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1. Blockchain-What is Blockchain? Jindian Bixin can understand Blockchain

Blockchain-What is Blockchain? Can Jindian Coin News understand the blockchain?

Block Pioneer animation video helps you understand what is blockchain, easy to understand

What is blockchain, does Maobei belong to blockchain?

Answer: Maobei does not belong to the blockchain, but only uses blockchain technology. The characteristic of the blockchain is that everything that happens will be recorded and cannot be deleted or changed.

Blockchain, what is a block

Comprehensive interpretation of blockchain

When talking about blockchain, people always compare it with Bitcoin. On October 31, 2008, a person named "Satoshi Nakamoto" sent an email to a cryptography email group, claiming, "I have been working on a new electronic cash system, which is completely peer-to-peer and does not require Any trusted third party.” He launched a new system using Bitcoin as the transaction currency.

What is blockchain technology? What is blockchain?

Blockchain is a distributed shared accounting technology. What it wants to do is to allow all parties involved to establish a trust relationship at the technical level.

Blockchain can be roughly divided into two levels, one is the underlying technology of the blockchain; the other is the upper-layer application of the blockchain, that is, based on the transformation of the blockchain, Optimize or innovate applications.

What is the core meaning of blockchain? Our understanding is that the core meaning of blockchain is to establish data credit among participants, and to create a single transaction under clear regulations through unilateral confrontation. The ecology of all aspects jointly guarantees complete opportunities. This is a system. This establishment can end the problems before the blockchain. Before the blockchain, it was impossible to achieve new sharing when data was shared, even if it was targeted. It just gives you an interface. After the blockchain is established, the participants can realize the sharing of credit.

What are the underlying platforms of blockchain?

Answer: There are mainly the following categories:

1. Bitcoin. The earliest blockchain development was based on the Bitcoin blockchain network. Since Bitcoin is the most widely used and truly decentralized in the world, in terms of blockchain applications, Bitcoin is the most widely used blockchain in the world. A strong anchor with the greatest authority.

2. Ethereum. It can be said that apart from Bitcoin, Ethereum is currently the most eye-catching blockchain platform. Ethereum is a Turing-complete blockchain one-stop development platform that uses multiple programming languages ​​to implement protocols. It uses a client written in Go language as the default client (i.e., a method of interacting with the Ethereum network, and supports a variety of other language client).

3. IBM HyperLedger. Also called fabric, its goal is to build a super ledger that is jointly maintained by the whole society. Fabric originated from IBM, and its original intention was to serve industrial production.IBM made 44,000 lines of code open source, which is a great contribution, giving us the opportunity to explore the principles of blockchain that are different from Bitcoin so closely.

4. LISK. It is a new generation of blockchain platform that allows the development of JavaScript (Javascript technology again, engineers, take note) and distribution-based decentralized applications using an easy-to-use, full-featured ecological blockchain system.

5. Online recording blockchain platform. It is the research and development result of the underlying technology of the Wanglu blockchain and a basic platform capable of commercial delivery. In addition to serving the Wanglu public chain, the Wanglu blockchain platform is also the basic platform for Wanglu to create private chains and alliance chains for customers.

What is blockchain? What is blockchain for digital currencies?

In a narrow sense, blockchain is a chain data structure that combines data blocks in a sequential manner in chronological order, and is cryptographically guaranteed to be non-tamperable and non-forgeable. Ledger. Broadly speaking, blockchain technology uses block chain data structures to verify and store data, uses distributed node consensus algorithms to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses automated scripts to A new distributed infrastructure and computing paradigm that uses smart contracts composed of code to program and manipulate data.
Nowadays, mainstream digital currencies are basically developed based on blockchain technology. Blockchain is the underlying technology of digital currency. The domestic tea-based digital currency Puyin was developed based on blockchain technology.

What is blockchain

The essence of blockchain is a decentralized accounting system, and Bitcoin is the currency that "exists in digital form" carried on this system. Blockchain is a system behind Bitcoin that consists of credit records and the settlement of credit records.

