1. A multi-chain NFT-based chain crossing method is characterized by comprising the following steps:

real assets outside the service chain are monitored in real time, collected and converted through an ETL gateway associated outside a propheter node chain in the service chain, and an NFT generation contract is called on the service chain to generate a corresponding NFT;

deploying an inter-chain parallel process based on each service chain light node, establishing a transaction parallel mechanism and a uniform cross-chain interaction protocol based on each service chain Merkle tree interaction in the parallel process, verifying cross-chain transactions in the parallel chain through the transaction parallel mechanism, and transmitting cross messages among the service chains based on the cross-chain interaction protocol; the light node is deployed in a public chain associated with each service chain;

and the light node sends a verification confirmation result to an NFT transfer contract, the NFT transfer contract calls a cross-chain interaction protocol to analyze a cross-chain interaction message, and the NFT transfer is executed when the mortgage transfer general evidence reaches a preset value.

2. The multi-chain NFT-based chain crossing method according to claim 1, wherein real off-chain assets are monitored in real time and collected and transformed by predicting ETL gateways associated outside a machine node chain in a service chain, and NFT generation contracts are invoked on the chain to generate corresponding NFTs, specifically as follows:

setting a predictive speaker node in a business chain in association with a user client, deploying an NFT (network file transfer) generation contract on the predictive speaker node chain, connecting an ETL (extract transform load) gateway outside the chain, and formulating out-of-chain asset categories and rarity grade standards in the same type of assets in the gateway according to NFT metadata attributes;

the predicting machine node cleans and classifies the collected off-chain assets and allocates rarity grades through an ETL gateway, and outputs NFT metadata including asset types and rarity grades to an NFT generation contract;

and the NFT generation contract allocates an ID number as a unique identity identification number according to the received NFT metadata, wherein the ID number is composed of a fixed PIN code input by a user client and a random number generated on a chain, and the ID number allocates the number of the random numbers according to the rarity level.

3. The multi-chain NFT-based chain crossing method according to claim 1, wherein the inter-chain parallel process is deployed based on each business chain light node, and a transaction parallel mechanism and a uniform chain crossing interaction protocol are established based on each business chain Merkle tree interaction in the parallel process, specifically as follows:

creating a public chain based on a substate architecture, deploying light nodes of each service chain on the public chain, setting a sharing interface as a slot to provide a parallel process by associating the light nodes, enabling the service chain to be a parallel chain through an auction slot, setting ID numbers of the parallel chains to which the slot belongs, recording corresponding parallel chain identifiers by the light nodes, and enabling the parallel chain identifiers to be composed of current public chain block numbers and parallel chain IDs when the public chain is added;

arranging a message queue of cross-link messages in each parallel link in the Merkle tree structure, and storing a hash head of a message queue only to be stored on a public link, wherein the cross-link messages comprise cross-link NFT ID numbers, circulation pass-certificate mortgage values, target parallel link identifications, target client accounts and source client accounts;

setting parallel chain process channels of a common chain, generating bit fields of corresponding parallel chains of each channel, storing a channel list in a common chain state, and carrying out inter-chain message communication through the parallel chain channels;

the parallel chain block head added into the public chain also comprises a cross-chain message root and a bit field in the parallel chain block, wherein the cross-chain message root is used for searching a message queue hash head from a receiving object, and the bit field is used for associating a target parallel chain process channel;

and recording a common chain state storage in the parallel chain, and realizing communication with other parallel chains by constructing a common chain block, wherein the common chain block comprises a parallel chain identifier, a message root and a channel bit field.

4. The multi-chain NFT based cross-chain method of claim 3, wherein the verifying the cross-chain transaction in the parallel chain through the transaction parallel mechanism comprises the following steps:

performing hash calculation on current chain-crossing messages in parallel chains, building a sequentially interactive Merkle tree structure by utilizing the hash value calculated by each parallel chain, and storing the Merkle roots which are correlated to each other into light nodes of the parallel chains;

and the light node records corresponding parallel chain block header information in real time, verifies the authenticity of the cross-chain information of the corresponding parallel chain by comparing the cross-chain message hash in the block header with the consistency of the cross-chain message hash existing in the Merkle root which is associated with the block header, and broadcasts the verification result on the chain.

5. The multi-chain NFT-based chain crossing method according to claim 3, wherein a flow pass certificate is further set in the common chain, and the flow pass certificate is a medium for parallel chain NFT chain crossing transfer, specifically:

the service chain acquires the authority of the auction slot through the mortgage flow transfer pass, and acquires the permission priority of the parallel chain and the time for occupying the parallel chain slot by comparing the number of the mortgage flow transfer pass of each service chain;

different parallel chain clients acquire the transfer authority between NFT chains by mortgage flow transfer certificates on the public chain and reaching a preset value.

