a case where it is determined that all messages sent by the off-chain device are received, a close message of the first session is provided to the off-chain device.

In one embodiment, providing the off-chain device with a close message of the first session includes modifying the state of the first session to a closed state.

In one embodiment, executing the fourth transaction further causes, in the event that it is determined that the message sent at least in part by the off-chain device has not been received, storing in the blockchain in association with the first session incoming request information, where the request information is used to request the off-chain device to resend the at least part of the message.

In one embodiment, executing the fourth transaction further results in modifying the state of the first session to a pre-closed state in the event that it is determined that a message sent at least in part by the off-chain device has not been received.

Another aspect of this specification provides a method for communication between a blockchain and an off-chain device, the method being performed by the off-chain device, comprising: acquiring a pre-opening message of a first session from the blockchain, the first session A session is a session between the blockchain and the off-chain device; send a second transaction to the blockchain, the second transaction includes confirmation information for the pre-opening message; open the first The data retention period for the session.

In one embodiment, sending the second transaction to the blockchain includes sending the second transaction to the blockchain within a first predetermined period of time.

In one embodiment, the method further includes, after the data retention period is opened, determining whether to obtain the open message of the first session from the blockchain within a second predetermined period, when the second predetermined period In the case where the opening message of the first session is not obtained from the blockchain within the period, the data retention period is ended.

In one embodiment, the method further includes, when a preset condition is met, sending a fourth transaction to the blockchain, where the fourth transaction includes pre-closing information of the first session.

In one embodiment, the method further includes, after sending the fourth transaction to the blockchain, obtaining a close message for the first session from the blockchain; and ending the data retention period.

In one embodiment, the method further comprises, after sending the fourth transaction to the blockchain, obtaining a request message from the blockchain for at least a portion of the messages in the first session that have been sent ; sending a fifth transaction to the blockchain, the fifth transaction including the at least part of the message.

Another aspect of the present specification provides a communication device between a blockchain and an off-chain device, the device is deployed on a blockchain node, and includes: a first execution unit configured to execute a first transaction to send a transaction to the blockchain. The off-chain device provides a pre-opening message of a first session, where the first session is a session between the blockchain and the off-chain device; the second execution unit is configured to execute a session sent by the off-chain device to provide the off-chain device with an opening message of the first session, and the second transaction includes confirmation information for the pre-opening message.

In one embodiment, the first execution unit is further configured to execute a first transaction to store a pre-opening message of the first session in the blockchain.

In one embodiment, the first execution unit is further configured to execute a first transaction to record the state of the first session as a pre-opened state in the blockchain.

In an implementation manner, the first contract is invoked in the first transaction, wherein the first execution unit is further configured to record the state of the first session in the account state of the first contract as pre-opened state.

In one embodiment, the first contract is invoked in the second transaction, and the second execution unit is further configured to execute the first contract invoked in the second transaction, so as to determine whether the first contract is invoked in the second transaction. The second transaction is executed within a predetermined period of time, and in the event that the second transaction is determined to be executed within the first predetermined period of time, an opening message of the first session is provided to the off-chain device.

In one embodiment, the first execution unit is further configured to end the first session if it is determined that the second transaction is executed after a first predetermined period of time.

In one embodiment, the second execution unit is further configured to modify the state of the first session to an open state.

In an implementation manner, the second execution unit is further configured to store an opening message of the first session in the blockchain.

In one embodiment, the apparatus further includes a third execution unit configured to, after providing the off-chain device with an opening message of the first session, execute a third transaction that invokes the first contract, the first The first data to be processed is included in the third transaction, so that it is determined whether the state of the first session is an open state, and in the case of determining that the state of the first session is an open state, the blockchain is connected with all and storing the first data in association with the first session.

In one embodiment, the apparatus further includes: a fourth execution unit configured to execute a fourth transaction sent by the off-chain device, where the fourth transaction includes pre-closing information, so as to determine whether to All messages sent by the off-chain device are received; in a case where it is determined that all messages sent by the off-chain device are received, a close message of the first session is provided to the off-chain device.

In an embodiment, the fourth execution unit is further configured to modify the state of the first session to a closed state.

In one embodiment, the fourth execution unit is further configured to, in the event of determining that a message sent at least in part by the off-chain device has not been received, in the blockchain associated with the first session storing request information, where the request information is used to request the off-chain device to resend the at least part of the message.

In one embodiment, the fourth execution unit is further configured to, in a case where it is determined that a message sent at least in part by the off-chain device has not been received, modify the state of the first session to a pre-closed state .

Another aspect of this specification provides a communication device between a blockchain and an off-chain device, the device is deployed on the off-chain device, and includes: a first obtaining unit configured to obtain a first session from the blockchain The first session is a session between the blockchain and the off-chain device; the first sending unit is configured to send a second transaction to the blockchain, in which the second transaction Including confirmation information for the pre-opening message; an opening unit, configured to open a data retention period of the first session.

In one embodiment, the first sending unit is further configured to send a second transaction to the blockchain within a first predetermined period of time.

In one embodiment, the apparatus further includes a determining unit configured to, after the data retention period is enabled, determine whether to acquire the opening message of the first session from the blockchain within a second predetermined period, A first ending unit, configured to end the data retention period when the opening message of the first session is not obtained from the blockchain within a second predetermined period of time.

