KR102230471B1 - Method of generating group proof for efficient transaction on blockchain network - Google Patents

Abstract

The present invention relates to a method of generating group proof for a peer-to-peer (P2P) network-based blockchain network. Specifically, the method comprises the steps of: generating, by a first node, a node chain composed of a plurality of nodes, based on a node value according to a block height on the blockchain network; transmitting, by the first node, an agreement request for transaction processing to second nodes of a group constituting the node chain; and when the first node obtains agreement corresponding to the agreement request from the second nodes, generating, by the first node, a block including proof of a group for the transaction. Therefore, the present invention can improve block reliability and scalability at the same time.

Description

Method of generating group proof for efficient transaction on blockchain network {METHOD OF GENERATING GROUP PROOF FOR EFFICIENT TRANSACTION ON BLOCKCHAIN NETWORK}

The present invention relates to a method of constructing a blockchain network, and more particularly, to a method of generating a group proof for performing an efficient transaction on a blockchain network.

In the blockchain, the consensus algorithm plays a key role in consensus on the order of processing of transactions and preventing the order from being changed afterwards. The initial form of blockchain, which is autonomous competition and connects a single chain, contains the basic configuration as a blockchain well, but there is a problem that it cannot reach the performance required in the real world. Therefore, although many blockchain consensus algorithms have been proposed and attempted to solve this problem, it is a situation that does not contain enough elements necessary for a sustainable blockchain system.

In order for a large number of nodes to participate in the actual blockchain network, the barrier to entry into the network must be low enough to prevent a small number of members from taking advantage, and although the sizes of the local chains may be different, freely between these local chains. In order for an asset to move, it must have no or negligible gain or loss depending on the size of the local chain. In other words, the biggest cause of the blockchain's economic imbalance is that resources outside the blockchain affect the internal economy of the blockchain, so the consensus algorithm should not be based on external resources, and the resource imbalance is a small local chain. There is a problem that it may worsen the security of the device.

Based on the above discussion, the following will provide a method of configuring a blockchain network.

The technical problems to be achieved in the present invention are not limited to the above technical problems, and other technical problems that are not mentioned will be clearly understood by those of ordinary skill in the art from the following description.

One aspect of the present invention for solving the above-described problem, a method for generating a group proof for a blockchain network based on a peer to peer network, is a node value according to a block height on the blockchain network. On the basis of, the first node generating a node chain composed of a plurality of nodes; Transmitting, by the first node, an agreement request for processing a transaction to second nodes of a group constituting the node chain; And when the first node obtains consent corresponding to the consent request from the second nodes, generating, by the first node, a block including proof of the group for the transaction. Characterized in that.

Further, the node chain may be reconfigured based on the node value for each time slot for generating the block.

Furthermore, in the step of generating the node chain, the first node sends a leader request message or a leader abandon message of the group based on the node value of the first node, at least one out connected to the first node. -Transmitting to an out-edge node; And when the first node does not receive a rejection message opposing the leader request message within a preset time unit to be smaller than the time slot, setting the first node as a leader node of the group.

Furthermore, the second nodes, when receiving the consent request, only when they have not already responded to the consent request within the time slot, the order of processing for the transaction processing and the previous block to be connected to the generated block ( Previous block) may be characterized in that it is configured to transmit the determined consent to the first node.

Further, the block may be configured to complete distribution before the preset time unit elapses from a start time of a next time slot of the time slot.

Further, the node chain may be characterized in that it has a DAG (Directed Acyclic Graph) structure.

According to an embodiment of the present invention, a new consensus algorithm capable of indirectly measuring the state of the network may be proposed through the selection of the best group member while randomly assigning a value according to the height to the real-name authenticated node. .

In addition, according to an embodiment of the present invention, the concept of a group is introduced to distribute profits to as many nodes as possible to induce the storage service of the block chain to occur smoothly, as well as to allow multiple nodes to participate, thereby reducing the reliability of the block. At the same time, you can increase the scalability.

The effects that can be obtained in the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those of ordinary skill in the art from the following description. will be.

The accompanying drawings, which are included as part of the detailed description for aiding understanding of the present invention, provide embodiments of the present invention, and together with the detailed description, the technical spirit of the present invention will be described.
1 shows a P2P network to which the blockchain network according to the present invention can be applied.
2 is a flowchart illustrating a scenario of creating and managing a block chain through group proof according to an embodiment of the present invention.
3(a) and 3(b) are reference diagrams for explaining a scenario of selecting a leader node of a group on a blockchain according to an embodiment of the present invention.
4 is a reference diagram for explaining a case of obtaining consent for group authentication according to an embodiment of the present invention.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The same reference numerals shown in each drawing indicate the same members. Various changes may be made to the embodiments described below. The embodiments described below are not intended to be limited to the embodiments, and should be understood to include all changes, equivalents, and substitutes thereto.