6. The multi-chain NFT-based chain crossing method of claim 1, wherein the light node sends a verification confirmation result to an NFT transfer contract, the NFT transfer contract invokes a chain crossing interaction protocol to parse a chain crossing interaction message, and when confirming that a mortgage flow pass certificate reaches a preset value, NFT transfer is performed, specifically as follows:

deploying an NFT transfer contract on a public chain, setting a preset value of flow pass evidence mortgage, and receiving a verification result of a light node by the NFT transfer contract;

when the result confirms that the interlinkage information is real, calling an interlinkage interaction protocol to obtain an interlinkage interaction message, verifying whether the mortgage flow transfer pass certificate of the source client side reaches a preset value, starting an NFT transfer function in the NFT transfer contract when the mortgage flow transfer pass certificate reaches the preset value, associating target parallel chain identification, and obtaining function input parameters including an ID number of the NFT, a target client side account and a source client side account;

and sending the ID number of the NFT to a target client account, and logging off the ID number of the NFT in the source client account.

7. The multi-chain NFT-based chain crossing method of claim 6, further comprising the steps of:

verifying whether the NFT needing to be transferred exists in the client account, and if not, associating with the predictive terminal node to generate a corresponding NFT; if the NFT branch exists, a branch function is started, and NFT branch is executed.

8. A multi-chain NFT-based chain crossing system is characterized by comprising an NFT generating module, a chain crossing intercommunication module and an execution module;

the NFT generation module is used for setting an ETL gateway which is associated outside a link through a node of a prediction machine in a service chain, monitoring real assets outside the link in real time through the prediction machine, collecting and converting the real assets, and responding to a user client on the link and the link to call an NFT generation contract to generate a corresponding NFT;

the cross-chain intercommunication module is used for setting inter-chain parallel processes by utilizing light nodes of each service chain, establishing a transaction parallel mechanism based on Merkle tree interaction of each service chain in the parallel processes, and verifying cross-chain transactions in the parallel chains by utilizing the transaction parallel mechanism; simultaneously, a uniform cross-chain interaction protocol is formulated based on the Merkle tree and is used for cross-message transmission among all service chains; the light node is deployed in a public chain associated with each service chain;

the execution module responds to a parallel chain client side cross-chain transfer request, the light node sends a verification confirmation result to an NFT transfer contract, the NFT transfer contract calls a cross-chain interaction protocol to analyze cross-chain interaction messages, and when the mortgage transfer pass evidence is confirmed to reach a preset value, NFT transfer is executed.

9. The multi-chain NFT-based cross-chain system of claim 8, wherein the cross-chain interworking module further comprises a hierarchy creation module, a right acquisition module, and a communication delivery module;

the system creation module is used for building a parallel chain architecture system which is communicated in a cross-chain mode and comprises a parallel chain formed by a plurality of different NFT service chains and a public chain for providing parallel slots, light nodes of all the parallel chains are deployed in the public chain, and a transaction parallel mechanism and a uniform cross-chain interaction protocol are formulated among all the parallel chains;

the permission acquisition module is used for mortgage flow passing evidence to acquire the permission of different NFT service chains to become parallel chains and the permission of parallel chain acquisition cross-chain transfer; and obtaining the authority for calling the cross-chain interaction protocol after the authenticity of the cross-chain information is verified and confirmed by the light node;

the communication transmission module is used for the correlation execution module to start the transfer contract to call the cross-chain interaction protocol to carry out cross-chain transfer communication between parallel chains.

Background

Non-homogeneous certificates (NFT) are encrypted certificates on a blockchain that represent ownership of a unique item. NFTs can represent either real assets (e.g., a piece of land) or digital assets (e.g., rare virtual cards). The bitcoin belongs to the homogenization general certificate, because one bitcoin can be exchanged with any other bitcoin. In contrast, each NFT is unique in that it essentially represents the scarcity of assets digitally, and this scarcity is verifiable.

The concept of storing unique items as data on blockchains is not uncommon to most people in the NFT community. Blockchains are a standard medium for exposing and trading NFT assets that are publicly transparent, tradeable worldwide, and more mobile. The blockchain also provides a secure environment for storing all trusted histories of the asset from creation to the present. This concept has its own value in registering and freely trading unique assets on a unified decentralized platform (i.e., blockchain). Now there is a bottleneck that the blockchain disconnects all external systems in order to guarantee its decentralized security properties, i.e. the NFT assets cannot interact with the data and other links down the chain.