Blockchain is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithm. The so-called consensus mechanism is a mathematical algorithm that establishes trust and obtains rights and interests between different nodes in the blockchain system [1].
Blockchain is an important concept of Bitcoin. The "2014-2016 Global Bitcoin Development Research Report" released by Huobi.com, Tsinghua University PBC School of Finance Internet Finance Laboratory and Sina Technology mentioned the area. Blockchain is the underlying technology and infrastructure of Bitcoin [2]. It is essentially a decentralized database and serves as the underlying technology of Bitcoin. 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 of its information (anti-counterfeiting) and generate the next block< br /> The evolution of blockchain is:
▪ Blockchain 1.0 - digital currency
▪ Blockchain 2.0 - Digital Assets and Smart Contracts
▪ Blockchain 3.0 - IFMChain, the blockchain officially links mobile terminals

2. How to define a blockchain block What are the application scenarios of blockchain?

Nowadays, many people think that blockchain is a universal technology that can do anything. This is a bit of a myth about blockchain technology!
Regarding the definition of blockchain technology, American scholar Melanie Swann defined blockchain technology as an open, transparent and decentralized technology in her book "Blockchain: A New Economic Blueprint and Introduction" database.

Definition of Blockchain: Narrow VS Broad

As for the application scenarios of blockchain technology, it is natural to combine the differences between blockchain and other technologies. In terms of system characteristics.

Blockchain technology features include:

Blockchain is a global A database storage system that can be operated collaboratively in various places is different from traditional database operations where read and write permissions are in the hands of a company or a centralized authority (a characteristic of centralization). Blockchain believes that anyone with the ability to set up a server can participate. Nuggets from all over the world have deployed their own servers locally and connected to the blockchain network to become a node in this distributed database storage system; once joined, the node enjoys exactly the same rights as all other nodes and obligations (decentralized, distributed characteristics).

At the same time, those who provide services on the blockchain can perform read and write operations on any node in the system. In the end, all nodes around the world will complete the process again and again according to a certain mechanism. Synchronize in sequence to achieve complete consistency of data in all nodes in the blockchain network.

At the beginning of this year, the term blockchain began to enter everyone’s lives. From national leaders to aunts who dance square dances, everyone knows this term. This term is widely known by Bit Brought by coins.

As we all know, the first few dozen bitcoins could only be exchanged for one pizza. At its peak, it was worth more than 20,000 US dollars, which has skyrocketed by more than a thousand times. This has also benefited a large number of wealthy people. Currently, there are blockchain The virtual currency generated by technology is gradually entering everyone's life, and many people have joined the ranks of currency speculation. I often hear people say that if you buy the right currency a hundred times, a bicycle will become a sports car, and one coin will turn a young model. You can imagine how many of them are involved. Attractive.

Since 2008, various games applying blockchain technology have also become popular, such as development games (Network Letts Dog, 360 Block Cat), mining games (NetEase Planet, Virtual Earth, Gongxinbao), these are attracting everyone to join in the name of blockchain, and of course there are some that are really reliable, which requires everyone toIdentified carefully.

The three words "blockchain" were completely ignited during the Spring Festival that just passed, and the limelight overshadowed everything else. Some people said that this is the arrival of a new era, and the past has become classic, and others To say that everything is hype is ultimately a bubble.

In fact, blockchain technology is not a new concept. It has been applied to many industries, such as electronic signatures, as early as the past two years. Recently, the third-party electronic signature platform eShanbao revealed the latest progress of blockchain applications to NewSeed.

Currently, blockchain technology is mainly used in e-signing products for certificate deposit and certificate issuance. The application scenarios include copyright protection and online signing. , web page forensics, phone recording, email storage of evidence, etc.

Take the rights protection of online works as an example. Since online rights protection generally adopts the method of collecting evidence after the fact, real-time confirmation of rights is not carried out in the process of evidence generation, so the entire confirmation process is difficult. The copyright process is time-consuming, difficult and costly to obtain evidence, and extremely difficult to prove and trace the source. It cannot meet the characteristics of rapid dissemination and large quantity of online works.

eShanbao's new intellectual property protection solution based on timestamp + blockchain starts from the user's real-name authentication and solidifies the information generated in the process in real time. Electronic data, and through the time source service synchronized with the National Time Service Center, online works are stamped with legally valid timestamps to prove that electronic files have not been tampered with in a certain period of time. Blockchain technology can establish point-to-point trust in the network, ensuring that all blockchain nodes can record complete copyright confirmation and transaction records, and can trace their origins, truly realizing anti-repudiation and anti-tampering, and realizing a kind of distribution. trust infrastructure.