In one embodiment, the apparatus further includes a second sending unit configured to, when a preset condition is met, send a fourth transaction to the blockchain, where the fourth transaction includes the first session pre-close information.

In one embodiment, the apparatus further includes a second obtaining unit configured to obtain a closing message of the first session from the blockchain after the fourth transaction is sent to the blockchain; A second end unit configured to end the data retention period.

In one embodiment, the apparatus further includes a third obtaining unit, configured to, after sending the fourth transaction to the blockchain, obtain from the blockchain a request for the first session that has been sent A request message for at least part of the message in the third sending unit, configured to send a fifth transaction to the blockchain, where the fifth transaction includes the at least part of the message.

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 methods.

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 the processor implements any one of the above methods when executing the computer program.

Through the communication scheme between the blockchain and the off-chain device according to the embodiment of this specification, the session can be opened after both the blockchain and the off-chain device confirm the channel, and the off-chain device guarantees the session during the session opening. The data retention period ensures secure two-way communication between the blockchain and off-chain devices. In addition, in the embodiment of this specification, by using a smart contract in the blockchain to conduct a session with an off-chain device, and recording the session status in the account status of the smart contract, it is convenient for each node to query the session status, and Communication with off-chain devices can be done based on session state.

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 blockchain system according to an embodiment of the present specification;

FIG. 2 shows a flowchart of a communication method between the blockchain 11 and the off-chain device 12 according to an embodiment of the present specification;

FIG. 3 shows a communication apparatus 300 between a blockchain and an off-chain device according to an embodiment of the present specification;

FIG. 4 is a communication apparatus 400 used between a blockchain and an off-chain device 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 blockchain system according to an embodiment of the present specification. As shown in FIG. 1 , the system includes a blockchain 11 and off-chain devices 12 . Among them, the contract C1 and the communication contract C2 are deployed in the blockchain 11 . The communication contract C2 is used for two-way communication with the off-chain device, and the contract C1 realizes data interaction with the off-chain device by calling the communication contract C2. The off-chain device 12 is a trusted device, and the trusted device can realize its trustworthiness through hardware, software, etc. For example, the off-chain device 12 can include a trusted execution environment (TEE), and the TEE has its own hardware The private key and public key, or the off-chain device 12 realizes its credibility through algorithms such as secure multi-party computation and zero-knowledge implementation, or the off-chain device 12 may be a device of a trusted authority, and so on.

The communication contract C2 can have a session with at least one off-chain device. The communication contract C2 includes, for example, a request to open a session function, a session open function, a data transmission function, a result return function, and a session close function, and the account database of the blockchain 11 records the communication between the communication contract C2 and each off-chain device. The session state, for example, the session state includes: a pre-open state, an open state, a pre-close state, and a closed state.

For example, node 1 in blockchain 11 wishes to call contract C1 for data processing. Since contract C1 calls communication contract C2, node 1 can first query the status of communication contract C2 in the account database of the blockchain to determine the status of communication contract C2. Whether the communication contract C2 has established a session with the off-chain device 12. If the session status between the communication contract C2 and the off-chain device 12 is found to be closed, node 1 can send transaction 1, and in transaction 1, call the request open session function in the communication contract C2 to send the pre-open session to the off-chain device 12. information. After the node of the blockchain 11 executes the transaction 1, the "pre-opening message" sent by the communication contract C2 to the off-chain device 12 is stored in the blockchain, and the communication contract C2 and the off-chain device's session 1 are stored in the blockchain. The state is recorded as "pre-open state". The off-chain device 12 can read the above-mentioned "pre-opening message" by reading the data in the blockchain 11, and send transaction 2 to the blockchain 11, and the transaction 2 calls the session opening function in the communication contract C2. The off-chain device 12 enables the data retention period while sending transaction 2, thereby ensuring the security of the data in the session. After executing the transaction 2, the node in the blockchain 11 modifies the state of the session 1 to "open state".

After node 1 determines that the state of session 1 has changed to "open state", it can send transaction 3 that calls contract C1. As shown in Figure 1, contract C1 uses data D1 as a parameter to call the data sending function in communication contract C2. When the node in the blockchain 11 executes the transaction 3, it executes the communication contract C2 called therein, thereby storing the data D1 in the blockchain for sending to the off-chain device 12. For example, as shown in FIG. 1, data D1 is sent to off-chain device 12 in blockchain 11 in the form of receipt R1 and Spv proof including data D1. The blockchain 11 can be any blockchain, such as Bitcoin chain, Ethereum chain, Hyperledger Fabric blockchain (hereinafter referred to as Fabric chain) and so on. Different blockchains have different on-chain data proof methods. For example, the Fabric chain uses the endorsement node signature method, and the Ethereum chain uses the Spv proof method. In the following, the blockchain 11 is used as an example to illustrate the Ethereum chain.

The off-chain device 12 can then read the receipt R1 and its Spv proof from the blockchain 11 . The off-chain device 12 includes an Spv client. After obtaining the receipt R1 and the Spv certificate, the off-chain device 12 uses the Spv client to verify the receipt R1 through the Spv verification method, and obtains the data from the receipt R1 after the verification. Data D1 sent by contract C2, and data D1 is processed.

