区块链政务共识机制是什么,区块链政务共识机制有哪些

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① The specific manifestations of the significance of blockchain in improving public services

The specific manifestations of the significance of blockchain in improving public services are as follows.
1. Improve the robustness of the public service system. The decentralized network architecture of the blockchain has strong anti-attack capabilities. The government data on the chain is distributed and stored. Even if some nodes fail, backups can still be read from other nodes. The consensus mechanism and timestamp design of the blockchain , effectively avoiding the risk of third-party tampering.
2. Reduce public service operating costs. Data on-chain can help reduce the later maintenance costs of public service systems, and building a chained system can help reduce institutional transaction costs incurred in providing public services.
3. Expand the coverage of public service supply. Blockchain technology will rapidly expand the providers and participants of public services, and gradually form network-based governance and services, promote direct mutual assistance and interaction between citizens, and even complete administrative management and public services without a public administrator. project, thereby further improving the precise matching between the supply and demand of public services, promoting the diversification of service entities, intelligent service methods, precise service content, and closed-loop service management.

② Consensus mechanism of blockchain

1. The goal of consensus mechanism of blockchain

What is blockchain? Simply put, blockchain is a decentralized database, or it can be called a distributed ledger. Traditionally, all databases are centralized. For example, a bank's ledger is stored in the bank's central server. The disadvantage of a centralized database is that the security and accuracy of the data depend entirely on the database operator (i.e., the bank), because anyone who has access to the centralized database (such as bank employees or hackers) can destroy or modify the data in it.

Blockchain technology allows databases to be stored on thousands of computers around the world. Everyone’s ledger is synchronized through a peer-to-peer network, and anyone in the network can Once a user adds a transaction, the transaction information will be notified to other users through the network for verification and recorded in their respective ledgers. Blockchain gets its name because it is a data structure composed of blocks containing transaction information linked in an orderly manner from back to front.

Many people’s question about blockchain is that if each user has an independent ledger, does it mean that they can add to their own ledger? Arbitrary transaction information, and how can thousands of ledgers ensure the consistency of accounting? Solving the problem of accounting consistency is the goal of the blockchain consensus mechanism. The blockchain consensus mechanism aims to ensure that the data in all nodes in the distributed system are exactly the same and can reach agreement on a certain proposal (for example, a transaction record). However, due to the introduction of multiple nodes in a distributed system, various very complex situations will occur in the system; asAs the number of nodes increases, node failure or malfunction, network communication between nodes is interfered or even blocked, etc. have become common problems. Solving various boundary conditions and unexpected situations in distributed systems also increases the difficulty of solving distributed consistency problems. Difficulty of sexual issues.

Blockchain can be divided into three types:

Public chain: full Anyone in the world can enter the system at any time to read data, send confirmed transactions, and compete for accounting in the blockchain. Public blockchains are generally considered "completely decentralized" because no one or institution can control or tamper with the reading and writing of data. Public chains generally encourage participants to compete for accounting through a token mechanism to ensure data security.

Alliance chain: Alliance chain refers to a blockchain in which several institutions jointly participate in management. Each institution runs one or more nodes, and the data in it only allows different institutions within the system to read, write and send transactions, and jointly record transaction data. This type of blockchain is considered “partially decentralized.”

Private chain: refers to a blockchain whose write permission is controlled by an organization or institution. The qualifications of participating nodes will be strictly restricted. Since the participating nodes are limited and controllable, private chains can often have extremely fast transaction speeds, better privacy protection, lower transaction costs, and are not prone to malicious attacks. , and can meet the necessary requirements of the financial industry such as identity authentication. Compared with centralized databases, private chains can prevent single nodes within an organization from deliberately concealing or tampering with data. Even if an error occurs, the source can be quickly discovered, so many large financial institutions are currently more inclined to use private chain technology.

2. Classification of blockchain consensus mechanisms

The difficulty of solving distributed consistency problems has given rise to several consensus mechanisms, each of which has its own advantages and disadvantages, and is also suitable for different environment and issues. The consensus mechanisms that are common knowledge include:

l PoW (Proof of Work) workload proof mechanism

l PoS (Proof of Stake) ) Equity/Equity Proof Mechanism

l DPoS (Delegated Proof of Stake) Share Authorization Proof Mechanism

l PBFT (Practical Byzantine Fault Tolerance) Practical Byzantine Fault Tolerance Algorithm

l DBFT (Delegated Byzantine Fault Tolerance) authorized Byzantine fault tolerance algorithm

l SCP (StellarConsensus Protocol ) Stellar Consensus Protocol

l RPCA (Ripple Protocol Consensus Algorithm) Ripple Consensus Algorithm

l Pool Verification Pool Consensus Mechanism

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(1) PoW (Proof of Work) workload proof mechanism

1. Basic introduction

In this mechanism, every node on the network is using the SHA256 hash function to calculate the hash sum of a constantly changing block header. Consensus requires that the calculated value must be equal to or less than a given value. In a distributed network, all participants need to continuously calculate the hash value using different random numbers until the goal is reached. When one node calculates an exact value, all other nodes must confirm with each other that the value is correct. Transactions in new blocks will then be verified to prevent fraud.

In Bitcoin, the above nodes that calculate hash values ​​are called "miners", and the PoW process is called "mining". Mining is a time-consuming process, so incentives have been proposed (such as granting miners a small share of Bitcoin). The advantage of PoW is complete decentralization, but its disadvantage is the waste of resources caused by consuming a lot of computing power, the cycle of reaching consensus is also relatively long, and the consensus efficiency is low, so it is not very suitable for commercial use.

2. Application examples of cryptocurrency

Bitcoin and Litecoin. The first three phases of Ethereum (Frontier, Homestead, and Metropolis) all adopt the PoW mechanism, and its fourth phase (Serenity) will adopt the proof-of-stake mechanism. PoW is suitable for public chains.

Although the PoW mechanism has successfully proved its long-term stability and relative fairness, under the existing framework, using the "mining" form of PoW will consume A lot of energy. The energy it consumes is just to continuously perform SHA256 calculations to ensure fair workload, and has no other meaning of existence. The current transaction efficiency that BTC can achieve is about 5TPS (5 transactions/second). Ethereum is currently subject to the upper limit of the total GAS amount in a single block. The transactions that can be achievedThe frequency is about 25TPS, which is far different from VISA and MASTERCARD whose average processing efficiency is one thousand times per second and peak value can reach ten thousand times per second.

3. Simple diagram understanding mode

(ps: The process of calculating hash values ​​by A, B, C, and D is "mining". In order to reward the time cost, the mechanism will use a certain number of Bitcoins as incentives.)

(Ps: In PoS mode, your "mining" income is proportional to the age of your currency (number of coins * number of days), and has nothing to do with the computing performance of the computer. We can think that the accumulation of any probabilistic events is proof of work, such as gold mining. Assuming that the gold content of ore is p% mass, when you get a certain amount of gold, we can think that you must have dug 1/p mass of ore. And The more gold you get, the more reliable the proof is.)

