区块链nounce,ontology区块链

区块链nounce和ontology区块链是当今区块链技术的重要组成部分，它们构成了区块链的基础。在这篇文章中，我们将探讨三个重要的关键词：智能合约，去中心化应用（DApp）和去中心化账本技术（DLT）。

智能合约是一种利用区块链技术实现的分布式自动执行协议，它可以实现自动执行合同中的条款，从而使双方无需借助中介机构就能实现自动执行协议。智能合约是基于区块链技术开发的，它可以被编程，从而可以实现自动化执行，提高了合同执行的效率和可信度。智能合约的执行过程是完全透明的，不受任何人的控制，所有参与方都可以在区块链上查看智能合约的执行状态，从而更好地保护双方的利益。

去中心化应用（DApp）是一种利用区块链技术开发的去中心化应用程序，它可以实现自动执行，不受任何人的控制。DApp可以实现去中心化的应用，不依赖于任何中心化的服务器，可以实现去中心化的数据存储，保证数据的安全性和可靠性。DApp的发展也推动了区块链技术的发展，使得区块链技术可以在实际应用中得到更多的推广。

去中心化账本技术（DLT）是一种利用区块链技术实现的分布式账本技术，它可以实现账本的去中心化存储，使得账本的数据可以实现去中心化的存储，从而更好地保护数据的安全性和可靠性。DLT也可以实现账本的实时更新，让数据可以实时可靠的更新，从而提高了账本的可用性。DLT也可以实现账本的可追溯性，使得账本的数据可以实现完整的追溯，从而更好地保护账本的安全性和可靠性。

以上是有关区块链nounce和ontology区块链的三个重要关键词：智能合约，去中心化应用（DApp）和去中心化账本技术（DLT）的介绍。它们是区块链技术的重要组成部分，它们可以实现自动化执行，提高了合同执行的效率和可信度，也可以实现去中心化的应用，保护数据的安全性和可靠性，以及实现账本的可追溯性，更好地保护账本的安全性和可靠性。

请查看相关英文文档

❶Do you have any recommendations for good blockchain books?

"Blockchain World" is produced by Jingtong Technology.
@ Blockchain God Tucao

❷ Introduction to Blockchain (1) - Let’s keep accounts together

When I was a child, I was curious about many novel things , full of desire to understand and learn, at that time countless exclamation marks often appeared in my brain. As I grow older and gain more experience, this kind of experience becomes less and less common, and I am not surprised by the new things that many people follow. When "blockchain" first appeared, I was completely attracted. After that, just like when I was a child, I was instinctively driven to learn and understand deeply, and found that "blockchain" is a new world that is about to come. s future.

The first time I heard the word "Blockchain" was in teacher Li Xiaolai's column "The Road to Freedom of Wealth", and I read it many times in the column after that. to the emergence of this term. Out of curiosity, I followed and read the articles on Lao Mao's public account "Cat Talk", and gradually gained a 0 to 1 understanding of the blockchain. block-block, chain-chain, blockchain-connect the blocks one by one into a chain, imagine the DNA extending infinitely in front of you...

This paragraph is about blocks on the network An explanation of the chain, to put it in simpler terms, the blockchain is an open, decentralized, trustless, and jointly maintained accounting system.

Let’s first look at the traditional centralized banking business model. When we do transactions, why do we need third-party centralized companies such as banks, Alibaba, and Tencent? Because there is no trust between people. A lends B 100 yuan today. If B does not recognize the loan tomorrow, what will A do? The bank helps solve this problem. Everyone creates a real-name certified account in the bank. With the help of this centralized company, A lends 100 yuan to the bank (deposit), and B takes out 100 yuan from the bank (withdraw/borrow). Then the bank Responsible for recording this transaction, A's account will be 100 yuan more, while B's account will be 100 yuan less. This method of relying on third-party centralized companies for accounting can be seen everywhere in our lives: for online shopping, we need Alibaba's Taobao City and JD.com; for loans, we need to find reliable small loan companies; for new books, we need to go through a certain publishing house... …In the final analysis, it’s because people don’t trust each other, or the risks and costs of maintaining trust are too high, so we need such centralized and powerful third-party companies to endorse transactions and let them Taking these risks, of course, they also make us money. However, relying on third-party centralized business models has brought us inefficient services, cumbersome procedures and diversion of value, such as banks queuing up to handle business, the lending process of small loan companies, and Taobao and JD.com’s rent collection from merchants. , the publisher’s share of the author’s manuscript fee, etc. This is the centralized system we are currently in, a world where third parties are trusted.

The blockchain world is a new world where no third party is needed, all transaction information is public, and everyone participates in bookkeeping! As the world's first proven and feasible blockchain application, Bitcoin subverts the traditional financial model by using automatic accounting and open accounting, information cannot be tampered with, and can be queried at any time, bypassing third-party centralization. Buyers and sellers conduct transactions directly. Such a transaction model must be efficient, low-cost, and open. Just imagine if blockchain technology becomes popular in the future, when you want to transfer a large amount of money to a friend abroad, you can skip the lengthy steps and get it instantly; if you write a book and publish it, you don’t have to worry about being pirated. There is no need for the publisher to earn your royalties; a peer-to-peer mutual insurance platform will be built directly between people, and the insurance company will become a consulting company, etc. (In fact, Bitcoin and Press.one are realizing such a subversion)

The Internet is currently booming. We have Didi taxis or shared bicycles for outside work, Ele.me for ordering food, and Ele.me for dining in restaurants. Dianping, convenient payment via WeChat and Alipay is everywhere. When we pay on the Internet, we need to rely on a third-party platform company trusted by both buyers and sellers to complete the transaction for us. These third-party companies have a large amount of transaction data and information on both parties to the transaction. If a hacker intrusion occurs and information is lost, we will bear the consequences for our "trust risk"; not to mention the delays caused by reviewing and clearing transaction data. The inconvenience, and the huge cost of managing such a huge amount of data.

