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① Tutorials for getting started with blockchain

However, there are very few simple and easy-to-understand introductory articles. What exactly blockchain is and what makes it special is rarely explained.
Next, I will try to write a best-understood blockchain tutorial. After all, it is not difficult. The core concept is very simple and can be explained clearly in a few sentences. I hope that after reading this article, you will not only understand the blockchain, but also understand what mining is, why mining is getting more and more difficult, and other issues.
It should be noted that I am not an expert in this area. Although I have been paying attention to it for a long time, my detailed understanding of blockchain started at the beginning of this year. You are welcome to correct any errors or inaccuracies in the article.
1. The essence of blockchain
What is blockchain? In a word, it is a special distributed database.
First of all, 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.
Secondly, 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.
2. The biggest features of blockchain
Distributed databases are not a new invention, and there have been such products on the market for a long time. However, blockchain has a revolutionary feature.
Blockchain has no administrator, it is completely centerless. Other databases have administrators, but blockchain does not. If one wanted to add auditing to the blockchain, it would not be possible because it is designed to prevent the emergence of a central authority.
It is precisely because it is unmanageable that blockchain can be uncontrollable. Otherwise, once big companies and large groups control the management, they will control the entire platform, and other users will have to take orders from them.
However, without an administrator, everyone can write data into it. How can we ensure that the data is trustworthy? What if it is modified by a bad person? Please read on, this is the wonderful thing about blockchain place.
3. Block
Blockchain is composed of blocks. Blocks are much like database records. Every time data is written, a block is created.
Each block contains two parts.
Head: records the characteristic values ​​of the current block
Body: actual data
The block header contains multiple characteristic values ​​of the current block.
Generation time
Hash of the actual data (i.e. block body)
Hash of the previous block
...
Here, you need to understand what a hash is , which is necessary to understand blockchain.
The so-called hashing means that the computer can calculate a characteristic value of the same length for any content. The hash length of the blockchain is 256 bits, which means that regardless of the originalWhatever the initial content is, a 256-bit binary number will be calculated in the end. And it can be guaranteed that as long as the original content is different, the corresponding hash must be different.
For example, the hash of the string 123 is (hexadecimal), which is 256 bits when converted to binary, and only 123 can get this hash. (Theoretically, it is possible for other strings to get this hash, but the probability is extremely low and can be approximated as impossible.)
Therefore, there are two important inferences.
Corollary 1: The hash of each block is different, and the block can be identified by the hash.
Corollary 2: If the content of the block changes, its hash will definitely change.
4. The non-modifiable nature of Hash
Blocks and hashes have a one-to-one correspondence, and the hash of each block is calculated based on the block header (Head). That is to say, the characteristic values ​​​​of the block header are connected together in order to form a very long string, and then the hash is calculated on this string.
Hash = SHA256 (block header)
The above is the calculation formula of block hash. SHA256 is the hash algorithm of the blockchain. Note that this formula only contains the block header and not the block body. In other words, the hash is uniquely determined by the block header.
As mentioned before, the block header contains a lot of content, including the hash of the current block body. , and the hash of the previous block. This means that if the content of the current block body changes, or the hash of the previous block changes, it will definitely cause the hash of the current block to change.
This point has great significance for blockchain. If someone modifies a block, the hash of the block changes. In order for subsequent blocks to still be connected to it (because the next block contains the hash of the previous block), the person must modify all subsequent blocks in sequence, otherwise the modified block will be removed from the blockchain . Due to the reasons mentioned later, hash calculation is very time-consuming, and it is almost impossible to modify multiple blocks in a short period of time, unless someone controls more than 51% of the computing power of the entire network.
It is through this linkage mechanism that the blockchain ensures its own reliability. Once the data is written, it cannot be tampered with. This is just like history, what happened happened, and it can’t be changed from now on.
Each block is connected to the previous block, which is where the name blockchain comes from.
5. Mining
Since synchronization between nodes must be ensured, the adding speed of new blocks cannot be too fast. Just imagine, you have just synchronized a block and are preparing to generate the next block based on it, but at this time, another node generates a new block, and you have to give up half of the calculations and synchronize again. Because each block can only be followed by one block, you can only generate the next block after the latest block. So, you have no choice but to sync as soon as you hear the signal.
So, the inventor of the blockchain, Satoshi Nakamoto (this is a pseudonym, and his true identity is still unknown) deliberately made it difficult to add new blocks.His design is that on average, the entire network can generate a new block every 10 minutes, which is only six per hour.
