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① What is "blockchain"

Blockchain is a public ledger. There is no centralized hardware or management organization. Any Everyone can automatically verify the authenticity of the ledger and easily discover whether the ledger has been tampered with by others.

In a word, the blockchain is a public ledger that can be verified by everyone.

The concept of being verifiable by everyone is crucial to blockchain.

Bitcoin uses the blockchain to record all transactions, so anyone knows the number of Bitcoins on each account.

So, as a publicly verifiable ledger, what are some use cases for blockchain?

In fact, there are many use cases that can be thought of. Blockchain is suitable for any data that can be recorded on a public ledger. Here are 4 examples:

1. Decentralized domain name server, namely domain currency. The domain name server is actually a ledger that records domain names.

2. Trustless public key encryption, such as https that discards unreliable certification authorities.

3. Ownership records, truthfully record the items and their corresponding owners.

4. Contracts and performance guarantees, the account book truthfully records the parties to the contract and saves the contract text.

But don’t forget that blockchain also has a very important component.

The ledger recorded using blockchain technology will always be updated. New data such as transactions, domain name inputs, records and contracts will be converted into hash values ​​of the same length by the hash algorithm and saved. However, hashing algorithms are not only not free but also very expensive.

Therefore, the ledger itself needs to have a recognition system to recognize the person who enters the block hash value.

In Bitcoin, this system is called mining and is rooted in the Bitcoin protocol. Bitcoin miners use a hash algorithm to convert transactions waiting for verification into hash values, and charge a certain amount of Bitcoin as a service fee.

Therefore, for non-monetary use cases, blockchain needs to find a way to bear the high cost of hashing algorithms.

I would like to remind everyone that my answer mainly focuses on the possible use cases of blockchain technology, and does not cover all aspects of blockchain, such as why hashing algorithms are so expensive. I'm sure you can find a lot of detailed information about Bitcoin and other blockchain applications online.

Supplement

Although blockchain technology has many advantages, there are still some less than ideal use cases. For example, there is no way to convert Bitcoin into any national currency; a ledger with billions of data entries would take up space and be impractical.

Bitcoin has shown the world that blockchain technology canIt is feasible in theory, and people are also trying to solve these increasingly prominent problems, such as technological transformation of Bitcoin or the introduction of a completely different blockchain technology. I think the following two methods are worth trying: one is to split the ledger according to certain standards such as the payer address, and the other is to introduce a main blockchain to verify the sub-blockchain. Blockchain technology is ever-changing and dazzling, and it’s unknown whether someone is already making such an attempt. But Bitcoin is still the world's first currency blockchain, what others call a cryptocurrency.

Whether in the technology circle or the financial circle, blockchain has become the hottest word, no one. Blockchain has core advantages such as decentralization and trustlessness, and can perfectly solve problems such as information asymmetry, high transaction costs, and trust of strangers in the development of the sharing economy, making "individual economy" possible. Based on this, blockchain technology is considered to be the core technology that has the greatest potential to trigger the fifth wave of disruptive revolution after steam engines, electricity, information and Internet technology.

In this context, a blockchain craze was born in society, and everyone praised it overwhelmingly. Dialectics tells us that everything has flaws, and only by seeing the pros and cons of things can we make rational decisions. Therefore, in this article, Xue Hongyan (Hong Yanweiyu), a senior researcher at Suning Financial Research Institute, focuses on pouring some cold water on the blockchain.

| What is Blockchain

Blockchain, English Blockchain, has a rather mysterious technological flavor in its name, and can be simply broken down into "data blocks" and "links". Each data block contains all the information exchange data of the system within a certain period of time, and is encrypted using cryptographic methods; the link means that each block has a link relationship with the next block, thus forming a blockchain.

It is generally believed that blockchain has two major characteristics: decentralization and trustlessness. A brief introduction is as follows:

Since each block contains all the information exchange data of the system within a specific period of time, Therefore, each block is equal, and the damage of a single block does not affect the security of the entire system, so the blockchain has decentralized characteristics.

Similarly, since each block contains all the information of the system, the authenticity of the information can be cross-verified. Only by breaking through more than 51% of the nodes can the information be tampered with. In a large enough blockchain system , the cost is extremely high, it can be considered that the information in the blockchain is true, so the blockchain has the characteristics of trustlessness.

Most people’s understanding of blockchain begins with Bitcoin. The relationship between the two is that blockchain is the underlying technology and concept, and Bitcoin is only the most popular application of blockchain at present. .

Maybe the above is not popular enough. Finally, let me summarize, what do you think the blockchain is? It is a disruptive new technology? NO! According to Xue Hongyan (Hong Yanweiyu), a senior researcher at Suning Financial Research Institute, blockchain is not so much a new technology as it is a new ideological concept. The information encryption and other technologies included in the blockchain have been around for a long time, and it is more of a conceptual innovation. This is also the reason why the blockchain has a huge impact. New technologies will be surpassed sooner or later, ranging from one or two years to four to five years; only innovative ideas have enough energy to affect all aspects of the economy and society.

| Blockchain is expected to change the underlying rules of the financial system

In applications in the financial field, blockchain will change the transaction process and record keeping methods, thus significantly reducing transaction costs. It has significantly improved efficiency and is considered to have a broad market environment in digital currency, cross-border payment and clearing, bill trading, securities issuance and trading, property rights transactions, customer credit reporting, anti-fraud, and anti-money laundering.

