区块链工作量证明的演进过程包括,区块链工作量证明原理
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❶ Consensus mechanism of blockchain
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; For a transaction, if several nodes with unrelated interests can reach a consensus, we can think that the entire network can also reach a consensus on it. 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.
❷ What is proof of work in blockchain mining?
The spelling of POW is Proof of Work. To put it simply, it is a work model that requires a lot of hard work to get relatively good pay.
Miners are diggingWhen a new block is created, the SHA-256 cryptographic hash function must be operated, and the random hash value in the block starts with one or more 0s. As the number of zeros increases, the amount of work required to find this solution will increase exponentially, and miners find this solution through repeated attempts.
The first miner to calculate the correct answer can obtain the accounting rights of the current block and receive rewards for newly issued Bitcoins. Theoretically speaking, the greater the computing power (strength), the faster the calculation (moving), and the higher the profit value. You should be able to understand this, POW means distribution according to work, the more work, the more reward. At present, Bitcoin, the big brother in the currency world, and Ethereum, the second brother now, all have this model.
❸ FileCoin: Proof of Useful Work
Proof of Useful Work was proposed by FileCoin, a well-known decentralized storage project, in its white paper a concept. Proof of Work, POW is an important consensus method for realizing blockchain, and FileCoin wants to implement a storage platform based on blockchain. So it also needs to achieve consensus, and what it chooses is the proof-of-work consensus.
First, let’s explain the conventional proof of work. It is a way for blockchain to achieve consensus. It is the method adopted by Bitcoin, so proof of work is commonly known as "mining". As a decentralized peer-to-peer trading system, Bitcoin must maintain a common and identical ledger on different nodes to record all transactions and ensure that transactions are not repeated and money is not spent more than once. A rule is needed to maintain the consistency of this ledger. Everyone abides by this rule together, which is a consensus. A common method used in blockchain is to divide the ledger into many pages, and each page is a block. Each block is accounted for by one node and then distributed to other nodes for replication, so that the ledgers on all nodes are the same. But which node records each block requires a rule that everyone can abide by. The method used by Bitcoin is to ask all nodes to do a simple math problem. The question is very simple, but the calculation is very heavy, and it usually takes about 10 minutes to get the answer. Although getting the answer is time-consuming, verifying that the answer is correct is easy. Then all nodes will do the questions at the same time, and the first node to do it will get the accounting rights of the next block. Because each block has only one node that made the earliest question, the accounting rights of each block are unique and can be easily verified by other nodes. Once a node verifies that other nodes have obtained the accounting rights of the block, it must copy the block and add it to the local blockchain, and at the same time start the competition for the accounting rights of the next block. In this way, Bitcoin ensures that the blockchain of all nodes is consistent.
The process in which nodes compete for block accounting rights through a large number of calculations is the workload proof. Therefore, the proof-of-work systemSystem (or protocol, function) is an economic countermeasure against denial of service attacks and other service abuses. It requires the initiator to perform a certain amount of calculations, which means it takes a certain amount of computer time. This concept was first proposed by Cynthia Dwork and Moni Naor in an academic paper in 1993. The term Proof of Work (POW) was only really proposed in 1999 in an article by Markus Jakobsson and Ari Juels.
There are many ways to achieve blockchain consensus, such as POS, DPOS, POA, PBFT, etc., but workload proof is the only one that has been verified by time (11 years) and runs on the public chain. The blockchain consensus mechanism.
What kind of problem does workload proof have? Let’s use Bitcoin as an example. The mathematical problem that Bitcoin nodes do in order to obtain the right to produce blocks is called hash operation. The amount of calculation is very large. Every mining machine participating in Bitcoin mining must perform this calculation all the time, which consumes a lot of electricity. Unlike other calculations such as big data processing, this calculation can generate some value. Its only purpose is to compete for a node and become the block producer of the next block. Bitcoin currently consumes about 2.55 billion watts of electricity per year, which is equivalent to 0.5% of global electricity and the electricity consumption of Ireland in one year. Opponents of POW have accused mining of wasting electricity resources on illusory digital currencies, and called it liberal "swill".
However, people who think POW is a waste of electricity don’t know that it is energy and computing power that create Bitcoin’s secure and unbreakable system.
A piece of cash worth 100 yuan is not just you and I who think it is worth 100, but the entire social group thinks it is worth 100. The value comes from consensus. Bitcoin is a community behavior. People from different countries gather in the community and use the Internet to establish order. Its meaning also comes from group consensus. As long as everyone believes that Bitcoin is valuable and only consensus exists, then it will have value, and The fiat currencies are exactly the same. Therefore, the generation of value recognition does not necessarily need to be driven by the state. Bitcoin has reformed a carrier and medium for transmitting trust. Over the past thousands of years, human society has established political power and consensus through many bloody wars. Now it can be achieved without bloodshed, just by consuming some electricity. Wouldn't it be more advanced to realize it?