Founder and CEO Jin Hongzhou believes that the application of decentralized blockchain technology has greatly improved the efficiency of data storage and certification, and The credibility of the identity of the parties reduces the cost of trust, but it cannot replace the original centralized public key encryption technology. The two should complement each other. Through the combination of the two, it can provide users with real-time and reliable Confirmation plan.

Next, e-Shanbao will also focus on building a smart contract platform based on blockchain technology. Jin Hongzhou said that data storage, Issuing certificates is only a relatively superficial application based on blockchain technology. It is the first step to implement blockchain technology, and the realization of real smart contracts is the second step. "Smart contracts cannot simply be understood as electronic contracts. They refer to a process, from the conclusion of the contract to the confirmation to the final execution." Jin Hongzhou explained.

Through the following limited cases, I hope everyone can understandThe actual performance of blockchain technology has stimulated interest in such solutions.

1. Administrative Services

Over the centuries, the roles and responsibilities of public administration have not changed significantly – or rather, what has changed dramatically is actually the scale of the data and the specific ways in which public agencies handle it. Although various digital technologies already exist to help collect and process data, issues such as anonymization, portability, and the immutability of large amounts of data remain unresolved.

Sasha Ivanov, founder, entrepreneur and CEO of Waves Platform and Vostok projects, said, "What the public administration currently lacks is a more convenient user experience (UX) for data use. To improve the user experience , we should introduce some kind of layer to it that acts as a trusted public environment that is transparent and can store data anonymously and immutably."

Governments are working on this by launching the U.S. Federal agency and enterprise-level initiatives such as the Federal Blockchain Initiative are gradually confronting the existence of such problems. The United States held its first federal government blockchain forum in July 2017, and the U.S. General Services Administration currently has more than 200 related use case repositories. Ivanov explained, “Distributed systems can really help us build such a reliable environment, improve our big data work, and even integrate all emerging technologies – including artificial intelligence and the Internet of Things. In fact, , whenever we face any kind of technology, it always embodies the sum of certain other technologies."

Now, the system supported by the blockchain can actually work - this This view has been unanimously recognized by all experts and has become the most important theoretical basis. In other words, what we need to do next is create more production-ready solutions.

2. Payment services

The government needs to process transactions, many of which involve the exchange of funds with citizens. Blockchain technology has huge potential application value in reducing the cost of fund transfers - including using new blockchain-based cryptocurrencies as intermediate transaction carriers, or using blockchain as a means of fund transfer, etc. Once a perfect solution is discovered, the business opportunities will be endless - especially for those who need to conduct frequent cross-border or Internet transactions.

The Jasper project was developed by the Bank of Canada to help it further think about how central banks and other financial institutions should implement payment operations between different banks based on distributed ledgers. The Bank of Canada has also developed its own digital currency variant, “CAD Coin,” to test the feasibility of using a national currency on top of the blockchain.

This project brings to an interesting conclusion that we should say no to proof-of-work public chain systems. In an article titledIn the paper "Project Jasper: Is a Distributed Batch Payment System Feasible?", the author observes that "Proof-of-work systems are not suitable for such large transaction processing systems because they assume that all transactions in the system need to be public to some extent. and observability.”

3. Digitization and Intellectual Property

Governments are responsible for maintaining copyright records and databases. These records prove ownership of intellectual property. A blockchain-based system would allow artists, performers and writers of all kinds to time-stamp their works and theoretically detect copyright infringements and even keep a permanent record of their rights. In fact, many governments have already taken important exploratory steps in this direction.

Iran recently announced that it will deploy this technology. "Iran Financial Tribune" quoted Morteza Mousavian as saying that "the Digital Media Department of the Ministry of Culture has reached an agreement with a blockchain company to jointly design a system that can be used to protect online copyrights." He also added that "the relevant procedures will It will soon be released to users in an easy-to-use format."

This work is still in the early exploratory stages, but it offers enterprise customers the possibility of preserving records through replication technology. From a theoretical level, companies can use blockchain solutions to conduct financial accounting and discover errors in real time.

4. Welfare distribution

The government has the responsibility to create a level playing field for citizens. Citizens who are chronically poor or economically disadvantaged certainly need government support and assistance to ensure that they are able to sustain themselves and develop. However, welfare distribution is neither simple nor often straightforward. Problems such as corruption and impersonation have been wreaking havoc on various distribution channels within government schemes.