Such a good technology is naturally sought after by everyone. Like many traditional financial people, Hong Yanweiyu resisted it at first, thinking that this thing was not that great, and did not do any research specifically. Later, as the research on financial technology gradually deepened, it was discovered that blockchain was an obstacle that could not be bypassed, because whether it was robo-advisory, big data risk control or online lending, they were only technological innovations at the financial business level and risk control level. It has not penetrated the bottom layer of the financial system. What is the underlying layer of the financial system? Naturally, it is payment and settlement, transaction rules and system interaction. What the blockchain changes is precisely the underlying rules.

Therefore, throughout the world, financial institutions are the most active in researching blockchain. If nothing else, they are really afraid. After the decentralization and trustless features of the blockchain are fully utilized, what else will the intermediaries of financial institutions do? It is estimated that this is also the first feeling of many people who have a preliminary understanding of blockchain.

In this article, Hong Yanweiyu focuses on pouring cold water on this view.

| Subverting the financial system, blockchain still faces two mountains

Marxist dialectics tells us that everything has two sides. The more prominent the advantages, the more obvious the flaws. It’s just the perspective. Just different. The two major problems with blockchain subverting the financial system lie precisely in the two major advantages of decentralization and trustlessness.

First, let’s talk about decentralization. First, we need to clarify a truth. Does centralization necessarily mean low efficiency? Of course not. Within a specific scope, the concentration of resources brought about by centralization can greatly improve efficiency. This is also the reason why human beings evolve from individuals to villages to tribes and then to countries in the process of evolution. Take UnionPay as an example. UnionPay is the clearing and settlement center for the domestic banking industry. After UnionPay is established, each bank only needs to connect with UnionPay to realize transactions with all banks. If it is decentralized, without UnionPay, each bank will need to When communicating with all counterparties, which one is more efficient? Therefore, there is no need to beat centralization to death with a stick. The decentralized characteristics of blockchain are destined to only be used in certain fields.How can it disrupt everything if the domain (that is, a domain not suitable for centralization) comes into play?

Furthermore, it is a matter of trust. There is nothing wrong with detrusting itself, but the technical logic behind it is deeply flawed. Blockchain relies on universal accounting to achieve trustlessness, that is, all transaction information is retained in each block for system cross-verification to identify authenticity. Here comes the problem. Each block retains all transaction information. There is no problem on a small blockchain. However, as more and more information is added, it will inevitably lead to an explosive growth of transaction information and will also bring information. Dramatic increase in storage costs. At the same time, the greater the amount of information, the longer cross-validation takes and the lower the efficiency. Therefore, the blockchain solves the trust problem, but it brings about rising costs and declining efficiency.

Nothing in the world is perfect, and the same is true for blockchain.

As a conclusion, Hongyanweiyu wants to clarify that blockchain, as a conceptual innovation, does have great value and can also have a disruptive impact in specific fields. However, the current one-sided thinking about blockchain is problematic. Eastern wisdom tells us that "the most brilliant and the golden mean", in the face of anything, it is wisest to maintain the golden mean.

(Text/Xue Hongyan, senior researcher at Suning Financial Research Institute; WeChat public account: Hongyan Weiyu)

As early as a few years ago, the word "mining" came with Bitcoin is well known for its popularity. Many people know about Bitcoin first and then the blockchain, and they even don’t know about the blockchain yet. By definition, blockchain is a series of data blocks generated using cryptographic methods. Each data block contains information about a Bitcoin network transaction, which is used to verify the validity (anti-counterfeiting) and generation of its information. Next block.

I am not a computer technology expert. The following introduction to blockchain comes from reading and comments from expert friends and is for reference only.

If you want to use one word to explain blockchain, it is: distributed accounting.

To understand what this word means, you need to first understand that traditional accounting has a center. For example, in a bank, when you withdraw money from a bank deposit or lend money to others through the bank, the bank is the center, and all these transactions are based on the bank's credit. What if the bank cheats? Or is it more serious, is the country cheating? The Kuomintang's indiscriminate issuance of gold yuan coupons at the end of its rule in mainland China, as well as the hyperinflation in Weimar Germany and Zimbabwe, which made the currency less valuable than toilet paper, are very famous examples.

Golden Yuan Coupons

This is the problem that blockchain is aimed at. They believe that decentralized accounting is non-modifiable and non-repudiable. How to achieve decentralized accounting? The basic idea is that all users store all transaction records, making it very difficult to illegally modify the ledger through mathematical methods.Disaster. In this way, the reliability of the ledger is guaranteed.

Specifically, all users exhaustively enumerate random number variables, and the first user to obtain a specific required hash function value (Hash) will have the right to record this round of transactions and obtain the corresponding Bitcoins award. It is transmitted in the form of data blocks, and the data blocks are connected into a chain by appending at the end, so it is called a block chain.

After listening to the introduction, you may feel that this idea is interesting, but it is not as exciting or revolutionary as advertised. Your feeling is right. In fact, the basic logic of blockchain has some unavoidable problems.

For example, the current size of the complete Bitcoin public ledger has exceeded 150 G, and is rapidly increasing at a rate of tens of G per year - just to support 5 million users and 30 million transactions per year. If its processing volume is one day comparable to that of Alipay, the size of the Bitcoin ledger will increase by more than 500 terabytes per year. This is equivalent to backing up the Alipay server's storage data on all users' personal computers. Do you think this is a good idea?