(2) PoS (Proof of Stake) equity/stake proof mechanism

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1. Basic introduction

PoS requires people to prove their ownership of the currency amount, and they believe that they have more currency people are less likely to attack the network. Selection based on account balance is very unfair, as the single richest person is bound to dominate the network, so many solutions have been proposed.

In the proof-of-stake mechanism, whenever a block is created, miners need to create a transaction called "coin rights", which will be determined according to a certain Proportionately sends some coins to miners in advance. Then the equity proof mechanism reduces the mining difficulty of nodes in equal proportions based on the proportion and time of tokens held by each node (coin age) according to the algorithm, so as to speed up the node's search for random numbers and shorten the time required to reach consensus.

Compared with PoW, PoS can save more energy and be more efficient. But since the mining cost is close to 0, it may be vulnerable to attacks. And PoS still essentially requires nodes in the network to perform mining operations, so it is also difficult to apply in the commercial field.

2. Application examples of digital currency

The more mature digital currencies under the PoS mechanism are Peercoin and NXT. Compared with PoW, the PoS mechanism is moreIt saves energy and introduces the concept of "coin days" to participate in random operations. The PoS mechanism allows more currency holders to participate in the accounting work without the need to purchase additional equipment (mining machines, graphics cards, etc.). The computing power of each unit token is positively related to the length of time it is held. That is, the more tokens a holder holds and the longer the time, the greater the probability that the holder can sign and produce the next block. Once it signs the next block, the currency days held by the currency holder will be cleared and a new cycle will be re-entered.

PoS is suitable for public chains.

3. How to generate block signers

Under the PoS mechanism, Because the signers of blocks are randomly generated, some currency holders will hold tokens for a long time and in large amounts to obtain a greater probability of generating blocks, and to clear as many of their "coin days" as possible. Therefore, the number of circulating tokens in the entire network will decrease, which is not conducive to the circulation of tokens on the chain, and prices will be more susceptible to fluctuations. Since there may be a small number of large investors holding most of the tokens in the entire network, the entire network may become more and more centralized as the running time increases. Compared with PoW, the cost of doing evil under the PoS mechanism is very low, so for forking or double-spending attacks, more mechanisms are needed to ensure consensus. Under stable conditions, approximately 12 transactions can be generated per second, but due to network delays and consensus issues, it takes about 60 seconds to fully broadcast the consensus block. In the long run, the speed of generating blocks (that is, clearing "coin days") is much lower than the speed of network propagation and broadcasting. Therefore, under the PoS mechanism, it is necessary to "limit the speed" of generated blocks to ensure the stability of the main network. run.

4. Simple diagram understanding mode

(PS: The more “shares” you own, the easier it is for you to obtain account rights. It refers to how much currency you get, which depends on the workload you contribute to mining and the performance of your computer. The better, the more mines will be allocated to you.)

(In a pure POS system, such as NXT, there is no mining process, and the initial equity The distribution has been fixed, and then only the equity is transferred among traders, very similar to stocks in the real world.)

(3) DPoS (Delegated Proof of Stake) ) Share authorization certification mechanism

1. Basic introduction

Due to PoSDue to various shortcomings, DPoS (Delegated Proof of Stake), the first equity representation mechanism pioneered by BitShares, came into being. The core element of the DPoS mechanism is election. Holders of each system's native tokens can participate in elections in the blockchain, and the balance of the tokens they hold is the voting weight. Through voting, shareholders can elect board members and express their attitudes on issues related to the development direction of the platform, all of which form the basis of community autonomy. In addition to voting in elections themselves, shareholders can also vote on their behalf by authorizing their election votes to other accounts they trust.

Specifically, DPoS was invented by the Bitshares project team. Stakeholders elect their representatives to generate and verify blocks. DPoS is similar to a modern corporate board of directors system. The BitShares system calls token holders shareholders, and shareholders vote to elect 101 representatives. These representatives are then responsible for generating and verifying blocks. If a currency holder wants to be called a representative, he must first use his public key to register on the blockchain and obtain a unique 32-bit identity identifier. Shareholders can vote on this identifier in the form of transactions and get votes. The top 101 people were selected as representatives.

Representatives take turns to generate blocks, and the profits (transaction fees) are equally divided. The advantage of DPoS is that it greatly reduces the number of nodes participating in block verification and accounting, thereby shortening the time required for consensus verification and greatly improving transaction efficiency. From a certain perspective, DPoS can be understood as a polycentric system, which has the advantages of both decentralization and centralization. Advantages: It greatly reduces the number of nodes participating in verification and accounting, and can achieve second-level consensus verification. Disadvantages: Voting enthusiasm is not high, and most token holders do not participate in voting; in addition, the entire consensus mechanism still relies on tokens, and many commercial applications do not require the existence of tokens.

The DPoS mechanism requires that before generating the next block, it must be verified that the previous block has been signed by a trusted node. Compared with PoS's "National Mining", DPoS uses a system similar to the "Congress" to directly select trusted nodes, and these trusted nodes (i.e. witnesses) exercise power on behalf of other currency holders. Witnesses Nodes are required to be online for a long time, thus solving a series of problems such as delays in block production that may be caused by PoS block signers not always being online. The DPoS mechanism can usually reach a transaction speed of 10,000 transactions per second, and can reach the level of 100,000 seconds when the network delay is low, which is very suitable for enterprise-level applications. Because Gongxinbao Data Exchange has high requirements for data transaction frequency and long-term stability, DPoS is a very good choice.

2. Institutions and systems under the share authorization certification mechanism

The board of directors is the authority of the blockchain network. The candidates for the board of directors are selected by system shareholders (i.e. currency holders). (person) is elected, and members of the Board of Directors have the right to initiate motions and vote on motions.

One of the important responsibilities of the Board of Directors is to adjust the variable parameters of the system as needed. These parameters include:

l Fee related: rates for various transaction types.

l Authorization related: parameters related to charges and subsidies for third-party platforms that access the network.

l Block production related: block production interval, block reward.

l Identity review related: review and verify the information of abnormal institutional accounts.

l At the same time, matters related to the interests of the Board of Directors will not be set by the Board of Directors.

In the Finchain system, witnesses are responsible for collecting various transactions broadcast when the network is running and packaging them into blocks. Their work is similar to that of the Bitcoin network In the Bitcoin network that adopts PoW (Proof of Work), a lottery method in which the probability of winning depends on the hash power determines which miner node generates the next block. In a financial chain network that adopts the DPoS mechanism, the number of witnesses is determined by voting by the board of directors, and the candidates for the witnesses are determined by voting by currency holders. The selected active witnesses package transactions and produce blocks in order. After each round of block production, the witnesses will randomly shuffle the cards to determine the new order before entering the next round of block production.

3. Application examples of DPoS

Bitshares uses DPoS. DPoS is mainly suitable for alliance chains.

