CN117440032A - Cross-chain system based on relay chain - Google Patents

Abstract

The invention relates to a relay chain-based cross-chain system, which comprises cross-chain modules, relay chains and access chains, wherein the access chains are in communication connection with the relay chains through corresponding cross-chain modules, the cross-chain modules are in communication connection, the relay chains serve as an intermediate layer and are connected with different block chain networks, and all components are cooperated to work, so that different block chains can communicate and share data and transactions. Based on the cross-chain system, the invention also provides a cross-chain process, which can solve the defects existing in the prior art, realize the cross-chain communication and data interaction among a plurality of blockchains, realize the efficient and safe blockchain intercommunication, and provide a unified protocol and rule so as to enable seamless data transmission among different blockchains.

Description

Cross-chain system based on relay chain

Technical Field

The invention relates to a relay chain-based cross-chain system.

Background

With the rapid development of blockchain technology, more and more blockchain networks are created and applied in different fields. Interoperability between these blockchain networks, however, remains a challenge. Because each blockchain network has its own rules and protocols, cross-chain interactions of data and assets between different blockchains are difficult. To solve this problem, a relay chain technique is proposed, which aims to achieve interworking between a plurality of blockchains.

Currently, relatively mature cross-chain mechanisms mainly include notary mechanisms, side-chain/relay, hash locking, distributed private key control, and the cross-chain mechanism will be analyzed from a plurality of aspects below. In the aspect of interoperability, hash locking is a cross dependency relationship, and has obvious defects relative to other cross-chain models; in the aspect of a trust model, a notary mechanism needs a plurality of trusted third parties as notarizers, thus being easy to cause centralization, and other cross-chain models do not have the problem in this aspect; in the aspect of cross-chain transaction processing, the limitation of hash locking is larger, cross-chain asset mortgage can be supported in most cases, but cross-chain asset transfer is not supported, and cross-chain primitive operation is not directly supported, and other cross-chain modes can better support related operation of cross-chain transaction; in terms of technical safety and performance, the security of the notary mode and the side chain/relay mode is low, and the transaction speed is still to be improved.

On the basis of the existing 4 main stream straddling technologies, researchers combine a notary mechanism with the advantages of simplicity in implementation, easiness in operation, bidirectional straddling and the like with side chains with independence and high-efficiency characteristics, and propose a notary plus side chain mixing technology, namely a relay chain technology. The relay chain scheme is based on the existing chain to set up a central platform for inter-chain intercommunication, and in order to solve the centralization problem, a brand new independent block chain is set up as a relay chain to specially process the operation between different chains, so that the relay chain scheme has the characteristics of being more public, transparent, strong in compatibility and the like, and is the most promising scheme for inter-heterogeneous chain interoperability at present.

The existing blockchain interworking technology has the following problems and challenges:

(1) The bottom layer architecture is different, and intercommunication is difficult: there are a variety of blockchain platforms in the industry that vary widely in overall architecture design, including computing, storage, networking, and the like.

(2) The data structure is different, mutually-acknowledged difficultly: the data structure design of different blockchain platforms tends to vary. Different blockchain platform data structures and expected application scenarios are different, so that a certain challenge still exists in order to realize mutual data recognition.

(3) Different interface protocols, the interconnection is difficult: different blockchain platforms differ greatly in terms of the functionality and format fields of their exposed access interfaces because of the architecture and data structure. Because of the incompatibility of interfaces and protocols, it is difficult to interconnect communications between heterogeneous blockchain platforms.

(4) The security mechanism is different, mutually trusted is difficult: when the links are connected between chains and between platforms, the mutual trust condition between the platforms is not established because a plurality of security mechanisms are irregular, sensitive data cross the security boundary, such as different consensus lists, different strict degree of access mechanisms, different authority configuration and the like.

(5) Different business modes, mutual access is difficult: the application scenes of different blockchain platforms are quite different, mutual access among the scenes is required to be achieved, for example, intercommunication of record information related to a financial scene blockchain and a government scene blockchain is required to be achieved, business logic which is more complex than that of a traditional digital asset cross-chain is faced, omission of any link in the process can cause abnormality to cause cross-chain failure, and how to guarantee integrity and consistency among transactions in the whole connection process is a great challenge.

In summary, existing blockchain interworking techniques have some technical drawbacks in achieving interoperability between blockchains. Therefore, a new approach is needed to address these issues and improve the efficiency and security of inter-blockchain communications.

Disclosure of Invention

In order to solve the existing problems, the invention provides a relay chain-based cross-chain system.

The invention adopts the following technical scheme:

a relay chain based cross-chain system comprising: the system comprises a spanning chain module, a relay chain and an access chain, wherein the spanning chain module corresponds to the access chain one by one, the access chain is in communication connection with the relay chain through the corresponding spanning chain module, and the spanning chain modules are in communication connection;

The first cross-link module generates and sends a cross-link contract calling request to the first access link according to a cross-link transaction request instruction received by the first access link; the first access chain executes the cross-link contract calling request and returns an execution result to the first cross-link module;

the first cross-link module submits a cross-link transaction request instruction to the relay link;

the relay chain verifies the credibility of the cross-chain transaction request instruction, and if the verification is passed, the relay chain judges whether a second access chain corresponding to the cross-chain transaction request instruction is in an access chain service list; if yes, the relay chain submits a cross-chain transaction request instruction to the second cross-chain module;

and the second access chain executes the cross-chain transaction request instruction sent by the second cross-chain module.