This output speed is not achieved through commands, but by deliberately setting up massive calculations. In other words, only through an extremely large amount of calculations can the effective hash of the current block be obtained and the new block added to the blockchain. Because the amount of calculation is too large, it cannot be done quickly.
This process is called mining, because the difficulty of calculating a valid hash is like finding a grain of sand that meets the conditions among the sand in the world. The machine that calculates hashes is called a mining machine, and the person who operates the mining machine is called a miner.
6. Difficulty coefficient
After reading this, you may have a question. People say that mining is difficult, but isn’t mining just about using a computer to calculate a hash? This is the strength of computers. How could it be? It becomes very difficult, why can’t it be calculated?
It turns out that not just any hash can be used, only hashes that meet the conditions will be accepted by the blockchain. This condition is particularly harsh, causing most hashes to fail to meet the requirements and must be recalculated.
It turns out that the block header contains a difficulty coefficient (difficulty), which determines the difficulty of calculating the hash. For example, the difficulty coefficient of the 100,000th block is 14484.16236122.
The blockchain protocol stipulates that the target value (target) can be obtained by dividing the difficulty coefficient by a constant. Obviously, the greater the difficulty coefficient, the smaller the target value.
The validity of the hash is closely related to the target value. Only hashes smaller than the target value are valid, otherwise the hash is invalid and must be recalculated. Since the target value is very small, the chance that the hash is smaller than this value is extremely slim, and it may be calculated 1 billion times before it is considered a hit. This is the fundamental reason why mining is so slow.
As mentioned earlier, the hash of the current block is uniquely determined by the block header. If the hash of the same block needs to be calculated repeatedly, it means that the block header must keep changing, otherwise it is impossible to calculate different hashes. All feature values ​​in the block header are fixed. In order to make the block header change, Satoshi Nakamoto deliberately added a random item called Nonce.
Nonce is a random value. The role of the miner is actually to guess the value of Nonce so that the hash of the block header can be smaller than the target value so that it can be written to the blockchain. Nonce is very difficult to guess. At present, we can only use trial and error one by one through exhaustive methods. According to the protocol, Nonce is a 32-bit binary value, which can reach a maximum of 2.147 billion. The Nonce value of the 100,000th block is 274148111. It can be understood that the miner started from 0 and calculated 274 million times before obtaining a valid Nonce value so that the calculated hash can meet the conditions.
If you are lucky, you may find Nonce in a while. If you are unlucky, you may have calculated 2.147 billion times without finding the Nonce, which is the current area.It is impossible for the block to calculate a hash that satisfies the condition. At this time, the protocol allows miners to change the block body and start a new calculation.
7. Dynamic adjustment of difficulty coefficient
As mentioned in the previous section, mining is random, and there is no guarantee that a block will be produced in exactly ten minutes. Sometimes it can be calculated in one minute, and sometimes it may take several hours. No result. Overall, with the improvement of hardware equipment and the increase in the number of mining machines, the computing speed will definitely become faster and faster.
In order to keep the output rate constant at ten minutes, Satoshi Nakamoto also designed a dynamic adjustment mechanism for the difficulty coefficient. He stipulated that the difficulty factor should be adjusted every two weeks (2016 blocks). If the average block generation speed in these two weeks is 9 minutes, it means that it is 10% faster than the legal speed, so the next difficulty factor will be increased by 10%; if the average block generation speed is 11 minutes, it means It is 10% slower than the legal speed, so the difficulty factor of the next step must be lowered by 10%.
The difficulty coefficient is adjusted higher and higher (the target value is getting smaller and smaller), which makes mining more and more difficult.
8. Forks of the blockchain
Even if the blockchain is reliable, there is still an unresolved problem: if two people write data to the blockchain at the same time, that is to say, two people write data to the blockchain at the same time. Blocks join because they are connected to the previous block, forming a fork. Which block should be adopted at this time?
The current rule is that new nodes always adopt the longest blockchain. If there is a fork in the blockchain, it will look at which branch is behind the fork to reach 6 new blocks first (called six confirmations). Based on a block calculation of 10 minutes, it can be confirmed in one hour.
Since the generation speed of new blocks is determined by computing power, this rule means that the branch with the most computing power is the authentic blockchain.
9. Summary
Blockchain, as an unmanaged distributed database, has been running for 8 years since 2009 without major problems. This proves it works.
However, in order to ensure the reliability of data, blockchain also has its own price. The first is efficiency. You have to wait at least ten minutes to write data to the blockchain. All nodes synchronize the data, which requires more time. The second is energy consumption. The generation of blocks requires miners to perform countless meaningless calculations. This is Very energy consuming.
Therefore, the applicable scenarios of blockchain are actually very limited.
There is no management authority that all members trust
The written data does not require real-time use
The benefits of mining can make up for its own costs
If the above conditions cannot be met, then the traditional database is Better solution.
Currently, the largest application scenario (and possibly the only application scenario) of blockchain is the cryptocurrency represented by Bitcoin.