The terms used in the examples are used only to describe specific embodiments, and are not intended to limit the embodiments. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements, numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility of the presence or addition.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiment belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present application. Does not.

In addition, in the description with reference to the accompanying drawings, the same reference numerals are assigned to the same components regardless of the reference numerals, and redundant descriptions thereof will be omitted. In describing the embodiments, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the embodiments, the detailed description thereof will be omitted.

1 shows a P2P network to which a blockchain network according to an embodiment of the present invention can be applied.

In a P2P network, nodes participating in the network communicate with each other with equal qualifications. P2P networks can take various forms depending on the connection state between nodes. In a P2P network that is autonomously created in the real world, there are several hubs and a decentralized form in which the network is maintained around them is common.

In order to participate in a P2P network, a tracker or bootstrapping node is generally needed, and unlike other general nodes, they do not leave the network and are responsible for managing connection addresses to other nodes. Carry out.

Many public blockchains use Kademlia to create P2P networks, but despite its excellent performance, Kademlia attacks specific nodes such as Eclipse attacks that hide some routing information, and Sybil attacks that pretend to be multiple nodes by themselves. There are several security issues that can be isolated. In particular, recent blockchains are trying to use S/Kademlia, which has improved this, but S/Kademlia uses a public key verified by a trusted third party to create a verifiable node identifier, or a public key created using a hash puzzle. Use the key.

In the initial block chain, nodes were not clearly separated from users, and in order for users to verify and manage their assets, considerable information about the blockchain was required, because in fact, it performs some functions of the node. However, in recent blockchains, nodes and users are separated, nodes maintain a blockchain network, preserve data, provide blockchain services to users, and users must manage their own assets through nodes.

The policy of separating nodes and users makes users have to rely heavily on nodes to manage their assets, but it has the effect of significantly improving the user's accessibility to the blockchain. In fact, a significant number of users currently use hot wallets that borrow accounts from exchanges, and many users who use cold wallets that directly manage accounts also do not play a role as nodes. In the blockchain, both nodes and users use the same type of identifier, but in the real world, nodes are actually operated under their real names, and users are using anonymous (pseudonyms).

In many public blockchain networks, when a node creates a block, all transaction fees included in the block are acquired. So, in practice, a node that provides a storage service is like providing a service for free. If a node generates more blocks and takes more transaction fees, they have to pay more for storage services, but the reality is, nodes that only make blocks and take transaction fees without doing any storage services. May exist. Therefore, such a fee system may eventually lead to the result that only a few nodes that can generate blocks well remain in the blockchain network.

Since the number of nodes in a blockchain network is directly related to security, this inevitably has a negative impact on network maintenance. However, there is rarely a case of charging a service fee for the storage service, and alternatively, a contract between the node providing the storage service and the user can be made through a smart contract.

Another approach is to ensure that the transaction fee is distributed fairly and abundantly to the nodes participating in the blockchain, so that nodes do not have to pay storage service fees from users, ideally everyone cooperates. Thus, you can create blocks in a predetermined order.

In conclusion, for a sustainable blockchain network, it is necessary to ensure that no gain is gained if a node provides services lazily, and it is necessary to set it so that there is some degree of competition.

Bitcoin, a representative blockchain, was designed as a P2P network in which numerous nodes participate. When a number of nodes participate, the survivability of data increases, but there is a problem that the network is spontaneously fragmented and difficulty in synchronizing data occurs. Blockchain's consensus algorithm aims to agree on the order of transaction processing between multiple nodes on this fragmented P2P network, and to prevent the agreed transaction order from being changed later.

Consensus on the processing order of transactions can be largely classified into three types according to the method, and some blockchains have a mixed structure to compensate for their respective shortcomings.

● Competition sequential chain structure: Old blockchains such as Bitcoin and Ethereum have a chain structure in which blocks are sequentially connected. Many nodes can participate by acquiring the right to create a block through a game between participants who want to create a block and then connecting it to the previous block, but it can be very slow if there is overheating competition for block generation between nodes.

● Minority consensus structure: EOS, NEO, etc. agree on the order of transaction processing among a small number of members. There is no reason to create a chain because blocks are generated in a pre-agreed order, and since PBFT (Practical Byzantine Fault Tolerant) protocol is mainly used, consensus is exponentially slow as the number of nodes increases, resulting in tens of nodes. It is difficult to pass. In this case, there is often no need for a chain connection.

● DAG (Directed Acyclic Graph) structure: IOTA, Hedera Hashgraph, and FANTOM use hash chains linked to multiple previous transactions, blocks, and events. Transactions are processed according to the connection status of the hash chain.Since accurate order control is difficult, smart contracts cannot be executed, only a few nodes participate, or special participants are required to organize them.