For another example, in the traditional banking system, if you lose your password, it is no big deal. Just report it to the system in time, and your wealth will not disappear. But in the blockchain system, if you lose your password, it will be a huge trouble, and your currency will not be recovered. Not happy? Is it surprising?

Blockchain is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithms. The so-called consensus mechanism is a mathematical algorithm to establish trust and obtain rights and interests between different nodes in the blockchain system

In layman’s terms, it is to play mahjong. Four people can take turns to be the banker, and each other can shoot four people. They all have their own ledger records, but if you want to modify the ledger, you must have more than 50% of the modification rights, so the cost of cheating on the ledger is very high.

In the future, blockchain will be used more in finance to combat money laundering and fraud, because all information can be traced, and in culture it can be used for copyright protection, etc.

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I have seen a lot of people’s explanations of blockchain in official terms, and some may not even be clear to the person explaining it. I will explain blockchain in vernacular below to ensure that everyone can read it. Gotta understand.

What is blockchain? Let me give an analogy. In 50 years, you can buy an electric fan from the supermarket. This electric fan will automatically mine coins for you when it is blowing. You can mine coins automatically while using the electric fan. When you use this electric fan, When the fan breaks down, you can use the mined coins to repair the electric fan. Of course, you can also use the mined coins to buy a new electric fan. Many people think wrongly! Wouldn’t the profits of merchants be less? Let me tell you about a certain brand, this oneWhen the brand's products are sold to you, the products themselves may even be sold to you at a loss. However, once the number of users becomes large and users become more sticky, they can be paid through small fees such as membership fees or service fees, or other methods. profit. Just like this, the mined coins can be purchased and repaired. Although the merchant's profit may be reduced, the merchant has gained more users and greater user stickiness. By this time, it only takes a minute for the merchant to make money.

And the electric fan you bought is equivalent to winding it up for you. What is winding up? If you put your electric fan on the street now, and 10 people come to snatch it, you have no way to prove that the ownership of this electric fan is yours. Once you put it on the chain, it is equivalent to being tied to you. Once it’s settled, you can prove it.

Therefore, the essence of blockchain is to help make people’s lives more convenient. It is equivalent to upgrading on the basis of the Internet, making it safer and more convenient. This is blockchain! It's that simple.

The security of the blockchain is reflected in its irreversibility and the data cannot be tampered with. We all know that in today's society, any data can be modified and conquered by hackers, but the data in the blockchain is impossible to change. Once generated, it cannot be modified unless all users in the blockchain work together. Agree to modify the data, but this is unlikely to happen.

At present, the blockchain is still very immature, just like the Internet bubble burst in 2000. When the bubble bursts, a truly valuable blockchain Internet will be hatched. company.

The wheel of history will not go backwards. Many people are unwilling to accept blockchain. Just like telling you that you can shop online 20 years ago, this is the same ridiculous thing. Time will eventually prove it. .

1. The main function of blockchain is to store information. Any information that needs to be saved can be written to the blockchain and read from it, so it is a database.

2. Anyone can set up a server, join the blockchain network and become a node. In the world of blockchain, there is no central node. Every node is equal and stores the entire database. You can write/read data to any node, because all nodes will eventually be synchronized to ensure that the blockchain is consistent.

3. Everyone works on the same blockchain, everyone publicly shares the current state of the blockchain, everyone agrees on the rules for new data submission and tampering with the blockchain is prohibited. It is difficult to operate in terms of computing power.

If we assume that the database is a ledger, reading and writing the database is an accounting behavior:

Anyone can verify this public ledger, but it does not existA single user can control it. Participants in the blockchain system will jointly maintain the update of the ledger: it can only be modified according to strict rules and consensus, and there is a very exquisite design behind this.

(1) Accounting, the system will find the person with the fastest and best accounting within a period of time, let this person do the accounting, and then broadcast the information on this page of the account book to everyone else on the entire network. node, which is equivalent to changing the database record; (consensus mechanism, cryptography)

(2) Verification, other valid nodes in the entire network check the correctness of the block accounting, and stamp the time Stamp to confirm that the block is legal; (timestamp, mathematics)

(3) Form a single chain, that is, compete for the next block after the previous legal block; (smart contract, encryption technology)

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(4) Storage, the account book is stored in blocks. As transactions increase, new data blocks will be appended to the existing chain to form a chain structure; (distributed structure, information technology) < /p>

(5) Backup, every participating trader is a node of the block network, and each node has a complete backup of the public account book, which is a distributed ledger.

Features

1. The blockchain has no administrator and is completely centerless. It is precisely because it cannot be managed that the blockchain cannot be controlled. Without an administrator, everyone can write data into it. In order to ensure the trustworthiness of the data: the technology of blockchain makes it impossible to tamper with the data once it is written.

2. Close to zero trust cost.

The cycle time required for Internet companies to build their credit is extremely long. For example, Taobao often takes several years to build its credit. In the blockchain, everyone trusts the code, algorithm and rules, so the cost of trust is extremely low.