② What is blockchain and how to introduce blockchain in a simple and easy-to-understand manner

Blockchain is a term in the field of information technology.

Essentially, it is a shared database in which the data storedData or information has the characteristics of "unforgeable", "leaving traces throughout the entire process", "traceable", "open and transparent" and "collectively maintained". Based on these characteristics, blockchain technology has laid a solid foundation of "trust" and created a reliable "cooperation" mechanism, which has broad application prospects.

On January 10, 2019, the Cyberspace Administration of China issued the "Blockchain Information Service Management Regulations". On October 24, 2019, during the 18th collective study session of the Political Bureau of the CPC Central Committee, General Secretary Xi Jinping emphasized that “blockchain should be used as an important breakthrough for independent innovation of core technologies” and “accelerate the development of blockchain technology and industrial innovation.” . "Blockchain" has entered the public eye and become the focus of society.

On December 2, 2019, the word was selected into the top ten buzzwords of 2019 by "Biwenqiezi".

(2) Extended reading of Baidu Blockchain Lecture:

Blockchain Financial Application:

Since 2016, various Major financial giants have also taken notice and launched blockchain innovation projects one after another to explore the possibility of applying blockchain technology in various financial scenarios. In particular, Puyin Group took the lead in pioneering the “blockchain+” standard digital currency.

The standard digital currency is an asset that has been identified, evaluated, confirmed, insured, etc. by a third-party organization and written into the blockchain through rigorous digital algorithms to form a standard correspondence between the asset and the digital currency. relationship, called a standard digital currency.

In order to realize the great leap forward development of blockchain finance, in order to promote the new development of China's economy, accelerate the circulation of global assets, and realize the dream of rejuvenation that generations of people have been striving for, Puyin Group will Puyin Blockchain Finance Guiyang Strategy Release Ceremony was held in Guizhou on the 9th;

At the meeting, the digital circulation of assets through blockchain, the blockchain financial transaction model, and the relationship between blockchain services and blockchain services will be discussed. The application of social public industries will be discussed. This conference will mark the beginning of the application of blockchain finance and the transformation and development of a new financial ecosystem.

Reference for the above content: Network-Blockchain Finance; Network-Blockchain

③ Popular explanation of blockchain technology

Blockchain is a distributed data storage, New application models of computer technologies such as point-to-point transmission, consensus mechanisms, and encryption algorithms. Blockchain is an important concept of Bitcoin, which is essentially a decentralized database. At the same time, as the underlying technology of Bitcoin, it is a series of data blocks generated by cryptographic technology. Each data block contains a batch of Bitcoin network transaction information, which is used to verify the validity of its information (anti-counterfeiting) and generate the next data block.
First of all, it is a special distributed database that is essentially readable and writable. The unit then entered into the database is a "block", which is decentralized.
It doesn’t seem to be easy to understand when explained in this way, so let’s give a simple example.