Further, the executing result of the cross-link contract call request by the first access chain includes: transaction version, hash value of transaction, transaction type, and timestamp.

Further, the relay chain verifies the credibility of the cross-chain transaction request instruction, including:

the verification content of the relay chain for verifying the credibility of the cross-chain transaction request instruction comprises the following steps: verifying the source and the proof of the cross-link transaction request instruction whether the cross-link verification rule on the first access link is satisfied; if the verification is not passed, the relay chain marks the cross-link transaction request instruction as an illegal cross-link transaction request, returns a failed receipt and error information to the first cross-link module, and the first access chain re-initiates the cross-link transaction request instruction until the relay chain verifies the correct cross-link transaction request instruction.

Further, if the relay chain judges that the second access chain corresponding to the cross-chain transaction request instruction is not in the access chain service list, the relay chain marks the cross-chain transaction request instruction as invalid cross-chain transaction, returns a failed receipt and error information to the first cross-chain module, and notifies the first access chain to rollback to finish the cross-chain.

Further, after the second access chain executes the cross-link transaction request instruction sent by the second cross-link module, the second access chain judges an execution result of executing the cross-link transaction request instruction; if the execution is successful, the relay chain receives a receipt of the successful execution of the second access chain, marks the cross-chain transaction as a successful cross-chain transaction, and ends the cross-chain; if the execution fails, the relay chain receives a receipt of the execution failure of the second access chain, marks the cross-chain transaction as a failed cross-chain transaction, and ends the cross-chain.

Further, after the second access chain judges the execution result of the execution of the cross-link transaction request instruction, the second access chain returns the execution result of the cross-link transaction to the relay chain, the relay chain verifies the execution result of the cross-link transaction and sends a result message to the first cross-link module, and then the first cross-link module returns a cross-link transaction response.

Further, the cross-link module comprises a network unit, a storage unit, a verification unit, a certificate unit and a permission unit, wherein the certificate unit is used for generating and maintaining an identity certificate, the network unit is used for establishing cross-link connection, the storage unit is used for receiving and storing cross-link transaction data, the verification unit is used for verifying the legitimacy of the cross-link transaction, and the permission unit is used for configuring and managing permissions of different roles and identities.

Further, the relay chain comprises verification nodes and supervision nodes, wherein the verification nodes are composed of all nodes of the access chain, and all nodes of the access chain are nodes containing all data of the corresponding access chain in the access chain.

Further, the inter-link modules communicate in a P2P mode to construct a peer-to-peer network.

Further, the operation of managing the access chain includes: registering, updating, auditing and logging off;

the registering process comprises the following steps: the access chain provides registration information comprising verifier information, consensus algorithm type, chain name and description and cross-chain gateway public key information, after registration, a relay chain manager examines and votes, and when more than half of manager passes the examination, the access chain is allowed to join;

The auditing process comprises the following steps: after the access chain registration is completed, the relay chain manager checks the information of the access chain registration, each relay chain manager checks and then votes, and if more than half of the relay chain managers pass the check, the access chain is agreed to be added;

the updating process comprises the following steps: when the access chain is newly added or replaced with a verification node or a new consensus algorithm is replaced, an access chain manager needs to perform access chain updating operation to update information of the access chain on the relay chain, and when the access chain is updated, the relay chain does not receive the cross-chain transaction of the access chain temporarily;

the process of cancellation includes: and when the access chain exits the cross-chain system, performing cancellation operation, and deleting the related information of the access chain on the relay chain by the system.

The beneficial effects of the invention include: the relay chain-based cross-chain system comprises cross-chain modules, relay chains and access chains, wherein the cross-chain modules correspond to the access chains one by one, the access chains are in communication connection with the relay chains through the corresponding cross-chain modules, the cross-chain modules are in communication connection, the relay chains serve as an intermediate layer and are connected with different block chain networks, and cooperative work among all components is realized through the corresponding cross-chain architecture of the cross-chain system, so that different block chains can communicate and share data and transactions; based on the cross-chain system, the invention also provides a cross-chain process, which can solve the defects existing in the prior art, realize the cross-chain communication and data interaction among a plurality of blockchains, realize the efficient and safe blockchain intercommunication, and provide a unified protocol and rule so as to enable seamless data transmission among different blockchains.

Drawings

In order to more clearly illustrate the technical solution of the embodiments of the present invention, the following briefly describes the drawings that are required to be used in the embodiments:

FIG. 1 is a cross-chain architecture diagram;

FIG. 2 is a cross-chain system architecture diagram;

FIG. 3 is a block diagram of a cross-chain module;

FIG. 4 is a diagram of the logical relationship between the various elements of the cross-chain module;

FIG. 5 is a schematic diagram of a cross-link by network;

fig. 6 is a schematic diagram of relay link node types;

fig. 7 is a schematic diagram of a registration operation in an access chain management operation;

FIG. 8 is a schematic diagram of a validation rule;

FIG. 9 is a schematic diagram of a Merkle tree structure;

fig. 10 is a schematic diagram of a cross-chain flow.

Detailed Description

In order to explain the technical solutions described in the present application, the following description will be given by way of specific embodiments.