3. The marginal cost of constructing and trading assets approaches zero.

If traditional assets are to be used for trading, they need to rely heavily on third parties, such as investment banks, banks, securities firms, etc., for packaging and endorsement, and the fees and thresholds are extremely high. With blockchain, these will not be a problem, and the cost is extremely low.

The value transfer attribute of the blockchain also naturally solves the payment problem, and has the genes to support global payments.

According to my current understanding

1. Blockchain is an outlet.

Everyone is talking about blockchain. Whether they have read it or not, whether they understand it or not, many people are forwarding blockchain articles in their circle of friends. The only new WeChat group is Blockchain related groups.

Investors are talking, entrepreneurs are talking, almost every major Internet company is talking about it, government departments are taking a stand, and tens of thousands of vertical media focusing on blockchain are quickly born.

If you don’t join any currency circle or chain circle, you will be completely out. Even well-known investment tycoonsZhu Xiaohu was unilaterally declared by the rising star Chen Weixing to belong to the old world.

2. Blockchain represents the story of sudden wealth.

Although ICO has been stopped by the national level, the most popular word-of-mouth about blockchain is still the increase in wealth by hundreds or thousands of times. Coins that were bought for a few cents or a few dollars are now worth dozens or hundreds of dollars. Everyone is talking about value-added stories.

There are Bitcoin and Ethereum. If you download a digital currency trading platform APP, the various currency codes composed of densely packed letters will feel like a stock exchange.

3. Blockchain is not only a technology, but also a belief at the conceptual level.

The basic layer, application layer, and a lot of blockchain knowledge seem to have a lot to do with the hot artificial intelligence.

Many people say that blockchain technology is mature, but applications have barely found an entrance. We can all shout loudly: Artificial Intelligence +, but if you shout "Blockchain +" now, it's not enough and you will be laughed at. The application scenarios are still being explored.

As for the previous Internet, it was an Internet of confidence. With the addition of blockchain, it became an Internet of value.

Such similar concepts are people’s good expectations for blockchain technology to solve the trust problem. If it is so easy to implement, blockchain can subvert finance, e-commerce, and many intermediaries. But why has the Internet not been subverted for so many years and real estate still relies on intermediaries?

4. Blockchain already has a history, so don’t think it is too new.

Just as many people claim that artificial intelligence is so new that it is a joke, its history can be traced back to the 1950s.

The blockchain is marked by the birth of Bitcoin, which was also 10 years ago. There is also a still mysterious founder Satoshi Nakamoto, who seems to have a Japanese name, and some say he is from the United States. From the Security Bureau, I think it can also be interpreted as "Chinese people are inherently smart", of course the latter is just a joke.

The reason why it has become so popular is because of the skyrocketing price of various digital currencies in 2017, which skyrocketed thousands of times in a few months and days. How could there be such an amazing speed in the past?

5. Blockchain is a knowledge system.

For me, whether it is a trend, whether it is a wealth game, or whether it is technology, we cannot ignore it or ignore it.

I started to make two columns to understand the blockchain from the perspective of characters, stories and characters. One is "Blockchain 100 People (Industry People)" and the other is "Blockchain 100 Investors". (Viewpoint)” Learn and spread at the same time.

As for the related books, of course I accept them all as ordered, and I can only be a follower of various trends, following suit.

Max.The mistake is not how we criticize the blockchain, but when we see it has a huge bubble and the crowd is enthusiastic about it, we ignore it, and we think we are noble and stay away from it.

The only way we have left is to be willing to be students, learn, and learn again.

Literal meaning: block, chain, using a chain to connect each block.

Blockchain = distributed data storage + point-to-point transmission + consensus mechanism + encryption algorithm

What is data storage? For example, a supermarket must have a ledger to record the entry and exit of various goods and transactions. This is storage.

What is distributed storage? It is the account book of this supermarket. Every employee has a copy. Every time there is something that needs to be recorded, it will be recorded in everyone's account book in a timely manner. Distributing each ledger (storage) to countless people (places) is distributed storage. (The supermarket employees here can be understood as blocks, and the ledger is the chain)

What is point-to-point transmission? In the same supermarket, there is no yogurt at the front desk. The shopping guide reports it to his superiors, and then reports it to his superiors.... Finally, he reports it to the warehouse. The warehouse records the accounting records in the ledger, and then transfers the goods to the front desk. As for point-to-point transmission, if there is no yogurt at the front desk, the shopping guide directly tells the warehouse, and the quantity sent by the warehouse to the shopping guide is recorded in the ledger. Everyone knows how many goods the warehouse has sent to the front desk. This is point-to-point transmission. There is no intermediate link, but the accounts can be made public for everyone who holds the ledger to see.

What is consensus mechanism? The consensus mechanism mainly includes two points. In a simple summary, the minority obeys the majority and everyone is equal. Similarly, the positions in this supermarket may be high or low, but everyone’s account books are indeed the same and equal. If someone makes a false account, then this person's account must be different from other people's accounts. At this time, it depends on whose account is remembered by more people. In theory, as long as the blockchain is large enough, then there is no need to make false accounts. Limit reduction! Because of the "minority obeys the majority" mechanism, if you want to make false accounts, then the number of false accounts you need to make must be at least greater than 50% of the total! On a network, if you need to change a piece of data, you must control at least 50% of the total number of computers to succeed.