When we shop on Taobao, because buyers and sellersWe don’t know each other’s credit, so we need to introduce a third-party platform—Alipay. Alipay is a trustworthy platform. The buyer first gives money to Alipay. After the seller delivers the goods, the buyer receives the money and notifies Alipay, who then lends the money to the seller. In this way, there is no need to worry about credit issues in the transaction.

④ After reading this article, you will have a thorough understanding of blockchain

In this article, all the content I introduced is in the field of blockchain in today’s world. The facts of what happened, not some imagination or opinions about the blockchain. I think that as long as you read this article carefully, you will easily have a basic and accurate understanding of blockchain.

The main content of understanding blockchain in just ten minutes is divided into four sections. 21 topics and 4 sections are:

The first national blockchain strategy.

Second, Bitcoin and its literal representation involve four topics.

Third, blockchain and its technical logic involve 13 topics.

Fourth, blockchain empowers the economy and society, involving three topics.

Let’s first look at the first part of the blockchain national strategy, the first part of the blockchain country. Everyone knows that we humans have experienced six information revolutions. Seven or eight years ago, the first information revolution created primitive language, social tacit understanding, and the second information revolution saw the emergence of writing. The third information revolution in feudal society invented papermaking and printing, and the fourth information revolution in the late 19th century invented radio.

In the fifth information revolution of the 20th century, television appeared again, and now in the sixth information revolution, computers and the Internet have appeared. The emergence of computers and the Internet has given rise to the rapid development of various new technologies. Especially in 2020, the digital economy has experienced epoch-making development.

Why do you say that? The characteristics of high bandwidth, low latency and large connections in the 5G era have enabled the implementation of the four major technologies of ABCD.

What are the four major ABCD technologies

The a here refers to Artificial Intelligence, which is artificial intelligence technology.

B refers to Blockchain, blockchain technology.

C refers to cloud computing cloud computing technology

D refers to big data technology.

The word blockchain is now completely popular all over the country. On October 25, 2019, the Central GovernmentThe Political Bureau conducted a collective study on the current development status of blockchain technology. So the requirement of this meeting is to use blockchain technology as a core technology.

As an important breakthrough for independent innovation, it is necessary to accelerate the innovative development of blockchain technology and industry. On April 20, 2020, the National Development and Reform Commission officially included blockchain into new infrastructure. Blockchain, why do you think it is so awesome? Let us say that blockchain is not an extension of the Internet, it is a subversion of the Internet. In the future, many, many technologies will grow on this blockchain and realize blockchainization.

So, how can we accurately learn and understand the blockchain?

We found that among the four major technologies of ABCD, only the block is naturally built-in It's financial. Therefore, we must learn and understand blockchain from the IT perspective and the financial perspective, and even learn and understand blockchain from the level of national governance. If you only study and understand blockchain from an IT perspective, it is impossible to understand the huge influence and influence of this technology. Then, your understanding of this will be biased. Even more, you may disapprove of blockchain technology. In addition, in the process of learning about blockchain, you should also pay attention to the fact that it has many new terms, so you need to concentrate on understanding it step by step.

Let’s first understand blockchain from a financial perspective.

Bitcoin and its birth performance

To understand the blockchain, it involves Bitcoin, and what about the birth of Bitcoin? , and it is inseparable from the evolution of currency. We know that currency is a special commodity that is separated from commodities and serves as a fixed general equivalent. In fact, we humans have used a lot of currencies, including physical currency, weighing currency, paper money, accounting currency, etc. As for accounting currency, it includes electronic currency and digital currency. Electronic currency itself is not a currency. It is just used to represent the same amount of currency. It is a token.

Then the total amount of his tokens will not increase due to the increase of electronic currency. Alipay, WeChat, payment, and online banking are typical electronic currencies. As for digital currency, it is itself a legal currency. The total amount of this fiat currency will increase with the increase of digital currency. We know that when it comes to physical currency, we humans have actually chosen many things as general equivalents.

Weighing currencies are some heavy metals. Later, people chose gold among the heavy metals. Why choose gold? Because gold has the characteristics of rarity and divisibility, and it also has the most chemical properties.Stable characteristics, what needs to be noted here is that gold is not issued by any country, it is provided by nature. Your country's total amount is as much as nature provides. Therefore, the country does not need to provide credit guarantees for the value of gold.