The off-chain device 12 is, for example, a TEE device, and after processing the data D1, for example, the acquired processing result is the processing result E1. The off-chain device 12 signs the processing result E1 using its hardware private key, and sends a transaction 4 that calls the communication contract C2 to the blockchain, where the call returns the result of calling the communication contract C2 with the processing result E1 and its signature as parameters function to provide the processing result E1 and its signature to the communication contract C2. Therefore, when the transaction 4 is executed in the blockchain, the communication contract C2 uses the preset public key of the off-chain device 12 to verify the signature of the processing result E1, and after the verification is passed, the contract C1 is called back to send the The processing result E1 is provided to the contract C1.

When the off-chain device 12 is about to end the session with the communication contract C2, it sends a transaction 5 to the blockchain 11, and in the transaction 5 calls the communication contract C2's request to close the session function. When the node in the blockchain 11 is executing transaction 5, it determines whether the reception of the data from the off-chain device 12 is completed. Change the state of session 1 to closed, thus ending the execution of transaction 5. The off-chain device 12 ends the above data retention period after reading the "session close message" from the blockchain 11, that is, deletes the data in the above session.

It can be understood that the above description with reference to FIG. 1 is only illustrative, and is not used to limit the scope of the embodiments of the present specification. For example, the blockchain 11 is not limited to calling the communication contract through the contract C1. For example, the communication contract C2 can also be called directly with the data D1 as the incoming parameter in the transaction, so that the data D1 can be processed by the off-chain device 12. The communication process between the above-mentioned blockchain and off-chain devices will be described in detail below.

FIG. 2 shows a flowchart of a communication method between the blockchain 11 and the off-chain device 12 according to an embodiment of the present specification.

As shown in FIG. 2 , in this method, the blockchain 11 and the off-chain device 12 communicate interactively, thereby realizing the session between the blockchain 11 and the off-chain device 12 . When a node in the blockchain 11 wishes to send data to the off-chain device 12, the node in the blockchain 11 can send the desired data in the form of provable data (eg transaction receipt, account data, etc.) by sending a transaction Stored in the blockchain so that the off-chain device 12 can receive this data by reading the receipt in the blockchain. When the off-chain device 12 wishes to send data to the on-chain, the off-chain device 12 may send a transaction to the blockchain through the blockchain client therein, thereby providing data to the blockchain through the transaction. In one embodiment, the blockchain 11 can communicate with the off-chain device 12 by executing a transaction that invokes the communication contract C2, which will be described below as an example. It can be understood that the communication method provided by the embodiments of this specification is not limited to executing a transaction that invokes the communication contract C2, but can also be executed by executing a transaction including a data field, as long as a message that can be explicitly sent through the data field of the transaction, and Either the recipient or the sender of the message is sufficient.

First, in step S202, the blockchain 11 sends a pre-opening message to the off-chain device 12.

As mentioned above, the account status of the communication contract C2 records the session status between the communication contract C2 and the off-chain device. For example, initially, the account status of the communication contract C2 records that the status of session 1 with the off-chain device 12 is closed, or the account status of the communication contract C2 does not record any session with the off-chain device 12, that is, The session state between the communication contract C2 and the off-chain device is closed. When the node 1 in the blockchain 11 wishes to perform data processing by invoking the communication contract C2, it can first query the account status of the communication contract C2, so as to know that the communication contract C2 has not established a session with the off-chain device 12. Therefore, node 1 may send transaction 1, in which the request to open session function in communication contract C2 is called with the off-chain device 12 identifier as an incoming parameter in transaction 1 to send a pre-open message to off-chain device 12.

Each node in the blockchain executes transaction 1 after consensus on transaction 1 to obtain a consistent state. When any node in the blockchain executes transaction 1, it stores the receipt R1 of transaction 1 in the blockchain. The receipt R1 includes the account of the communication contract C2, the identifier of the off-chain device 12, and the pre-opening message. The pre-opening message is, for example, "OpenSyncMsg". In one embodiment, the receipt R1 may further include an identifier of session 1 (eg "session 1"). At the same time, the nodes in the blockchain also record the session status between the communication contract C2 and the off-chain device 12 in the account status of the communication contract C2. For example, session 1 is used as the identifier of the session, and the status of session 1 is recorded as "pre- On state". Table 1 schematically shows a table of session states recorded in the account state of the communication contract C2 in the blockchain node.

Table 1

会话标识session ID	链下设备标识Off-chain device identification	会话状态 session state

会话1session 1	链下设备12Off-Chain Devices 12	预开启状态pre-opened state
会话2session 2	链下设备16Off-Chain Devices 16	开启状态open state
……

As shown in Table 1, multiple sessions may be recorded in the account state of the communication contract C2, such as session 1, session 2, and different sessions are sessions with different off-chain devices, and may have different session states . For example, session 1 is a session between communication contract C2 and off-chain device 12, and the state of session 1 is a pre-opened state.