With the development of DeFi and NFT, it is not yet able to carry large-scale NFT ecology in terms of the capacity of today's etherhouses. In this case, one is to perform the extension by using the method of Layer2, and the other is to perform the development by a multi-chain mode. With the development of multiple chains of the wave card, the Solana, the Heco, the BSC, etc., NFT assets on different public chains are also beginning to grow. Under such a background, the protocol related to the cross-chain NFT also starts to attract attention, and the use of the cross-chain technology to make the NFT have a circulation value and better adapt to the application of Web3 is a problem to be solved.

Disclosure of Invention

Based on the background and the problems in the prior art, the invention aims to design a multi-chain NFT-based chain-crossing method and a multi-chain NFT-based chain-crossing system, perform safe NFT generation and efficient chain-crossing transfer in a multi-chain system, and increase the ecological mobility of the NFT in a block chain.

A multi-chain NFT-based chain crossing method relates to the generation and chain crossing transfer of NFT, and specifically comprises the following steps:

setting a predictive machine node in a service chain, carrying out real-time monitoring and collection conversion on real assets outside the service chain through an ETL gateway associated outside the predictive machine node chain, and calling an NFT generation contract on the service chain to generate a corresponding NFT;

deploying an inter-chain parallel process based on each service chain light node, establishing a transaction parallel mechanism and a uniform cross-chain interaction protocol based on each service chain Merkle tree interaction in the parallel process, verifying cross-chain transactions in the parallel chain through the transaction parallel mechanism, and transmitting cross messages among the service chains based on the cross-chain interaction protocol; the light node is deployed in a public chain associated with each service chain;

and the light node sends a verification confirmation result to an NFT transfer contract, the NFT transfer contract calls a cross-chain interaction protocol to analyze a cross-chain interaction message, and the NFT transfer is executed when the mortgage transfer general evidence reaches a preset value.

The prediction machine is combined with the NFT, and the NFT intelligent contract completes real-time monitoring and data interaction on the real world by using the prediction machine. Most fundamentally, real assets such as land and art can be imported quickly and easily under the chain by setting a prediction machine. Further, it is to enhance the dynamic association of NFT with the real world.

A parallel process system is constructed based on a plurality of NFT business chains, multi-chain fusion can be carried out on a consensus level, transaction transactions are unified, external cross-chain transactions are converted into internal consensus cross-chains, a cross-chain interaction protocol is formulated, namely, a unified cross-chain standard specification is formulated, NFT interaction information of each business chain is transferred to a public chain to be managed, further, transfer and transmission of transaction communication are carried out, and efficient cross-chain exchange of NFT is achieved.

Further, real assets outside the chain are monitored in real time and collected and converted through predicting machine node off-chain association ETL gateways in a service chain, and NFT generation contracts are called on the chain to generate corresponding NFTs, specifically as follows:

setting a predictive speaker node in a business chain in association with a user client, deploying an NFT (network file transfer) generation contract on the predictive speaker node chain, connecting an ETL (extract transform load) gateway outside the chain, and formulating out-of-chain asset categories and rarity grade standards in the same type of assets in the gateway according to NFT metadata attributes;

the predicting machine node cleans and classifies the collected off-chain assets and allocates rarity grades through an ETL gateway, and outputs NFT metadata including asset types and rarity grades to an NFT generation contract;

and the NFT generation contract allocates an ID number as a unique identity identification number according to the received NFT metadata, wherein the ID number is composed of a fixed PIN code input by a user client and a random number generated on a chain, and the ID number allocates the number of the random numbers according to the rarity level.

The Oracle is a computer program which provides external data to an intelligent contract operated based on the blockchain technology and connects data of the external world (out-of-chain) with data of the blockchain world (on-chain), and the Oracle is used for improving safe and reliable data interaction between the world on the blockchain and the real world outside the blockchain. The method aims to establish a credible data gateway between a block chain and the Internet, and aims to break the constraint of acquiring data by an intelligent contract and enable the block chain to have the capability of accessing the Internet data under the condition of ensuring credibility. At present, known items of Defi such as MakerDAO, Compound, Synthetix, dYdX and the like all need price dataflow services provided by a prediction machine. The predictive engine queries, verifies and authenticates the external data, then relays it to the closed blockchain system, and then the authenticated data is used to verify the intelligent contract. The predictive machine establishes a bi-directional communication line with the blockchain: data may be sent in or transmitted out.