In particular, some consensus algorithms have been developed to compensate for the shortcomings of the sequential chain structure (especially performance problems), but if the blockchain is only collecting transactions, making them into blocks, and connecting them, these new attempts will not have any problems, but the blockchain is Since it is a system that must ensure reliability and safety from a large number of participation, there is a problem in that the number of participating nodes should not be limited or the existence of a special participant who deeply participates in the operation of the blockchain network should not be assumed.

In most systems that operate anonymously, such as blockchain, there is a risk of a civil attack. In the Sybil attack, one participant attacks the system by creating a fake identifier, and in the blockchain, it can be used to withdraw an existing consensus block or to degrade network performance by causing excessive competition. Therefore, the credential in the blockchain must not be obtained through a Sybil attack, and must be included in the block. In other words, the credential of each block shows that the block is by a qualified participant of a certain level or higher, thereby limiting the competition for block generation, and the accumulated credential makes it impossible to withdraw the block. Examples include Proof-of-Work (PoW) and Proof-of-Stake (PoS).

PoW includes an answer to a hash puzzle that can only be obtained through a brute-force search, and typically, as in the example of Bitcoin, as the price of cryptocurrency in the real world increases, the competition for block generation intensifies. The difficulty of the hash puzzle is so high that only a few participants with huge hash power can generate blocks.

PoS neutralizes the Sybil attack by giving different opportunities to create blocks according to the amount of stake it owns, and if the stake is split to a fake identifier, the chance of creating blocks decreases as much as the split, so there is no benefit. Since PoS does not require huge hash power, it is possible to operate lighter than PoW-based blockchain, but how to distribute block creation opportunities according to stakes and whether this distribution can be verified to everyone should be considered. It is also necessary to consider how to prevent a Nothing-at-Stake attack in which shares are divided and voted on each other's chains.

In most blockchains, participants are considered to have anonymity, so it is considered that complex credentials are required.However, in the real world, most block creators (nodes) have fixed and known connection addresses and protocols, so it is difficult to say that anonymity is guaranteed. . In the case of blockchains in which a small number of already elected outcrops are consensus, information about nodes is well known in most cases, and there is no reason to maintain anonymity for the creator of the block.

According to the number of nodes, there is no standard as to how far to consider decentralized. It is known that the number of Bitcoin nodes reaches 10,000 (as of January 2019), EOS only has 21 nodes, and Cardano can have up to 50 nodes. Considering the fact that there are about 9,000 banks in the world that have joined the Society for Worldwide Interbank Financial Telecommunication (SWIFT), and there are many banks that are not subscribed, the blockchain network with less than 100 nodes is small. Therefore, in order to say that the current banking system is centralized based on this, at least the number of nodes participating in the blockchain network should be at least tens of thousands.

On the other hand, consensus algorithms using proof of work such as DPoS (Delegated Proof-of-Stake) claim that a few nodes elected through stake delegation actually operate the blockchain network, but based on this, they are decentralized. In this case, it is difficult to view this as decentralization when a few elected nodes do not actually change, and thus the number of nodes actually participating in the operation becomes an important criterion for decentralization.

When an actual branch occurs in a blockchain that uses a consensus algorithm that allows branching of the chain, the block producer must select one chain. As long as the credentials of the block are correct, it is the freedom of the block creator to select which chain, but many blockchains use the Longest Chain Rule (LCR), which selects the longest chain as an intuitive selection strategy. This is because some blockchains choose the chain with the highest security, and it is the most profitable choice from the perspective of the entire blockchain, and other block producers believe that they will make the same choice. In general, due to the cost of credentialing, this strategy is likely to be in line with LCR.

However, all nodes should be viewed as operating for their own benefit, and so are the block generators. Also, it is difficult to choose what is the longest chain in a situation where the speed of the network continues to increase. Therefore, if the criteria for selection that benefit the block producers are not clear, block producers will randomly choose a chain, making the chain's connections more competitive and congesting the blockchain.

From the block producer's point of view, he must select a chain with a high probability of surviving the block he created. This is because if a block created by itself is discarded, it does not produce any gain. Therefore, the consensus algorithm needs to be designed so that the choice of the block producer does not affect the security, and it should be able to directly or indirectly show the viability of the block. This has the effect of lowering the level of competition and making the network situation more smooth.

Bitcoin's TPS (Transaction Per Second) is known to be around 3~5, while Ethereum's is known to be around 12~20. Since the VISA network can handle up to 65,000 cases (as of August 2017) in 46 million stores worldwide, it is not easy to replace the real-world financial system with such a blockchain. When the performance problem of the block chain emerges greatly, many block chains create new consensus algorithms, while suggesting a method of operating chains in parallel under the judgment that it is not easy to meet the performance required in real life with a single chain. It is becoming, for example, a side chain, an off-chain, and a local chain.