In China, the National Council of Social Security Fund is conducting early research on how to use blockchain technology to improve the delivery of national benefits to citizens. At the same time, India is also taking action. Andhra Pradesh and Telangana are already using blockchain to support their civilian resource supply systems.

It is said that many companies, including Microsoft, are also considering using the same technology. These solutions, which will touch individual employees and functional roles, are expected to gradually appear in small businesses in the near future.

5. Bidding activities

In order to build public infrastructure or provide related services, the government hopes to achieve economies of scale and competitive gains through bidding as much as possible. However, the bidding process is often not fair or transparent. Public procurement has long been a major scene of rampant corruption around the world. Transparency International pointed out that “many governments will award project contracts to a certain supplier in the absence of fair competition. This makes it easier for those with more political resources toCompanies unfairly outmaneuver competitors; or companies in the same industry negotiate their bids in advance to ensure each company gets a share of the tender pie. This will significantly increase the cost of delivering services to the public – we have found that corruption issues can increase project costs by 50%. ”

So, how can blockchain technology solve the bidding problem? According to Ivanov, “Unlike decentralized centralized systems, independent ledgers powered by blockchain will be able to improve bidding or Transparency of any other financial processes that need to be tracked. The intervention of blockchain technology will help track the use of funds and ensure that they are paid out as expected and within the allowed time. ”

Currently, Japan’s Ministry of Interior and Communications has announced a blockchain-based bidding system, which means that in industries with serious collusion problems, small and medium-sized enterprises are expected to usher in a more transparent bidding method and Brighter development prospects.

Although quite a few of the cases mentioned previously are far from finalized, they do provide many possibilities for enterprises and governments. Of course, the key lies in implementation; and we All this should also be viewed with optimism, that is, although blockchain technology is often misunderstood by people, it is and will eventually find a direction in which it can exert its own energy!

In layman's terms, blockchain is like There are more than a dozen beacon towers on the Great Wall. If an enemy comes at one place, they will send out smoke. The other beacon towers will know about it and enter a defensive state together. In technical language, it is a distributed ledger, and each node will keep accounts separately. The failure of a single node will not affect the entire network.

How is this distributed network different from the distributed servers of Google Network? Google Network and others The distributed servers still belong to the Google network and are controlled by their central scheduling algorithm. The distributed nodes in the blockchain do not know each other and have no legal affiliation. If you want to go offline and shut down That's fine, but because of the currency rewards, there will always be people who will start up as new nodes to support this network.

After the popular and technical explanation, I hope You already understand. Then the first application scenario is finance. I put the money in Alipay. If Alipay doesn't recognize it one day, there is nothing you can do. But on the blockchain, it is useless if a node does not recognize it. Because other nodes still have my records. The second one is the contract. Nowadays, contracts are signed on paper, which is easy to forge, but it cannot be forged if it is placed on the blockchain.

There are more application scenarios. It is recommended to check the top 100 digital Huobi online to understand the corresponding projects behind them and become a blockchain expert.

Area Blockchain technology was first used in Bitcoin. Blockchain provides reliable and trustworthy organizational data for cross-subject business scenarios.s method. JD.com is essentially a supply chain company, and blockchain technology will be first used in many scenarios of the supply chain.

Blockchain is a decentralized technology. Blockchain can be applied to all products currently covered by the Internet.

The most popular application industry at present is the financial industry.

An application that has been implemented is product traceability. Alibaba and JD.com are already using blockchain technology to fully trace the origin of some of the products they sell. Consumers can trace the origin of the purchased products. There are also many blockchain applications in the digital advertising industry. Since digital advertising traffic fraud causes losses of tens of billions of dollars every year, there are already blockchain application projects based on digital advertising, such as DCAD, which is based on blockchain. The digital advertising application of blockchain technology mainly solves the problem of traffic fraud

In the future, as the application of blockchain technology becomes more mature, it will be applied in many industries, creating a new ecosystem based on technological trust. Mode

The characteristics of blockchain are distributed accounting and decentralization, but the ultimate goal is to make people get along more equally. Technology is meaningful only when it serves human values, and technology that meets human value needs will develop. Therefore, blockchain is in line with human pursuit of freedom and equality, so its trend to become mainstream is unstoppable.

Currently, there are many blockchain gimmicks, which are basically used to issue coins. The newly launched ono is a decentralized, free and global social platform. Due to decentralization, your chat communication information is peer-to-peer and cannot be viewed by others. In other words, your every word and deed will no longer be recorded and reviewed at any time like it is now on WeChat, QQ, and Facebook, freeing you from the trouble of surveillance.

