Everyone can hear the word blockchain every day recently, so what is blockchain? Explanations such as "distributed, difficult to tamper, and consistent storage" are too technical and dry. Let me give you some popular science here: Blockchain is mainly designed to solve the trust problem between individuals who do not trust each other.

To give a popular example: Lao Li and Lao Wang live in the same village. Lao Li has been a little tight recently and wants to borrow some money from Lao Wang. As for Lao Wang, he was worried about what would happen if he defaulted on the loan after borrowing money from Lao Li, so he called in the "highly respected" village chief. But thinking about it, the village chief couldn't be trusted either. The village chief had even stolen other people's sweet potatoes before! what to do?

The blockchain method is: After Lao Wang borrowed 1,000 yuan from Lao Li, he then used a loudspeaker to shout in the village, "I, Lao Wang, borrowed 1,000 yuan from Lao Li today. Everyone hurry up." "Record it", so everyone in the village recorded it in their own account books and kept it carefully. This is good, Lao Li can't rely on him anymore. Even if there are dishonest people in the village, there are still many good people. Lao Li can't find everyone in the village to secretly erase his loan records. In this way, the blockchain solved the trust problem of borrowing money between Lao Wang and Lao Li, who did not trust each other.

Before the emergence of blockchain, how did we solve the trust problem between individuals who did not trust each other? It's simple, just find a "witness" who is "highly respected" and trusted by both parties, such as the village chief in the story, such as Alipay between the buyer and seller, such as the notary office, etc. However, it is possible that such "witnesses" may not always be honest, so the blockchain simply allows everyone to act as a witness.

Lao Wang is relieved, but Lao Li has a headache! Lao Li has to wait until everyone in the village has recorded the money before he can get the money lent to him. There is no uncle or aunt in the family who is slower. Therefore, there is still a certain distance between blockchain and application, and efficiency issues need to be significantly improved.

Recall how you usually trade with others: you can choose a beautiful dress in a physical store, confirm that the other party’s clothes are of good quality, and the other party confirms that your money is real money. Then we face each other, hand over the money and get the goods.

What if we are thousands of miles apart and neither know nor trust each other but still want to trade? Then there needs to be a third party that we all trust, which is to achieve the so-called independent consciousness mechanism. For example: you can complete the transaction through a third-party witness guarantee on Taobao. The money is first given to Alipay - Alipay collects the payment and lets the seller deliver the goods - the seller delivers the goods - you confirm receipt - Alipay then gives the money to the seller.

However, what if this centralized organization does evil and Dad Ma tears up the account books and refuses to admit that you gave the money, or joins forces with the seller to defraud you of money?

Or maybe the government lends you 1 million, and finally pays you back by issuing extra currency, and the 1 million shrinks to 10,000, leaving you to bear the loss of inflation. What should you do?

Is there a third party that is not controlled by any government or organization, can complete arbitration in an open and transparent manner, has records that will not be tampered with, and has no risk of running away?

Don’t worry, our protagonist blockchain technology solves this problem - the transactions between you can be witnessed by everyone in this blockchain system, and everyone’s small ledger will record you transaction. If B denies receiving money from A, or if A says that he borrowed 300 yuan, passers-by A, B, B, and D will question him. How exactly is it done?

1) The system issues a small ledger to everyone, so that everyone has the right to keep accounts. We call it distributed accounting.

2) In order to encourage everyone to help others keep accounts, the system code is set to reward tokens such as Bitcoin to the keepers. In order to prevent a group of people from being blocked in keeping accounts, the tokens are also set to There are only a limited number of A, B, C and D. They need to be calculated through the mechanism specified by the system. Only the fastest and best can get the right to keep accounts. After the records are broadcast to everyone through the system, everyone will copy the same ledger and get rewards through calculation. The process is called mining, and passers-by A, B, C, and D who keep accounts are miners.

3) One day, A, who originally recorded the transaction, Game Over, but the ledger still exists in other people's ledgers. Neither A nor B can deny it. We have written how to arbitrate and distribute through code, without the need for banks, governments, enterprises and other centralized organizations to serve as third-party witnesses (decentralization), and the direct point-to-point (P2P) transaction method is called decentralization.

4) The system packages multiple transactions into blocks and links them in chronological order to become the final ledger that everyone has. This is blockchain technology

In fact, the blockchain Simply understanding it as a ledger is just the simplest interpretation. If you separate each of its characteristics, it can be applied in many fields.

Now the traditional financial industry, securities firms, and investment institutions are rushing to enter the market. Many fields such as the Internet of Things, games, storage, copyright, anti-counterfeiting, credit reporting, payment, prediction markets (gambling, etc.), and communities have already entered the market. The exploration and application of blockchain began.