The embodiment aims to solve the problems and challenges of the blockchain intercommunication technology and provides a relay chain-based cross-chain system. The cross-link system includes a plurality of key modules including a cross-link architecture, a cross-link module, an access link, a relay link, a cross-link flow, and the like. These modules work cooperatively to enable different blockchains to interwork shared data and transactions. The function and function of each module will be described in detail below.

Introducing a cross-chain system overall structure, wherein the system structure is divided into three key layers, each layer is responsible for different functions and modules, as shown in fig. 1, a first layer is a base layer, and the first layer comprises a core module which needs to be provided by a blockchain, wherein the core module comprises a network module, a storage module, a consensus module, a virtual machine and an encryption mechanism, and the modules provide the basic functions and security of the blockchain; the second layer is a component layer mainly comprising service modules related to the cross-links, and provides various components for the service flow call, including components such as access link management, verification rule management and the like, and is used for supporting various aspects of the cross-link operation; the third layer is an interface layer, the relay chain provides external interface service, and a user can conveniently initiate a cross-chain request and inquire cross-chain transaction content.

The inter-blockchain cross-chain interworking should not be limited to a single blockchain or a particular class of chains, but should be applicable to multiple mutually independent blockchains with different blockstructures and consensus algorithms to achieve inter-chain interoperability. The architecture of a relay chain based cross-chain system is shown in fig. 2, comprising: the access device comprises a spanning chain module, a relay chain and an access chain, wherein the spanning chain module corresponds to the access chain one by one, the access chain is in communication connection with the relay chain through the corresponding spanning chain module, and the spanning chain modules are in communication connection. The overall logic of the cross-chain system is: the access chain sends the cross-chain transaction to the relay chain through the cross-chain module for verification and processing; the relay link verifies the validity of the cross-link transaction and broadcasts the valid transaction to other access links; the cross-link module is responsible for transferring messages between the access link and the relay link, and ensuring smooth processing and response of the cross-link transaction. Through the cooperative work of the key modules, the efficient intercommunication among multiple chains and the trusted execution of the cross-chain transaction are realized.

The cross-link data sender and the cross-link data receiver correspond to different access link networks, respectively. A cross-chain data sender refers to the role that a certain access chain plays when it needs to pass the data or transactions of the chain to other chains. Correspondingly, a cross-chain data receiver refers to the role that is played when one access chain needs to acquire data or transactions from other chains. This flexibility ensures two-way communication of the system, enabling the different chains to act as sender or receiver as desired.

The cross-chain module plays a key role in the whole system and is responsible for processing collection, verification, transfer and execution of cross-chain transactions. The cross-chain module is composed of a plurality of units that work cooperatively to achieve the function of cross-chain interaction.

Core functions of the cross-chain module: because of the high degree of heterogeneity between different blockchain systems, individual blockchain systems do not natively support multi-chain interworking. Thus, the cross-chain module plays a key role here, and its core functional units include: a network unit, a storage unit, a verification unit, a certificate unit and a rights unit, as shown in fig. 3.

The functions and implementation processes of the units of the cross-chain module are specifically as follows:

The functions of the network element are: the network element is responsible for communicating with other blockchain systems, establishing cross-chain connections and transmitting cross-chain transactions. The network unit is concretely realized as follows: communication protocol: adopting a customized communication protocol based on message transmission in a relay chain, wherein the protocol comprises a data exchange format, an encryption mechanism and a signature mechanism so as to ensure the reliability and the safety of messages in cross-chain communication, the message transmission is transferred through a relay chain node, the relay chain plays a role in message transmission, and all cross-chain interactions are ensured to pass through a core relay chain; connection management: the relay chain node maintains a connection pool, monitors all block chain systems connected with the relay chain, and when the connection is found to be interrupted or the node fails, the relay chain node is responsible for automatically reconnecting and reestablishing the connection so as to maintain the connectivity of the whole cross-chain network; data encryption: messages for cross-chain communications are encrypted and signed using elliptic curve cryptography (Elliptic Curve Cryptography, ECC), with each blockchain system's cross-chain module having its own key pair for encrypting and signing messages to protect data privacy and communications security.

The function of the memory cell is: the storage unit is used for storing the cross-chain transaction and related data, including source certification, execution results and the like of the cross-chain transaction. The storage unit is concretely realized as follows: and (3) data structure design: the Merkle Tree is used on the relay chain to store hash values and state roots of cross-chain transactions, which ensures that all blockchain systems can verify the integrity of transactions and data and have efficient data retrieval capability; backing up data: the relay link node can regularly backup the cross-link transaction data to an external decentralised storage system, such as an IPFS or a distributed file system, so that the availability and the restorability of the data are increased, and the data are not lost even if the relay link node fails; data index: the storage units on the relay chain can establish indexes, and the key attributes such as hash and time stamp based on cross-chain transaction are helpful for improving data retrieval efficiency, so that each blockchain system can quickly access the cross-chain data.

The verification unit has the functions of: the verification unit is responsible for verifying the legality and the credibility of the cross-link transaction, verifies the cross-link transaction according to the cross-link verification rule on the access link, comprises verifying the source of a request and proving whether the rule is met, and ensures that only the legal cross-link transaction can be submitted to the relay link for processing. The verification unit is concretely realized as follows: verification rules: the verification unit on the relay chain defines a cross-chain verification rule comprising a verification request source, signature verification, data consistency and other rules, wherein the rules are formulated according to a common recognition mechanism of the relay chain and the requirements of a cross-chain flow; digital signature verification: the identity authentication and authorization system based on the relay chain is adopted to verify the validity of the digital signature of the cross-chain transaction, and only the verified transaction can be received by the relay chain and further transmitted to the target blockchain system; rule engine: the verification unit on the relay chain uses the intelligent contracts to execute the verification rules, and each step in the cross-chain flow triggers the corresponding intelligent contracts to ensure the verification efficiency and consistency.