Side chain is a method to solve performance problems by operating several blockchains in parallel depending on the purpose, and generally has an independent economic structure, and requires a main chain that can connect assets between chains. It should be. Off-chain is a method in which participants' assets are frozen in the original main chain and then transacted between them without leaving a record on the blockchain. The Lightning Network or Leiden Network uses an off-chain method. Local chains are similar to side chains, but they operate economically compatible blockchains at the same time. Assets can be moved freely between local chains. In order to create a local chain, there should be no economic profit or loss due to the size of the chain or external resources, so it is impossible to implement it with a consensus algorithm such as PoW or PoS.

In Bitcoin, the timestamp value is determined to be valid when it is greater than the median value of the timestamp of the previous 11 blocks and is less than 2 hours more than the time corrected through the network. However, this loose time management is not suitable for systems requiring high throughput, so many blockchains assume that time is synchronized between nodes.

In order to synchronize the time between nodes, it will be necessary to use a clock synchronization algorithm between them. There are various methods of clock synchronization algorithms, but in reality, NTP (Network Time Protocol) services such as OpenNTPD or Chrony can be used.

Based on the above description, the present invention proposes a sustainable blockchain system in which numerous nodes actually participate to form a blockchain for sufficient decentralization, and dramatically improve processing performance through a local chain.

In the blockchain system according to the present invention, in order to create a local chain, the consensus algorithm must not be resource-based first, and the first thing to consider for creating a non-resource-based consensus algorithm is an answer to how to prevent a Sybil attack. In the present invention, it is premised on preventing a civil attack through real name authentication.

The blockchain system according to the present invention operates on a decentralized P2P network, and at this time, it is assumed that the P2P network may be partially fragmented, but the connection between fragmented local networks is maintained. In addition, it is assumed that more than 50% of nodes do not conspire for specific malicious actions, and more than 50% of nodes can act for their own benefit, but are semi-honest nodes that do not violate policy. It is assumed that the time of all nodes is synchronized with a very small time difference, and all messages between nodes are assumed to be protected with a digital signature including the current time to prevent forgery, modification, and retransmission. In addition, it is assumed that the node's network ID has a structure that can be verified from the node's ID.

2 is a flowchart illustrating a scenario of creating and managing a block chain through group proof according to an embodiment of the present invention.

According to the present invention, the computing device participates as a node in the blockchain network (S210). According to the present invention, a computing device (hereinafter, a node) that wants to participate in a blockchain network first undergoes a real name authentication procedure. For example, even though it is a public blockchain, only corporations that must have certain qualifications can participate as a node, or if only a specific country can participate, the real name authentication method may vary depending on the operation purpose of the network.

Nodes participating in the blockchain network can obtain node identification information (e.g., node ID) and transaction information (e.g., signing key, public key, etc.) when real-name authentication is performed.

The identification information of the node means information that can be used to verify the network ID of the node, for example, the ID of the node.

The signing key is a node-specific key used when a node creates a transaction in a blockchain network. The public key is a key that is publicly disclosed to anyone to verify the validity of a transaction, and is distributed in the form of a certificate. At this time, the random seed is distributed together, and it is preferable that the random seed is also verifiable like a certificate.

In an example according to the present invention, since a verifiable random seed necessarily requires the intervention of a trusted third party, a trusted third party's signature may be attached to the random seed like a certificate. To this end, according to the present invention, the random seed has a structure having a structure similar to that of a certificate, which can be used to transmit to other nodes.

As another example of using a random seed according to the present invention, a verifiable random function (VRF) may be used as shown in Equation 1 for a signature key of a trusted third party.

In Equation 1, S _i is the random seed of the node, p _i is the proof value of VRF, sk _TTP is the signature key of a trusted third party, and pk _i is the public key.

However, in the case of using VRF, a trusted third party has to make a random seed and a proof to the node, and there is a burden of transmitting the certificate, random seed, and proof to other nodes.

Another example of using the random seed according to the present invention is to calculate the random seed as in Equation 2 using a certificate containing the public key of the node.

In Equation 2, S _i is the random seed of the node, and pk ⁱ is the public key. PBKDF2 (password-based key derivation function version 2) is a representative function for deriving a key based on a user password. This is because the signature of a trusted third party is contained in the certificate, and the signature of the third party is unpredictable under the assumption that the signature is secure, so a random seed can be generated using this. This has the advantage of not having to pass a separate random seed to other nodes because only a certificate is required.