In summary, in order to design a decentralized and secure digital currency, energy and computing power are necessary costs. Proof of work is the only solution to build a secure property rights authentication system in a decentralized form. Therefore, people who think POW is a waste of electricity don’t know that it is energy and computing power that create Bitcoin’s secure and unbreakable system. Now the computing power of the entire Bitcoin network has reached a very terrifying level. It is impossible for anyone to launch a 51% computing power attack. The POW algorithm makes the Bitcoin systemunbreakable.
Consumption incurred to create value is not waste.
But, with so much computing power, can it be used to create more value? In FileCoin terms, are there any other uses for proof of work?
FileCoin is a star project in the distributed storage industry. His development team, Protocol Lab, is the team that developed the IPFS protocol, so many people can't tell the difference between FileCoin and IPFS. It can be said that FileCoin’s ICO in 2017 pushed the industry to its peak and also led to a series of similar projects. This article is not intended to praise or belittle this project. I just want to express some of my own opinions based on my own experience in this industry, and try to be objective and fair. I hope it can provide some inspiration to those working in this industry.
FileCoin proposed in the white paper to implement a useful proof-of-work, which actually recognized that to create a secure and unbreakable blockchain, workload must be consumed. However, they don't want the calculations made for this workload to be completely wasted, so they want to make use of this workload. Therefore, the method they thought of was to add storage space usage to the proof of work. In this way, in order to form a consensus, all nodes must provide storage space to store files. This storage space can store user data, which is useful.
Let’s take a look at how FileCoin implements this useful proof-of-work consensus.
The consensus mechanism adopted by Filecoin is not a simple proof of work, but a mechanism called Expected Consensus (EC for short). Like other mainstream consensus mechanisms, the goal is to allow miners to compete for a highly unique block right and receive rewards. The miner who obtains the right to produce blocks is called Leader. In each round of block competition, in order to ensure the reliability of the ledger, there is a unique leader to perform accounting.
In other words, the core of consensus is to choose who will be the leader. There are generally two ways to select a leader, interactive or non-interactive. Interaction requires miners to vote for each other. For example, PBFT is interactive. Several people participating in the election send messages to each other, and the person who gets the majority of votes (more than 2/3) is the leader. Expected consensus uses a non-interactive method to elect Leaders. The participating parties do not send messages to each other at all, but each node performs calculations independently and privately. Finally, a node says, I won the election, and then provides a proof that others can easily verify that he indeed won the election. This testThe proof method is zero-knowledge proof.
The expected consensus mechanism will preset an expected value of blocks for the blockchain network. For example, one block is generated every epoch, but there may be empty blocks or multiple blocks in one epoch. So in Filecoin, each height is not a block, but a set of blocks, called TipSet. This TipSet may contain multiple blocks. So actually Filecoin is a TipSet chain. The expected consensus cannot guarantee that only one Leader will be elected in each round, so there will be the possibility of multiple Leaders in a round, so that the chain structure becomes a DAG mesh structure. Therefore, FileCoin will also weight blocks to achieve effective convergence.
There is one benefit to the EC consensus adopted by FileCoin. For the traditional POS consensus mechanism, a major problem is the inability to control forks. In other words, due to the low mining cost, participants can mine multiple chains at the same time to gain benefits. The expected consensus has designed this point, which is to use the weight and mortgage mechanism to encourage miners to choose the best chain, and to punish miners who mine multiple chains at the same time, which can promote convergence very quickly. This shows that it is a good way to use POW and POS together.
The possibility of each miner obtaining a block is positively related to the current effective storage amount accounting for the total storage amount of the entire network. This expected consensus mechanism is actually more like POS equity proof, except that it replaces the equity (Staking) in POS with an effective storage ratio. But where does the effective storage for miners come from? It is obtained by storing user data. How to prove that miners store user data, FileCoin created a new proof mechanism called POST spatio-temporal replication proof. This POST is the workload of FileCoin. By replacing power-consuming computing power with storage space for storing useful data, meaningless arms competition has turned into competition in the storage service market. This is truly where FileCoin advances. However, in order to successfully produce a block, after the miner is selected as the block producing node through the expected consensus, he must make a POST proof within one block time (currently 45 seconds) and submit it successfully before the block can be produced. Otherwise, the opportunity is lost. Therefore, in order to ensure that miners can produce blocks within the specified time, the official finally decided to use GPU. Although this GPU does not work non-stop like the proof of work, there are still energy-consuming calculations that are contrary to the useful idea of proof of work in the entire process of achieving consensus.