The off-chain device 12 can monitor the receipt including the account address of the communication contract C2 and the identification of the off-chain device 12 through its Spv client, or the off-chain device 12 can monitor the receipt including "session 1", whenever the area is determined. When the receipt is stored in the blockchain 11, the receipt can be read from the blockchain 11, and the Spv certification data of the receipt can be read accordingly. Alternatively, the blockchain 11 can actively push information, and each time it is determined that the blockchain 11 stores the receipt generated by the execution of the communication contract C2 and sent to the off-chain device 12, the receipt and the corresponding Spv proof data are stored in the blockchain 11. Actively push to off-chain device 12. Therefore, after the above-mentioned receipt R1 is stored in the blockchain 11, the off-chain device 12 can read the receipt R1 and its Spv proof from the blockchain 11, that is, receive the pre-opening message of the session 1 in the receipt R1.

It can be understood that although it is described above that the pre-opening message is provided to the off-chain device 12 in the form of a receipt, the embodiment of the present specification is not limited thereto. For example, blockchain 11 may provide a pre-open message to off-chain device 12 through the state of session 1 in the account state of communication contract C2. The off-chain device 12 can obtain the message by reading the state of the session 1 in the blockchain 11 .

The node 1 in the blockchain 11 can query whether the transaction sent by the off-chain device 12 for confirming the above-mentioned pre-opening message is included in the predetermined number of blocks after the transaction 1 is formed into a block, if not included, the node 1 can be as follows: As shown by the dotted line in Figure 2, a transaction that calls the session closing function in the communication contract C2 is sent. After the transaction is executed, the information of the session 1 recorded in the account state of the communication contract C2 is deleted, or the state of the session 1 is modified to Disabled. Optionally, after the transaction is executed, a session close message is stored in the blockchain 11 so that the off-chain device 12 can obtain the information.

In step S204, the off-chain device 12 sends pre-opening confirmation information to the blockchain 11.

After reading the receipt R1 and its Spv proof, the off-chain device 12 verifies the receipt R1 by using the Spv proof through the Spv client. After the verification is passed, the "OpenSyncMsg" message can be read from the receipt R1. The off-chain device 12 can send transaction 2 to the blockchain 11 through the client within a predetermined period after the receipt R1 is read. In the transaction 2, for example, the session opening function in the communication contract C2 is called to send the pre-received transaction to the blockchain 11. Turn on the confirmation message. After sending transaction 2, the off-chain device 12 opens a session with the communication contract C2 in the blockchain 11, and accordingly opens a data retention period corresponding to the session, during which the off-chain device 12 has a pair of Any communication data with the communication contract C2 in this period is retained to ensure data security. Table 2 schematically shows a table of data retention periods for individual sessions recorded in the off-chain device 12 .

Table 2

会话标识session ID	合约地址contract address	数据保留时段Data retention period

会话1session 1	通信合约C2地址Communication contract C2 address	开启turn on
会话2session 2	合约C3地址Contract C3 address	关闭closure
……

As shown in Table 2, communication device 12 may establish sessions with multiple contracts, such as session 1 and session 2, and so on. In the communication device 12, the communication data in each session can be associated with "session 1", so that when the data retention period of the session 1 is on according to Table 2, the communication in the session 1 is reserved in the communication device 12 data, when it is determined that the data retention period of session 2 is closed according to Table 2, the communication data in session 2 can be deleted, and the record of session 2 can be deleted in Table 2.

In step S206, the blockchain 11 sends an opening message to the off-chain device 12.

When a node in blockchain 11 executes transaction 2 after consensus on transaction 2, it is first determined whether the state of session 1 is a pre-open state. If the state of session 1 is the pre-open state, change the state of session 1 to the open state, and store the receipt R2 corresponding to transaction 2 in the blockchain 11. The receipt R2 includes the account and chain of the communication contract C2. The identification of the lower device 12 and an opening message (eg OpenMsg). If the account state of the communication contract C2 does not include the information of the session 1 (or the state of the session 1 is closed), the execution of the transaction 2 is ended, that is, the above operations of modifying the session state and depositing the receipt R2 are not performed.

After sending the transaction 2, the off-chain device 12 determines whether the above-mentioned opening message sent by the blockchain 11 is read within a predetermined period of time, and if the above-mentioned opening message is read within the predetermined period of time, it can be confirmed that the blockchain 11 has received To the transaction 2 sent by it, then continue to retain the above-mentioned data retention period (as shown in the data retention period T1 in Figure 2), if the above-mentioned opening message is not read within a predetermined period of time, then end the above-mentioned data retention period (as shown in Figure 2). 2 in the data retention period T2). The predetermined period of time may be predetermined based on transaction block times in the blockchain 11 . In one embodiment, after the transaction 2 is executed, the above-mentioned receipt R2 is not stored in the blockchain 11, and the off-chain device 12 can determine whether the transaction 2 is read by the blockchain within a predetermined period of time after the transaction 2 is sent. 11 The pending data sent to it, if the pending data sent to it is read within a predetermined period, continue to retain the data retention period, and if the pending data is not read within the predetermined period, end the data retention period.

In step S208, the blockchain 11 sends the data D1 to be processed to the off-chain device 12.

After node 1 executes transaction 2 so that the state of session 1 becomes the open state, node 1 can start data processing through off-chain device 12 . Node 1, for example, sends transaction 3, in which transaction 3 calls the data sending function in communication contract C2 with data D1 and the identifier of off-chain device 12 as parameters. Nodes in the blockchain execute transaction 3 after consensus on transaction 3, and deposit receipt 3 of transaction 3 after executing transaction 3. The receipt 3 includes the identification of the communication contract C2, the identification of the off-chain device 12 and the data D1. Similar to the above reading receipt R1, the off-chain device 12 can read the receipt 3 and its Spv proof from the blockchain 11 through the client, verify the receipt 3, and obtain the data D1 and the communication contract C2 from the receipt 3. logo.