The Internet allows everything to be connected. Can blockchain make everything connected trustworthy?

Let me explain the blockchain using the natural stones of heaven and earth:

All science, philosophy, morality? Heaven and earth are included.

Every thing and every culture is related to the Taoism of heaven and earth.

Blockchain naturally cannot escape the laws of heaven and earth: smooth, random, infinite, and impermanent.

It is this strange stone, and the overall data movement on its surface. First, the whole is invisible and formless. Second, the lines and points adhere to a pattern: the path of impermanence. That is to say, every line and every point they pursue is not a closed goal or a limited purpose. I can understand it better when I say this: when a painter wants to paint a chicken, it has a purpose and an ending, while strange rocks, when created by nature, have no ending. Therefore, the phase is not closed, and the line and point data are not terminated. The technology of block connection is this way of destiny. Impermanence is invisible and has no end. (No centralization means formlessness, no form, no closed structure, no closed thoughts? Just act like a "stone").

Confucius Lingshi Museum in Qufu, Shandong

Hello everyone, I am Pippi. I will use a few life examples to explain to you what blockchain is?

A decentralized, tamper-proof, distributed storage, data block link system that uses encrypted information as the link address is called blockchain

There are many things about this. High-tech composite products cannot be simple. No matter how simple it is, it is still a long paragraph, and it may not be clear.

The strict definition of blockchain refers to a ** designed based on cryptography technology. * Identification mechanism method, a distributed database technology in which multiple nodes in a peer-to-peer network simultaneously maintain a continuously growing, chained list ledger constructed of timestamps and ordered record data blocks. This technical solution allows any number of nodes participating in the system to calculate and record all information exchange data in the system over a period of time into a data block (block) through cryptographic algorithms, and generate the fingerprint of the data block for linking ( chain) and check the next data block, all participating nodes in the system will jointly determine whether the record is true.

Blockchain is a general term for technical solutions similar to NoSQL (non-relational database). It is not a specific technology and can be implemented through many programming languages ??and architectures. There are also many ways to implement blockchain. Common ones currently include POW (Proof of Work), POS (Proof of Stake), DPOS (Delegate Proof of Stake), etc.

The concept of blockchain was first proposed in the paper "Bitcoin: A Peer-to-Peer Electronic Cash System", written by the self-proclaimed Satoshi Nakamoto ( Satoshi Nakamoto). Therefore, Bitcoin can be regarded as the first application of blockchain in the field of financial payments.

Popular explanation

No matter how big the system or how small the website, there is usually a database behind it. So who will maintain this database? Under normal circumstances, whoever is responsible for operating the network or system will maintain it. If it is a WeChat database, it must be maintained by Tencent's team, and Taobao's database must be maintained by Alibaba's team. Everyone must think that this approach is natural, but this is not the case with blockchain technology.

If we imagine the database as a ledger: for example, Alipay is a typical ledger, and any change in data is accounting. We can think of database maintenance as a very simple accounting method. The same is true in the world of blockchain. Everyone in the blockchain system has the opportunity to participate in accounting. The system will select within a period of time, maybe within ten seconds, or maybe ten minutes, to select the person with the fastest and best accounting during this period. This person will do the accounting, and he will combine the changes in the database during this period with Changes in the ledger are recorded in a block. We can imagine this block as a page of paper. After confirming that the record is correct, the system will link (chain) the data fingerprint of the past ledger to this paper, and then This piece of paper is sent to everyone else in the entire system. Then the cycle starts over and the system looks for the next person who can do the accounting quickly and well, and everyone else in the system gets a copy of the entire ledger. This also means that everyone in this system has exactly the same ledger. This technology is called blockchain technology, also known as distributed ledger technology.

Since everyone (computer) has exactly the same account book, and everyone (computer) has completely equal rights, the entire system will not be affected by a single person (computer) losing contact or going down. system breakdown. Since there are exactly the same ledgers, it means that all data is open and transparent, and everyone can see the digital changes in each account. Its very interesting feature is that the data in it cannot be tampered with. Because the system will automatically compare, it will consider the account books with the largest number of the same number as the real account books, and the small number of account books with different numbers as others are false account books. In this case, it makes no sense for anyone to tamper with their own ledger, because unless you can tamper with most of the nodes in the entire system.

If the entire system has only five or ten nodes, it may be easy to do, but if there are tens of thousands or even hundreds of thousands, and they are distributed in any corner of the Internet, unless someone can control most of the computers in the world , otherwise it would be unlikely to tamper with such a large blockchain.

Elements

Combined with the definition of blockchain, we believe that it must have the following four elements to be called a public blockchain technology. If it only has the first three elements, we will Consider it private blockchain technology (private chain).