However, as for gold, it has some flaws in its use, and it is difficult to carry when you go out again, so there are descendants. Paper money appeared in the Northern Song Dynasty. At that time, paper money was not currency in the current sense. The currency at that time was still gold, but we used paper money to represent gold. We called it the gold standard. The gold standard is the gold standard, which is a monetary system with gold as the standard currency. The core essence of the gold standard is that how much currency a country issues should be decided based on how much gold your country has. It does not mean you can issue as much currency as you want.

At that time, the Great Depression of the United States reached January 10, 1934. On this day, the newly elected President of the United States made a very important decision to abandon the gold standard and issue 3 billion US dollars. Think about it, abandoning the gold standard, in theory, means that he can issue as much currency as he wants. Even if there is no gold in the treasury, he can issue banknotes as long as he wants to. Then someone will ask, if you issue so many words, can you still exchange them for gold of equal value?

Look at the banknotes at this time, they have been separated from gold, and national credit has emerged. , this, we call it currency guaranteed by national credit. Now, when mainstream countries issue currency, they also issue it with national credit as a guarantee.

What are the benefits? The advantage is that it can regulate the economy. When the economy is not doing well, a little more hair can drive economic development. The increase or decrease in this variable will cause a chain reaction of the entire economic aggregate. This is the multiplier effect in economics. Once a country masters this thing, some countries will be fascinated by it. But if it is not well controlled, it will lead to national credit bankruptcy. As a result, many people began to reflect. This reflection is, when issuing currency, is it better to use national credit as a guarantee, or is it better to stick to the gold standard based on the total amount of gold. This question involves the birth of Bitcoin

⑤ How does blockchain empower digital city construction | Blockchain classroom

Cities are actively embracing blockchain, the Internet of Things, Digital technologies such as artificial intelligence accelerate urban economic growth and improve the quality of urban life and the sustainable development of the environment. The digital transformation of cities also provides a good experimental field for the value mining and application of blockchain technology.

The construction of a digital city not only needs to achieve city-wide coverage of connected devices, but also needs to consider the entireData collection and decision-making automation issues. The data on the blockchain has the advantages of being difficult to tamper with, safe and trustworthy, and can help the construction of digital cities in the following aspects:

The blockchain adopts a distributed storage structure, so each node in the system All data on the system is stored, making the data open, transparent and easy to manage. At the same time, cryptographic technologies such as privacy computing integrated in the blockchain can achieve safe sharing of data without leaking data privacy, or by setting access permissions, authorized nodes can obtain corresponding data to ensure data security.

Thanks to the distributed network structure, even if a single or a small number of nodes fail, the entire blockchain network can still operate normally, greatly reducing the risk of system failure due to network attacks or technical problems. Compared with traditional cities, digital cities rely more on technology. Improving system stability will also help maintain the normal operation of digital city life.

Digital city innovation case empowered by blockchain

Dubai’s digital city project integrates blockchain, Internet of Things, artificial intelligence Smart and other new digital technologies are committed to making Dubai "the happiest city in the world".

A major innovation in Dubai Digital City is to strive to realize the on-chain operation and management of all government data transactions in 2021, and realize the electronicization of an average of 100 million paper-based processes per year. This blockchain-enabled digital reform is expected to save process management costs worth US$1.5 billion, save 25 million hours of process processing time, and reduce 114 million tons of carbon emissions. In addition, the Dubai government is actively cooperating with many blockchain companies, focusing on key areas and implementing multiple blockchain application cases.

The European Commission also recognized the importance of blockchain in reforming government services, and established the European Blockchain Partnership in 2018, covering local law enforcement agencies, national governments and the private sector in Europe. enterprise. The Commissioner of the European Commission’s Department of Digital Economy and Society is also confident in the value of blockchain technology in digital city construction and stated: “We believe that all public services in the future will be built on the infrastructure of blockchain.”

For example, the government of South Tyrol in Italy has used blockchain technology to digitize citizen data. Residents only need to register basic personal information once to enjoy services provided by different government departments, streamlining government affairs processing procedures, reducing costs and increasing efficiency.