Also, when talking about expected consensus, we said that the block produced in each epoch is not a block, but a group of blocks, so the concept of epoch is very important. How to control the era?? Before each miner participates in the election, he needs to generate a Ticket. This Ticket is actually a random number. He needs to go through a process of VDF and VRF. The full name of this VDF is Verifiable Delay Function, which is a verifiable delay function. His calculation process is serial and takes a certain amount of time, and this time cannot be reduced through multi-core parallelization. This ensures that no one can obtain acceleration by optimizing the hardware for the time each miner must spend when generating a Ticket. This function sounds perfect, but this VDF does not exist at all! Now the FileCoin test network directly uses a waiting function sleep, which is UDF, Unverifiable Delay Function. The closest VDF solution available today also consumes a lot of computing resources. To put it bluntly, it still consumes electricity and is not environmentally friendly.
Therefore, useful proof of work is still just a good wish. The ideal is very full, but the reality is very skinny. FIL, known as the next Bitcoin, will continue to work hard to achieve this subversive consensus.
Summarize the process for FileCoin storage miners to obtain incentives: users store data and pay FIL fees -> miners store data -> generate copy proof -> complete space-time proof -> select blocks after EC consensus Leader -> Obtain packaging rights -> Miners obtain FIL rewards
From this flow chart, you can see that miners can obtain rewards in two places. One is that you can get users' FIL rewards when storing user files. One is to obtain FIL after obtaining the block packaging rights. A prerequisite for obtaining block packaging rights is to have enough user data. Therefore, when the storage demand is not large enough, miners will charge very low fees from users. When there are not enough users, they will even pay FIL to store data themselves, just to be able to store enough data and be selected as Leader in the EC consensus to receive packaging rewards. The effect of this is that FileCoin is very user-friendly and storage fees are very low. Therefore, it will definitely attract many applications to be developed on this platform. But the disadvantages are also obvious. If the storage capacity is not large enough, miners will not be able to compete with others for the right to produce blocks, so they will not receive rewards. In the end, the entire platform will develop in the direction of big miners and big mining pools, which is contrary to FileCoin's original intention of utilizing all idle servers to achieve distributed storage. In other words, we must wait until the industry reaches a certain scale and the technology becomes more mature before there are opportunities for mining with small mining machines.
Let’s go firstLet’s briefly talk about the pros and cons of centralized storage and decentralized storage. Centralized storage devices are managed in a unified manner, with good reliability and high performance. Decentralized storage data is naturally dispersed, easy to circulate, and has good disaster tolerance, but low reliability. From an economic perspective, centralized storage requires heavy asset investment and high costs. Decentralized storage passes through the blockchain incentive layer, and users can join by themselves. It is light-asset and can reduce the total cost of storage. In the future, the storage and processing of application data will still be based on centralized storage, while decentralized storage, because it is a distributed network, can mainly be used for popular data traffic distribution. At the same time, because there is no centralized ownership, it can become the first choice for decentralized applications.
There is a saying in the market that decentralized networks are suitable for the backup of cold data. In fact, this is not the advantage of decentralized storage. It is because it is too difficult to put hot data on decentralized networks. It’s unreliable and the processing performance can’t keep up. Therefore, if decentralized storage can achieve a certain scale effect, greatly reduce storage costs, regard cold data backup as a core business, and target cold data that is not stored by enterprises today because the cost is too high, it will be a great opportunity. Good direction for development.
In this way, technically speaking, decentralized storage does not necessarily have advantages over centralized storage. If a new model can be implemented that combines decentralized economic incentives and centralized storage, it can absorb the advantages of both. Truly achieve useful workloads. The large-scale mining farm model data center that FileCoin may promote in the future may be more marketable.
Today, 11 years later, Bitcoin has not realized its original intention of becoming a peer-to-peer electronic payment currency, but it cannot stop humans from buying it and owning it. Similarly, I believe that FileCoin has received support from a large enough community, miners and developers, even if it will not lead to the full implementation of distributed storage applications in the foreseeable future (perhaps this has never been the goal of FileCoin), but I I still believe that many people will buy it and hold it because of its consensus. Rising to the philosophical level, human beings are paying for the truth.
So in real life, what is useful, or in other words, are we using storage for consensus or consensus for storage? FileCoin is the former. FileCoin wants to achieve a decentralized consensus based on storage workload, which is perfect in theory. Human beings have to pay a price for pursuing perfection. That's why we waited so long on this project. But once realized, it may bring great value to mankind and bring infinite appeal to the market.