1. Point-to-point peer-to-peer network (peer-to-peer power, physical point-to-point connection)

2. Verifiable data structure (verifiable PKC system, non-tamperable database)

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3. Distributed knowledge mechanism (solve the Byzantine generals problem and double payment)

4. Nash equilibrium game design (cooperation is an evolutionarily stable strategy)

Characteristics

Combined with the definition of blockchain, blockchain will have four main characteristics: decentralized, trustless, and collectively maintained. ), reliable database (Reliable Database). And the four characteristics will lead to two other characteristics: open source (Open Source) and privacy protection (Anonymity). If a system does not possess these characteristics, it will not be considered an application based on blockchain technology.

Decentralized: The entire network has no centralized hardware or management organization. The rights and obligations between any nodes are equal, and the damage or loss of any node will not affect the entire network. operation of the system. Therefore, the blockchain system can also be considered to have excellent robustness.

Trustless: Data exchange between each node in the entire system does not require mutual trust. The operating rules of the entire system are open and transparent, and all data contents are also public. Therefore, within the rule range and time range specified by the system, nodes cannot and cannot deceive other nodes.

Collectively maintain: The data blocks in the system are jointly maintained by all nodes with maintenance functions in the entire system, and anyone can participate in these nodes with maintenance functions. of.

Reliable Database: The entire system will be divided into databases so that each participating node can obtain a copy of the complete database. Unless more than 51% of the nodes in the entire system can be controlled at the same time, modifications to the database on a single node are invalid and cannot affect the data content on other nodes. Therefore, the more nodes and stronger computing power participating in the system, the higher the data security in the system.

Open Source: Since the operating rules of the entire system must be open and transparent, for the program, the entire system must be open source.

Privacy protection (Anonymity): Since nodes do not need to trust each other, there is no need to disclose their identities between nodes, and the privacy of each participating node in the system is protected. of.

One of the meanings of blockchain: solving the Byzantine Generals Problem

The core problem solved by blockchain is not "digital currency", but in an environment of asymmetric information and uncertainty. , how to establish a "trust" ecological system that satisfies the occurrence and development of economic activities. This problem is called the "Byzantine Generals Problem", also known as "Byzantine Fault Tolerance" or the "Two Armies Problem". This is a difficult problem faced when information machines interact in a distributed system, that is, any point in the entire network When nodes cannot trust the other party they are communicating with, how can they create a knowledge base for secure information exchange without worrying about data being tampered with. Blockchain uses an algorithmic proof mechanism to ensure the security of the entire network. With it, all nodes in the entire system can automatically and securely exchange data in a trustless environment. For more introduction, please see "Bitcoin and the Byzantine Generals Problem".

The second meaning of blockchain: realizing cross-border value transfer

When the Internet was born, the earliest core problem to be solved was information production and transmission. We can quickly generate and copy information through the Internet to every corner of the world with a network, but it still cannot solve value transfer and credit transfer. The so-called value transfer here refers to a method that everyone in the network can recognize and confirm, accurately transferring a certain part of the value from a certain address to another address, and it must be ensured that when the value is transferred, the original address is reduced The transferred portion, while the new address increases the value transferred. The value mentioned here can be a monetary asset, or some kind of physical asset or virtual asset (including securities, financial derivatives, etc.). The results of this operation must be recognized by all participating parties, and the results cannot be manipulated by any one party.

There are also various financial systems in the current Internet, and there are also many payment systems provided by government banks or third parties, but they still rely on centralized solutions. The so-called centralized solution is to put all value transfer calculations on a central server (cluster) through the endorsement of a certain company or government credit. Although all calculations are automatically completed by the program, you must trust this centralization. person or institution. In fact, through centralized credit endorsement, credit can only be limited to certain institutions, regions or countries. It can be seen from this that the fundamental problem that must be solved is credit. Therefore, the core issue of value transfer is transnational credit knowledge.

In such a complex global system, it is difficult to establish a global credit knowledge system out of thin air. Due to the different political, economic and cultural conditions of each country, for two It is almost impossible for a country's enterprises and the government to completely trust each other. This means that whether it is endorsed by the credit of individuals or corporate governments, even if the value exchange between countries can be completed, there will still be huge time and economic costs. . But in the long history of mankind, no matter how different the religion, politics and culture of each country are, the only way to gain knowledge is mathematics (basic science). Therefore, it is no exaggeration to say that mathematics (algorithm) is the greatest common denominator of global civilization and the basis for the most knowledge gained by human beings around the world. If we use mathematical algorithms (programs) as endorsement, all rules are based on an open and transparent mathematical algorithm (program), which can allow all people with different political and cultural backgrounds to gain knowledge.