In step S210, the off-chain device 12 sends the processing result of the data D1 to the blockchain 11.

The off-chain device 12 is, for example, a TEE device, in which a data processing program is preset and has its hardware private key and public key. After obtaining the identifiers of the data D1 and the communication contract C2, the off-chain device 12 uses the preset data processing program to process the data D1, thereby obtaining the processing result (processing result E1) of the data D1, and uses its hardware private key to process the data D1. The result E1 is digitally signed. After that, the off-chain device 12 sends transaction 4 to the blockchain 11, in which the result-returning function in the communication contract C2 is called with the processing result E1 and the TEE signature as incoming parameters. The hardware public key of the off-chain device 12 is preset in the result return function. When the node 1 in the blockchain 11 executes the transaction 4, it uses the hardware public key to verify the TEE signature, and the data D1 can be obtained after the verification is passed. The processing result E1. When the contract C1 is called in the transaction 3 and the communication contract C2 is called in the contract C1 as shown in Fig. 1, the result return function in the communication contract C2 is called in the transaction 4, and the result E1 is processed in the function. Call the contract C1 for the incoming parameters, so that when the node 1 executes the transaction 4, after obtaining the processing result E1 through the communication contract C2, the contract C1 is executed with the processing result E1 as the parameter, so as to obtain the final execution result of the contract C1.

When other nodes (such as node 2) in the blockchain 11 want to call the communication contract C2, similar to the node 1, they first query the session status between the communication contract C2 and the off-chain device 12 in the account status of the communication contract C2, When the status of the session 1 between the communication contract C2 and the off-chain device 12 is queried, the node 2 can send data to the off-chain device 12 similar to the node 1 (for example, the data D2 shown in FIG. 2 ). ) and receive the processing result E2 of the data D2.

In step S212, the off-chain device 12 sends pre-shutdown information to the blockchain 11.

The off-chain device 12 sends a pre-close message for session 1 to the blockchain when predetermined conditions are met. The predetermined condition is, for example, any one of the following: the off-chain device 12 has not received the data to be processed for a continuous predetermined length of time, and the blockchain 11 stores the request chain in the blockchain 11 by executing the communication contract C2. The message that the off-chain device 12 closes session 1, the off-chain device 12 completes processing a predetermined amount of data, and so on.

Specifically, the off-chain device 12 sends transaction 5 to the blockchain 11 through the client, and in the transaction 5 calls the close session function of the communication contract C2 to send a pre-close message to the blockchain 11 .

In step S214, the blockchain 11 sends a shutdown message to the off-chain device 12.

When the node in the blockchain 11 executes the transaction 5, it determines whether it has received all the messages or data sent by the off-chain device 12; The state of session 1 in the account state in contract C2 is deleted (ie, session 1 is closed), or the state of session 1 is modified to the closed state, the execution of transaction 5 is ended, and receipt 5 is stored in blockchain 11. The receipt 5 includes the account of the communication contract C2, the identification of the off-chain device 12 and the session close message (eg "CloseMsg").

When executing the transaction 5, according to the preset between the communication contract C2 and the off-chain device 12, it can be determined by different methods whether all messages or data sent by the off-chain device 12 are received.

In one embodiment, the communication contract C2 can number the data sent each time. For example, as shown in FIG. 2 , the sent data are numbered as data D1 and data D2, and the off-chain device 12 also sends back corresponding numbers. The data results of the blockchain are numbered, for example, the processing result of the data D1 is numbered as the processing result E1, and the processing result of the data D2 is numbered as the processing result E2. The blockchain 11 can determine which data the processing result corresponds to based on the number of the received processing result. When the off-chain device 12 sends the pre-close message, the number of the last processing result (for example, "10") sent by it in transaction 5 can be used as a parameter to call the request to close the session function in the communication contract C2. When the transaction 5 is executed in 11, it is determined whether the processing result E1-processing result E10 has been received, thereby determining whether all the messages or data sent by the off-chain device 12 have been received. In this embodiment, after the off-chain device 12 sends the pre-close message through transaction 5, it is possible that the pending data D11, data D12, etc. have been sent to the off-chain device 12 on the blockchain 11 side, and the transaction is executed At 5:00, these data numbers can also be recorded in the state of session 1 of the communication contract C2 for the user to query, or for processing when the session is opened next time.

In another embodiment, for example, the communication contract C2 and the off-chain device 12 are pre-configured: the off-chain device 12 closes the session after processing a predetermined number (eg, 20) of data. Thus, when transaction 5 is executed in blockchain 11, it can be determined whether 20 processing results have been received, and thus whether all messages or data sent by off-chain device 12 have been received.

In one embodiment, a transaction that invokes contract C1, which invokes communication contract C2, is executed for data processing, for example, in the blockchain. The off-chain device 12 returns the processing of the data by calling back the transaction of the communication contract C2, wherein the communication contract C2 returns the returned processing result to the contract C1 through the callback contract C1, and the contract C1 stores the processing result in the contract C1 after obtaining the processing result in the account status. Therefore, the blockchain node can determine whether to receive all the messages or data sent by the off-chain device 12 by querying the account status of the contract C1.