At the same time, based on blockchain technology, Estonia has built a national health information electronic system. Through this blockchain platform, doctors can easily query patients' blood tests, recent treatments, X-ray examinations and other related data with authorization. Patients can also clearly check their medical records, prescriptions issued by doctors and other information. And blockThe data on the chain is difficult to tamper with and the entire process is traceable, which can ensure the security and integrity of the data on the platform.

Wanxiang Blockchain has also begun active exploration in blockchain-enabled digital city construction, using blockchain to integrate new digital technologies such as the Internet of Things and artificial intelligence to build a safe and trustworthy digital base. And through technologies such as private computing, knowledge graphs, digital twins, and distributed business incentives, we can manage production and life in a more refined and dynamic way, forming a smart, low-carbon, and comfortable resilient city with technology integration, comprehensive application, and high-end development. Help build a harmonious urban ecology with economic prosperity, job happiness, and sustainable development.

Wanxiang Blockchain is committed to building a digital city that “truly understands you”. Through the integration of blockchain and new technologies, a trusted digital base is built to allow every resident to have an exclusive digital avatar. Truly gain data sovereignty and enjoy a safe and comfortable urban life without having your privacy protected from prying eyes.

⑥ An easy-to-understand explanation of blockchain

A simple explanation of blockchain technology is as follows:

To put it simply: blockchain is the use of a package of existing A new generation of network system formed using advanced network technology. This network system has a new structure, a new mechanism, and unprecedented new value. Five major technologies or innovations are specifically used: encryption technology, P2P network technology, distributed storage technology, consensus mechanism, and smart contracts.

Essentially: it is a shared database, and the data or information stored in it is "unforgeable", "full-process traces", "traceable", "open and transparent" and "collectively maintained" ” and other characteristics. Based on these characteristics, blockchain technology has laid a solid foundation for "trust-based sales" and created a reliable "cooperation" mechanism. Yunchun has broad application prospects.

2. Openness.

In addition to the encryption of private information of all parties to the transaction, the blockchain data is open to everyone and provides a flexible script code system. The entire system information is highly transparent and within the rules specified by the system. Nodes cannot deceive each other.

3. Autonomy.

Consensus technology, smart contracts.

⑦ "Blockchain - Financial Black Technology" - Shanghai Jiao Tong University

The theme of this lecture is "Blockchain - Financial Black Technology", and the speaker is from Kuo Mei Wenxiang, the co-founder of Yue Technology, is also the founder of 91pool, the world’s largest mining pool for Ethereum’s original chain ETC. This lecture attracted many students, and even though it rained heavily that day, the venue was still full.

Before the lecture officially started,
Mei Wenxiang asked three questions:
How many students know about Bitcoin?
How many students know about blockchain?
How many students know about smart contracts?
Just judging from the hands raised at the scene, even if they are facing a new knowledge and new field - "blockchain", Jiaotong University students have done their homework in advance before listening to the lecture.

Mei Wenxiang talked about the basic knowledge of blockchain from three aspects: the origin of blockchain, blockchain, and smart contracts. First of all, the speaker used humorous language and vivid metaphors to tell everyone that although it is less than 10 years ago, the current development of blockchain is like physics-magnetic field, "invisible and intangible, but objectively existing", " "Bitcoin" is the first "son" of "blockchain". The three characteristics of blockchain, "shareable, trustworthy, and shared ledger," determine that blockchain will become a more powerful technology in the near future.

I came into contact with "blockchain" 3 years ago. Even though I have been working in the Internet finance industry for 6 years, I resolutely chose to get back on the road and began to explore the research and application of the blockchain field. Soon after Founded WNT Kuoyue Technology and officially started many practices of blockchain applications, such as: "91 Charter" of blockchain financial leasing platform, "Yijian" of blockchain art appraisal platform and "Yijian" of digital currency production platform 91 Coin Pool”.

Wonderful question-and-answer session

As the lecture came to an end, students from Jiaotong University actively raised their own questions to the speaker. The speaker answered them patiently and frankly said that blockchain Learning is a process that cannot be rushed.