In fact, blockchain technology can be used in any field. Information that previously required third-party confirmation can be completed online and confirmed at multiple nodes, making it difficult (almost impossible) to delete.

At present, blockchain is still in its infancy, and the technology is not mature enough, but it is also a better time to enter.

What is blockchain

If we use non-technical terms to explain blockchain, blockchain is a place where data is stored. However, the data stored in the blockchain is safe and reliable and does not need to be managed by anyone, so In the Internet, a place where data and information are exploding, having such a place would be like a magical treasure.

What can the blockchain do?

If you ask what the blockchain can do, it is better to say what applications require the use of the blockchain. As mentioned earlier, blockchain is a safe place, so wherever data needs to be protected securely on the Internet, blockchain technology needs to be used. For example:

Because the use of blockchain technology can better understand the data of policyholders, in today’s Internet, data is value and wealth.Therefore, value protection and value transmission are the future development directions of the Internet, and blockchain technology can truly achieve this.

If there are any deficiencies, you are welcome to comment and correct me.

In a narrow sense, blockchain is a chained data structure that combines data blocks in a sequential manner in chronological order, and is cryptographically guaranteed to be non-tamperable and non-tamperable. Fake distributed ledger.

The two parties involved in the transaction do not need to know who the other party is, nor do they need a third party for trust endorsement. They only need to trust a common algorithm to establish mutual trust and conduct direct transactions.

Its characteristics are trustlessness and decentralization. The destruction of each node's ledger has no impact on the entire blockchain. The blockchain runs point-to-point payments without a center that may cheat, and the security is greatly improved. Improved, the entire transaction network has changed from a star structure to a point-to-point P2P structure.

In the future, blockchain will be used in many fields and will have a great impact on human life. . It can be widely used in fields ranging from digital currency to securities and financial contracts, medical care, games, artificial intelligence, smart contracts, Internet of Things, e-commerce, file storage and other fields.

1. Cloud storage

This is the statistics of current cloud storage on the Internet. In terms of volume, Google has the largest volume, which is 8,000PB. So what if we share the idle data on the Internet?

Starlight Cloud builds a blockchain data computing and storage lake through Starlight Chain, with a total storage capacity of 15,000P (approximately 15.72864 billion G) in the future. This will be more than 10 times that of Alibaba Cloud's 1500PB! It is also more than four times the size of the Taizhou Storage Center, the largest storage lake in the world after expansion.

2. Medical aspects

Using blockchain technology to save personal medical records also retains personal medical historical data, which can be used when seeing a doctor or planning for your own health in the future. Historical data can be called directly. These data are highly private, and the use of blockchain technology also helps protect patient privacy.

3. Five characteristics of blockchain

Blockchain is a term in the field of information technology. In essence, it is a shared database . Five major characteristics of blockchain:

1. Decentralization means that all nodes running in the entire blockchain network can perform accounting and have one accounting right. This is completely This avoids one of the drawbacks of centralized operations. It is not a centralization, it is a disintermediation;

2. Openness, this is for the public chain of the blockchain, because the information of the public chain can be read by anyone. Go in and write, as long as it's completeAll nodes in the network system and nodes with accounting rights can do this;

3. Anti-tampering, that is, anyone who wants to change the information in the blockchain must attack 51 in the network Only % of the nodes can change the data, which is very, very difficult;

4. Anonymity, its anonymity is based on its algorithm that is addressed by address, not by individual Identity is something the government is more worried about. There are two things that are uncontrollable in the entire blockchain. The first is the uncontrollable anonymity of the identity. It is not known who initiated the transaction; the second is that it has a cross-border payment, which involves the transfer of currency funds. One piece;

5. Traceability, its mechanism is to set the next block to have a hash value of the previous block, just like a hook, only the previous hash value is recognized To be able to hang it up, it is a complete chain. Another good feature of traceability is that it facilitates data query, because this block has a unique identifier. For example, if you go to the database to query something, there are many algorithms to find it in blocks, and In this blockchain network, time nodes are used to define the block in this time period before addressing it, which is more convenient.