After the off-chain device 12 reads the receipt 5 and its Spv certificate from the blockchain 11, it verifies the receipt 5, and obtains the account and "CloseMsg" of the communication contract C2 from the receipt 5, so as to correspond to the communication contract C2 The data retention period T1 is ended, that is, the communication data in the session 1 is deleted, thereby ending the session 1.

When executing transaction 5, in the event that it is determined that the message partially sent by the off-chain device 12 is not received, a receipt 5 is deposited in the blockchain, the receipt 5 including the account of the communication contract C2, the off-chain device 12 and the identifiers of the unreceived partial messages (such as message numbers), and modify the state of session 1 to the pre-closed state. After reading the receipt 5, the off-chain device 12 sends the transaction 6, in which the partial message is used as the incoming parameter to call the close session function of the communication contract C2, and the blockchain 11 receives the transaction 6 and After executing transaction 6, in the case of determining that all messages or data sent by the off-chain device 12 are received, delete the information of session 1 in the account state in the communication contract C2 (ie close session 1), or delete session 1's information. The state is modified to a closed state, and a receipt 6 is deposited in the blockchain 11, which includes the account of the communication contract C2, the identification of the off-chain device 12, and a session close message (eg "CloseMsg").

It can be understood that although the communication scheme provided by the embodiment of this specification is described above by taking the communication contract C2 as an example, the embodiment of this specification is not limited to this. For example, it can be performed on the blockchain 11 side by sending a transaction including a data field The communication process shown in FIG. 2, wherein each time a message is sent, a session identifier (such as "session 1") and message content (such as pre-opening message, pre-opening confirmation message, open message, Pending data, pre-close messages, close messages, etc.) to record session state and data in each transaction. Preferably, the blockchain node can also create a session state database locally to record the state of each session similarly to the contract account state, so as to facilitate the query of the session state.

In addition, in the above description, when the node of the blockchain 11 needs to determine the session state between the blockchain 11 and the off-chain device 12, it is determined by querying the session state in the account state of the communication contract C2. It can be understood that, The embodiment of the present application is not limited to this, and the nodes in the blockchain 11 can also determine the status of the session 1 by querying the ledger data of the blockchain for the receipts of each transaction related to the session 1. For example, when the receipt of transaction 2 is queried in the ledger data, but the receipt that includes the pre-close message sent by the off-chain device 12 is not queried, it can be determined that the state of session 1 is the open state. Similarly, other statuses of session 1 may be determined based on the queried other transaction receipts related to session 1 . That is to say, in the solution of the embodiment of the present application, it is not necessary to record the state of the session 1 in the account state of the communication contract C2.

FIG. 3 is a communication apparatus 300 between a blockchain and off-chain devices according to an embodiment of the present specification. The apparatus is deployed on a blockchain node and includes: a first execution unit 31 configured to execute a first execution unit 31. A transaction to provide a pre-opening message of a first session to an off-chain device, wherein the first session is a session between the blockchain and the off-chain device; the second execution unit 32 is configured to execute the The second transaction sent by the off-chain device is used to provide the off-chain device with an opening message of the first session, and the second transaction includes confirmation information for the pre-opening message.

In an embodiment, the first execution unit 31 is further configured to execute a first transaction to store the pre-opening message of the first session in the blockchain.

In one embodiment, the first execution unit 31 is further configured to execute a first transaction, so as to record the state of the first session as a pre-opened state in the blockchain.

In an implementation manner, the first contract is invoked in the first transaction, wherein the first execution unit 31 is further configured to record the state of the first session in the account state of the first contract is pre-opened.

In an implementation manner, the first contract is invoked in the second transaction, and the second execution unit 32 is further configured to execute the first contract invoked in the second transaction, so as to determine whether to The second transaction is executed within a first predetermined period of time, and in a case where it is determined that the second transaction is executed within the first predetermined period of time, an opening message of the first session is provided to the off-chain device.

In one embodiment, the first execution unit 31 is further configured to end the first session if it is determined that the second transaction is executed after a first predetermined period of time.

In an embodiment, the second execution unit 32 is further configured to modify the state of the first session to an open state.

In an embodiment, the second execution unit 32 is further configured to store the opening message of the first session in the blockchain.

In one embodiment, the apparatus 300 further includes a third execution unit 33 configured to, after providing the off-chain device with the opening message of the first session, execute a third transaction that invokes the first contract, where the The third transaction includes the pending first data, so that it is determined whether the state of the first session is an open state, and in the case of determining that the state of the first session is an open state, in the blockchain The first data is stored in association with the first session.

In one embodiment, the apparatus 300 further includes: a fourth execution unit 34 configured to execute a fourth transaction sent by the off-chain device, where the fourth transaction includes pre-closing information, so that: determining whether all messages sent by the off-chain device are received; in the case of determining that all messages sent by the off-chain device are received, providing the off-chain device with a close message of the first session.

In an embodiment, the fourth execution unit 34 is further configured to modify the state of the first session to a closed state.