4. Simple diagram understanding mode

(4) PBFT (Practical Byzantine Fault Tolerance) Practical Byzantine Fault Tolerance Algorithm

1. Basic introduction

PBFT is an algorithm based on strict mathematical proof, which requires three stages of information interaction and local consensus to achieve the final unanimous output. three levelsThe segments are pre-prepare, prepare, and commit. The PBFT algorithm proves that as long as there are more than 2/3 normal nodes in the system, it can ensure that a consistent consensus result can be output in the end. In other words, in a system using the PBFT algorithm, it can tolerate no more than 1/3 of the total number of nodes in the system (including nodes that intentionally mislead, intentionally damage the system, time out, repeatedly send messages, forge signatures, etc., also known as " Byzantium" node).

2. Application examples of PBFT

The famous alliance chain Hyperledger Fabric v0.6 uses PBFT, and v1.0 launched an improved version of PBFT, SBFT. PBFT is mainly suitable for private chains and consortium chains.

3. Simple diagram understanding mode

The above figure shows a simplified PBFT protocol communication model, where C is the client, 0 – 3 represents the service node, where 0 is the master node and 3 is the fault node . The basic process of the entire protocol is as follows:

(1) The client sends a request to activate the service operation of the master node;

(2) When the master node receives the request, it starts a three-phase protocol to broadcast the request to each slave node;

(a) Sequence number allocation phase, the master node assigns a sequence number n to the request, broadcasts the sequence number allocation message and the client's request message m, and will construct a pre-prepare message to each slave node;

(b) In the interaction phase, the slave node receives the pre-prepare message and broadcasts the prepare message to other service nodes;

(c) In the sequence number confirmation phase, after each node verifies the request and sequence in the view, it broadcasts the commit message, executes the received client request and responds to the client.

(3) The client waits for responses from different nodes. If m+1 responses are the same, the response is the result of the operation;

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(5) DBFT (Delegated Byzantine Fault Tolerance) authorized Byzantine fault tolerance algorithm

1. baseThis introduction

DBFT is based on PBFT. In this mechanism, there are two types of participants, one is the "super node" who specializes in accounting , one is an ordinary user in the system who does not participate in accounting. Ordinary users vote for super nodes based on the proportion of their equity holdings. When a consensus (accounting) needs to be passed, a spokesperson is randomly selected among these super nodes to formulate a plan, and then other super nodes use Byzantine fault tolerance to algorithm (see above), that is, the principle of majority submission. If more than 2/3 of the super nodes agree with the speaker plan, a consensus is reached. This proposal becomes the final published block, and the block is irreversible, and all transactions in it are 100% confirmed. If a consensus proposal has not been reached within a certain period of time, or if illegal transactions are discovered, other super nodes can reinitiate the proposal and repeat the voting process until a consensus is reached.

2. Application examples of DBFT

NEO, a domestic cryptocurrency and blockchain platform, is the developer and adopter of the DBFT algorithm.

3. Simple diagram understanding mode

Assume that there are only four super nodes in the system voted by ordinary users. When a consensus needs to be passed, the system will randomly select one of the representatives to speak. People make plans. The spokesperson will hand over the prepared plan to each representative. Each representative will first determine whether the speaker's calculation results are consistent with their own records, and then discuss with other representatives to verify whether the calculation results are correct. If 2/3 of the representatives unanimously agree that the calculation results of the speaker's plan are correct, then the plan is passed.

If less than 2/3 of the representatives reach a consensus, a new speaker will be randomly selected and the above process will be repeated. This system is designed to protect the system from leaders who are unable to function.

The above figure assumes that all nodes are honest and reach 100% consensus, and plan A (block) will be verified.

Given that the spokesperson is a randomly selected representative, he may be dishonest or malfunctioning . The above figure assumes that the spokesperson sends malicious messages to 2 of the 3 representatives (scenario B), and at the same time sends a correct message to 1 representative (scenario A).

In this case the malicious information (Option B) cannot pass. The calculation results of the representatives in the middle and on the right were inconsistent with those sent by the spokesperson, so they could not verify the plan drawn up by the spokesperson, causing the two people to reject the plan. The representative on the left received correct information that was consistent with his own calculation results, so he was able to confirm the plan and successfully completed a verification. However, this plan still failed to pass because less than 2/3 of the representatives reached a consensus. A new spokesperson will then be randomly selected and the consensus process will begin again.

The above picture assumes that the speaker is honest, but One of the representatives experienced an anomaly; the representative on the right sent incorrect information to the other representatives (B).

In this case, the correct information (A) formulated by the speaker can still be verified, because both the honest representatives on the left and the middle can verify that the correct information (A) formulated by the spokesperson The plan drawn up by the spokesperson reached a 2/3 consensus. The representative can also determine whether the speaker is lying to the node on the right or the node on the right is being dishonest.

(6) SCP (Stellar Consensus Protocol) Stellar Consensus Protocol

1. Basic introduction

SCP is a consensus algorithm developed and used by Stellar (a decentralized global payment protocol based on the Internet). It is based on the Federated Byzantine Agreement ( Federated Byzantine Agreement). Although traditional non-federated Byzantine protocols (such as PBFT and DBFT above) ensure that consensus can be reached through distributed methods and achieve Byzantine fault tolerance (can tolerate at most failed nodes that do not exceed 1/3 of the total number of nodes in the system), it is a Centralized system - The number and identity of nodes in the network must be known and verified in advance. The difference of the Federated Byzantine Agreement is that it can be decentralized and Byzantine fault-tolerant at the same time.

[…]

(7) RPCA (Ripple Protocol Consensus Algorithm) Ripple Consensus algorithm

1. Basic introduction

RPCA is Ripple (a baseAn open source payment protocol based on the Internet that can realize decentralized currency exchange, payment and settlement functions) consensus algorithm developed and used. In Ripple's network, transactions are initiated by the client (application) and broadcast to the entire network through the tracking node or validating node. The main function of the tracking node is to distribute transaction information and respond to client ledger requests. In addition to all the functions of the tracking node, the verification node can also add new ledger instance data to the ledger through the consensus protocol.

Ripple's consensus occurs between verification nodes. Each verification node is pre-configured with a list of trusted nodes, called UNL (Unique Node). List). Nodes on the list can vote on the transaction. The consensus process is as follows:

(1) Each verification node will continuously receive transactions sent from the network. After verification with the local ledger data, they are illegal. The transactions will be discarded directly, and the legal transactions will be summarized into a transaction candidate set (candidate set). The transaction candidate set also includes transactions left over from the previous consensus process that could not be confirmed.

(2) Each verification node sends its own transaction candidate set as a proposal to other verification nodes.

(3) After the verification node receives a proposal from other nodes, if it is not from a node on UNL, it will ignore the proposal; if it is from a node on UNL, it will compare it with the proposal. Transaction and local transaction candidate set, if there is the same transaction, the transaction gets one vote. Within a certain period of time, when a transaction receives more than 50% of the votes, the transaction enters the next round. Transactions that do not exceed 50% will be left for the next consensus process to be confirmed.

(4) The verification node sends transactions with more than 50% of the votes as proposals to other nodes, and at the same time increases the threshold of the required votes to 60%, repeating steps (3) and (4) until the threshold Reach 80%.