The encryption algorithm is easy to understand. That is, when you go to the warehouse to adjust goods, the system will protect your privacy very well. It will only record the time, location, and person with a certain number who went to adjust the yogurt. It couldn't be the time, place, or Zhang San went to mix the yogurt. Taken together, this is the core component of the blockchain.

Personally, I think its main function is to decentralize and protect data from being tampered with! Decentralization and data protection are actually related. A supermarket only has one ledger, and any scheduling needs to go through the person who manages the ledger. If you need to make false accounts, you only need to control the person who manages the ledger. And if that supermarket uses blockchain technology, then he will make false accounts. If so, you need to control the company that is larger than the one you own.50% of the total number of supermarket accounts is obviously controlled by so many people. As the number of holders increases, it is almost impossible.

② What are the core blockchain technologies of blockchain technology?

What is the hottest Internet topic at the moment? You don’t need to explain it to the editor to know that it is the blockchain. Blockchain technology, but many friends have only heard of this technology and do not have much in-depth understanding of it. So what are the blockchain technologies? Below we will bring you an introduction to the core technology of blockchain for your reference.
What are the core elements of blockchain technology?
Blockchain technology can be a public ledger (visible by anyone) or a permissioned network (visible only by those authorized), which solves supply chain challenges , because it is an immutable record that is shared among network participants and updated in real time.
Blockchain technology----data layer: designing the data structure of the ledger
Core technology 1. Block + chain:
Technically speaking, block is a data structure that records transactions. Reflects the flow of funds for a transaction. The blocks of transactions that have been reached in the system are connected together to form a main chain, and all nodes participating in the calculation record the main chain or part of the main chain.
Each block consists of a block header and a block body. The block body is only responsible for recording all transaction information in the previous period, mainly including the number of transactions and transaction details; the block header encapsulates the current version number, previous A block address, timestamp (recording the time when the block was generated, accurate to seconds), random number (recording the value of decrypting the answer to the math question related to the block), target hash value of the current block, and Merkle number Root value and other information. From a structural point of view, most functions of the blockchain are implemented by the block header.
Core technology 2. Hash function:
The hash function can convert data of any length into a set of fixed-length codes through the Hash algorithm. The principle is based on a cryptographic one-way hash function. This kind of function is easy to verify, but difficult to crack. Usually, the industry uses y=hash(x) to represent it. This hash function implements operations on x to calculate a hash value y.
Commonly used hash algorithms include MD5, SHA-1, SHA-256, SHA-384 and SHA-512, etc. Taking the SHA256 algorithm as an example, inputting any string of data into SHA256 will result in a 256-bit Hash value (hash value). Its characteristics: the same data input will get the same result. As long as the input data changes slightly (for example, a 1 becomes a 0), a completely different result will be obtained, and the result cannot be predicted in advance. Forward calculation (calculating the corresponding Hash value from the data) is very easy. Reverse calculation (cracking) is extremely difficult and is considered impossible under current technological conditions.
Core technology 3. Merkle tree:
Merkle tree is a hash binary tree, which can be used to quickly verify the integrity of large-scale data. In the blockchain network, the Merkle tree is used to summarize all transaction information in a block, and ultimately generates a unified hash value of all transaction information in the block. Any change in transaction information in the block will cause Merkle tree changes.
Core technology 4. Asymmetric encryption algorithm:
Asymmetric encryption algorithm is a key secret method that requires two keys: public key and private key. The public key and the private key are a pair. If the public key is used to encrypt data, only the corresponding private key can be used to decrypt it, thereby obtaining the corresponding data value; if the private key is used to sign the data, then only the corresponding public key can be used to sign the data. In order to verify the signature, the sender of the verification information is the holder of the private key.
Because encryption and decryption use two different keys, this algorithm is called an asymmetric encryption algorithm, while symmetric encryption uses the same key in the encryption and decryption processes.
Blockchain technology----network layer: realize the decentralization of accounting nodes
Core technology 5. P2P network:
P2P network (peer-to-peer network), also known as point-to-point technology, is no Central server, Internet system that relies on user groups to exchange information. Unlike a centralized network system with a central server, each client in a peer-to-peer network acts as both a node and a server. Domestic Xunlei software uses P2P technology. The P2P network has the characteristics of decentralization and robustness.
Blockchain technology----Consensus layer: allocate the task load of accounting nodes
Core technology 6. Consensus mechanism:
Consensus mechanism is how to reach consensus among all accounting nodes to identify The validity of a record is both a means of identification and a means of preventing tampering. There are currently four main types of consensus mechanisms: PoW, PoS, DPoS and distributed consensus algorithms.
PoW (Proof of Work, proof of work): PoW mechanism, which is like Bitcoin’s mining mechanism, miners package existing transactions that have not been recorded by the network into a block, and then continue to traverse and try to find a random number , so that the hash value of the new block plus the random number meets certain difficulty conditions. Finding a random number that meets the conditions is equivalent to determining the latest block of the blockchain, and is also equivalent to obtaining the current round of accounting rights of the blockchain. Miners broadcast blocks that meet the mining difficulty conditions in the Yuanfu network. After verifying that the block meets the mining difficulty conditions and that the transaction data in the block meets the protocol specifications, other nodes in the entire network will each Blocks are linked to their own version of the blockchain, thereby forming a network-wide consensus on the current network state.
PoS (ProofofStake, Proof of Stake): PoS mechanism requires nodes to provide proof of a certain number of tokens to obtain a distributed consensus mechanism for competing for blockchain accounting rights. If you rely solely on the token balance to determine the bookkeeper, you will inevitably make the rich win, which will lead to the centralization of bookkeeping rights and reduce the fairness of the consensus. Therefore, different PoS mechanisms will be used in the proof of rights.On the basis of different methods are used to increase the randomness of accounting rights to avoid centralization. For example, in the PeerCoin PoS mechanism, the Bitcoin with the longest chain age has a greater chance of obtaining accounting rights. NXT and Blackcoin use a formula to predict the next accounting node. The more tokens you own, the greater the probability of being selected as an accounting node. In the future, Ethereum will also switch from the current PoW mechanism to a PoS mechanism. Judging from the information currently available, Ethereum's PoS mechanism will use nodes to place bets on the next block. The winner of the bet will receive an additional Ethereum currency award. Those who do not win will be deducted Ether coins to reach consensus on the next block.
DPoS (DelegatedProof-Of-Stake, share authorization certificate): DPoS is easy to understand and is similar to the modern corporate board of directors system. The DPoS mechanism adopted by BitShares is that shareholders vote to select a certain number of witnesses. Each witness has two seconds of authority to generate blocks in order. If the witness cannot generate a block within the given time slice, The block generation authority is given to the witness corresponding to the next time slice. Shareholders can replace these witnesses at any time by voting. This design of DPoS makes the generation of blocks faster and more energy-saving.
Distributed Consistency Algorithm: Distributed Consistency Algorithm is based on traditional distributed consistency technology. Among them are Byzantine fault-tolerant algorithms that solve the Byzantine Generals problem, such as PBFT (Byzantine fault-tolerant algorithm). In addition, distributed consensus algorithms (Pasox, Raft) that solve non-Byzantine problems are not explained in this article. This type of algorithm is currently a commonly used consensus mechanism in alliance chain and private chain scenarios.
Taken together, POW is suitable for public chains. If you build a private chain, it is more suitable to use POS because there is no trust problem in verification nodes; and because there are untrustworthy local nodes in the alliance chain, it is more suitable to use DPOS.
Blockchain technology----Incentive layer: Develop a "salary system" for accounting nodes
Core technology 7. Issuance mechanism and incentive mechanism:
Take Bitcoin as an example. Bitcoins are initially rewarded by the system to miners who create new blocks, and this reward is halved approximately every four years. At the beginning, miners were rewarded with 50 Bitcoins for each new block recorded, and this reward is halved approximately every four years. By analogy, by around AD 2140, newly created blocks will no longer receive rewards from the system. By then, the total number of Bitcoins will be approximately 21 million. This is the total number of Bitcoins, so it will not increase indefinitely.
Another source of incentives is transaction fees. When there are no system rewards for newly created blocks, the miners' income will change from system rewards to transaction fees. For example, when you transfer, you can specify 1% of it as a handling fee to be paid to the miner who records the block. If the output value of a transaction is less than the input value, the difference is the transaction fee, which will be added to the incentive for that block. As long as a given amount of electronic currency has entered circulation, the incentive mechanism can gradually changeInstead of relying entirely on transaction fees, there would be no need to issue new currencies.
Blockchain technology----contract layer: giving the ledger programmable features
Core technology 8. Smart contract:
Smart contract is a set of programmed rules and logic that respond to scenarios. Implemented by decentralized, trusted shared script code deployed on the blockchain. Normally, after the smart contract is signed by all parties, it is attached to the blockchain data in the form of program code, and is recorded in a specific block of the blockchain after being propagated through the P2P network and verified by nodes. Smart contracts encapsulate a number of predefined states and transition rules, scenarios that trigger contract execution, response actions under specific scenarios, etc. The blockchain can monitor the status of smart contracts in real time, and activate and execute the contract by checking external data sources and confirming that specific trigger conditions are met.
The above is what blockchain technologies the editor has brought to you? All content of the introduction to the core technology of blockchain.