Future Development

The Internet will make global interactions closer and closer, accompanied by a huge trust gap. Currently, the existing mainstream database technology architecture is private and centralized. On this architecture, the problems of value transfer and mutual trust can never be solved. Therefore, blockchain technology may become the next generation database architecture. Through decentralized technology, it will be possible to complete the huge progress of mathematical (algorithm) endorsement and global mutual trust on the basis of big data.

As a specific distributed access data technology, blockchain technology uses multiple nodes participating in calculations in the network to jointly participate in the calculation and recording of data, and mutually verify the authenticity of their information. Effectiveness (anti-counterfeiting). From this point of view, blockchain technology is also a specific database technology. The Internet has just entered the era of big data, but from the current point of view, big data is still in a very basic stage. But when it enters the blockchain database stage, it will enter the big data era of real strong trust endorsement. All data here has acquired indestructible quality, and no one has the ability or need to question it.

Perhaps we are now at a major turning point - the early stages of a major transition that is almost as profound as the changes brought about by the Industrial Revolution. Not only are new technologies exponential, digital and combined, progress and changes, but more surprises may be ahead of us. In the next 24 months, the planet will grow more computing power and record more data than it has in all of history combined. In the past 24 months, this value increase may have exceeded 1,000 times. This digital data information is growing faster than Moore's Law. Blockchain technology will not only be used in the field of financial payments, but will expand to all current applications, such as decentralized Weibo, WeChat, search, renting, and even taxi-hailing software may appear. Because blockchain will allow humans to collaborate on a large scale in a trustless manner without geographical restrictions.

Blockchain is a technology based on which many applications have been produced, including all industry businesses related to data and information. Bitcoin is one of the most well-known applications. The popular explanation of blockchain is that if you buy a lipstick online, you first find the product you like and place an order with the seller. You first give the money to the intermediary platform. After the seller ships the goods and the buyer confirms receipt, the intermediary platform then transfers the money. Transfer it to the seller, because of the trust issue, both buyers and sellers rely on the intermediate platform, and the blockchain, as a decentralized distributed ledger database, focuses on removing this intermediate platform while solving the trust issue at the same time. In the blockchain, everyone has their own ledger to record everything that happens. If a seller takes money but does not deliver goods during a transaction, this record will exist permanently and cannot be modified, and there is no need to interact with each other. To exchange information, the blockchain world will choose the person's ledger that records the fastest and best quality at the same time node to copy, send and connect in series. Finally, the thicker and thicker the stack is, the more blocks will be formed.

When everyone talks about virtual currencies, they often cannot do without the concept of blockchain. So what is the magic of blockchain?

Blockchain is an underlying technology, essentially a decentralized distributed ledger database. It sounds very high-end and out of reach, but it is actually very easy to understand.

For example, if you want to buy something on Taobao, the first thing you usually have to do is to open Taobao, find the product you want, place an order and pay the money to Taobao, which is the transaction intermediary. Taobao will pay the seller after receiving the goods and confirming receipt. This was originally just a transaction between me and the seller, but it has an additional "center", namely Taobao.

During the transaction process, this "center" has unlimited power and can even modify the bill at will. Therefore, the “center” often needs a strong backend to endorse it.

So, a man named Satoshi Nakamoto wanted to get rid of this center with infinite power. He wanted to create a decentralized system in which everyone is the center and has Accounting authority. So, he created Bitcoin.

In the Bitcoin system, everyone has a small ledger to record every transaction that occurs. A transaction is only valid after being confirmed by a majority of people. If the seller doesn't deliver the goods, everyone's little ledger will record it, leaving him nowhere to escape.

At this time, you may have questions. Since it is just a public ledger, why is it called a blockchain? This involves the issue of public knowledge. The blockchain system is a system composed of many "centers", and the entire blockchain belongs to all individuals participating in accounting. At this time, new problems arise. A system must be in order to survive in the long term. If the bookkeeper can act recklessly regardless of the cost, it may happen that he originally just bought a mobile phone, but received a Tesla instead.

As a result, Satoshi Nakamoto invented a consensus method called PoW. This method increases the cost of bookkeeping for bookkeepers and prevents them from doing evil easily. PoW uses cryptography to require bookkeepers to compete for computing power to obtain accounting rights. The first bookkeeper to calculate the result can obtain the accounting rights of a block packaged from several transactions. At the same time, you will receive certain tokens as rewards. This is what we commonly call "mining".

Now that the bookkeeper has recorded a block containing several transactions, the system needs to be organized and sorted, and it is impossible to have countless blocks distributed in the system in an orderly manner. So it is necessary to link all blocks end to end in chronological order. At this time, the blockchain was born. The core of blockchain is technology.