But decentralization is not a panacea for everything. One of the biggest advantages of centralization is that it is very efficient. Weakly centralized consensus like dPOS or alliance chain takes into account the advantages of both, can bring applications to the market more quickly, and start the distributed storage industry in advance.Promote the implementation of distributed storage applications. Therefore, we pursue both the use of storage for consensus and the use of consensus for storage, and make our choices based on actual needs. In this process, I believe that the blockchain will further develop, gradually optimize, and become more and more useful.
❹ What is proof of work
A very important concept in the blockchain is proof of work, which is called Proof of Work in English and abbreviated as POW. I believe that many people are confused when they first come into contact with this concept, "Hey, proof of work? Do you mean to prove how much work I have done?"; I believe that many people who invest in Bitcoin or are so-called "can become rich overnight" Investors deceived by the "new digital currency" of "rich people" are more "familiar" with this concept because they have heard too many of those "currencies" claiming that they have safer algorithms and more reliable proof-of-work mechanisms. Because you listen a lot, you seem to understand it, but you just don’t really understand it. This cognitive asymmetry is often the main reason why monsters such as MLM coins can take advantage of it.
When I introduced you to the "Byzantine Generals Problem" before, I mentioned that the Byzantine Generals mainly solved the problem of how to achieve consensus among multiple nodes (if you forget what the background of the story was at that time , then go through the previous courses carefully), but it did not introduce in depth how to achieve consensus. How to achieve consensus is the most critical issue in the blockchain, and it is also the most discussed one. Before the birth of the blockchain, there was a lot of research on consensus algorithms in the field of distributed systems, but we are not going to go into it here. .
1. Proof of work is really used to prove how much work you have done
In fact, as mentioned in the first paragraph of this article, many people have just begun to understand The concept, "Proof of work is mainly used to prove how much work a person has done" is basically correct. The computer field is not just filled with some unfamiliar concepts. This concept is easy to understand, but it confuses us.
Let’s go back to the story of the Byzantine Generals Problem. In that story, who should we trust? Who can take on this important task and become that heroic general?
Perhaps because information is constantly being transmitted between city-states, and the amount of transmission is too large, the generals of each city-state are selling their melons and boasting about themselves. It is basically difficult to distinguish who to trust. Careful friends can use their imagination. In fact, there is the simplest and crudest method: see who is the smartest! We trust whoever is the smartest.
The question of who is the smartest is actually too subjective. There is no other way but to rely on strength. Just like we have experienced countless exams - come on, generals, let's do the questions. The person who answers accurately and the fastest wins.
So, Zhiduoxing narrated: Please listen to the question, what is the value of a value such as 1?23456789, followed by a 5-digit random number. Please find a random number such that the first 5 digits of the calculated hash value are all 0.
Generals, don’t be confused. Just because you don’t know doesn’t mean others don’t know, so the smartest general quickly figured it out, wrote his name on it, and handed in the test paper. The teacher verified that it was completely correct, so he was selected as the Byzantine general to command the heroes.
If you don’t know hashing algorithms, please go back and review the previous lessons. In addition, here is a reminder that the general must write his name to show that he has calculated the question correctly. This is also very important in the blockchain. It means that the signature shows that he wins, and he can get a reward in the end.
The interesting process introduced above is the so-called proof of work.
2. How to understand mining, mining machines and mining pools?
Proof-of-work is most common in Bitcoin. When everyone didn’t quite understand this thing, we already saw the promotional words “mining” and “mining machine” in many places. That What we couldn't understand at all at the time was how to mine on a computer? I can't open my mind at all. I was also confused for a long time. When I saw someone selling mining machines on Taobao, I looked down with disdain and said it must be a scam.
Many times, contempt is actually caused by our own lack of understanding. It is not until it grows into a behemoth, and it is not until Luo Fat mentions "there is a species sitting up next to it" that we realize that our understanding seems to be a little bit... late. Even so, we cannot give up our understanding of a new thing.
The so-called mining is actually a computer operation process for the workload proof mentioned above. You may be wondering, how could such a lofty metaphor as a general's calculation turn into such a hard-working concept as mining? In fact, Byzantine General just described the background of the story and some details of the proof of work in an interesting way, and mining is closer to the process of proof of work in the blockchain - because it is really hard work!
In fact, the "Zhiduoxing" or "teacher" mentioned above is the mysterious figure Satoshi Nakamoto, the inventor (or organization) of Bitcoin. To put it bluntly, this problem presented by Satoshi Nakamoto is a calculation problem that a fool can only try to calculate from 1, 2, 3...n honestly, which is also mentioned in cryptography. brute force concept. This kind of calculation process is boring, energy-consuming and time-consuming. It is so hard that it can best be described as "mining". And this "mine" is Bitcoin, a thing as scarce as gold.