③ What is blockchain? Explanation of blockchain technology

Blockchain is a new application model of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithm. Blockchain is an important concept of Bitcoin. It is essentially a decentralized database.

At the same time, as the underlying technology of Bitcoin, it is a series of data blocks generated using cryptographic methods. Each data block contains a batch of Bitcoin network transaction information, which is used to verify its Validity of information (anti-counterfeiting) and generation of the next block.

The blockchain is a public data list, and each record in it is called a block. These blocks are connected together like a chain to form a blockchain. Just like an idiom solitaire, there must be some connection between adjacent words to form a word chain. The same is true for blockchain, but the connection between blocks is much more complex.

(3) Blockchain information exchange csdn extended reading

Blockchain technology innovation does not mean speculating on virtual currencies, and the use of blocks should be prevented Chains issue virtual currencies and speculate on air coins. At the same time, we should also note that blockchain is still in its early development stage and needs further development and improvement in terms of security, standards, supervision, etc.

The general direction is not wrong, but it is necessary to avoid rushing in and duplicating construction, and to open up the imagination space of the blockchain in orderly competition. China has a good foundation in the field of blockchain. Some large Internet companies have already laid out their plans. The talent pool is relatively sufficient and the application scenarios are rich. It is fully qualified to achieve a leading position in this new track.