4. The network structure of the blockchain is a local area network

Yes.
If the public chain is regarded as the Internet, then the private chain is a completely closed local area network under blockchain technology, which can be understood as a weakly centralized or multi-centered system.
A completely private blockchain refers to a blockchain whose write permission is only in the hands of one organization. Read permissions are either open to the public or arbitrarily restricted. Private chain participating nodes are limited and controllable, and their writing permissions are controlled by an organization and institution. The qualifications of participating nodes will be strictly restricted. In a private chain, the participants are all their own, so there is no need to give economic incentives through a consensus algorithm. Therefore, its efficiency has obvious advantages over public chains.

5. What is blockchain

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. As the underlying technology of Bitcoin, it is a series of data blocks generated using cryptographic methods. Each data block contains a batch of The information of Bitcoin network transactions is used to verify the validity of its information (anti-counterfeiting) and generate the next block.

(5) Extended reading of blockchain network

Characteristics of blockchain:

1. Certificate deposit

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The "non-tamperable" feature of blockchain provides a solution to the problem of "certificate storage" in economic and social development. As long as the authenticity of on-chain information and data can be ensured, then blockchain can solve the problem of “storage” and storage of information."Proof" problem.

For example, in the field of copyright, blockchain can be used to store electronic evidence, which can ensure that it is not tampered with, and can link original platforms, copyright bureaus, judicial agencies and other parties through distributed ledgers, which can greatly Improve the efficiency of handling infringements.

2. Sharing

The "distributed" characteristics of the blockchain can break through the "data barriers" between departments and achieve information and data sharing. Different from centralized data storage, the information on the blockchain will be distributed to each node through point-to-point broadcasting, and all information can be "truthfully recorded" through "whole network witness".

6. What is blockchain

In the simplest terms, blockchain is a distributed ledger.

To understand what this means, we first have to look at its opposite: a centralized ledger. Because blockchain technology started with finance, we will also introduce it below using banks as an example.

The following is our process for using bank debit card transactions:

You can swipe your card to purchase goods in stores.

The merchant sends a statement to your bank for the agreed upon amount.

Your bank will verify that you may have authorized the purchase.

The bank sends the money to the merchant.

Finally, the bank records this information in its ledger.

There’s a lot of technology involved here, but that’s basically it. The last step is important - the bank records all transactions made by the customer. This ledger goes all the way back to the first transaction the bank made.

This ledger is kept, maintained and regulated by the bank. You can read it in your online bank account, but you can't change it. The bank has complete control. If it decides to make a change, there's nothing you can do about it.

Crucially, if hackers were able to access a bank’s ledger, that could cause a lot of problems. They can change the account balance to make it look like certain transactions never occurred, etc.

This is why distributed ledgers are so cool.

Blockchain Network Visualization

If a bank operates on a distributed ledger, each member of the bank will have a copy of the ledger, and whenever any member of the bank When they make a purchase, they tell every other member of the bank.

Each member will validate the transaction and add it to the ledger (the added records are called "blocks"). This has some important benefits, as there is no centralized authority that can manipulate records. Hackers accessing one ledger won't be a big problem because other ledgers can easily verify it.

On the other hand, it requires a lot of work. In short, the second system is the blockchain (at least infinancial plan).

As mentioned above, blockchain is a decentralized list of transactions. If I send Xiao Ming 2 Bitcoins, I send a message to everyone in the network saying "I am sending Xiao Ming 2 Bitcoins" and they all record the transaction.

The future of blockchain, how will it change our lives?

One thing that is important about blockchain is that it is a public resource and no one really owns it because everyone owns it.

Blockchain is not just science fiction. We don’t need to understand the mechanism behind this technology, but you do need to understand that it may completely change our lives in the next 20 years.

This may sound bold, but remember, 20 years ago we were browsing the Internet on Netscape, using state-of-the-art Motorola flip phones, and buying our first DVD players. At that time, if we imagined that a computer could be held in our hands and that we could buy cars, make payments, and watch movies, it would have been considered a fantasy.

Although the impact of blockchain may not be as obvious as the Internet, nor as tangible as mobile phones, blockchain will effectively solve many worries in daily life. Such as intermediaries cheating people, transaction delays, etc. In our current lives, middlemen are everywhere and we take them for granted as a part of life. If one day these intermediaries cease to exist, you will find that the world will become a different place.