But let us not forget that this kind of mechanized calculation is what computers are best at, so leave everything to the computer. This is how the concept of "mining machine" came into being.With the development of technology, everyone found that computers were too powerful and there was no need to use them all for such calculations, so they continued to streamline and integrate mining algorithms into some chips, which not only saved energy, but also made calculations faster. This includes CPU mining, GPU mining, FPGA mining, ASIC mining, etc.
The emergence of mining pools is due to the limit on the total number of Bitcoins and the rigid requirement of halving in four years. The competition in mining has become increasingly fierce in the later stages, and the difficulty of mining Bitcoins has become more and more intense. As they grow bigger, they can only fight side by side in a group. This group is called "Mining Pool". People with mining machines can choose to join a certain mining pool. The mining pool gathers the power of all mining machines to perform calculations similar to the arithmetic problems above; during calculation, random number segments are allocated, and different number segments are given to different miners. Computer calculations have greatly improved the efficiency of calculations, so that they can gather together to fight and share the benefits.
In fact, some of the concepts introduced above are very elementary. The purpose is still to hope that many people without relevant foundation can understand them. Only when these most basic concepts are understood, it will be easier to go to the back. No?
❺ Blockchain consensus mechanism POS and DPOS
As the first consensus mechanism in the blockchain and one that has withstood sufficient practical testing, the workload proof algorithm solves the following problems: The issue of consistency of transaction information in distributed systems builds a trust mechanism for nodes that do not trust each other in a decentralized network, and is also a key technical link for the successful application of Bitcoin.
After several years of actual operation, the shortcomings of this algorithm have also been revealed. The Bitcoin network completes 600 trillion SHA256 operations per second, consuming a large amount of power resources. In the end, these calculations have no practical effect. or scientific value. The only purpose of these operations is to solve the proof-of-work problem. Another real threat is the concentration of computing power. Proof-of-work is essentially a process of using exhaustive methods to find hash values that meet specified conditions. The stronger it is, the higher the possibility of obtaining accounting rights (that is, mining). At first, it was the first people to use graphics cards to mine, and later to use FPGA mining machines, and then to use ASIC special chips to mine. People are now the ones who are constantly making better ASICs. In addition, there are "miner" nodes that unite to form mining pools, such as Ghash. Ghash issued a statement in 2014 that it will ensure that no more than 40% of the computing power of the entire network will be exceeded in the future. , this kind of self-discipline statement is a great irony of Bitcoin’s trustless mechanism.
Since the birth of Bitcoin, people have begun to try other consensus mechanisms besides the proof-of-work algorithm, such as the representative proof-of-stake POS, delegated proof-of-stake DPOS, and Byzantine Fault Tolerance (BFT). and Practical Byzantine Fault Tolerance (PBFT), etc. Below we will mainly introduce POS and DPOS, leaving BFT and PBFT for the next article.
Rights and interestsProve POS
POS is a type of consensus algorithm, or the design idea of a type of consensus algorithm, not one. The first one to adopt POS was Peercoin. Peercoin is a type of cryptocurrency launched by a geek with the pseudonym Sunny King in August 2012. It adopts the proof-of-work mechanism + the proof-of-stake mechanism, and introduces the proof-of-stake mechanism into cryptocurrency for the first time. Peercoin introduces the concept of "coin age". Each coin generates 1 coin age every day. For example, if you hold 100 coins for a total of 30 days, then your coin age will be 3000 at this time. When a new block is generated, other nodes that want to obtain accounting rights also need to calculate the hash value of Bitcoin. The difficulty of obtaining the hash value that meets the conditions is related to the difficulty value. This difficulty value here is related to the age of the currency. Inversely proportional, that is, the older your currency is, the greater the probability of obtaining a hash value that meets the conditions. At the same time, your currency age is cleared, and the system will give you corresponding "interest" after accounting. You will get 365 coins every time it is cleared. Age, the interest earned is: 3000 * interest rate / 365, the interest rate of Peercoin is 1%, which is 0.08 coins.
It can be seen that under the POS mechanism, the more coins you hold, the easier it is to obtain accounting rights, which is close to the winner-takes-all feeling. But the more coins you hold, the closer it is to an honest person. nodes, the greater the loss caused by destroying the entire network. There is a loophole in Peercoin's POS mechanism. For people who do not hold coins, they have little benefit, so some malicious attacks have no loss for them. This is a Nothing-at-stake attack. Subsequent more successful POSs have introduced mechanisms to deal with this kind of attack.
The Ethereum system aims to introduce proof of stake, known as Casper, this year. Under the proof-of-stake consensus mechanism, users will be able to have “currency rights” in the Ethereum network. Users who act honestly and confirm legitimate transactions will receive interest proportional to their equity; users who act maliciously and attempt to cheat the network will lose their equity.