The certificate unit functions as: the certificate unit is used for managing and verifying identity certificates among the blockchain systems, ensuring that the cross-chain modules have legal identities and verifying the identity certificates of other blockchain systems, and ensuring the security of cross-chain communication and the reliability of identity authentication. The certificate unit is concretely realized as follows: certificate generation: the certificate units on the relay chain are responsible for generating and maintaining identity certificates of the blockchain system, and the certificates comprise public keys, private keys and digital signatures, so that the identity of the blockchain system and the authenticity of data are ensured; certificate verification: the relay chain node verifies the identity certificates of other blockchain systems to ensure the validity and the credibility of the identity certificates, and the process is realized through a certificate management intelligent contract on the relay chain; identity authentication: authentication in the cross-chain flow is performed by an authentication smart contract on the relay chain. This ensures that the cross-chain module has a legal identity and can trust the identity of other blockchain systems.

The authority unit has the functions of: the authority unit is used for managing and controlling the access authority of the cross-chain transaction, and authorizes and limits the access of the cross-chain transaction according to different roles and identities, and ensures that only users with legal authorities can initiate and process the cross-chain transaction. The authority unit is concretely realized as follows: rights configuration and verification: defining and managing rights of different roles on a relay chain, ensuring that a node has legal rights for executing cross-chain transactions, and ensuring safety through identity verification and rights level verification; cross-chain transaction authorization: according to the relay chain rule, the inter-chain transaction is authorized, only authorized transactions can enter the relay chain processing flow, and the safety of the system is enhanced; auditing and monitoring: the use condition of the authority is continuously monitored, an audit report is generated, potential abnormal conditions are timely detected, compliance and safety of the system are guaranteed, and real-time monitoring is carried out in cooperation with the supervision node.

The logical relationship between the various units of the cross-chain module is shown in fig. 4. The cross-chain module workflow is as follows:

(1) The certificate unit generates and maintains identity certificates: the certificate unit generates an identity certificate of the blockchain system, which comprises a public key and a private key, and performs certificate issuing; the certificate unit is responsible for managing and verifying identity certificates of other blockchain systems to ensure the security of cross-chain communication and the reliability of identity authentication.

(2) The network element establishes a secure cross-link connection: the network element is responsible for establishing communication connection with other blockchain systems using custom communication protocols (e.g., protocols based on TCP/IP or HTTP); the protocol includes data transmission formats, message encryption and decryption mechanisms, and message authentication rules to ensure reliability and security of cross-chain communications.

(3) The storage unit receives and stores cross-chain transaction data: the storage unit receives cross-chain transaction data, including source certification, execution results and the like of the cross-chain transaction; the data is organized in an efficient data structure, possibly using a database system or a distributed storage system, to increase the efficiency of data retrieval.

(4) The verification unit verifies the legitimacy of the cross-chain transaction using the storage unit data: the verification unit is responsible for verifying the legitimacy and the credibility of the cross-chain transaction, and uses the data in the storage unit for verification; the verification rules comprise rules of verification request source, digital signature verification, data consistency and the like, and are based on the characteristics and security requirements of the blockchain system.

(5) The rights unit configures and manages rights for different roles and identities: the right unit is used for configuring and managing the access right of the cross-chain transaction and comprises role definition, right level division and right distribution; when a transaction is initiated, the rights unit performs a rights check to verify whether the transaction initiator has legal rights to perform a cross-chain transaction.

(6) The verification unit completes the verification of the cross-chain transaction: the verification unit completes the verification of the cross-chain transaction, and ensures the validity and the authenticity of the transaction; the verification unit may verify the rights of the transaction with reference to the rights unit configuration information.

(7) Cross-chain messaging: when the cross-link transaction needs to be transferred between the access link and the relay link, the network unit is responsible for transmitting the cross-link message; the cross-chain message comprises information such as a transaction request, a verification rule, an identity certificate and the like; the units work cooperatively, from certificate generation to verification of the cross-chain transaction, the security, the legality and the consistency of the cross-chain transaction are ensured, and the authority unit configuration information can be referred in the verification stage so as to ensure that only users with legal authorities can initiate and process the cross-chain transaction.

And the cross-link modules communicate in a P2P mode to construct a cross-link network, and the cross-link network is a peer-to-peer network. The cross-link network is a P2P network consisting of a plurality of cross-link modules, as shown in fig. 5. This peer-to-peer network allows data and information to be transferred between the cross-chain modules, including cross-chain transactions, validation rules, etc., ensuring efficient transfer and processing of data between the different chains. This communication mechanism is the basis for implementing multi-link interworking.

Before the relay chain joins the cross-chain network, the cross-chain module is responsible for connecting the relay chain with other cross-chain modules in the cross-chain network. The cross-link module represents the identity of the access link in the cross-link network, and the administrator of other access links registers the relevant verification information of the newly added access link with the relay link. Through the transmission of the network identification and the verification information, the cross-chain transaction for verification can be rapidly and conveniently carried out. In this way, the relay chain is able to perform trusted cross-chain interactions with other chains in the cross-chain network. The implementation and logical relationships across links by the network are described below.