A prediction machine is used for acquiring a large amount of off-chain data resources for generating NFT, and the data resources are classified and integrated through an ETL gateway, wherein the ETL gateway is used for collecting data from the outside of the chain, and then extracting, converting and loading the data to a prediction machine node.

The ID number is formed by a fixed PIN code and a random number generated on a chain, different addresses can be bound as a user PIN code, applications in a business chain and other chains are allowed to give various attributes to the ID number, the random number on the chain is increased, the ID number is enabled to be non-falsifiable and traceable, and the ID number is used as a unique identifier of the NFT, so that the NFT can be transacted and circulated in the business chain together with the attributes attached to the NFT.

Further, the inter-chain parallel process is deployed based on each service chain light node, and a transaction parallel mechanism and a uniform cross-chain interaction protocol are formulated based on each service chain Merkle tree interaction in the parallel process, specifically as follows:

creating a public chain based on a substate architecture, deploying light nodes of each service chain on the public chain, setting a sharing interface as a slot to provide a parallel process by associating the light nodes, enabling the service chain to be a parallel chain through an auction slot, setting ID numbers of the parallel chains to which the slot belongs, recording corresponding parallel chain identifiers by the light nodes, and enabling the parallel chain identifiers to be composed of current public chain block numbers and parallel chain IDs when the public chain is added;

arranging a message queue of cross-link messages in each parallel link in the Merkle tree structure, and storing a hash head of a message queue only to be stored on a public link, wherein the cross-link messages comprise cross-link NFT ID numbers, circulation pass-certificate mortgage values, target parallel link identifications, target client accounts and source client accounts;

setting parallel chain process channels of a common chain, generating bit fields of corresponding parallel chains of each channel, storing a channel list in a common chain state, and carrying out inter-chain message communication through the parallel chain channels;

the parallel chain block head added into the public chain also comprises a cross-chain message root and a bit field in the parallel chain block, wherein the cross-chain message root is used for searching a message queue hash head from a receiving object, and the bit field is used for associating a target parallel chain process channel;

and recording a common chain state storage in the parallel chain, and realizing communication with other parallel chains by constructing a common chain block, wherein the common chain block comprises a parallel chain identifier, a message root and a channel bit field.

The message hash in the parallel chain block head stores the current NFT cross-chain transfer request information in the parallel chain, the Merkle tree among chains records the cross-chain message in each parallel chain, and the authenticity of the cross-chain information is verified by comparing the consistency of the cross-chain message and the cross-chain message, so that the safety in the NFT cross-chain process is guaranteed, and the problems of malicious transaction and double flowers are prevented.

In particular, the verification of cross-chain transactions in parallel chains by a transaction parallel mechanism comprises the following steps:

performing hash calculation on current chain-crossing messages in parallel chains, building a sequentially interactive Merkle tree structure by utilizing the hash value calculated by each parallel chain, and storing the Merkle roots which are correlated to each other into light nodes of the parallel chains;

and the light node records corresponding parallel chain block header information in real time, verifies the authenticity of the cross-chain information of the corresponding parallel chain by comparing the cross-chain message hash in the block header with the consistency of the cross-chain message hash existing in the Merkle root which is associated with the block header, and broadcasts the verification result on the chain.

The transaction parallel mechanism is used for performing transaction, signature verification and parallel on each parallel chain based on a public chain, and performing cross-chain message synchronization and path transfer in each parallel chain. Specifically, a Merkle tree is set, a light node stores Merkle tree roots to acquire cross-chain transaction information of each parallel chain, verification is performed by the light node, parallel processing is performed on the cross-chain information of each parallel chain connected in series on a public chain, cross-chain efficiency is improved, and performance of a parallel chain system is expanded.

The method comprises the steps of building a Merkle tree structure, formulating a uniform cross-chain interaction protocol based on the Merkle tree, supporting the switching of consensus algorithms such as Raft, SBFT, PBFT and Kafka aiming at different multi-chain structures, realizing the configurable consensus algorithm, fusing cross-chain consensus and executing cross-chain message transmission.

Particularly, a circulation pass certificate is further arranged in the public chain, and the circulation pass certificate is a medium for cross-chain transfer of the parallel chain NFT, and specifically includes:

the service chain acquires the authority of the auction slot through the mortgage flow transfer pass, and acquires the permission priority of the parallel chain and the time for occupying the parallel chain slot by comparing the number of the mortgage flow transfer pass of each service chain;

different parallel chain clients acquire the transfer authority between NFT chains by mortgage flow transfer certificates on the public chain and reaching a preset value.