Delegated Proof of Equity DPOS
Delegated Proof of Equity DPOS is a variant of POS. Typical examples of using DPOS are BitShares. The basic principle is that the entire network votes to select 101 node agents. Account permissions, the permissions of these representative nodes are exactly the same. The representative nodes take turns keeping accounts and can choose to create blocks or not. But they cannot change the details of the transaction, and the behavior of malicious or late representative nodes will be made public, and the network may vote them out simply and quickly. Representative nodes that are expelled will lose their accounting rights and corresponding income.
As a weakly centralized consensus mechanism, DPOS retains some key advantages of centralized systems, such as transaction speed (the time of each block is 10 seconds, and a transaction gets 6- 10It takes about 1 minute after a confirmation, and a complete 101 block cycle only takes about 16 minutes), but each currency holder has the ability to decide which nodes can be trusted, and in fact, representative nodes will actively reduce their income To win more votes, the remaining income will be paid as dividends to all BitShares holders. DPOS is somewhat similar to representative democracy and the joint-stock company board of directors system. It is an elite system, but its identity is subject to the people below. In DPOS, the holders of the currency at least have the right to decide the identity of the representative node-or miner.
❻ What is blockchain technology? What are the core components of blockchain technology?
What is blockchain technology? What are the core components of blockchain technology? What is blockchain technology:
Blockchain is a new application model of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm, etc. The so-called consensus mechanism is a mathematical algorithm that establishes trust and obtains rights and interests between different nodes in the blockchain system.
Blockchain is an important concept of Bitcoin. It is essentially a decentralized database and serves as the underlying technology of Bitcoin. The blockchain is a series of data blocks generated using cryptographic methods. Each data block contains information about a Bitcoin network transaction and is used to verify the validity of its information (anti-counterfeiting) and generate the next block.
The core components of blockchain technology:
Blockchain mainly solves the trust and security issues of transactions, so it proposes four technological innovations to address this issue:
The first one is called distribution A type of ledger means that transaction accounting is completed by multiple nodes distributed in different places, and each node records a complete account, so they can all participate in supervising the legality of the transaction and can also jointly testify for it.
Different from traditional distributed storage, the uniqueness of blockchain distributed storage is mainly reflected in two aspects: First, each node of the blockchain stores complete data according to the block chain structure. Traditional distributed storage generally divides data into multiple parts for storage according to certain rules. Second, the storage of each node in the blockchain is independent and of equal status, relying on the consensus mechanism to ensure storage consistency, while traditional distributed storage generally synchronizes data to other backup nodes through the central node. [8]
No node can record ledger data independently, thus avoiding the possibility of a single bookkeeper being controlled or bribed to record false accounts. Also because there are enough accounting nodes, theoretically speaking, the accounts will not be lost unless all nodes are destroyed, thereby ensuring the security of the accounting data.
The second one is called asymmetric encryption and authorization technology. The transaction information stored on the blockchain is public, but the account identity information is highly encrypted and can only be accessed with the authorization of the data owner. This ensures data security and personal privacy.
The third one is called the consensus mechanism, which is how all accounting nodes reach a consensus to determine the validity of a record. This is both a means of identification and a means of preventing tampering. Blockchain proposes four different consensus mechanisms, which are suitable for different application scenarios and strike a balance between efficiency and security.
The consensus mechanism of the blockchain has the characteristics of "the minority obeys the majority" and "everyone is equal". "The minority obeys the majority" does not entirely refer to the number of nodes, but can also be computing power, the number of shares, or other factors. A characteristic quantity that a computer can compare. "Everyone is equal" means that when a node meets the conditions, all nodes have the right to give priority to the consensus result, which will be directly recognized by other nodes and may eventually become the final consensus result. [8]
Taking Bitcoin as an example, it uses proof of work. Only when more than 51% of the accounting nodes in the entire network are controlled, it is possible to forge a non-existent record. When there are enough nodes joining the blockchain, this is basically impossible, thus eliminating the possibility of fraud.
The last technical feature is called smart contracts. Smart contracts are based on these trustworthy and non-tamperable data and can automatically execute some predefined rules and terms. Take insurance as an example. If everyone's information (including medical information and risk occurrence information) is true and trustworthy, it will be easy to automate claims settlement in some standardized insurance products.
In the daily business of insurance companies, although transactions are not as frequent as those in the banking and securities industries, the reliance on trusted data continues unabated. Therefore, the author believes that using blockchain technology from the perspective of data management can effectively help insurance companies improve their risk management capabilities. Specifically speaking, it is mainly divided into risk management of policyholders and risk supervision of insurance companies.