From a larger perspective, human beings can develop civilization because they have achieved effective cooperation among large-scale groups of people. The "invisible hand" explained by Adam Smith also realizes the division of labor and cooperation in human society through the market mechanism.

From this perspective, blockchain has greatly expanded the breadth and depth of human trust and collaboration. Perhaps, blockchain is more than just the next generation of the InternetTechnology is the next generation of cooperation mechanisms and organizational forms.

④ What changes can blockchain bring to data sharing

What changes can blockchain bring to data sharing
Currently, text and text are shared on social networking sites Taking photos and sharing each other's joys, sorrows and joys has become an important part of public life.
With the progress of the times, sharing is gradually entering the real society. A series of shared economic models such as shared bicycles, shared umbrellas, shared power banks, and shared cars have emerged, bringing great convenience to human life. .
As a distributed shared ledger, blockchain technology seems to be inherently inseparable from sharing, and industry insiders continue to claim that this technology can bring revolutionary progress to sharing.
So, what is the difference between blockchain-based sharing and Internet-based sharing? This article takes data sharing as an example to answer this question.

Blockchain shares more than just data
Data sharing is an innate need of human beings. For example, talking about life ideals in a cafe, writing text, etc., these are all An important way for ordinary people to communicate information with others.
The emergence of the Internet has broken the geographical and time limitations of data sharing. It allows different people to communicate instantly in different locations on the earth. The emergence of email, online instant messaging and other technologies has greatly improved the efficiency of information transmission. efficiency.
In addition, the Internet can collect massive amounts of data, providing a larger capacity than paper archives, allowing users to obtain rich information in a short period of time.
So, how is all this different under blockchain technology?
In fact, blockchain technology is not concerned with the sharing of data, but the sharing of data control permissions. The permissions here mainly refer to the power to modify and increase data. It mainly contains two meanings:< br />One is who can modify the data
The other is how to modify it.
In the Internet model, data reading, writing, editing and deletion are generally accompanied by identity authentication operations. Only specific people can modify the data. In the blockchain model, especially the public chain system Under this system, anyone can participate in reading and writing data, and a trustless system is built in the form of a distributed ledger. The various organizations or individuals participating in reading and writing can not trust each other, but can store the final status of the data in the system. Reach a consensus.
To put it simply, the essential difference between blockchain-based sharing and Internet-based sharing is that blockchain shares not just data, but the control of data. So, how exactly does blockchain handle data control?
Blockchain controls data through rules
Before the emergence of blockchain technology, Internet data was usually controlled by a single entity. Since the website operator has complete control over the central server, these organizations can edit and process the data at will. Although organizations also need to complete data modification and other behaviors under certain laws and agreements,, but because it is the party that controls the resources, it is difficult for individual users to enjoy complete control.
To give a simple example, a user uploads a photo to the website platform and hopes that friends can see the photo. Excluding some illegal elements, who has the final control over this photo?
Obviously, from the user's point of view, this photo belongs to them, but in fact, these social networking sites are the real controllers. They can modify it at will, but users have nothing to do.
In other words, under the existing Internet system, as long as you have the right to operate the website platform, you can completely control the data on the platform.
Under the blockchain system, data is not controlled by any authoritative party, and its authority is controlled by rules. The main goal of these rules is to stipulate what kind of information is valid, and also stipulates How participants should provide feedback on it.
These rules are usually pre-defined and participants joining the blockchain network must abide by the rules. Of course, technically speaking, participants can ignore certain rules and construct invalid data based on their own interests. However, due to the existence of the blockchain consensus mechanism, other participants can exclude these invalid data from the network based on predefined rules.
For example, in the blockchain blacklist sharing platform system launched by Suning Financial, there are many such rules-no data can be queried without points, only the organization has the authority to modify the data of this organization, etc. Once an institution performs an operation outside the rules, these operations will be regarded as invalid transactions and are prohibited from occurring.
In general, blockchain regulates data writing behavior based on a technical rule system, while the Internet controls data through power and resources. This is the foundation of blockchain-style sharing and Internet-style sharing. sexual distinction.
Blockchain rules are jointly maintained by participants
Although there are some rules in the Internet environment, because the rules are completely maintained by the power parties, it is difficult to avoid black-box operations and other behaviors. In the blockchain system, the rules are jointly maintained by all participants, and each participant will independently verify the data according to the rules.
In this process, we cannot assume that all participants can fully comply with the rules. Therefore, each participant will independently verify the data it receives and determine whether it violates the rules. If the verification data is valid, then the participant will accept the data and forward it to others, otherwise, it will be rejected directly.
Within the blockchain network, new data can be considered valid data and added to the final blockchain shared ledger only when relevant participants agree.
Depending on how the blockchain is constructed, there are big differences in how data is confirmed. For example, in a public chain, most participants need to agree on the validity of the data, while in a consortium chain or private chain, Only a few participants need to agree.
In this way, refer toThe participants themselves are managers, which is the core expression of blockchain decentralization: no institution is superior to others and has complete control over the data.
Blockchain is a form of permission sharing, allowing each participant to serve as a data provider, verifier and user at the same time, jointly maintaining the security and validity of blockchain data.
Since the popularity of blockchain, blockchain for everything seems to have become the advertising slogan of the industry, especially some data sharing applications are considered to be excellent examples of blockchain.
In fact, the emergence of the Internet has solved the problem of data sharing to a certain extent. Blockchain realizes the sharing of permissions. This is the most revolutionary change that blockchain has brought to the industry.