A circulation pass is provided as a means to incentivize or penalize NFT cross-chain participants, which is not used for trading, but only as a way of circulating similar points in the public chain.

Further, the light node sends a verification confirmation result to an NFT transfer contract, the NFT transfer contract invokes a cross-chain interaction protocol to analyze a cross-chain interaction message, and when confirming that a mortgage flow pass certificate reaches a preset value, NFT transfer is executed, which specifically includes:

deploying an NFT transfer contract on a public chain, setting a preset value of flow pass evidence mortgage, and receiving a verification result of a light node by the NFT transfer contract;

when the result confirms that the interlinkage information is real, calling an interlinkage interaction protocol to obtain an interlinkage interaction message, verifying whether the mortgage flow transfer pass certificate of the source client side reaches a preset value, starting an NFT transfer function in the NFT transfer contract when the mortgage flow transfer pass certificate reaches the preset value, associating target parallel chain identification, and obtaining function input parameters including an ID number of the NFT, a target client side account and a source client side account;

and sending the ID number of the NFT to a target client account, and logging off the ID number of the NFT in the source client account.

The NFT transfer contract is used for responding and executing the inter-chain transfer of the NFT, the inter-chain cross-chain interaction protocol opens the cross-chain message channel of the source chain and the target parallel chain, the contract is started, and the NFT transfer process is implemented.

In particular, the following steps are also included:

verifying whether the NFT needing to be transferred exists in the client account, and if not, associating with the predictive terminal node to generate a corresponding NFT; if the NFT branch exists, a branch function is started, and NFT branch is executed.

A multi-chain NFT-based chain crossing system comprises an NFT generating module, a chain crossing intercommunication module and an execution module;

the NFT generation module is used for setting an ETL gateway which is associated outside a link through a node of a prediction machine in a service chain, monitoring real assets outside the link in real time through the prediction machine, collecting and converting the real assets, and responding to a user client on the link and the link to call an NFT generation contract to generate a corresponding NFT; the NFT generation module is deployed in each service chain, that is, each service chain may generate an NFT specific to its chain according to its respective attribute.

The cross-chain intercommunication module is used for setting inter-chain parallel processes by utilizing light nodes of each service chain, establishing a transaction parallel mechanism based on Merkle tree interaction of each service chain in the parallel processes, and verifying cross-chain transactions in the parallel chains by utilizing the transaction parallel mechanism; simultaneously, a uniform cross-chain interaction protocol is formulated based on the Merkle tree and is used for cross-message transmission among all service chains; the light node is deployed in a public chain associated with each service chain; the cross-chain intercommunication module integrates a plurality of NFT service chains, constructs a parallel chain architecture system, fuses a plurality of chains to form cross-chain consensus, and establishes a uniform cross-chain execution standard to enable NFT cross-chain transfer to be carried out quickly and efficiently.

The execution module responds to a parallel chain client side cross-chain transfer request, the light node sends a verification confirmation result to an NFT transfer contract, the NFT transfer contract calls a cross-chain interaction protocol to analyze cross-chain interaction messages, and when the mortgage transfer pass evidence is confirmed to reach a preset value, NFT transfer is executed.

Furthermore, the cross-chain intercommunication module also comprises a system establishing module, a permission obtaining module and a communication transmission module;

the system creation module is used for building a parallel chain architecture system which is communicated in a cross-chain mode and comprises a parallel chain formed by a plurality of different NFT service chains and a public chain for providing parallel slots, light nodes of all the parallel chains are deployed in the public chain, and a transaction parallel mechanism and a uniform cross-chain interaction protocol are formulated among all the parallel chains;

the permission acquisition module is used for mortgage flow passing evidence to acquire the permission of different NFT service chains to become parallel chains and the permission of parallel chain acquisition cross-chain transfer; and obtaining the authority for calling the cross-chain interaction protocol after the authenticity of the cross-chain information is verified and confirmed by the light node;

the communication transmission module is used for the correlation execution module to start the transfer contract to call the cross-chain interaction protocol to carry out cross-chain transfer communication between parallel chains.

In the invention, an independent NFT is automatically generated in a business chain by using a prediction machine united intelligent contract, a parallel chain architecture system is constructed based on a unified cross-chain interaction protocol, an NFT cross-chain transfer transmission channel is provided, a circulation authority and a verification mechanism are set, the safety of NFT cross-chain transfer is improved, a cross-chain transfer contract is deployed on a public chain, a cross-chain request is quickly responded, and a bid is executed.