Imagine that by 2040, blockchain may become a mature and widely used technology. When one day you can't live without the blockchain just like you can't live without the Internet now, you will be surprised to find that this decentralized accounting technology has simplified the complexity and become a part of your lifestyle

7. The most straightforward explanation of blockchain

In recent years, the term "blockchain" has become a hot topic, and news media have reported on it, but everyone may not understand blockchain. Knowledge is still at the stage of looking at flowers in the mist. Today we are going to unveil its mystery.

In fact, the essence of blockchain is very simple and can be explained in one sentence: decentralized distributed database.

The main function of the blockchain is to store information. Anyone can write information and read it at the same time, so it is a public database.

Characteristics of blockchain

Distributed database technology has long existed in the market, but the difference is that although blockchain is also a distributed database , but it has no administrator and is completely decentralized.

Decentralization is a disruptive feature of blockchain technology. It does not require a centralized agent and realizes a direct point-to-point interaction, enabling high-efficiency, large-scale, and information interaction without a centralized agent. way becomes reality.

But, without an administrator, everyone can write data into it, how can we ensure that the data is trustworthy? What should I do if I am changed by a bad person? The designers have already thought of this, which proves that blockchain is a truly epoch-making product.

Block

The 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:

Block header (Head): records the characteristic value of the current block
Block body (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
...
Every time in the system Each node has the latest complete database copy. Modifying the database of a single node is invalid because the system will automatically compare and consider the same data record that appears the most times to be true. At the same time, every step of the data record will be retained on the blockchain, and the information at each step can be traced.

Here, you need to understand what a hash is, which is necessary to understand the blockchain.

The so-called "hash" 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 no matter what the original 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 approximately considered 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.

The immutability of hashes

Blocks and hashes are in one-to-one correspondence, and the hash of each block is for the "block header" (Head) computational. 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 includes the block header, not theContains the block body, that is, the hash is uniquely determined by the block header.

As mentioned earlier, 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 is of great significance to the 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.

8. What exactly is the blockchain?

The blockchain is a special network ledger. The core of blockchain technology is digital encryption. As early as 1991, a group of young people invented a new encryption technology that mutually verifies each other in order to prevent the date of electronic documents from being tampered with. They use cryptography to concatenate and protect concatenated text records (also known as blocks) of content.

The unit in which blockchain stores data is a block, and each block is strictly queued in order to form a "chain". If someone wants to change the content of a certain block, the unique characteristics of the block will also change accordingly, and subsequent blocks will immediately reject it, and this "fake" block will have to be detached from the chain.

(8) Blockchain network extended reading

Users from all over the world can connect their servers to the area In the blockchain network, it becomes an independent node in this distributed database storage system. Once joined, the node has the same rights and obligations as all other nodes.

Thus, people who provide services on the blockchain can perform read and write operations on any node in the system. All nodes around the world will complete synchronization again and again according to a certain mechanism, so that the data of all nodes in the blockchain network is completely consistent.

It is precisely because of the two characteristics of immutability and decentralization. Blockchain has well solved the trust problem that is a headache in modern business society. It has already emerged in social fields such as financial services, Internet of Things, public services, social welfare and supply chain management.

9. What exactly is blockchain

Let’s talk about some basic concepts first.

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

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

The definition refers to the "decentralized database" nature of blockchain3354. This is very different from the traditional "centralized database" in storage, update and operation.

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

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

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

The database structure may look like this:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

This brings up an important attribute of blockchain: traceability.

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

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

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

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

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

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

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

A new technology is often used totask service.

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

Let’s go back to 2008.

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

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

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

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

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

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

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

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

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

So many currencies have different functions and are divided into different categories: digital currencies represented by Bitcoin are positioned as "digital gold" and have certain value storage and hedging characteristics; Ethereum The digital currency represented by Bitcoin has become the "operational fuel" in its network system; the stable currency represented by USDT and Libra has good payment properties due to its low volatility; the digital currency issued by the central bank represented by DCEP will definitely To a certain extent, it replaces M0, allowing commercial institutions and ordinary people to receive and pay without delay when they are out of cash and disconnected from the Internet.

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

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

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

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

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

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

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

Give two examples.

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

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

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

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

Give two examples as well.

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

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

Blockchain technology naturally has financial attributes

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

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

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

Give me an example.

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

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

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

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

Finally, blockchain can realize multi-party collaborative data calculations while protecting data privacy, and is expected to solve the problems of "data monopoly" and "data islands" and realize the value of data circulation.