Chongqing Jinwowo Analysis: The consensus mechanism is the core of blockchain technology. The consensus mechanism largely determines the degree of mutual trust between nodes in the entire blockchain system, and also determines other users’ views on the blockchain. The degree of trust in online data
What is the core component of blockchain technology? Analysis by Chongqing Jinwowo: Blockchain technology consists of three core technologies: consensus mechanism, common defense mechanism, and distributed storage.
The three core technologies are supported by machine trust, that is, through the support of network technology, breakthroughs in difficult problems such as point-to-point transaction, decentralization, non-tampering of recorded information, irreversible transactions, and information encryption are achieved through network technology support.
The development of blockchain technology is becoming more and more prosperous with the continuous expansion of applications. This powerful development force coming from the needs of various industries has caused rapid changes in blockchain technology, allowing various industries to achieve great results. The results are attracting more and more attention, and professional technology and resources are constantly concentrated in this industry, thus bringing the development of blockchain technology into a new stage, andThe impact of the development of this blockchain technology has also attracted much attention.
When talking about blockchain technology, Bitcoin has to be mentioned. Many people know that the electronic currency Bitcoin does not rely on the issuance of a specific monetary institution, but is generated through a large number of calculations by a specific algorithm. In fact, the core that truly supports Bitcoin is blockchain technology.
How does the invisible and intangible Bitcoin operate through blockchain technology? The interpretation circulated in the industry is that blockchain can be regarded as a technical solution for collectively maintaining reliable databases through "decentralization" and "trustlessness". In layman’s terms, this technology can be understood as a technology in which everyone participates in accounting. In the past, people used centralized servers to keep accounts, but in the blockchain technology system, everyone can participate in accounting and jointly identify Authenticity of records.
"Through this technology, even if there is no neutral third-party organization, two parties that do not trust each other can achieve cooperation. In short, the blockchain is like a 'machine that creates trust.'" Bubi Company It is a leading blockchain service provider in China and has made many breakthroughs in the blockchain technology platform. It can meet scenarios with tens of millions of users and has the ability to quickly build upper-layer application businesses.
The blockchain technology used by all parties involved in recording and storing information adopts a decentralized distributed structure, which saves a lot of intermediary costs and can better ensure data security; at the same time, it has a time stamp that cannot be tampered with. It can effectively solve problems such as data tracking and information anti-counterfeiting.
Will it become the next trend of Internet finance?
Although blockchain emerged with Bitcoin, the derived value of this technology has transcended digital currency. Bubi Blockchain focuses on the innovation of blockchain technology and products. It already possesses a number of core technologies and has developed its own blockchain service platform. With decentralized trust as the core, we are committed to building an open value circulation network to allow digital assets to flow freely. What Bubi wants to do is to create a new technology and product - to realize real value circulation and bring the Internet to a new level. With the application of this technology, there will be no central organization when transferring assets, and direct transfer of assets between us can be achieved.
In the current international financial market, the U.S. Central Bank, Swiss Bank, and some insurance and futures companies are all competing to develop blockchain technology. Fang Liang introduced that in the Internet financial industry, blockchain technology will first affect financial infrastructure such as payment systems, securities settlement systems, and transaction databases; later, the technology will also expand to general financial services, such as credit systems and "anti-money laundering" "wait.
"The payment and clearing system in the financial field will evolve towards decentralization. The electronic ledger supported by blockchain technology is a reliable system that is error-free and cannot be tampered with. It has various functions for payment, clearing, transaction, confirmation of rights, etc. A profound impact," Li Yan said.
Therefore, industry insiders believe that blockchain technology may be the next trend in the Internet financial industry. As the interconnection of all things deepens, China’sYang Tao, assistant director of the Institute of Finance of the Chinese Academy of Social Sciences, also said that blockchain will make it possible for all individuals to become important nodes in the allocation of financial resources. It will also promote the improvement of existing financial system rules and build a shared and win-win financial system. Develop an ecosystem.
Blockchain technology will affect many industries
"Blockchain technology has been widely used in the era of big data." Li Yan said frankly that in addition to the Internet financial field, blockchain technology has been used in many industries. It has been applied in many fields and has shown great prospects.
For example, the healthcare industry has benefited greatly from blockchain technology. In reality, patient private information leaks often occur, and centralized database or file cabinet management in medical departments is no longer the optimal choice. Medical institutions are using blockchain technology to keep patients' private information confidential.
In addition, blockchain technology also has important legal implications. In some civil fields, it is often necessary to provide evidence to determine blame, and blockchain technology can record every step and help judicial authorities identify the specific responsible person.