Drawings

Fig. 1 is a structural diagram of service chain NFT generation and metadata acquisition according to the present invention;

FIG. 2 is a diagram of a parallel chain architecture;

FIG. 3 is a schematic diagram of a transaction parallel mechanism;

FIG. 4 is a schematic diagram of a chain interaction protocol;

FIG. 5 is a flow chart of the execution of an inter-NFT chain transition;

FIG. 6 is an overall flow diagram of cross-chain transfer of different NFTs;

FIG. 7 is a diagram of a multi-chain NFT cross-chain system architecture.

Detailed Description

In order to clearly illustrate the present invention and make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, so that those skilled in the art can implement the technical solutions by referring to the description text, and the interactive processes of the specific implementations can be described by using the common asset transaction process as an example, so as to facilitate the understanding of those skilled in the art.

Example 1:

a multi-chain NFT based chain crossing method relates to the generation and chain crossing transfer of NFT, and comprises the following steps:

(1) generating NFT in each service chain;

(2) building a multi-chain parallel architecture system;

(3) execution of multi-chain based NFT cross-chain branching.

The specific implementation is as follows:

(1) and (3) generating NFT in each service chain:

in a plurality of service chains (including service chains 1,2 … n), a preplanning machine node is arranged in each service chain, an NFT generation contract is deployed on each preplanning machine node, the preplanning machine node is associated with an ETL gateway through RPC communication, the category of off-chain resources and the rarity grade standard in the same-class resources are formulated in the ETL gateway according to the attribute of NFT metadata, and the ETL gateway is connected with a plurality of mainstream big data websites through API interfaces and used for collecting the off-chain data resources of the related NFT metadata, cleaning and converting and classifying, wherein the structure diagram is shown in FIG. 1.

Responding to a service chain client to generate an NFT request, calling an NFT to generate a contract and monitoring a predictive machine node, wherein the predictive machine node adopts a distributed predictive machine, performs mutual verification among a plurality of predictive persons (Oracles), provides a distributed oracle to collect service data resources related to the NFT, and outputs NFT metadata including asset types and rarity levels to the NFT generation contract through cleaning and classification of an ETL gateway;

the generating program of the unique identification ID number of the NFT is configured in the NFT generating contract, the generating program acquires a fixed PIN code (such as 6-bit effective digits) input by a user client, a random function is introduced to generate a random number and the PIN code is combined to establish the ID number, the number of the random number is confirmed according to the provided rarity grade, the higher the guarantee grade is, the more the random number is, and the same type of NFT has value grading.

Taking a football business game as an example, wherein NFT assets mainly exist in the form of player quantity limiting cards, a prediction machine node monitors offline football website match data in real time, the prediction machine and an ETL gateway convert the offline football website match data according to the wonderful performance of players in the match, appearance and identity of the players in the real world are used as NFT metadata attributes to be sent to a link, and the capacity is digitized to generate corresponding quantity limiting rare exclusive NFT cards.

(2) Building a multi-chain parallel architecture system:

there are service chains 1,2 … n, each of which can generate NFTs (NFT1, NFT2 … NFTn) for its respective attributes,

as shown in fig. 2, for a parallel chain architecture, a common chain is first created based on a substate architecture, and the common chain serves as an interaction chain for NFT cross-chain transfer, fuses transaction consensus of multiple service chains, and hosts consensus logic. Multiple Restful interfaces are provided on a common chain for access to the service chains, and each interface is compiled with a parallel chain ID number (Para1, Para2 … Para) for distinguishing the individual parallel chains.

The method comprises the steps that a certain amount of circulation general certificates are issued at the initial stage of public chain creation, all business chain clients can acquire the circulation general certificates in a mode of purchasing in advance or participating in public chain business acquisition incentive at the later stage, when NFT (network file transfer) cross-chain transfer requirements exist, business chains 1 and 2 … n can acquire the authority of auction slots through selectively mortgaging the held circulation general certificates, and when the slots are auctioned each time, the number of the mortgaged circulation general certificates determines that parallel chain slots occupy priority and occupy time;

different parallel chain clients acquire the right of transfer between NFT chains by mortgage flow transitive evidence on a common chain.