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

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

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

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

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

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

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

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

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

Related Q&A: What is blockchain

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

In a narrow sense, blockchain is a chain data structure that combines data blocks in a sequential manner in chronological order, and is cryptographically guaranteed to be non-tamperable and non-forgeable. distributed ledger.

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

Blockchain infrastructure:

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

10. Illustration of what is blockchain

Blockchain is so popular that it has begun to affect my life. I don’t even want to understand it. Today I will take a look at what it is. It's blockchain.

Structure of this article:

As its name suggests,
A blockchain is a chain composed of a set of blocks.
A block is a block of information that contains information. , the chain also contains information.

Blockchain technology was first developed by a group of researchers in 1991 to time-stamp digital documents so that these documents cannot be tampered with. It essentially played no other role after that, until 2009, when Satoshi Nakamoto used blockchain technology to create the digital cryptocurrency Bitcoin.

A blockchain is a distributed ledger that is completely open to everyone. It has a very interesting property: once certain data is recorded in a blockchain, the data is very It is difficult to change.

Let’s take a look at the composition of a block:

Each block contains some data, the hash value of this block, and the hash value of the previous block. Hope value.

The data saved in the block is related to the type of blockchain. For example, the blocks in the Bitcoin blockchain save relevant transaction information, including sellers, buyers, and transaction Bitcoins. quantity.

Each block contains a hash value. The hash value is used to identify a block and all the content it contains, and it is unique, like a fingerprint. Once a block is created, its hash value is calculated accordingly. If you change something in the block, the hash value will change. If the fingerprint of a block changes, it will no longer be the previous block.

The third element contained in the block is the hash value of the previous block. This element enables the formation of links between blocks and enablesThe blockchain is very secure.

Suppose we have a blockchain containing 3 blocks
Each block contains its own hash value and the hash value of the previous block
No. 3 Block points to block No. 2, and block No. 2 points to block No. 1
Block No. 1 is a bit special, it cannot point to the previous block because it is the first
We put 1 The block number is called the genesis block.

Now suppose we tamper with the second block
This will cause the hash value of the second block to change
This will then cause block 3 and 3 All subsequent blocks connected to the block number become illegal
Because the previous block number they store now becomes illegal
So changing one block alone will jointly make all subsequent blocks The content becomes invalid.

But to prevent tampering, hashing is not enough
Because today’s computer computing speed is powerful enough and can calculate thousands of hash values ​​per second
This way You can tamper with a block and recalculate the hashes of other blocks, making your block legal again.

So in order to reduce this risk, the blockchain also uses a technology called proof of work
This is a mechanism that slows down the creation process of new blocks
In the Bitcoin area In the blockchain, it takes about 10 minutes to complete the required proof of work and add a new block to the blockchain
This mechanism makes the tampering of the blockchain more difficult
because once it is tampered Once a block is obtained, the proof of work of all subsequent blocks needs to be recalculated.

Therefore, the security of blockchain technology mainly comes from hash value and workload proof mechanism.

Blockchain also has a mechanism to protect its own security, which is distributed
Compared to using a centralized entity to manage the blockchain network, blockchain uses A peer-to-peer network that anyone can join
When someone joins this network, he will get a copy of the entire blockchain
This person can use this to verify that all The blocks are still legal and untampered, that is, different nodes can use this to verify each other.

When someone creates a new block,
the new block is sent to everyone on the network.
Everyone then verifies the block to ensure that the block has not been tampered with
If everything is verified to be correct, then everyone can add the new block to their own block On the chain
We can call it that everyone on the network has reached a "consensus".

All nodes in the blockchain network have reached a consensus
They agree on which blocks in the network are legal and which are illegal
Those blocks that have been tampered with will will be rejected by other users on the network
So, to successfully tamper with a blockchain, you need to tamper with all blocks on the blockchain
Recomplete the proof of work for each block and control More than 50% of the users in the blockchain network
Only in this way will the block you tamper with will be recognized by everyone
It can be said that this is basically impossible to do!

Blockchain technology itself is also constantly developing
For example, a later technological improvement is called smart contracts
Smart contracts are simple programs stored on the blockchain
br /> It can automatically execute based on the conditions recorded in the contract. As long as the conditions are met, the transaction will be automatically completed in accordance with the contract
For example, automated Bitcoin transactions can be realized under specific conditions.

Learning materials:
https://www.youtube.com/watch?v=SSo_EIwHSd4