And connecting a relay chain and a cross-chain module: the cross-link module is responsible for connecting the relay link with the cross-link modules of other access links before the relay link joins the cross-link network. These cross-link modules represent the identity of the access chains in the cross-link network.

Information broadcasting: the cross-link module broadcasts its own information including identification and authentication information on behalf of the access chain. The administrator of the other access chain registers the relevant authentication information of the newly joined access chain with the relay chain.

Global hash table: the cross-link module maintains a global hash table for recording the list of access links registered with the relay link. When one access chain is added to the routing network, the corresponding cross-chain module broadcasts the information of the access chain, and other cross-chain modules update the global hash table according to the broadcast information.

Cross-chain transaction delivery: when the cross-link transaction is transferred, the relay link node carries out multiple signatures on the cross-link transaction, and finds a cross-link module corresponding to the target access link through a routing algorithm. The cross-link module utilizes cross-links to transmit cross-link transactions by the network.

Verifying a source of a cross-chain transaction: the target cross-chain module will verify the authenticity of the source of the cross-chain transaction. Once authenticated, the cross-chain transaction is sent to the corresponding access chain. The relay chain verifies the validity of the source of the cross-chain transaction and returns the execution result to the source access chain.

Through a cross-link routing network, the relay chain can perform trusted cross-link interaction with other chains in the cross-link network, so that the safety and reliability of cross-link transactions are ensured. This network enables logical connections between the relay links and other access links, enabling multi-link interworking.

The relay link plays a vital role as a core for connecting and coordinating the various access links as a core component for verifying the cross-link transactions issued by the access links. The communication between the cross-chain module and the relay chain is the key of the system, and ensures that data and transactions between different chains can be verified and transferred on the relay chain. The cross-link module realizes asynchronous processing and transmission of data by assistance of a relay link. The mechanism enables the system to effectively process cross-chain transactions and ensures the security and authenticity of data. Each access chain is connected to the relay chain with an equal identity. The function of the relay chain integrates a notary mechanism and a side chain scheme, and the collection, verification and forwarding of the information are completed.

The main responsibilities of the relay chain include access chain management, trusted verification of cross-chain transactions, reliable routing, transaction rollback, and the like.

(1) Access chain management:

the relay chain acts as a "notary" to the cross-chain transaction, helping other access chains to verify the cross-chain transaction. The relay chain comprises two types of nodes, namely an authentication node and a supervision node.

In the verification process, the verification node of the relay chain needs to store the blockchain information of all access chains, which has higher performance requirements on the node. However, as more and more access chains are added to the cross-chain system, the data volume to be stored by the authentication node is rapidly enlarged, so that a threshold for becoming the authentication node is increased, the authentication node of the relay chain is immobilized, and a centralized security problem may be caused.

In order to solve the above-mentioned problem, the present embodiment manages the authentication node of the relay link, which is formed by the entire node inside the access link, that is, the node containing all the data of the access link. In this embodiment, the whole nodes in the access chain are divided into two parts, one part participates in the consensus in the access chain, and the other part is added to the relay chain to form the verification node of the relay chain, so as to help the relay chain to verify the cross-chain transaction, as shown in fig. 6.

The verification node verifies the cross-chain transaction: when verifying a cross-chain transaction of an access chain, the chain is checked and verified by a verification node that the chain joins to a relay chain. Only if all of the verification nodes associated with the cross-chain transaction are verified and signed endorsed, the cross-chain transaction is considered a legitimate transaction, and any one of the full nodes is not verified and the transaction is considered invalid. By the verification mode, the verification node of the relay chain does not need to store the blockchain data of other access chains, is only responsible for checking and verifying the cross-chain transaction related to the verification node, and reduces the threshold of becoming the verification node of the relay chain. And the relay chain verification node is dynamically replaced, so that the fixation of the relay chain verification node is prevented, and the decentralization degree of the system is reduced.

And (3) monitoring nodes: all verification processes will be recorded and saved on the block of the relay chain for review by the supervising node. The supervision node is responsible for storing the data of all access chains and the world state of the whole cross-chain system, and synchronizing the data of the access chains in real time so as to comprehensively examine the behaviors of all verification nodes. Although the supervising node itself does not have the right to verify the cross-chain transaction, by supervising the behavior of the verifying node, the safe operation of the cross-chain system can be ensured.

Thus, the relay chains serve the hub role of connecting and coordinating the individual access chains. The verification node is composed of all nodes of an access chain and is responsible for assisting the relay chain to verify the validity of the cross-chain transaction, which is a key step for ensuring the validity of the cross-chain transaction. The supervision nodes are all nodes of the relay chain, and the task of the supervision nodes is to supervise and verify the behavior of the nodes so as to ensure the safety and compliance of the system. This dual layer node structure enhances the stability and security of the system.

The access chain management operation comprises registration, updating, auditing and cancellation, and provides basic service for the management of the access chain by the relay chain.

As shown in fig. 7, the registration process includes: the access chain needs to provide registration information including verifier information, consensus algorithm type, chain name and description, and cross-chain gateway public key information, after registration, relay chain administrators audit and vote, and when more than half of administrator audits pass, the access chain is allowed to join.