"Especially in the field of assets, whether it is physical assets such as real estate and cars, or intangible assets such as health and reputation, this technology can be used to complete registration, transactions, and tracking. It can be said that any production and life that lacks trust In all fields, blockchain technology will have its place."
The development of blockchain technology has also brought about changes in the operational concepts of various industries. New technologies and new concepts have promoted new developments in various industries. This The impact of this driving force on society and the promotion of economic activities are also huge. Many new industry phenomena will occur one after another, and the public is also waiting and watching, expecting this brand-new technology to be used by various industries and better benefit all industries.
The so-called blockchain technology, also known as distributed ledger technology, is an Internet database technology that is characterized by decentralization. , open and transparent, allowing everyone to participate in database records.
Explained in layman’s terms: If the database is assumed to be a ledger, reading and writing the database can be regarded as a bookkeeping behavior. The principle of blockchain technology is to find out the fastest and best bookkeeping within a period of time. This person will keep accounts, and then send this page of information to everyone else in the entire system. This is equivalent to changing all the records in the database and sending them to every other node in the entire network, so blockchain technology is also called a distributed ledger.
What is the core technology of Jinwowo blockchain technology?
Chongqing Jinwowo analyzes the core technologies of blockchain technology as follows:
Distributed ledger technology, asymmetric encryption technology and smart contracts.
The core of the blockchain is that it stores all information in an independent personal computer network, making it decentralized, distributed structure.
This means that the system is not owned by a controlling company or person, but that everyone can use and run the system.
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What is blockchain technology?Blockchain has been hyped up like crazy, but you know nothing about it!
Blockchain is a distributed database system participated by different nodes and an open ledger system.
It consists of a series of data blocks or data packets generated according to cryptographic methods, that is, blocks. Each block of data information is automatically timestamped, thus Calculate a data encryption value, that is, a hash value (hash).
Blockchain technology is essentially a distributed accounting technology. It allows everyone to have an instantly synchronized ledger in their hands. Every transaction that occurs in the entire network will have thousands of backups and synchronous records. When perpetrators attempt to tamper with ledger data, they must change the ledger in the hands of the majority of people to achieve their goal.
❼ What is the consensus mechanism known as the "soul of the blockchain"?
We know that the blockchain is a decentralized distributed accounting technology. In the blockchain system, Without a centralized accounting institution like a bank, how to ensure the consistency of each transaction on all accounting nodes? The consensus mechanism solves this problem, so it can also be said that the consensus mechanism is the soul of the blockchain.
Currently, the more common consensus mechanisms include: PoW (Proof of Work), Proof of Stake and Delegated Proof of Stake:
01
PoW (Proof-of-Work)
Proof of Work Mechanism
The full name of POW is Proof of Work, which means “Proof of Work” or “Proof of Work”. digHow much monetary reward a miner receives depends on the effective work of the mining contribution. That is to say, the better the performance of the mining machine and the longer the mining time, the more monetary rewards are obtained.
BTC is the most successful cryptocurrency under the POW mechanism. Although the POW mechanism has successfully proven its long-term stability and relative fairness, under the existing framework, the use of POW's "mining" form will consume a large amount 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 amount of GAS in a single block, and the transaction frequency that can be achieved is about 25TPS, which is the same as the average thousand times per second and peak performance. There is a huge difference between VISA and MASTERCARD, which can achieve processing efficiency of 10,000 times per second.
02
PoS (Proof-of-Stake)
Proof of Stake Mechanism
POS is Proof of Stake or Equity Proof, the full name is Proof of Stake. The proof-of-stake model is a model that issues interest based on the amount and time of the currency held.
POS mechanism, compared to POW, POS mechanism saves energy and introduces the concept of "coin age" 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 "coin age" held by the currency holder will be cleared and a new cycle will be re-entered.
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, as many as possible to clear his "coin days". 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 term, the speed of generating blocks (i.e. clearing the “coin age”)It is far lower than the speed of network propagation and broadcasting. Therefore, under the PoS mechanism, it is necessary to "speed limit" the generated blocks to ensure the stable operation of the main network.
03
DPoS
Delegated Proof of Stake Mechanism
DPOS is delegated proof of stake.
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.
04 Other consensus mechanisms
There are other consensus mechanisms in the blockchain system, such as PBFT commonly used in alliance chains, POI used in New Economic Coin (NEM), etc. These consensus mechanisms are proposed to solve some shortcomings of existing consensus mechanisms. But there are not as many systems currently in use as POW, POS and DPOS.
The consensus mechanism is the core of the blockchain system, which determines the degree of decentralization, performance and security of a blockchain system. Therefore, in the development of public chains, the design of the consensus mechanism is the core and key.