(5) The verification node formally writes the transactions confirmed by 80% UNL nodes into the local ledger data, which is called the last closed ledger, which is the last (latest) status of the ledger.

In Ripple's consensus algorithm, the identities of participating voting nodes are known in advance. Therefore, the algorithm is more efficient than anonymous consensus algorithms such as PoW. Transactions The confirmation time only takes a few seconds. This also determines that the consensus algorithm is only suitable for alliance chains or private chains. The Byzantine Fault Tolerance (BFT) capability of the Ripple consensus algorithm is (n-1)/5, which means it can tolerate 20% of the nodes in the entire network becoming Byzantine.Tribunal error without affecting the correct consensus.

2. Simple diagram understanding mode

Schematic diagram of node interaction in the consensus process:

Consensus algorithm process:

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(8) POOL verification pool consensus mechanism

Pool verification pool The consensus mechanism is a mechanism developed based on traditional distributed consensus algorithms (Paxos and Raft). The Paxos algorithm is a consensus algorithm based on message passing and highly fault-tolerant proposed in 1990. In the past, Paxos has been the standard for distributed protocols, but Paxos is difficult to understand and even more difficult to implement. Raft is a consensus algorithm released in 2013 that is simpler than Paxos and can realize the problems solved by Paxos. The process of reaching consensus in Paxos and Raft is like an election. Candidates need to convince the majority of voters (servers) to vote for them and follow their actions once selected. The difference between Paxos and Raft lies in the specific process of election. The Pool verification pool consensus mechanism is based on these two mature distributed consensus algorithms, supplemented by a data verification mechanism.

③ Consensus mechanism of blockchain

1. How to confirm and reach consensus on transaction information on the network?

Although the consensus mechanism is often mentioned, the meaning and understanding of the consensus mechanism are not clear. Therefore, it is necessary to understand the relevant concepts, principles and implementation methods of the consensus mechanism.

The transaction information of the blockchain is transmitted to each node in the network through network broadcast. How to confirm the broadcast information and reach a consensus among the entire network nodes and finally write it into the block? If there is no corresponding reliable and secure implementation mechanism, it will be difficult to realize its basic functions. Therefore, the consensus mechanism is a key to the operation of the entire network.

The consensus mechanism solves the problem of how the blockchain can achieve consistency in a distributed scenario. The blockchain can reach a relatively balanced state among many nodes because of the consensus mechanism. So how does the consensus mechanism fit into the idea of ​​decentralization?Do you want to solve the problem of mutual trust between nodes?

When the idea of ​​distribution was proposed, people began to design consensus algorithms based on the FLP theorem and the CAP theorem. Standardly speaking, the consistency of an ideal distributed system should meet the following three points:

1. Termination: The consistency result can be completed within a limited time.

2. Consensus: The final decision-making results of different nodes should be the same.

3. Validity: The result of the decision must be a proposal put forward by other processes.

However, in actual computer clusters, the following problems may exist:

1. Nodes have different transaction processing capabilities, and the data throughput of network nodes is different

2. The communication channel between nodes may be unsafe

3. There may be malicious nodes

4. When asynchronous processing capabilities reach a high degree of consistency, The scalability of the system will become worse (cannot tolerate the addition of new nodes).

Scientists believe that it is impossible to achieve complete consistency in a distributed scenario. However, engineers can sacrifice part of the cost in exchange for the consistency of distributed scenarios. The above two major theorems also have this idea. Therefore, various formula mechanisms based on blockchain design can be regarded as sacrificing part of the cost in exchange for more adaptability. My idea is to make a flexible transformation on this idea, that is, sacrificing part of the cost at the appropriate time and space in exchange for consistency adapted to the scene at that time, and a flexible blockchain system can be realized that is pluggable. Pull-out blockchain system. Today I will introduce my views and analysis on various consensus mechanisms. Distributed systems with or without malicious nodes are divided into Byzantine fault-tolerant and non-Byzantine fault-tolerant mechanisms.

The FLP theorem is the impossibility of FLP. It proves that in a distributed scenario, no matter any algorithm, even if only one process hangs up, there is an inability to reach consensus for other non-failed processes. possible.

FLP is based on the following assumptions:

Can only be modified once: Each process initially records a value (0 or 1). The process can receive messages, change the value, and send messages. When the process enters the decide state, the value will no longer change. The protocol ends successfully when all non-failed processes enter the decided state. This is relaxed to the extent that some processes enter the decided state, even if the agreement is successful.

Asynchronous communication:  The biggest difference from synchronous communication is that there is no clock, no time synchronization, no timeout, no failure detection, messages can be delayed arbitrarily, and messages can be out of order.

Communication is robust: As long as the process does not fail, the message will be delayed indefinitely, but will eventually be delivered; and the message will only be delivered once (no duplication).

Fail-Stop model: A process failure is like a downtime and no more messages are processed.

Number of failed processes: At most one process fails.

CAP is the most discussed theory in distributed systems, especially in the field of distributed storage. CAP was proposed by Eric Brewer at the PODC meeting in 2000. It was a result of Eric Brewer's research on data consistency (consistency), service availability (availability), and partition fault tolerance (partition- tolerance) conjecture:

Data consistency (consistency): If the system returns success for a write operation, then subsequent read requests must read the new data; if the system returns failure, then all read operations No one can read this data. For the caller, the data has strong consistency (also called atomic and linearizable consistency) [5]

Service availability (availability) : All read and write requests are responded to within a certain period of time, can be terminated, and will not wait forever

Partition-tolerance: In the case of network partitions, the separated nodes can still function normally External services

If AP is satisfied at a certain moment, the separated nodes can provide external services at the same time but cannot communicate with each other, which will lead to inconsistent status, that is, C cannot be satisfied; if CP is satisfied, C will not be achieved in the case of network partitions , the request can only wait forever, that is, A is not satisfied; if CA is to be satisfied, the node status must be consistent within a certain period of time, and network partitions cannot occur, so P cannot be satisfied.

C, A, and P can only satisfy at most two of them. Like the FLP theorem, the CAP theorem also indicates an unreachable result (impossibility result).

④ Blockchain consensus mechanism

The so-called "consensus mechanism" is to complete the verification and confirmation of transactions in a very short time through the voting of special nodes; A transaction, if several nodes with unrelated interests canIf we can reach a consensus, we can think that the entire network can also reach a consensus on this. Beijing Muqi Mobile Technology Co., Ltd., a professional blockchain outsourcing development company, welcomes discussions for cooperation. Below we will look at several consensus mechanisms of blockchain, hoping to help everyone understand the basic technology of blockchain.

Due to the development of blockchain technology, everyone is no longer unfamiliar with the term consensus mechanism. With the development of technology, various innovative consensus mechanisms are also developing.

POW proof of work

Bitcoin uses the PoW proof of work mechanism, and later Ethereum used the PoW consensus mechanism. Pow is equivalent to calculating a difficult mathematical problem, which is to calculate the hash value of a new block, and the difficulty of the calculation will be adjusted every period of time. Although PoW is a consensus mechanism that is relatively recognized by everyone, calculations will consume a lot of energy and may pollute the environment.