⑤ What is the concept of blockchain? Read it in three minutes!

On October 25, 2019, Xinwen Broadcast sent a very important signal: the country must vigorously develop blockchain. After that, blockchain has become an Internet celebrity, and the figure of "blockchain" is floating in the streets and alleys. In fact, many technology companies have already deployed blockchain technology.

Although blockchain is very popular, many people do not know much about blockchain.

What is blockchain?

Let’s first take a look at how Du Niang explained it. Network display: Blockchain is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithms.

Why is blockchain called blockchain?

The blockchain is linked by blocks one by one, and the blocks are storage units one by one, which record the communication information of each block node. The blocks are much like the records of the database. Writing data every time creates a block. With the expansion of information exchange, one block continues with another, and the result is called a blockchain.

What are the characteristics of blockchain?

Blockchain mainly has the following characteristics:

1. Decentralization: In the blockchain system, every node has equal rights. and obligations, there is no central control here. Decentralization has well established trust relationships with each other. Although there is no central management organization, people can collaborate with each other and trust each other. This mainly applies blockchain distributed ledger technology.

2. Openness: Blockchain data is open to everyone. Except for some encrypted information that is not open, everyone can check the data here.

3. Independence: The entire blockchain system does not rely on other third parties. All nodes can automatically and securely verify and exchange data within the system without any human intervention.

4. Security: Blockchain has certain securityNature, cannot be tampered with. Because everyone in the blockchain system has the same ledger, if someone wants to tamper with it, it is possible to forge a non-existent record only if they control more than 51% of the accounting nodes. Of course, this is basically impossible. This is mainly due to the core technology of the blockchain: the consensus mechanism. The consensus mechanism has the characteristics of "the minority obeys the majority" and "everyone is equal".

5. Anonymity: Many people think that if the blockchain is so open and transparent, will we lose privacy? In fact, no, although the transaction information in the blockchain is open and transparent, the identity information of the account is encrypted and can only be accessed with authorization.

Now let me tell you a story to help you better understand the blockchain.

There are three people in the family, mom, dad, older brother and younger brother. Last year, my father was in charge of the family's account books. He was responsible for all the family's income and expenses alone.

However, on the day of Double Eleven, my mother, who has always been frugal, wanted to buy herself a beautiful piece of clothing on a certain online store. When she checked the account book, she found something was wrong. It stands to reason that except for some money deposited in banks and financial management, the whereabouts of the daily consumption money at home are all in this account book, but no matter how you look at it, it is wrong. Some consumption is clearly not recorded, but is recorded.

Later, my father took the initiative to confess that he couldn’t help but buy a pack of cigarettes.

Later, my mother changed her strategy and the whole family kept accounts. Everyone recorded their monthly consumption expenditure in their own account books. Whenever there was a transaction or consumption at home, my mother would shout, "Book it," and everyone would record the transaction in their own books. This is the decentralized accounting model, where everyone is the center and everyone has a ledger.

The previous accounting model for dad was centralized accounting. If dad wanted to do something alone, it would be difficult for anyone to see it. The decentralized accounting model has solved the problem of centralization very well. The disadvantage of bookkeeping is that it is very difficult for dad to tamper with the books.

For example, if dad wants to take some money from the ledger and secretly buy cigarettes, the amount of money is limited, and if he wants to take the money, he has to change the ledger, but he only tampered with his own ledger. No, he had to change the accounts of three people including himself. And this is undoubtedly more difficult than reaching the sky.

So, many times my father had the idea of ​​smoking, but he had no choice but to give up the idea due to the current situation.

Are blockchain and Bitcoin the same thing?

In fact, blockchain and Bitcoin are not the same thing. It is just the underlying technology of Bitcoin. Bitcoin is the first digital currency applied by blockchain.

2008 Satoshi NakamotoThe concept of blockchain was once proposed, and in the following years, became a core component of the electronic currency Bitcoin, serving as a public ledger for all transactions. Blockchain was first applied to Bitcoin.

The origin of blockchain is to solve the problem of trust, and one of the most successful applications of blockchain is digital currency. Bitcoin is arguably the most successful application of blockchain so far.

What are the applications of blockchain?

The application of blockchain is actually very wide. In addition to digital currency, the future applications of Bitcoin are still very extensive. Blockchain technology has been widely used in different industries. Such as product traceability, copyright protection and transactions, payment and settlement, Internet of Things, digital marketing, medical care, etc., promoting different industries to quickly enter the "blockchain+" era.

1. Payment and clearing: Blockchain can abandon the role of transit banks, realize point-to-point payment, reduce transit fees, and accelerate fund utilization.

2. Product traceability: For example, if we buy a piece of clothing on a certain store, we can see the past and present life of this piece of clothing.

3. Securities trading: Traditional securities trading requires the coordination of four major institutions, which is inefficient and costly. Blockchain technology can independently complete one-stop services.

4. Supply chain: Introducing blockchain technology into the supply chain system, synchronizing information within the system can control all links, better complete division of labor and collaboration, and facilitate subsequent accountability.

5. Intellectual property rights: With copyright on the chain, our photographic works, musical works, literary works, etc. will become our information, and the ownership of the information will be confirmed and become our property.