In one embodiment, the fourth execution unit 34 is further configured to associate in the blockchain with the first session in the event that it is determined that a message sent at least in part by the off-chain device has not been received request information for requesting the off-chain device to resend the at least part of the message.

In one embodiment, the fourth execution unit 34 is further configured to, in a case where it is determined that a message sent at least in part by the off-chain device has not been received, modify the state of the first session to pre-closed state.

FIG. 4 shows an apparatus 400 for communication between a blockchain and an off-chain device according to an embodiment of the present specification. The apparatus is deployed in the off-chain device, and includes: a first obtaining unit 401 configured to: The blockchain obtains a pre-opening message of a first session, where the first session is a session between the blockchain and the off-chain device; the first sending unit 402 is configured to send a second transaction to the blockchain , the second transaction includes confirmation information for the pre-opening message; the opening unit 403 is configured to open the data retention period of the first session.

In one embodiment, the first sending unit 402 is further configured to send the second transaction to the blockchain within a first predetermined period of time.

In one embodiment, the apparatus 400 further includes a determining unit 404 configured to, after the data retention period is enabled, determine whether to obtain the opening of the first session from the blockchain within a second predetermined period of time message, the first ending unit 405 is configured to end the data retention period in the case that the opening message of the first session is not obtained from the blockchain within a second predetermined period of time.

In one embodiment, the apparatus 400 further includes a second sending unit 406 configured to, when a preset condition is met, send a fourth transaction to the blockchain, where the fourth transaction includes the first transaction Pre-close information for a session.

In one embodiment, the apparatus 400 further includes a second obtaining unit 407 configured to, after sending the fourth transaction to the blockchain, obtain the closure of the first session from the blockchain message; and a second ending unit 408, configured to end the data retention period.

In an implementation manner, the apparatus further includes a third obtaining unit 409, configured to, after sending the fourth transaction to the blockchain, obtain from the blockchain a pair of the sent first transaction A request message for at least part of the messages in the session; the third sending unit 410 is configured to send a fifth transaction to the blockchain, where the fifth transaction includes the at least part of the message.

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 objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

A method for communication between a blockchain and off-chain devices, the method being performed by a blockchain node, comprising:

executing a first transaction to provide an off-chain device with a pre-opening message of a first session, wherein the first session is a session between the blockchain and the off-chain device;

A second transaction sent by the off-chain device is executed to provide the off-chain device with an opening message of the first session, the second transaction including confirmation information for the pre-opening message.
The method of claim 1, wherein executing the first transaction further comprises executing the first transaction to deposit a pre-opening message for the first session in the blockchain.
According to the method of claim 1 or 2, executing the first transaction further comprises executing the first transaction to record the state of the first session as a pre-open state in the blockchain.
The method according to claim 3, wherein the first contract is invoked in the first transaction, wherein recording the state of the first session as a pre-opened state in the blockchain comprises: The state of the first session is recorded as a pre-opened state in the account state of a contract.
The method of claim 4, wherein the first contract is invoked in the second transaction, and the executing the second transaction sent by the off-chain device comprises executing all the functions invoked in the second transaction. the first contract such that it is determined whether the second transaction is to be executed within a first predetermined period of time, and in the case where it is determined that the second transaction is to be executed within the first predetermined period of time, an opening message of the first session is provided to the off-chain device .
6. The method of claim 5, wherein executing the first contract invoked in the second transaction further causes, in the event that the second transaction is determined to be executed after a first predetermined period of time, ending the first contract a session.
The method according to any one of claims 1-2 and 4-6, wherein providing the off-chain device with an open message of the first session comprises modifying the state of the first session to an open state.
7. The method of claim 7, wherein providing the off-chain device with the start message of the first session comprises storing the start message of the first session in a blockchain.
The method of claim 8, further comprising, after providing the off-chain device with the opening message of the first session, executing a third transaction invoking the first contract, the third transaction including the pending first data, so as to determine whether the state of the first session is an open state, and in the case of determining that the state of the first session is an open state, it is stored in the blockchain in association with the first session. Describe the first data.
The method of claim 1, further comprising:

executing a fourth transaction sent by the off-chain device, the fourth transaction including pre-closing information,

so as to determine whether all messages sent by the off-chain device are received;

In the event that it is determined that all messages sent by the off-chain device are received, a close message of the first session is provided to the off-chain device.
11. The method of claim 10, wherein providing a close message of the first session to the off-chain device comprises modifying the state of the first session to a closed state.
11. The method of claim 10, wherein executing the fourth transaction further causes, in the event of a determination that a message sent at least in part by the off-chain device was not received, communicate with the first transaction in the blockchain Request information is stored in association with the session, and the request information is used to request the off-chain device to resend the at least part of the message.
13. The method of claim 12, wherein executing the fourth transaction further causes, in the event that a message sent at least in part by the off-chain device is determined not to be received, modifying the state of the first session to Pre-closed state.
A method for communication between a blockchain and an off-chain device, the method being performed by the off-chain device, comprising:

Obtain a pre-opening message of a first session from the blockchain, where the first session is a session between the blockchain and the off-chain device;

sending a second transaction to the blockchain, where the second transaction includes confirmation information for the pre-opening message;