A process of auditing, comprising: after the access chain registration is completed, the relay chain manager checks the information of the access chain registration, especially the verifier information and the public key information. Each relay chain manager can vote after auditing, and when the votes do not pass, auditing suggestions are attached to the votes for the access chain manager to check the reasons of unsuccessful registration. And if more than half of relay chain administrators pass the verification, the access chain is agreed to be added.

An update process comprising: when the access chain is newly added or replaced with a verification node or a new consensus algorithm is replaced, an access chain manager needs to perform access chain updating operation to update the information of the access chain on the relay chain. The updating operation of the access chain is basically the same as the above-mentioned registration and audit flow, and will not be described here again. At the time of updating, in order to guarantee verification of the cross-link transaction (the verification logic of the verification rule may change), the relay link does not receive the cross-link transaction of the access link.

A process of logging off, comprising: and when the access chain exits the cross-chain system, performing cancellation operation, and deleting the related information of the access chain on the relay chain by the system.

(2) And (3) verification rule management:

the verification rule is the basis for verifying the existence and the validity of the cross-link transaction by the relay link, is realized through an intelligent contract, runs in the virtual machine and needs to be deployed, checked, updated and logged off. Because of the different application scenes of the blockchain, the underlying principles are different, so that the blockchains are heterogeneous, and the transaction verification rules are different. The relay link cannot provide a unified authentication rule for the access link, and when the access link is required to join the relay link, an administrator of the access link deploys the authentication rule on the relay link. As shown in fig. 8, the deployment, registration and auditing process of the validation rules is illustrated.

And (3) verifying rule deployment: the developer of the access chain needs to develop corresponding verification rules according to the characteristics of the self blockchain. Since the root hash value of all transactions is recorded in the block header, each transaction has a corresponding merck path, which has uniqueness. For non-existent transactions, it is not possible to pseudo-create a merck path to the root hash. Thus, verifying the existence of a transaction only requires verifying whether it has a legitimate merck path.

Authentication rule registration: deployment of the validation rule contract is performed by an administrator of the access chain. After successful deployment, the address of the verification rule is obtained, but the verification rule at the moment cannot be used, and the verification rule needs to be mutually bound with an access chain. The administrator of the access chain needs to register the authentication rules of the access chain, and when the cross-chain transaction is initiated, the authentication engine knows which authentication rule is specifically selected to perform the authentication of the cross-chain transaction. After receiving the registration request of the verification rule, an administrator of the relay chain acquires specific information of the verification rule for verification, and only the verification rule passing the verification can be used.

And (5) updating the verification rule: when the access chain authentication rules change, the access chain administrator needs to update the authentication rules. The updating step is similar to the registering step, the deployment is carried out firstly, then the registering and the checking are carried out, and finally the new verification rule passing the checking is mutually bound with the access chain.

(3) Cross-chain transaction verification:

in the process of crossing the chain, for each cross-chain transaction, the relay chain needs to check the cross-chain transaction to prevent the cross-chain transaction from being forged or tampered. This verification process includes two parts: relay chain registration verification rules: i.e., defining and recording rules and conditions that allow for cross-chain transactions. These rules may include verifying the legitimacy of the transaction, verifying the identity and rights of the transaction parties, etc.; relay chain verification transaction: when a cross-link transaction request arrives at the relay link, the relay link needs to verify the transaction, so as to ensure that the transaction accords with the registered verification rule. This may be accomplished by verifying the digital signature of the transaction, verifying the expiration date of the transaction, verifying whether the parties to the transaction have sufficient rights, and the like. Through such a verification process, the relay chain can ensure the authenticity and integrity of the cross-chain transaction, and prevent counterfeiting or falsification.

(4) Reliable routing:

the relay chain not only needs to verify the legitimacy of the cross-chain transaction, but also takes over the responsibility of the cross-chain transaction routing. The routing object includes two aspects: firstly, cross-link transaction and secondly, cross-link fruit receipt with callback. All transactions to be routed in a block are constructed as Merkle trees, the Merkle tree root of which is signed by the verifying node. Fig. 9 is a schematic diagram of Merkle tree construction.

(5) Rollback mechanism:

the rollback mechanism is divided into two cases, failure rollback and timeout rollback. Failure rollback refers to when the execution of a cross-link transaction fails, the cross-link module submits a failed receipt to the relay link, and after the relay link verifies the receipt, the source access link module is required to rollback the corresponding request. The timeout rollback is that when the cross-link transaction has no response for a long time, the rollback operation is needed to ensure the consistency of the states of the two cross-link parties.

When timeout rollback occurs on the source chain, for example, the source cross-chain module cannot connect to the relay chain for network reasons, and the source cross-chain module directly rolls back the corresponding request. When the timeout rollback occurs on the destination access chain, that is, the relay chain does not receive the cross-link receipt of the destination service within the specified timeout time, the relay chain sets the cross-link transaction to the rollback state. The source cross-chain module can acquire cross-chain transaction and proof information needing to be rolled back and roll back requests on the source chain. When the destination link module submits the receipt of the destination access link service to the relay link, the relay link returns the state information that the transaction has been rolled back, and the destination link module executes corresponding rollback operation after receiving the information.

By the rollback mechanism, the integrity and consistency of the cross-chain transaction can be ensured, and the problem of inconsistent data caused by execution failure or overtime is prevented.