POS Equity Proof

The probability of obtaining accounting rights is determined by the number and duration of holding Tokens. Compared with POW, POS avoids a large amount of resource waste caused by mining and shortens the time for each node to reach consensus. If the network environment is good, it can be achieved in milliseconds and has low requirements on node performance.

However, the shortcomings of POS are also obvious. Nodes holding more Tokens have a greater chance of obtaining accounting rights. This will lead to the "Matthew Effect", where the rich will get richer, destroying the decentralization of the blockchain. Centralization.

DPOS Proof of Equity

The principle of DPOS Delegated Proof of Equity is the same as that of POS. The main difference is that DPOS Token holders can vote to elect agents as super nodes, responsible for Produce blocks and maintain consensus rules on the network. If these nodes fail to perform their duties, new nodes will be voted in. The same disadvantage also tends to be centralized.

POA Proof of Authority

POA nodes can reach consensus without communication, so it is extremely efficient. And it can also resist computing power attacks very well and has high security. But POA requires a centralized authoritative node to verify identity, which means it will harm the decentralization of the blockchain, which is also a compromise between decentralization and improved efficiency.

⑤ What exactly is blockchain

Let’s talk about some basic concepts first.

The network said that blockchain is a new usage model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanisms, and encryption algorithms. It is essentially a decentralized database, and as the underlying technology of Bitcoin, it is a series of data blocks generated by cryptography.

We try to translate "what is blockchain" into "human language".

The definition refers to the "decentralized database" nature of blockchain3354. This is related to the legendTraditional "centralized databases" are very different in storage, update and operation.

A centralized database can be thought of as having this shape:

For example, if I want to use Alipay to pay a Taobao seller, all data requests from when I make money to when he receives the money will be centrally processed by Alipay. The advantage of this data structure is that as long as Alipay is responsible for the efficient and safe operation of the system, others can unconditionally believe it without worrying; the disadvantage is that if there is a problem with Alipay, such as being hacked, the server being burned, a traitor appearing, and the company running away (Of course, the possibility of the above is extremely low), the balance details and other information in our Alipay will be confused.

Then some people think that this kind of low-probability event can use any technical means to avoid individual risks, and not only hand over the data to a centralized organization. For example, everyone can store and process data.

The database structure may look like this:

This picture is a schematic structural diagram of a "distributed database". Each point is a server, they all have equal rights to record and calculate data, and information is spread point-to-point. At first glance, it seems that it can indeed resist the risk caused by the crash of a certain node, but it is also very confusing and inefficient intuitively. Who will handle my information, and who has the final say on the outcome?

At this time, the "consensus mechanism" in the definition of blockchain comes into play. The consensus mechanism mainly "stipulates" the following things: who will process a data request (what qualifications are required); who will verify the results (to see if he has handled it well); how to prevent processors and verifiers from colluding with each other, etc.

Some people may like to be questioned when a "rule" is made. In order to form a stronger consensus, in addition to making the rules more reasonable, they must also be more attractive so that people are interested and motivated to participate in data processing. This involves the incentive mechanism of the public chain. We will start again later when we discuss the classification of blockchain and the role of digital currencies.

When we hand over a transaction to a distributed network, there is also a "psychological threshold": there are so many nodes that can process information, and I don't know any of them (unlike Alipay, if it hurts me, I can go and file a lawsuit against it). They all have my data, why should I trust them?

At this time, encryption algorithm (the last descriptive word in the definition of blockchain) comes on stage.

In the blockchain network, the data requests we send will be encrypted according to cryptographic principles into a string of characters that the recipient cannot understand at all. Behind this encryption method is the support of a hash algorithm.

Hash algorithms can quickly convert any type of data into hash values. This change is one-way irreversible, deterministic, random, and anti-collision. Because of these characteristics, the person handling my data request could record the information for me, but they had no idea who I was or what I was doing.

So far, the working principle of the decentralized network has been introduced. But we seem to have overlooked one detail. The previous diagram is a net. Where are the pulleys and chains? Why do we call it blockchain?

To understand this matter, we need to clarify several knowledge points first:

The previous picture is actually a "macro" database perspective, showing the basic rules and processes of the blockchain system for processing information. And specifically at the "micro" data log level, we will find that the ledger is packaged, compressed, stored in blocks, and strung together in chronological order to form a "chain structure", like this:

Figure Each ring in can be regarded as a building block, and many links are linked together to form a blockchain. Blocks store data, unlike ordinary data storage: on a blockchain, the data in a later block contains the data in the previous block.

In order to academically explain the fields of each part of the data in the block, we tried to use a book metaphor to describe what a blockchain data structure is.

Usually, when we read a book, we read the first page, then the second and third pages. The spine is a physical existence that fixes the order of each page. Even if the book is scattered, the order of each numbered page can be determined.

Inside the blockchain, each block is labeled with a page number, the second page contains the first page's content, the third page's content contains the first and second page's content. The tenth page contains the previous Nine pages of content.

It is such a nested chain that can be traced back to the original data.

This brings up an important attribute of blockchain: traceability.

When the data in the blockchain needs to be updated, that is when new blocks are generated in sequence, the "consensus algorithm" comes into play again. This algorithm stipulates that a new block can only be formed if it is recognized by more than 51% of the nodes in the entire network. To put it bluntly, it is a matter of voting, and it can be elected if more than half of the people agree. This makes the data on the blockchain difficult to tamper with. If I were to force a change, there would be too many people to bribe and the cost would be too high to be worth it.

This is what people often call the "non-tamperable" feature of blockchain.

Another reason why blockchain gives people a sense of trust is because of "smart contracts."

Smart contracts are commitment agreements defined and automatically executed by computer programs. It is a set of transaction rules executed by code, similar to the current automatic repayment function of credit cards. If you turn on this function, you don’t have to worry about anything. The bank will automatically deduct the money you owe when it is due.

When your friend borrows money from you but doesn't remember to pay it back, or makes excuses not to pay it back, smart contracts can prevent breach of contract. Once the terms in the contract are triggered, such as when it is time to repay the money, or there is a limit in his account, the code will automatically execute, and the money he owes you will be automatically transferred back whether he wants it or not.

Let’s briefly summarize. Blockchain technology is mainly decentralized, difficult to tamper with, and traceable, which represents more security and trustlessness. But it also brings new problems: redundancy and inefficiency, which requires many nodes to agree with the rules and actively participate.

This concludes the "drying" section. Next, let’s talk about unofficial history and the official history of blockchain.

A new technology is often used to serve a certain task.

Or goals. So where was blockchain first used, and who came up with it first?

Let's go back to 2008.

On September 21, Wall Street investmentBanks have collapsed one after another, and the Federal Reserve announced that it will transform the only two remaining investment banks (Goldman Sachs Group and Morgan Stanley) into commercial banks; it hopes to survive the financial crisis by absorbing savings. On October 3, the Bush administration signed a $700 billion financial rescue package.