Accordingly, the public key certificate used in the present invention can help to use a P2P communication protocol (eg, S/Kademlia) with improved security.

When participating in a blockchain network, the value of a group of nodes is calculated when creating or managing blocks. The value of the nodes in the blockchain can be determined according to the height of the block and the order of the nodes constituting the blockchain. The block height represents the amount of blocks made from the first block to the current block, which symbolizes the beginning of the blockchain network, and this number is expressed as the block height. For example, block 0 refers to the block created when the blockchain network was initially started.

Accordingly, in an example of the present invention, the value v _(i,h) of the i-th node at the height h of the current block may be calculated as in Equation 3.

는 가치 측정 함수,

는 참여 빈도 가중치,

는 위험도 평판을 나타낸다.In Equation 3, s _i is the random seed _{of the node, id i} is the ID of the node,

Is the value measurement function,

Is the participation frequency weight,

Represents the risk reputation.

는 노드가 갖는 시드 s 로부터 현재 높이 h 로부터 계산되는 무작위 값과 노드의 아이디를 비교하여 계산될 수 있다. 예를 들어, 수학식 4와 같이 계산될 수 있다.Value measurement function

May be calculated by comparing the ID of the node with a random value calculated from the current height h from the seed s of the node. For example, it can be calculated as in Equation 4.

는 해밍 거리(Hamming distance)나 유클리드 거리(Euclidean distance)처럼 기하학적 거리를 계산하는 함수를 의미하며,

는 SHA-256(secure hash algorithm - 256bit)과 같은 암호학적 해시 함수를 의미하는데, 이상적으로는 의사 난수 생성기(pseudo random number generator)를 의미한다. 세로줄( | ) 옆의 변수의 밑 첨자는 비트의 시작 위치, 위 첨자는 비트의 끝 위치를 의미한다. 즉, 랜덤시드와 현재 블록 높이를 의사 난수 생성기등을 통하여 비트의 시작 위치부터 비트의 끝 위치까지에 대응하는 암호학적 해시값을 생성한 후, 노드 식별 정보(예, 노드의 아이디)중 비트의 시작 위치부터 비트의 끝 위치까지에 대응하는 식별값을 추출하여, 기하학적 거리를 계산할 수 있다. 파라미터

는 필요에 따라 적절하게 선택하여 사용하면 되는데, 예를 들어 (3, 64, 16)와 같은 값이 사용될 수 있다.In Equation 4,

Denotes a function that calculates geometric distance, such as Hamming distance or Euclidean distance,

Means a cryptographic hash function such as SHA-256 (secure hash algorithm-256bit), ideally means a pseudo random number generator. The subscript of the variable next to the vertical line (|) means the start position of the bit, and the superscript represents the end position of the bit. That is, after generating a cryptographic hash value corresponding to the bit start position to the end position of the bit through a pseudo-random number generator, etc., the random seed and the current block height are By extracting the identification value corresponding to the start position to the end position of the bit, it is possible to calculate the geometric distance. parameter

If necessary, you can select and use appropriately. For example, values such as (3, 64, 16) can be used.

는 블록체인 네트워크위 탈중앙화를 위하여 본 발명에서 이용되는 파라미터로, 노드가 최근에 참여하였던 빈도가 많을수록 낮은 값을 갖는 함수이며, 예를 들어, 수학식 5와 같이 계산될 수 있다. t 는 최근 블록의 길이이고

는 h 번째 블록의 그룹 구성원의 집합이다.Participation frequency weight

Is a parameter used in the present invention for decentralization on a blockchain network, and is a function having a lower value as the frequency with which a node recently participated is increased, and can be calculated as, for example, Equation 5. t is the length of the latest block

Is the set of group members in the h-th block.

는 최소 1에서 최대 2까지의 값을 갖게 되며, 최근 t 블록에서 지수적으로 증가하는 전체 가중치의 합 대비 최근 블록에 참여한 경우를 제외한 가중치의 합의 비율에 1을 더하여 결정된다. 수학식 5에서, α를 계산하기 위하여 밑을

를 사용하였으나, 1 보다 큰 적합한 실수를 사용하면 되며, 밑이 1에 가까운 경우, 참여 빈도 가중치는 일정 범위에서 균등하게 되고, 크면 클수록 최근 블록에 더 많은 가중치를 두게 된다.In Equation 5

Has a value from a minimum of 1 to a maximum of 2, and is determined by adding 1 to the ratio of the sum of weights excluding the case of participating in the recent block to the sum of the total weights exponentially increasing in the recent t block. In Equation 5, in order to calculate α

Is used, but a suitable real number greater than 1 can be used. If the base is close to 1, the participation frequency weight becomes even within a certain range, and the larger the value, the more weight is placed on the recent block.