After the auction is successful, deploying a light node of the parallel chain on the public chain, and recording an identification number of the parallel chain in the light node, wherein the identification number comprises a parallel chain ID number and a public chain block chain number when the parallel chain is linked;

as shown in fig. 3, which is a schematic diagram of a transaction parallel mechanism, in the parallel chain system, a transaction parallel mechanism is used to perform hash calculation on current cross-chain information in each parallel chain, hash values are calculated by using each parallel chain to build a sequentially interactive Merkle tree structure, associated Merkle roots are stored in parallel chain light nodes, and cross-chain transactions in the Merkle roots are verified by using the light nodes to form parallel transaction information flows;

each parallel chain light node records corresponding parallel chain block head information in real time, each block head contains currently occurring cross chain transaction information Tx on a chain where the block head is located, the authenticity of the cross chain information of the corresponding parallel chain is verified by comparing the consistency of the cross chain information Hash in the block head with the cross chain information Hash existing in a Merkle root, and the verification result is broadcasted on the chain.

As shown in fig. 3, the tile header information of Para1 is recorded for light node 1, which includes Tx1, hashTx1 is calculated, and Hash (1,2) ═ hashTx1| hashTx2 is obtained by using a transaction parallel mechanism; hash (1, n) ═ HashTx1| HashTxn;

the light node 2 records block header information of Para2, including Tx2, calculates hashTx2, and obtains Hash (1,2) ═ hashTx1| hashTx2 by adopting a transaction parallel mechanism; hash (2,3) ═ HashTx2| HashTx 3;

the light node 3 records block header information of Para3, including Tx3, calculates hashTx3, and obtains Hash (2,3) ═ hashTx2| hashTx3 by adopting a transaction parallel mechanism; hash (3,4) ═ HashTx3| HashTx 4;

until a light node n records block header information of Paran, including Txn, calculating hashTxn, and acquiring Hash (n-1, n) which is hashTx (n-1) | hashTxn by adopting a transaction parallel mechanism; hash (1, n) ═ HashTx1| HashTxn;

consistency was verified by double: hashTx1| hashTx2 and Hash (1,2), hashTx2| hashTx3 and Hash (2,3), hashTx3| hashTx4 and Hash (3,4), until hashTx1| hashTxn and Hash (1, n), thereby confirming the authenticity of Tx1, Tx2, Tx3 … Txn.

Establishing a uniform cross-chain interaction protocol based on the Merkle tree, wherein the uniform cross-chain interaction protocol is used for message transmission among all parallel chains to form a cross-chain message flow; as shown in fig. 4, in the parallel chain architecture chain {1,2, … n }, there exists a parallel chain1, 2,3 … n, and the cross-chain interaction protocol is implemented as follows:

1) para1 to other parallel chains: 1- >2 (NFT cross-chain messages of Para1 to Para 2), 1- >3, …, 1- > n;

chain2 to other parallel chains: 2- >1 (the cross-chain message of Para2 to Para1), 2- >3, …, 2- > n;

until chain1n is the same.

According to the following sequence, H (Head _ { HC }), (Head _ { HC } -, H (m) | b | | H (previous Head _ { HC })) $

Message queue hashes are performed sequentially and store only message queue hash header $ Head _ { HC } $ onto the common chain:

where $ m $ is a message, $ H () $ is a hash function, and $ b $ is the public link block number of the last message sent, including the previous message.

Firstly, carrying out hash calculation on a message queue to obtain $ H (1) $, $ H (11) $, $ H (111) $. $ H (1n) $, taking hash Head information $ Head _ {1} $, $ Head _ {11} $, $ Head {111} $, $ Head _ {1n } $, and sequentially storing the hash Head information $ Head _ $ 111} $andthe hash Head information $ 1n } onto respective parallel chains, and then carrying out hash operation to obtain a message root (Merkle root).

2) Parallel chain thread channels (1,2, … n) of the common chain are set, each channel generates bit fields corresponding to the parallel chain, a channel list is stored in the state of the common chain, and inter-chain message communication is carried out through the parallel chain channels;

3) the parallel chain block Head of the public chain block also comprises a parallel chain block message root (Merkle root) and a bit field, and $ Head _ { HC } $issearched from a receiving object through the (Merkle root);

4) when the identifier sign of Para1 is used as the last identifier to be added into the storage state of the public chain, the public chain identifies a block in common, searches $ Head _ {1} $througha Merkle root according to the block header information of the block, can query the cross-chain message 1- >2, 1- >3 corresponding to Para1, and associates the parallel thread channels of Para2 and Para3 … Para according to the bit field to perform cross-chain message communication.