A data retention period for the first session is started.
15. The method of claim 14, wherein sending the second transaction to the blockchain comprises sending the second transaction to the blockchain within a first predetermined time period.
The method according to claim 14 or 15, further comprising, after the data retention period is opened, determining whether to obtain the open message of the first session from the blockchain within a second predetermined period, when the second predetermined period In the case where the opening message of the first session is not obtained from the blockchain within the period, the data retention period is ended.
The method of claim 14, further comprising, when a preset condition is met, sending a fourth transaction to the blockchain, the fourth transaction including pre-close information for the first session.
18. The method of claim 17, further comprising, after sending a fourth transaction to the blockchain, obtaining a close message for the first session from the blockchain; ending the data retention period.
18. The method of claim 17, further comprising, after sending the fourth transaction to the blockchain, obtaining a request message from the blockchain for at least a portion of the sent messages in the first session; Sending a fifth transaction to the blockchain, the fifth transaction including the at least part of the message.
A communication device between a blockchain and an off-chain device, the device is deployed on a blockchain node, comprising:

a first execution unit configured to execute a first transaction to provide an off-chain device with a pre-opening message of a first session, where the first session is a session between the blockchain and the off-chain device;

A second execution unit configured to execute a second transaction sent by the off-chain device to provide the off-chain device with an opening message of the first session, where the second transaction includes the pre-opening message Acknowledgment of the message.
The apparatus of claim 20, wherein the first execution unit is further configured to execute a first transaction to store a pre-opening message of the first session in the blockchain.
The apparatus according to claim 20 or 21, wherein the first execution unit is further configured to execute a first transaction to record the state of the first session as a pre-open state in the blockchain.
The apparatus of claim 22, wherein a first contract is invoked in the first transaction, wherein the first execution unit is further configured to convert the first session in an account state of the first contract The state is recorded as the pre-open state.
The apparatus of claim 23, wherein the first contract is invoked in the second transaction, and the second execution unit is further configured to execute the first contract invoked in the second transaction, such that It is determined whether to execute the second transaction within a first predetermined period of time, and in the event that the second transaction is determined to be executed within the first predetermined period of time, an open message of the first session is provided to the off-chain device.
25. The apparatus of claim 24, wherein the first execution unit is further configured to end the first session if the second transaction is determined to be executed after a first predetermined period of time.
The apparatus according to any one of claims 20-21 and 23-24, wherein the second execution unit is further configured to modify the state of the first session to an open state.
The apparatus of claim 26, wherein the second execution unit is further configured to store an opening message of the first session in the blockchain.
The apparatus of claim 27, further comprising a third execution unit configured to execute a third transaction invoking the first contract after providing the off-chain device with an opening message of the first session, the third The transaction includes the first data to be processed, so as to determine whether the state of the first session is an open state, and in the case of determining that the state of the first session is an open state, in the blockchain with the The first session stores the first data in association.
The apparatus of claim 20, further comprising:

a fourth execution unit, configured to execute a fourth transaction sent by the off-chain device, where the fourth transaction includes pre-closing information,

so as to determine whether all messages sent by the off-chain device are received;

In the event that it is determined that all messages sent by the off-chain device are received, a close message of the first session is provided to the off-chain device.
The apparatus of claim 29, wherein the fourth execution unit is further configured to modify the state of the first session to a closed state.
29. The apparatus of claim 29, wherein the fourth execution unit is further configured to, in the event of determining that a message sent at least in part by the off-chain device has not been received, communicate with the fourth execution unit in the blockchain The request information is stored in association with a session, and the request information is used to request the off-chain device to resend the at least part of the message.
31. The apparatus of claim 31, wherein the fourth execution unit is further configured to modify the state of the first session if it is determined that a message sent at least in part by the off-chain device has not been received for the pre-closed state.
A communication device between a blockchain and an off-chain device, the device is deployed on the off-chain device, comprising:

a first obtaining unit, configured to obtain a pre-opening message of a first session from the blockchain, where the first session is a session between the blockchain and the off-chain device;

a first sending unit, configured to send a second transaction to the blockchain, where the second transaction includes confirmation information for the pre-opening message;

An enabling unit, configured to enable a data retention period of the first session.
The apparatus of claim 33, wherein the first sending unit is further configured to send a second transaction to the blockchain within a first predetermined period of time.
The apparatus according to claim 33 or 34, further comprising a determination unit configured to, after a data retention period is opened, determine whether to acquire an open message of the first session from the blockchain within a second predetermined period of time , a first end unit configured to end the data retention period when the opening message of the first session is not obtained from the blockchain within a second predetermined period of time.
The apparatus according to claim 33, further comprising a second sending unit configured to send a fourth transaction to the blockchain when a preset condition is met, the fourth transaction including the first session Pre-close information.
The apparatus according to claim 36, further comprising a second obtaining unit configured to obtain a closing message of the first session from the blockchain after sending the fourth transaction to the blockchain; and a second end unit, configured to end the data retention period.
The apparatus according to claim 36, further comprising a third obtaining unit configured to, after sending the fourth transaction to the blockchain, obtain, from the blockchain, a link to the first session that has been sent. A request message for at least part of the message; a third sending unit, configured to send a fifth transaction to the blockchain, where the fifth transaction includes the at least part of the 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 1-19.
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 1-19 when executing the computer program or instruction .