은 블록 높이를 키로 하는 노드 리스트

로부터 획득할 수 있다. 만약 해당 노드 리스트에 노드의 아이디가 들어 있다면 0이 되고, 들어 있지 않다면 항상 가치 측정함수의 값보다 크도록 설정된 임의의 최대 가치와 동일하다. 즉, 노드의 가치

는 가치와 가중치의 곱을 평판 중 더 작은 값을 가지므로 위험도 평판

이 0이면 노드의 가치가 0이 되어, 블록 생성에 참여하기 어렵게 된다. 예를 들어,

는 수학식 6과 같이 나타낼 수 있다.Risk reputation

Is a list of nodes with block height as key

Can be obtained from If the node's ID is included in the node list, it is 0. If it is not, it is always equal to the random maximum value set to be greater than the value of the value measurement function. In other words, the value of the node

Is the product of the value and the weight, whichever is the smaller

If this is 0, the value of the node becomes 0, making it difficult to participate in block generation. E.g,

Can be expressed as in Equation 6.

Accordingly, the value of the group consisting of a plurality of nodes can be calculated by summing the values of the notes belonging to the group, and can be expressed as in Equation 7.

Therefore, each node group constituting the blockchain network can calculate the value of the group by using the list of nodes that participated in the creation of the block. In this case, the number of group members belonging to one group should all be the same. Even in the case of obtaining consent signatures to form a group from more nodes, it is desirable to calculate the value of the group by including only a predetermined number.

A node that wants to create a block through a transaction on the blockchain can create a block on the selected chain based on the value of the node group. If the block chain diverges due to several groups competing, the node that wants to generate the next block must select one chain. This is done by the autonomous selection of nodes, but in order to obtain the consent of other nodes, a rational choice must be made. It is preferable that the node calculates the values of the groups that created blocks included in the previous chain and selects the block with the highest value.

The value of the group increases when the diversity of group members is secured compared to the previous group. If blocks are continuously generated by groups with similar group composition, the value of the group is continuously lowered (i.e., the weight of participation frequency decreases). The diversity of group members indirectly proves that the group leader of the block is in an environment with high connectivity, which again means that if the network environment in which one is located is not bad, the block to be created is likely to survive. .

Blockchain network constructs a group consisting of a plurality of nodes based on the node value in order to generate group proof, and establishes a node (hereinafter, a leader node) for creating/connecting blocks on the blockchain in a P2P network. Set (S220).

In the blockchain network according to the present invention, blocks are not created through completely autonomous competition (eg, Bitcoin, Ethereum), and one block is created in a time slot divided by a predetermined length of time. That is, there may be a plurality of nodes capable of creating a group in one time slot, and a block creator may seek cooperation/consent of neighboring nodes to determine the transaction processing order determined by the block producer.

In the present invention, a node that has cooperated with a block producer is hereinafter defined as a “group”, and it is assumed that several groups compete in one time slot.

When there is a competing chain, it is desirable for the block producer to select a chain with a high probability of survival as described.To this end, in the blockchain network according to the present invention, the sum of the values of the nodes randomly determined in each timeslot is used. Thus, a method of providing an indirect index on the viability of a block is as described above.

However, in order to select a leader node in a P2P network, nodes of the entire network participate and messages are transmitted to the entire network, so there is a problem that the number of messages increases.

Accordingly, in the present invention, before selecting a leader node of a group consisting of a plurality of nodes, the network may configure a node chain (eg, DAG structure). For example, the direction of the graph is determined from a node with a high value to a node with a low value. If the values of the nodes are the same, the direction of the graph is determined with a smaller node when the node ID is converted to a number.

The node chain in the present invention is defined as a list consisting of a plurality of nodes connected from a source to a sink. It is defined that a node without an incoming connection (in-edge) becomes a source, and a node without an outgoing connection (out-edge) becomes a sink. There can be multiple sources and sinks in the network, and since the value of the node changes according to the time slot, the node chain changes every slot.

When the selection procedure for the group's leader node starts, source nodes send a leader request message containing their own node values to neighboring nodes (ie, out edge nodes). If its value is not high enough or does not intend to become a leader node, it can send a leader abandon message instead.

When intermediate nodes that are not sink or source receive a reader request message or a reader abandon message from all of their incoming connections (in-edge), they send the reader request message of the node with the highest value to all outgoing connections. If no leader request message is received, this node can send a leader request message with its ID to the outgoing connection or send a leader abandonment message if its value is high enough and has a willingness to become a group leader.

If a node receives a reader request message from a different source node from an incoming connection during this process, a rejection message containing information about the reader request message is transmitted to the connection from which the reader request message of the source node with a lower value is received.

The node receiving the rejection message from the outgoing connection forwards the rejection message to the incoming connection. Rejections are not sent again for incoming connections that have sent a rejection once.