In this embodiment, the cross-link flow involves the role of the client in addition to the three roles of the relay link, the access link, and the cross-link module. The relay chain and the access chain are responsible for own transaction processing, so that the unreplausibility, the untampereability and the traceability of data in the system are ensured, the cross-chain module is responsible for the transmission of cross-chain transaction, the realization of a cross-chain transaction model and the transmission and the reception of cross-chain information, and a client side generally refers to other information systems for carrying out information interaction with a blockchain. The cross-chain flow is shown in FIG. 10.

The method comprises the steps that an access chain, a chain crossing module and a client of an initiator are set to be a first access chain, a first chain crossing module and a first client respectively, and an access chain, a chain crossing module and a client of a destination are set to be a second access chain, a second chain crossing module and a second client respectively. For convenience in explanation of each step, the first access chain, the first span chain module and the first client are referred to as an access chain a, a span chain module a and a client a for short, and the second access chain, the second span chain module and the second client are referred to as an access chain B, a span chain module B and a client B for short. The following are the detailed steps of the cross-chain flow:

The method comprises the steps that a client A initiates a cross-link transaction, a cross-link transaction request instruction is sent to an access link A, the access link A receives the cross-link transaction request instruction, and the cross-link transaction request instruction is used for requesting to conduct the cross-link transaction;

the access chain A returns a response of the cross-chain transaction to the client A;

the cross-link module A generates and sends a cross-link contract calling request to the access link A; the access chain A executes a cross-link contract calling request and sends a source certification to the cross-link module A;

the access chain A executes a cross-link contract calling request, returns an execution result to the cross-link module A, and returns the execution result to the cross-link module A; the execution result comprises: transaction version, hash value of transaction, transaction type and timestamp;

the cross-link module A submits a cross-link transaction request instruction to a relay link;

the relay chain verifies the credibility of the cross-chain transaction request instruction, and the verification content comprises the following steps: verifying the source and the proof of the cross-link transaction request instruction whether the cross-link verification rule on the access link A is satisfied; if the verification is not passed, the relay chain marks the cross-chain transaction request instruction as an illegal cross-chain transaction request, returns a failed receipt and error information to the cross-chain module A, and the access chain A needs to reinitiate the cross-chain transaction request instruction until the relay chain verifies the correct cross-chain transaction request instruction;

If the verification is passed, the relay chain judges whether an access chain B corresponding to the cross-chain transaction request instruction is in an access chain service list or not; if the relay chain judges that the access chain B corresponding to the cross-chain transaction request instruction is not in the access chain service list, the relay chain marks the cross-chain transaction request instruction as invalid cross-chain transaction, returns a failed receipt and error information to the cross-chain module A, and informs the access chain A to rollback to finish the cross-chain;

if the relay chain judges that the access chain B corresponding to the cross-chain transaction request instruction is in the access chain service list, the relay chain submits the cross-chain transaction request instruction to the cross-chain module B;

the access chain B executes a cross-chain transaction request instruction sent by the cross-chain module B;

the access chain B judges the execution result of executing the cross-chain transaction request instruction; if the execution is successful, the relay chain receives a receipt of the successful execution of the access chain B, marks the cross-chain transaction as a successful cross-chain transaction, and ends the cross-chain; if the execution fails, the relay chain receives a receipt of the failure of the execution of the access chain B, marks the cross-chain transaction as a failed cross-chain transaction, and ends the cross-chain;

the access chain B returns the execution result of the cross-chain transaction to the relay chain;

the relay chain verifies the execution result of the cross-chain transaction and sends a result message to the cross-chain module A;

The cross-link module A returns a response of the cross-link transaction to the client A;

and the client B inquires the execution condition of the cross-link transaction from the access link B and acquires a return result.

The cross-link flow defines the way data and transactions are transferred in the whole system, and specifies how a cross-link data sender initiates a cross-link request, how a relay link verifies and processes the cross-link transaction, and how a cross-link data receiver obtains the required data. This procedure ensures the ordering and controllability of data transfer, enabling the modules to work cooperatively to meet the data sharing requirements between different access chains.

Through the mechanism, the cross-link data sender can asynchronously send the cross-link ledger data, and the cross-link data receiver can acquire the required data based on the relay link, so that the cross-link requirement of a low-real-time scene is met. In addition, through a periodical consensus mechanism, the decentralization of the relay chain is realized, so that the safety and the authenticity of the cross-chain data are improved. The system architecture and the communication mode help solve the challenges of the blockchain intercommunication technology, and ensure the reliable transfer and processing of the cross-chain data. The cross-chain flow standardizes the data and transaction transmission modes in the whole system, and ensures the orderly operation of the system.

Therefore, in order to realize the efficient availability, safe reliability and convenient management of the cross-chain interaction, the embodiment is based on the abstraction of a blockchain system, the architecture of the cross-chain system and the top-level design of the trusted interaction flow, and realizes the following core functions of the cross-chain:

cross-chain architecture: a flexible and extensible cross-chain architecture is constructed to support interworking and interaction between a plurality of blockchain networks. By ensuring the consistency and the safety of data, seamless connection among different block chains is realized.

And (5) a cross-chain module: and designing a cross-link module to realize the message interaction function between the access link and the relay link. Meanwhile, a cross-link routing network is formed by interconnecting a plurality of cross-link modules, so that wider cross-link interaction is realized.