Twenty-eight days later, on November 1, 2008, a new post appeared in a cryptography mailing group: "I am developing a new electronic currency system that is completely peer-to-peer and does not require a third party. Three-party trust institution." The text of the post is a paper titled "Bitcoin: A Peer-to-Peer Electronic Cash System", signed by Satoshi Nakamoto.

The paper explains the design of this peer-to-peer electronic cash system with a more rigorous logic. It first discusses the problem that financial institutions are subject to "trust based" (based on credit), and then explains step by step how to achieve "no third-party agency" , and cleverly solved the technical problems left by the predecessors.

Two months later, Satoshi Nakamoto released the first version of the open source Bitcoin client and mined 50 Bitcoins for the first time. The block that generated the first batch of Bitcoins is called the "Genesis block". The genesis block was compiled into block 0 and was not uploaded to the chain. It took Satoshi Nakamoto 6 days to mine this block. This also sparked discussion in the bitcointalk forum. Bitcoin "believers" thought of the Bible, "God created the heavens and the earth in six days, and then rested on the seventh day."

Although concepts such as decentralized, token, and economy did not appear in the paper, Satoshi Nakamoto explained in detail the role of blocks and chains in the network. working principle. So, there is Block Chain.

This paper later became the "Bible" of the "Bit Cult", technology became the cornerstone of faith, and developer documentation became the "Code of Hammurabi".

After that, Bitcoin realized the first real-life payment by exchanging pizza, WikiLeaks, whose account was blocked by the US government, miraculously survived by relying on Bitcoin, Satoshi Nakamoto's "decentralization" and retirement, and the appearance of the real and the fake A series of legends such as and refutation of rumors, combined with the expectations, imagination and speculation of later generations, became "Bible stories".

There are also people who are not satisfied with the world described in the "Old Testament" and start new sects, write the doctrines into white papers, and tell the story of their faith in the ten years after Bitcoin. Just like the writing of the 66 books of the Bible spanned 1,500 years, and after 2,000 years of interpretation, Christianity has divided into 33,000 branches.

CoinMarketCap shows that there are more than 4,900 types of digital currencies, and the overall digital currency market size is nearly 140 million yuan. Bitcoin still leads the entire digital currency market with a market share of 66%, and the recent price has been hovering around US$7,200 per coin.

So many currencies have different functions and are divided into different categories: digital currencies represented by Bitcoin are positioned as "digital gold" and have certain value storage and hedging characteristics; represented by Ethereum Digital currency has become the "operational fuel" in its network system; stablecoins represented by USDT and Libra have good payment properties due to their low volatility; central banks represented by DCEP issue digital currencies, which to a certain extent Replacing M0 allows commercial institutions and ordinary people to receive and pay without delay when they are out of cash and disconnected from the Internet.

It can be seen that after 10 years of development of blockchain technology, the first and largest application is digital currency.

Digital currency has also become an attractive reward for participants to maintain the public chain.

So besides digital currency, where else can blockchain technology be used?

Let us recall what the essence of blockchain is—a decentralized database, and its corresponding characteristics: traceability, publicity, anonymity, and tamper-proofing. In theory, you can try to use blockchain to transform traditional scenarios that use centralized databases to see if they are suitable.

Next, let’s talk about several industries and scenarios where blockchain has been successfully implemented:

Blockchain can prove the existence of a certain file or digital content at a specific time through hash timestamps, providing judicial authentication, Identity proof, property rights protection, anti-counterfeiting traceability, etc. provide perfect solutions

In the field of anti-counterfeiting traceability, blockchain technology can be widely used in various fields such as food and medicine, agricultural products, alcohol, and luxury goods through supply chain tracking.

Give two examples.

Blockchain can allow government data to be run, greatly streamlining service processes

The distributed technology of blockchain can allow government departments to be centralized on one chain, and all service processes are delivered to smart contracts, and the workers only need to be in one department Through identity authentication and electronic signature, smart contracts can be automatically processed and transferred, and all subsequent approvals and signatures can be completed in sequence.

Blockchain invoices are the earliest use of blockchain technology in China. The tax department launched the "Tax Chain" platform for blockchain electronic invoices. The tax department, the issuer, and the payee join the "Tax Chain" network through unique digital identities, truly realizing "instant invoicing for transactions" and "instant reimbursement after invoicing" - in seconds Level invoicing and minute-level reimbursement accounting greatly reduce tax collection and management costs, and effectively solve problems such as data tampering, over-reporting of one ticket, and tax evasion.

Poverty alleviation is another practical application of blockchain technology. Utilize the characteristics of openness, transparency, traceability, and non-tampering of blockchain technology to achieve transparent use, precise investment, and efficient management of poverty alleviation funds.

Give two examples as well.

The eID network identity operation agency guided by the Third Research Institute of the Ministry of Public Security is jointly developing a "digital identity chain" with Gongyilian, which will be issued to Chinese citizens based on the citizen's identity number as the root and cryptographic algorithm. Since it was put into operation, the eID digital identity system has served the full life cycle management of 100 million eIDs, effectively alleviating the problems of personal identity information being fraudulently used, abused and privacy leaked.

Odaily Planet Daily compiled 5 identity chain projects registered with the Cyberspace Administration of China

Blockchain technology naturally has financial attributes

In terms of payment and settlement, under the blockchain distributed ledger system, multiple market participants jointly By maintaining and synchronizing a "general ledger" in real time, payment, clearing, and settlement tasks that currently take two or three days can be completed in just a few minutes, reducing the complexity and cost of cross-bank and cross-border transactions. At the same time, the underlying encryption technology of the blockchain ensures that participants cannot tamper with the ledger, ensuring that transaction records are transparent and safe. Regulators can easily track transactions on the chain and quickly locate high-risk capital flows.

In terms of securities issuance transactions, the traditional stock issuance process is long, costly and complicated. Blockchain technology can weaken the role of underwriting institutions and help all parties establish a fast and accurate information exchange and sharing channel. The issuer can handle the issuance on its own through smart contracts. , regulatory authorities conduct unified review and verification, and investors can also bypass intermediaries for direct operations.

In terms of digital bills and supply chain finance, blockchain technology can effectively solve the financing difficulties of small and medium-sized enterprises. It is difficult for current supply chain finance to benefit small and medium-sized enterprises in the upper reaches of the industrial chain, because they often do not have direct trade relations with core enterprises, and it is difficult for financial institutions to evaluate their credit qualifications. Based on blockchain technology, we can establish a consortium chain network covering core enterprises, upstream and downstream suppliers, financial institutions, etc. The core enterprises issue accounts receivable vouchers to their suppliers. After the bills are digitized and uploaded to the chain, they can be uploaded to the supplier Transfer between them, each level of supplier can realize the corresponding amount of financing with the digital bill certificate.

Give me an example.