Finally, if the source (or the node that issued the reader request message) does not receive any rejection message, the node is set as the leader node of the group.

Accordingly, in the process of setting a group leader node according to the present invention, a plurality of group leaders may exist. That is, because all sources may give up the group leader, and some intermediate nodes may try to become the group leader if their sources give up the position of the group leader. In addition, an intermediate message may be unintentionally omitted. In this case, since the group leader election is not completed, a plurality of source nodes may become group leader nodes.

Therefore, a node whose value is higher than a certain level can express its intention to become the leader node of the group to neighboring nodes, and in this case, a node with a higher value than itself wants to become the group leader within a given time e. If you don't express your opinion, you are set up as the leader node of the group that makes up the node chain. Here, the given time e is a time unit set in advance to be smaller than the time slot, and is preferably set to be greater than or equal to a time during which a message can be transmitted from all source nodes to all sink nodes.

The blockchain network generates and processes a transaction based on the node chain configured in step S220 (S230).

라고 할 때, 그룹 리더는 자신이 모은 트랜잭션의 처리 순서와 연결할 이전 블록을 정하여 이를 자신이 알고 있는 주변 노드 중 노드의 가치가 높은 g개 이상의 노드들에게 동의 요청(agreement request)를 송신한다. 이때, 트랜젝션 처리는, 해시 체인의 연결 상태에 따라 처리순서가 결정됨이 바람직하다.In other words, the size of the group

In this case, the group leader determines the processing order of the transaction collected by him and the previous block to be connected, and sends an agreement request to at least g nodes with high node value among neighboring nodes that he knows about. In this case, it is preferable that the order of transaction processing is determined according to the connection state of the hash chain.

Accordingly, nodes that have received a request for consent for transaction processing check the information on the transaction, transaction processing order, and previous block, and there is no particular problem, and if they have not already responded to the consent request to other nodes, they agree (agreement). Is transmitted to the leader node of the group constituting the node chain.

The leader node finally generates a block by attaching the digital signature generated by the group to the block (S240). That is, the leader node generates a block containing the group's proof by collecting g agreements. At this time, the generated block can be set to complete distribution to all nodes on the blockchain network by e time of the next time slot. That is, the time unit for setting as the leader node of the node chain can be viewed as a time during which a message can be transmitted from at least all source nodes to all sink nodes.

3(a) and 3(b) are reference diagrams for explaining a scenario in which a leader node of a group on a blockchain is elected according to an embodiment of the present invention.

Referring to FIG. 3(a), the case of becoming the leader node of the group will be described. Nodes 310, 320, and 330, which are nodes without an incoming connection (in-edge), become source nodes, and are based on their own node value. Sends a message to an out-edge node with an outgoing connection. For example, node 310 transmits a reader request message'E_LEADER(A:40)' including its node identification information A and its node value 40 to the out-edge node, and node 330 also sends node identification information. Sends a reader request message'E_LEADER(C:20)' including C and its node value of 20 to the out-edge node. At this time, the node 320 may transmit the leader abandon message'E_GIVEUP(B:30)' even though the node value is at a level at which the node value can be selected as the leader node.

Accordingly, node 340, which is an intermediate node, receives'E_LEADER(A:40)' and'E_GIVEUP(B:30)', and selects'E_LEADER(A:40)', which has the high value of the node, and It transmits to the connected out-edge node.

However, node 350, which is an intermediate node, transmits a leader abandon message in case of B among'E_LEADER(C:20)' and'E_GIVEUP(B:30)'. )'to transmit to the out-edge node connected to node 350.

Node 360 receives'E_LEADER(A:40)' and'E_LEADER(C:20)', but selects node 310 with a node ID of A, which has a high node value, as the source node. Since node 360 is a sink node with no outgoing connection, it does not transmit'E_LEADER(A:40)', but needs to transmit a rejection message for'E_LEADER(C:20)' to node 350.

Referring to FIG. 3(b) to explain a scenario in which the rejection message is propagated, the node 360 sends the rejection message'E_REJECT(A:40, C) including the node ID and the node value of the source node to the node 350, which is an incoming connection to itself. :20)', and node 350 sends'E_REJECT(A:40, C:20)' to node 330.

Accordingly, a group of node chains in which node 310 is set as a leader node is created.

4 is a reference diagram for explaining a case of obtaining consent for group authentication according to an embodiment of the present invention. Nodes having five roles may exist in the scenario according to FIG. 4.

The group leader 410 transmits a leader request message and does not receive a reject message for this, thereby indicating a node set as a leader node of the group.

A competitor 420 transmits a leader request message to become a group leader, but receives a reject message for this, indicating a node that is not set as a leader node.