And (3) a cross-chain process: the method comprises the steps of designing and optimizing a flow of cross-link interaction, including the initiation of a cross-link request, the verification and the confirmation of a relay link, and the return and the processing of a cross-link result. Through optimizing the flow, the high efficiency and reliability of cross-chain interaction are ensured.

Through the comprehensive application of the core technical points, the cross-chain system of the embodiment realizes high-efficiency, safe and reliable cross-chain interaction, and provides a convenient treatment and intercommunication solution for the blockchain ecological system.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the scope of the embodiments of the present application, and are intended to be included within the scope of the present application.

Claims (10)

1. A relay link based cross-link system comprising: the system comprises a spanning chain module, a relay chain and an access chain, wherein the spanning chain module corresponds to the access chain one by one, the access chain is in communication connection with the relay chain through the corresponding spanning chain module, and the spanning chain modules are in communication connection;

the first cross-link module generates and sends a cross-link contract calling request to the first access link according to a cross-link transaction request instruction received by the first access link; the first access chain executes the cross-link contract calling request and returns an execution result to the first cross-link module;

the first cross-link module submits a cross-link transaction request instruction to the relay link;

The relay chain verifies the credibility of the cross-chain transaction request instruction, and if the verification is passed, the relay chain judges whether a second access chain corresponding to the cross-chain transaction request instruction is in an access chain service list; if yes, the relay chain submits a cross-chain transaction request instruction to the second cross-chain module;

and the second access chain executes the cross-chain transaction request instruction sent by the second cross-chain module.

2. The relay chain based cross-link system of claim 1, wherein the execution result of the first access chain executing the cross-link contract invocation request comprises: transaction version, hash value of transaction, transaction type, and timestamp.

3. The relay chain based cross-chain system of claim 1, wherein the relay chain verifies the trustworthiness of the cross-chain transaction request instruction, comprising:

the verification content of the relay chain for verifying the credibility of the cross-chain transaction request instruction comprises the following steps: verifying the source and the proof of the cross-link transaction request instruction whether the cross-link verification rule on the first access link is satisfied; if the verification is not passed, the relay chain marks the cross-link transaction request instruction as an illegal cross-link transaction request, returns a failed receipt and error information to the first cross-link module, and the first access chain re-initiates the cross-link transaction request instruction until the relay chain verifies the correct cross-link transaction request instruction.

4. The relay link-based cross-link system of claim 1, wherein if the relay link determines that the second access link corresponding to the cross-link transaction request instruction is not in the access link service list, the relay link marks the cross-link transaction request instruction as an invalid cross-link transaction, returns a failed receipt and error information to the first cross-link module, and the relay link notifies the first access link to rollback to end the cross-link.

5. The relay link-based cross-link system according to claim 1, wherein after the second access link executes the cross-link transaction request instruction sent by the second cross-link module, the second access link determines an execution result of executing the cross-link transaction request instruction; if the execution is successful, the relay chain receives a receipt of the successful execution of the second access chain, marks the cross-chain transaction as a successful cross-chain transaction, and ends the cross-chain; if the execution fails, the relay chain receives a receipt of the execution failure of the second access chain, marks the cross-chain transaction as a failed cross-chain transaction, and ends the cross-chain.

6. The relay link-based cross-link system of claim 5, wherein after the second access link determines the execution result of the execution of the cross-link transaction request instruction, the second access link returns the execution result of the cross-link transaction to the relay link, the relay link verifies the execution result of the cross-link transaction and sends a result message to the first cross-link module, and the first cross-link module returns a cross-link transaction response.

7. The relay chain based cross-chain system of claim 1, wherein the cross-chain module comprises a network unit, a storage unit, a verification unit, a certificate unit and a rights unit, the certificate unit is used for generating and maintaining identity certificates, the network unit is used for establishing cross-chain connection, the storage unit is used for receiving and storing cross-chain transaction data, the verification unit is used for verifying the legitimacy of the cross-chain transaction, and the rights unit is used for configuring and managing rights of different roles and identities.

8. The relay chain-based cross-chain system of claim 1, wherein the relay chain comprises an authentication node and a supervision node, the authentication node is composed of all nodes of an access chain, and the all nodes of the access chain are nodes containing all data of a corresponding access chain in the access chain.

9. The relay chain-based cross-link system according to claim 1, wherein the cross-link modules communicate with each other in a P2P manner to construct a peer-to-peer network.

10. The relay link-based cross-link system of claim 1, wherein the access link management operations comprise: registering, updating, auditing and logging off;

The registering process comprises the following steps: the access chain provides registration information comprising verifier information, consensus algorithm type, chain name and description and cross-chain gateway public key information, after registration, a relay chain manager examines and votes, and when more than half of manager passes the examination, the access chain is allowed to join;

the auditing process comprises the following steps: after the access chain registration is completed, the relay chain manager checks the information of the access chain registration, each relay chain manager checks and then votes, and if more than half of the relay chain managers pass the check, the access chain is agreed to be added;

the updating process comprises the following steps: when the access chain is newly added or replaced with a verification node or a new consensus algorithm is replaced, an access chain manager needs to perform access chain updating operation to update information of the access chain on the relay chain, and when the access chain is updated, the relay chain does not receive the cross-chain transaction of the access chain temporarily;

the process of cancellation includes: and when the access chain exits the cross-chain system, performing cancellation operation, and deleting the related information of the access chain on the relay chain by the system.