As shown in fig. 5, the execution flow of the inter-NFT chain transfer is specifically as follows:

deploying an NFT transfer contract when a public chain is constructed, acquiring a light node verification result when an NFT cross-chain transfer request occurs to a parallel chain, analyzing cross-chain information after the authenticity of the cross-chain information is confirmed, verifying whether a flow pass certificate of mortgage of a parallel chain client reaches a threshold value, starting a transfer function in the contract after the threshold value is reached, associating a target parallel chain identifier according to an inter-chain cross-chain interaction protocol, and acquiring function input parameters including an NFT ID number, a target client account and a source client account; wherein the input parameters are obtained by analyzing the cross-chain information.

The transfer function performs: and sending the NFT ID number to a target client account, and logging off the NFT ID number in the source client account.

Example 2:

as shown in FIG. 6, the specific process of cross-chain transfer of different NFTs is as follows:

(1) a business chain where a user client side is located obtains a parallel chain slot through auction by a mortgage stream pass-through certificate, becomes one of parallel chains, and is allocated with a parallel chain identifier (x, Para1), wherein x is the block number of a current public chain, Para1 is the ID number index of the current parallel chain, a light node peer1 of Para1 is deployed on the public chain, and the parallel chain identifier is recorded;

(2) the user client of Para1 mortises a flow pass in a flow pass resource pool on the public chain and issues an NFT cross-chain transfer request (including an NFT ID number, a user client account, and a target client account) on Para 1;

(3) responding to the cross-chain transfer request, the talker node verifies whether the NFT needing to be transferred exists in the client account, and if not, the talker node is called to generate the NFT with the ID identification number;

(4) if the cross-chain information exists, cross-chain information Tx1 is generated, hash operation is carried out on the cross-chain information Tx1, the hash operation is stored in Para1, the peer1 records block header information in the parallel chain in real time, and authenticity of the cross-chain information is verified through a transaction parallel mechanism light node;

(5) after the reality is confirmed, transferring a transfer contract, verifying whether the mortgage flow pass-through certificate reaches a threshold value, and after the mortgage flow pass-through certificate reaches the threshold value, associating a target parallel chain according to a cross-chain interaction protocol between the parallel chains, establishing a cross-chain communication message flow, and acquiring a target chain identifier;

(6) starting a transfer function, inputting NFT transfer parameters, sending the NFT ID number to a target client account, and canceling the NFT ID number in the user client account to realize the inter-chain transfer of the NFT.

Example 3:

fig. 7 is a structural diagram of a multi-chain NFT-based cross-chain system of the present invention, which includes an NFT generation module, a cross-chain interworking module, and an execution module;

the NFT generation module is used for setting a prediction machine node in a service chain, monitoring real assets outside the chain in real time through the prediction machine, and generating corresponding NFT with a user client responding to the chain;

the cross-chain intercommunication module is used for combining service chains containing different NFTs into a plurality of parallel chains, building a public chain based on the parallel chains, setting a transaction parallel mechanism among the parallel chains, formulating a uniform cross-chain interaction protocol and building an NFT cross-chain interaction system with a multi-chain structure; the transaction parallel mechanism is used for performing cross-chain transaction verification of each parallel chain on a public chain and simultaneously performing synchronous transaction information on each parallel chain;

the cross-chain intercommunication module also comprises a system establishing module, a permission obtaining module and a communication transmission module;

the system creation module is used for building a parallel chain architecture system which is communicated in a cross-chain mode and comprises a parallel chain formed by a plurality of different NFT service chains and a public chain for providing parallel chain slots, light nodes of all the parallel chains are deployed in the public chain, and a transaction parallel mechanism and a uniform cross-chain interaction protocol are formulated among all the parallel chains;

the permission acquisition module is used for mortgage flow passing evidence to acquire the permission of different NFT service chains to become parallel chains and the permission of parallel chain acquisition cross-chain transfer; and obtaining the authority for calling the cross-chain interaction protocol after the authenticity of the cross-chain information is verified and confirmed by the light node;

the communication transmission module is used for the correlation execution module to start the transfer contract to call the cross-chain interaction protocol to carry out cross-chain transfer communication between parallel chains.

The execution module responds to the cross-chain transfer requests of different parallel chain user clients, calls a cross-chain interaction protocol to perform cross-chain information interaction on parallel chains and performs cross-chain transfer of different NFTs in a common chain.

Also included in the system are a memory storing a computer program and a processor and a computer readable storage medium executing the multi-chain NFT cross-chain method.

The embodiments described above are presented to enable a person having ordinary skill in the art to make and use the invention. It will be readily apparent to those skilled in the art that various modifications to the above-described embodiments may be made, and the generic principles defined herein may be applied to other embodiments without the use of inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications to the present invention based on the disclosure of the present invention within the protection scope of the present invention.