At this point, the lecture ended successfully.

⑧ Getting Started with Blockchain What You Need to Know!

What is a blockchain?
Literally: a blockchain is a chain composed of small blocks that record various information, similar to what we will Bricks are stacked one after another, and they cannot be removed after being stacked. Each brick also has various information written on it, including: who stacked it, when it was stacked, what material the brick was made of, etc. You can use this information There is no way to modify it.
From a computer perspective: Blockchain is a relatively special distributed database. Distributed database is to store data information separately in eachEach computer has the same stored information. If one or two computers in Taiwan are broken, the information will not be lost and you can still view it on other computers.
Blockchain is distributed, so it has no central point. Information is stored in all nodes that join the blockchain network, and the data of the nodes is synchronized. A node can be a server, laptop, mobile phone, etc.
What you need to know is that the data stored in these nodes are exactly the same.
Blockchain Features
Decentralization: Because it is distributed storage, there is no central point. It can also be said that each node is a central point. Applications in life do not require a third-party system (bank , Alipay, real estate agencies, etc. are all third parties).
Openness: The system data of the blockchain is open and transparent, and everyone can participate. For example, when renting a house, you can know the previous rental information of the house and whether there have been any problems. Of course, some individuals here Private information is encrypted.
Autonomy: The blockchain adopts consensus-based specifications and protocols (such as a set of open and transparent algorithms), and then each node operates according to this specification, so that everything is done by machines and there is no human touch. Element. This changes trust in people to trust in machines, and any human intervention has no effect.
Information cannot be tampered with: If the information is stored in the blockchain, it will be saved permanently and there is no way to change it. As for the 51% attack, it is basically impossible to achieve.
Anonymity: There is no personal information on the blockchain, because it is all encrypted and is a string of letters and numbers, so your ID card information and phone number will not be resold. Phenomenon.
Block structure
A block contains two parts:
1. Block header (Head): records meta-information of the current block
2. Block body (Body): actual data
>Contains data as shown below:
How blockchain works
Let’s take transfer as an example:
Currently our transfers are centralized, and the bank is a centralized ledger. For example, there is 400 in account A There are 100 yuan in account B.
When A wants to transfer 100 yuan to B, A needs to submit a transfer application through the bank. After the bank verification is passed, 100 yuan will be deducted from A's account and 100 yuan will be added to B's account.
After calculation, the balance of account A after deducting 100 is 300 yuan, and the balance of account B after adding 100 is 200 yuan.
The steps for transferring money on the blockchain are: A wants to transfer 100 yuan to B. A will tell everyone about the transfer on the Internet, and everyone will check whether there is enough money in A's account. To complete this transfer, if the verification is passed, everyone will record this information in the blockchain on their own computers, and the information recorded by everyone will be synchronized and consistent, so that A can successfully transfer100 yuan is transferred to B's account. You can see that there is no bank involved.
Related questions
What is the relationship between blockchain and Bitcoin?
Bitcoin was proposed by Satoshi Nakamoto in 2009, and then the blockchain technology was refined with reference to the implementation of Bitcoin.
If Bitcoin is noodles, then blockchain is flour. Later, everyone discovered that flour can be used to make steamed buns and steamed buns in addition to noodles.
Why do I need to help you store block information?
I don’t have time to do it without profit. To put it simply, you help me store information and I will give you corresponding rewards.
Key technical points that need to be understood in blockchain?
Use Hash and asymmetric encryption to ensure that data cannot be tampered with:
Hash: y = hash(x), perform a hash operation on x to obtain y , the original information x can be hidden, because you cannot calculate x through y, thus achieving anonymity.
Asymmetric encryption: The public key and the private key are a pair. If the public key is used to encrypt the data, only the corresponding private key can be used to decrypt it; if the private key is used to encrypt the data, then only It can be decrypted with the corresponding public key.
Consensus algorithm: Ensure data consistency between nodes.
Is there a sentence or two that can explain the blockchain?
Yes.
Mahjong is a traditional Chinese blockchain project. A group of four miners work together. The miner who first collides with the correct hash value of 13 numbers can obtain the accounting rights and be rewarded.