The China Enterprise Cloud Chain, jointly launched by ICBC, Postal Savings Bank of China, 11 central enterprises, etc., has covered 48,000 companies since its establishment in 2017, with the amount of rights confirmed on the chain reaching 100 billion yuan, and factoring financing of 57 billion yuan. , cumulative transactions reached 300 billion yuan. After receiving the loan application, financial institutions can verify the authenticity of the contract on the chain and whether the contract has been verified multiple times (multiple loans); the smart contract automatically clears and settles, reducing costs and increasing efficiency; at the same time, the accounts payable of core enterprises can have The corresponding vouchers will be split by the first-level suppliers and handed over to the second- and third-level suppliers in the chain to help them with financing; core enterprises can also use this to understand whether the entire chain is operating normally and avoid emergencies. Redemption pressure.

Blockchain technology will greatly optimize the existing use of big data and play a huge role in data circulation and sharing

The aforementioned areas are areas that we are relatively familiar with. As more new technologies develop, blockchain may be able to be combined with them and play a role in unexpected cross-fields and new scenarios that are currently unforeseen.

In the future, the Internet, artificial intelligence, and the Internet of Things will generate massive amounts of data. The existing centralized data storage (computing model) will face huge challenges. Edge storage (computing) based on blockchain technology is expected to become a future solution. Furthermore, the non-tampering and traceability mechanism of blockchain ensures the authenticity and high quality of data, which becomes the basis for the use of all data such as big data, deep learning, and artificial intelligence.

Finally, blockchain can protect dataAchieving multi-party collaborative data computing under the premise of privacy is expected to solve the problems of "data monopoly" and "data islands" and realize the value of data circulation.

In response to the current blockchain development stage, in order to meet the blockchain development and use needs of general business users, many traditional cloud service providers have begun to deploy their own BaaS ("Blockchain as a Service") solutions. The combination of blockchain and cloud computing will effectively reduce enterprise blockchain deployment costs and promote the implementation of blockchain usage scenarios. In the future, blockchain technology will also play an important role in many fields such as charity, insurance, energy, logistics, and the Internet of Things.

During this trial process from traditional technology to blockchain, we found that when certain scenarios have stronger demands for traceability, tamper-proofing, and decentralization, they also have problems with the weaknesses of blockchain (such as performance). , the requirements are not high, and this field is quite suitable for combining blockchain.

At the same time, in the process of blockchain evolution, it has also developed from a highly decentralized public chain accessible to everyone to a consortium chain with different permissions and maintained by multiple centers. Balances the advantages and disadvantages of the two systems.

Typical examples of alliance chains include: FISCO BCOS jointly developed by WeBank and the Golden Alliance Open Source Working Group, Fabric, a major contribution from IBM, and Ant Alliance Chain led by Ant Blockchain, etc.

These trustless systems represent more secure data authentication and storage mechanisms, where data is effectively authenticated and protected. Businesses or individuals can exchange or enter into contracts digitally, where these contracts are embedded in code and stored in transparent, shared databases where they cannot be deleted, tampered with, or revised.

It is boldly predicted that in the future, contracts, audits, tasks, and payments will all be digitized with unique and secure signatures. Digital signatures will be permanently identified, authenticated, legalized, and stored, and cannot be tampered with. There is no need for an intermediary to guarantee each of your transactions. You can conduct transactions without knowing the basic information of the other party. While improving information security, it effectively reduces transaction costs and improves transaction efficiency.

Generally speaking, there has been a lot of progress in the implementation of blockchain compared to two years ago.

Many improvements are at the bottom of the system, and users cannot directly see that blockchain is used, but they have actually benefited from it; some applications are still in pilot mode, and users have not yet been able to experience it. In the future, blockchain is expected to be used on a large scale and become one of the Internet infrastructure.

I hope that after reading this, you have a general understanding of what blockchain is and what blockchain can do.

Related Q&A: What is blockchain

Blockchain is actually equivalent to a disintermediated database, which is composed of a series of data blocks. Each of its data blocks contains information about a Bitcoin network transaction, which is used to verify the validity of the information and generate the next block.

In a narrow sense, blockchain is a chain data structure that combines data blocks in a sequential manner in chronological order, and is cryptographically guaranteedAn untamperable and unforgeable distributed ledger.

In a broad sense, blockchain is actually a distributed infrastructure and computing method, which is used to ensure the security of data transmission and access.

Blockchain infrastructure:

Blockchain is composed of six infrastructures: data layer, network layer, consensus layer, incentive layer, contract layer and usage layer.

⑥ How to better understand the consensus mechanism in the blockchain

Jin Wowo explained with a vivid metaphor: If consensus is the foundation of the blockchain, then the consensus mechanism It is the soul of blockchain.
When explaining what a blockchain is, it can be summarized with a concise and clear decentralized distributed ledger, but in this ledger, how are things generated in almost the same time sorted forward and backward? , involving the consensus mechanism of the blockchain network.
So Jinwowo Network Technology believes that the consensus mechanism is an algorithm that reaches consensus on the order of things within a period of time.

⑦ Four consensus mechanisms of blockchain

The consensus mechanism of blockchain can be divided into the following four categories: Proof of Stake mechanism, Proof of Work mechanism, Pool verification and pool shares Authorization certification mechanism.
Blockchain is a chain composed of blocks one after another. Each block stores a certain amount of information, and they are connected into a chain in the order in which they were generated. This chain is saved in all servers. As long as one server in the entire system can work, the entire blockchain is safe. These servers are called nodes in the blockchain system, and they provide storage space and computing power support for the entire blockchain system.

⑧ One of the blockchain consensus mechanisms: POW workload proof mechanism

Blockchain can be understood as a public ledger that cannot be tampered with, and all participants can verify transactions and proceed Accounting is a distributed ledger. So who will keep the accounts? How to ensure the consistency and accuracy of the ledger? That is, what is the consensus mechanism of the blockchain?

The consensus mechanism of the blockchain is to solve the problem of who will keep accounts (construct blocks) and how to maintain the consistency of the blockchain. There are many consensus mechanisms currently used in blockchain projects, such as: POW workload proof mechanism, POS equity proof mechanism, DPOS share authorization proof mechanism, etc. This article explains the POW workload proof mechanism.

The first successful application of blockchain is the POW proof-of-work mechanism adopted by the Bitcoin system. That is, taking the Bitcoin system as an example to illustrate the POW mechanism, first of all, the Bitcoin system has an incentive mechanism that allows all participants to compete for the right to bookkeeping, that is, whoever has the right to bookkeeping will receive the Bitcoin reward for constructing a new block (the current reward is 12.5 Bitcoin), and obtain the handling fees of all transactions in the new block as a reward.

How do participants compete for accounting rights? Participants use their own computing power to calculate a mathematical problem, and whoever calculates the result first, whoever has the right to keep accounts will also be rewarded for constructing new blocks. This mathematical problem is to find a random number Nonce so that the result of the hash calculation of the block header is less than the target value. The Nonce itself is a field in the block header, so by constantly trying the value of Nonce to satisfy the hash of the block header. It is hoped that the calculated result is less than the target value. By dynamically adjusting the target value, the difficulty of the calculated Nonce value can be adjusted.