The group member 430 is a cooperative node that has set 410 as a leader node by receiving a leader request message from the group leader, and constitutes a node chain.

An active node (440) is defined as a node that has received a reader request message, but has not set 410 as a leader node for some reason. That is, in the present invention, since a plurality of chains can be set, there are nodes that require distribution of the generated blocks even if they are not group members.

A dead node (450) is defined as a node that exists on the blockchain network, but cannot send messages or blocks.

When the time slot starts, the group leader 410 and the competitor 420 transmit a leader request message to form a group (S401). At this time, the leader request message is transmitted to the group member 430 and the active node 440, but the leader request message is not transmitted to the dead node 450, or even if it is transmitted, the related operation is not performed.

When the group member 430 and the active node 440 receive the leader request message from the group leader 410 and the competitor 420, since the node value of the group leader 410 is higher, a reject message is transmitted to the competitor 420 (S403). Since the competitor 420 receives the rejection message, it plays a role as a cooperating node as a member of the group, and the group leader 410 is set as the leader node because it does not receive the rejection message within a preset time unit e.

Group leader 410 transmits an agreement request to group members 420 and 430 to create and process transactions, but request consent to active node 440 that is not set as a group member for some reason even if it does not send a rejection message. Do not transmit. Group members 420 and 430 check information on the transaction and transmit an agreement to the group leader 410.

When the group leader 410 obtains consent from the group members 420 and 430, the group leader 410 generates and distributes a block attached with a digital signature including a group proof for the transaction (S407).

The created block needs to be distributed to not only 420, 430, which are members of the group constituting the node chain, but also to all nodes on the blockchain network, so it must be distributed to 440, which is a preset time unit from the start of the next time slot. Distribution is completed until e elapses.

The embodiments described above may be implemented as a hardware component, a software component, and/or a combination of a hardware component and a software component. For example, the display devices, methods, and components described in the embodiments include, for example, a processor, a controller, a central processing unit (CPU), a graphics processing unit (GPU), and ALU (arithmetic logic unit), digital signal processor (digital signal processor), microcomputer, field programmable gate array (FPGA), programmable logic unit (PLU), microprocessor, Application Specific Integrated Circuits (ASICS), or It may be implemented using one or more general purpose computers or special purpose computers, such as any other display device capable of executing and responding to instructions.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiment, or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -A hardware display device specially configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The above-described hardware display device may be configured to operate as one or more software modules to perform an input of an embodiment, and vice versa.

As described above, although the embodiments have been described by the limited drawings, various modifications and variations are possible from the above description to those of ordinary skill in the art. For example, the described techniques are performed in a different order from the described method, and/or components such as the described system, structure, display device, circuit, etc. are combined or combined in a form different from the described method, or have different configurations. Appropriate results can be achieved even if substituted or substituted by elements or equivalents. Therefore, other implementations, other embodiments, and those equivalent to the claims also fall within the scope of the claims to be described later.

Blockchain network configuration method and apparatus as described above can be applied to various network industry fields.

Claims (6)

In the method of generating group proof for a blockchain network based on a peer to peer network,
Generating a node chain composed of a plurality of nodes by a first node based on a node value according to a block height on the block chain network;
Transmitting, by the first node, an agreement request for processing a transaction to second nodes of a group constituting the node chain; And
When the first node obtains consent corresponding to the consent request from the second nodes, the first node generating a block including a proof of the group for the transaction, and ,
The node value is determined as a smaller value among a value obtained by multiplying a value measurement function by a participation frequency weight and a risk reputation through the following equation.

How to create a group proof.

: The value of the i-th node at the block height h

: Value measurement function,

: Participation frequency weight,

: Risk reputation The method of claim 1,
The node chain,
For each time slot for generating the block, it characterized in that it is reconstructed based on the node value,
How to create a group proof. The method of claim 2,
The step of creating the node chain,
Transmitting, by the first node, a leader request message or a leader abandon message of the group to at least one out-edge node connected to the first node, based on the node value of the first node ; And
In the case where the first node does not receive a rejection message opposed to the leader request message within a preset time unit to be smaller than the time slot, setting the first node as a leader node of the group,
How to create a group proof. The method of claim 3,
The second nodes,
When the consent request is received, the consent determined based on the processing order for the transaction processing and a previous block to be connected to the generated block is provided only when the consent request is not already responded within the time slot. Characterized in that it is configured to transmit to the first node,
How to create a group proof. The method of claim 3,
The block,
Before the preset time unit elapses from the start time of the next time slot of the time slot, the distribution is set to be completed,
How to create a group proof. The method of claim 2,
The node chain,
Characterized in that it has a DAG (Directed Acyclic Graph) structure,
How to create a group proof.

Images