The process of hash calculation Nonce is usually compared to a sieve throwing game. Based on the number of sieves participating in the game, the difficulty of the game can be adjusted by adjusting the number of sieve points thrown. For example: 100 people participate in throwing sieves, there are 100 sieves in total, and the required number of points is 100 to win, then whoever among the 100 people throws 100 points first is the winner, and has the right to keep accounts. If you find that everyone rolls 100 points too quickly, you can increase the difficulty and require a roll of 80 points to win. If another 100 people participate in the game, the number of sieves is increased in the game. For example, the number of sieves is increased to 200. The difficulty of the game is also adjusted by setting the number of throw points.

The sieve is similar to the computing power of the Bitcoin network, and the number of points thrown is similar to the dynamically adjustable target value of the Bitcoin network.

The longest chain in the blockchain is regarded as the correct chain. If two blocks appear at the same time, the two blocks will be temporarily recorded in parallel, and the subsequent blocks will be based on one of them. One block will form the longest chain as the consistent chain, and the other block will be discarded. Bitcoin is based on the confirmation of 6 blocks, so the discarded block will not receive Bitcoins. The reward of the system is a waste of computing power (electricity bill) competing for accounting rights. Based on workload incentives, participants must do their best to construct correct blocks, that is, to meet the consistency of the blockchain. That is, all users on the entire network can reach a unique and consistent public ledger.

At present, the computing power of the entire Bitcoin system has reached an astonishing 24.75EH/s, of which 1E=1000P, 1P=1000T, 1T=1000G, 1G=1000M, 1M=1000K, 1K=1000, H/s is one hash calculation (hash collision) per second, that is, 24.75E hash calculations are performed per second, and there is still continuous computing power added to the Bitcoin system. The competition for Bitcoin accounting rights involves hardware providing computing power from CPUs, GPUs, professional mining machines, and mining pools. At present, the stand-alone version of professional mining machines can no longer compete for accounting rights. Multiple mining machines must be combined into a mining pool to compete for accounting rights.

⑨ CreditEase Puhui: Promoting the normalized application of blockchain technology and empowering the development of financial technology

Recently, in the “14th Five-Year Plan” outline, it was pointed out that it is necessary to comprehensively promote Blockchain technology innovations such as smart contracts, consensus algorithms, encryption algorithms, and distributed systems, focusing on the development of blockchain service platforms and financial technology with alliance chainsWe will provide application solutions in technology, supply chain management, government services and other fields, and improve the supervision mechanism.

It can be seen that blockchain application innovation has officially become one of the national strategies and will definitely have a significant impact on the financial industry. Under such a situation, financial institutions are accelerating blockchain-related exploration and promoting blockchain technology to play a greater role in the financial field. Next, follow CreditEase Puhui to learn about blockchain-related knowledge!

What is blockchain

Blockchain is a chained data structure that combines data blocks in a specific order in chronological order. Records of all transactions since the birth of the system are stored. The data on the blockchain is jointly maintained and stored by nodes throughout the network, and cryptography ensures that the block data cannot be tampered with or forged. So the blockchain is essentially a distributed shared database.

Blockchain is an innovative application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanisms, and encryption algorithms in the Internet era. It is an information technology solution that solves trust problems and reduces trust costs. . The application of blockchain technology can eliminate traditional trust intermediaries, subvert the old centralized model that has existed for thousands of years, solve the trust problem between strangers without the need for centralized trust intermediaries, and significantly reduce the cost of trust. Trust costs.

How blockchain can solve the pain points of supply chain finance

Supply chain finance is based on core customers, based on real trade background, and uses self-reimbursement trade financing. , which provides comprehensive financial products and services to upstream and downstream enterprises in the supply chain through professional means such as accounts receivable pledge registration and third-party supervision to close capital flows or control property rights.

The foundation of supply chain finance is the supply chain. The supply chain involves information flow, capital flow, logistics and business flow, and is naturally a multi-subject and multi-collaboration business model. In this case, if you want to carry out trade financing, you will first encounter many authenticity issues, such as the authenticity of the transaction and the authenticity of the documents, which require confirmation by multiple parties and consume a lot of manpower and material resources; secondly, the multiple entities involved , there is a problem of difficulty in interconnection. For example, the supply chain management system, enterprise resource management system, and even financial system used by each entity are different, making docking difficult. Even if they are connected, it will be difficult to share information due to inconsistent data formats and data dictionaries.

Characteristics of blockchain

1. Decentralization

The distributed structure of blockchain means that data is not recorded and stored in the center. Instead of using a dedicated computer or host, each node participating in the data transaction records and stores all data information. To this end, the blockchain system adopts an open source, decentralizedProtocol to ensure complete recording and storage of data. The blockchain has built a complete set of protocol mechanisms, allowing each node in the entire network to participate in recording data while also participating in verifying the correctness of the recording results of other nodes. Only when most nodes (or even all nodes) in the entire network confirm the correctness of the record will the data be written into the block. In the distributed structure network system of the blockchain, the network nodes participating in the recording will update and store all data in the entire network system in real time. Therefore, even if some nodes are attacked or destroyed, the data update and storage of this system will not be affected.

2. Unforgeable

The principle of blockchain recording requires all nodes participating in the recording to jointly verify the correctness of the transaction record. Since all nodes are recording every transaction in the entire network, once the information recorded by a node does not match that of other nodes, other nodes will not recognize the record, and the record will not be written into the block.

3. Non-tampering

It is almost impossible to change a certain block and the transaction information within the block. If this block is changed, every subsequent block will be changed. Therefore, anyone trying to tamper with the data must simultaneously invade at least 51% of the nodes participating in the global record and tamper with the data.

Mathematical encryption

Each transaction requires a valid signature before it will be stored in the block. Only valid digital keys can generate valid signatures. Keys come in pairs and consist of a private key and a public key. Among them, the public key is public, and the private key is only visible and used by the owner, and is used for transaction signatures to prove digital identity.

What are the advantages of introducing blockchain?

First, to solve the problem of information islands, multiple stakeholders can set rules in advance to accelerate data interoperability and information sharing;

Second, according to property rights law , Electronic Contract Law, Electronic Signature Law, etc., the accounts receivable certificates of core enterprises can be converted into transferable and bankable confirmation certificates through the blockchain, so that the credit of core enterprises can be transmitted along trusted trade links. Based on mutual confirmation, the entire certificate can derive various operations such as splitting and traceability;

Third, provide credible trade data, such as providing an online basis under the blockchain architecture Tightly structured and complete records of contracts, documents, payments, etc. improve information transparency and achieve penetrable supervision;

Fourth, achieve cost reduction and efficiency improvement. After the credit of the core enterprise is transferred, small and medium-sized enterprises can use the credit line of the core enterprise to reduce financing costs and improve financing efficiency;

Fifth, realize smart liquidation of contracts. Automatic settlement based on smart contractsCalculate, reduce manual intervention, reduce operational risks, and ensure the safety of payment collection.

CreditEase Puhui believes that blockchain supports commercial applications with high performance, high scalability, and high security, provides financial technology companies with multi-level data security and privacy protection, and supports automatic monitoring and failure Alerts help track all transactions that occur in the system and contribute to the healthy and orderly development of the financial technology industry.