So how is blockchain technology implemented? For example, if there is an army that wants to seize an enemy fortress, and each soldier wears a special helmet with a red button, each time a fortress is captured, the army headquarters will award a medal. First, a soldier A took the lead in occupying the first fort 1. He announced to other comrades through his helmet that he had occupied fort 1. At this time, the helmet would record the coordinate information of fort 1 and pass it to other soldiers along with A's shouting. All soldiers and others heard A's shouting through the helmet and pressed the red button to indicate that the message had been recorded simultaneously. Then everyone knows that fortress 1 has been occupied by A, and A is rewarded with a medal. Then others will immediately capture other fortresses and broadcast their achievements in the same way. In this way, the information that different fortresses were captured by different soldiers in this battle is all stored in everyone's helmet. Here, the helmet is the public ledger (strictly speaking, the helmet's program), and everyone participates in accounting; each capture information constitutes a block, and all information arranged in a certain order forms a blockchain; In addition to keeping accounts (pressing the red button), participants also scramble to grab the right to package new data (capture the fortress).

Then comeCheck out the advantages of this shared accounting method. 1. Decentralization. The ledger is jointly recorded and maintained by everyone. It doesn’t matter who records it first, because if there is an incentive (medal), someone will do it, and there is no need for a third party to intervene (no need for the command of a general or combat department, reducing military expenses and commanders) risk of sacrifice). 2. Data cannot be tampered with. If you want to modify the accounted data, you must modify more than 51% of the node information to succeed. Just imagine, if this army has one million people (actually the number of blockchain nodes is much larger than this number), it would be an almost impossible task to modify the helmets of more than half of the army. 3. Information is open and transparent. Everyone can check this transaction information in their own ledger (all fortress capture information has been recorded in everyone's helmet).

This is the first article I started writing. The last time I wrote so many words was probably in the college entrance examination. The first article was about a new field that I had never touched before. The text was a bit confusing and mediocre, and I didn’t know whether the analogy I made was correct or not, but I finally started to do it. Writing is indeed a skill that everyone should have, and it is a skill that can be improved through deliberate practice and urge yourself to maintain it.

❸ 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 a series of data blocks generated 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 results?

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 we 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 marked with a page number, the second page contains the content of the first page, the third page contains the content of the first and second pages. 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 leads to an important attribute of the 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 pay back 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 to serve a certain task.

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, and 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 Bitcoins is called Genesisblock" (genesis block), the genesis block was compiled into block 0 and was not uploaded to the chain. It took Satoshi Nakamoto 6 days to dig out this block. This also triggered discussions in the bitcointalk forum. Bitcoin's "believers "They thought of the Bible, "God created the heavens and the earth in six days, and then rested on the seventh day."

Although decentralized, token, and economy did not appear in the paper (Economic) and other concepts, but Satoshi Nakamoto explained in detail how blocks and chains work in the network. So, there is a blockchain (Block Chain).

This paper, Later it became the "Bible" of the "Bit Cult", technology became the cornerstone of faith, and developer documents became the "Code of Hammurabi".

Later, Bitcoin realized the first real-life payment by exchanging pizza, and was WikiLeaks, whose accounts were blocked by the U.S. government, relied on a series of legends such as Bitcoin's miraculous survival, Satoshi Nakamoto's "decentralization" and retirement, true and false appearances and refutation of rumors, etc., which combine the expectations, imagination and speculation of future generations. , became a "Bible story."

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

CoinMarketCap shows that there are more than 4,900 types of digital currencies, and the overall market size of digital currencies 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 store-of-value and hedging properties; digital currencies represented by Ethereum have become the "operational fuel" in their network systems; USDT and Libra are The stablecoin represented by DCEP has good payment properties due to its low volatility; the central bank issued digital currency represented by DCEP has replaced M0 to a certain extent, allowing commercial institutions and ordinary people to use it when they have no cash and are disconnected from the Internet. Delaying receipts and payments.

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 some of its corresponding characteristics: Traceability, publicity, anonymity, and tamper-proofing. So in theory, traditional scenarios where centralized databases are used can be tried to be transformed with blockchain to see if it is suitable.

Next, let’s talk about a few Successfully implemented blockchain industries and scenarios:

Blockchain can prove a certain file or data through hash timestampThe existence of word content at a specific time provides a perfect solution for judicial authentication, identity certification, property rights protection, anti-counterfeiting and traceability, etc.

In the field of anti-counterfeiting and traceability, blockchain technology can be widely used in food, medicine, and food through supply chain tracking. Agricultural products, wine, luxury goods and other fields.

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 significantly 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. Since it was put into operation, 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 fraudulently used, 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 transactions on the chain and quickly locate high-risk capital flows.

In terms of securities issuance transactions, the traditional stock issuance process is long, costly and complicated. 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 build aThis kind of alliance chain network covers core enterprises, upstream and downstream suppliers, financial institutions, etc. The core enterprises issue accounts receivable vouchers to their suppliers. The bills can be transferred between suppliers after being digitized on the chain. Each level of suppliers can Financing of the corresponding amount can be achieved with digital bill certificates.

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 non-tampering and traceability mechanism of blockchain ensures the authenticity and high quality of 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 cases 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 AntAnt Alliance Chain led by Ant Blockchain and so on.

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, which is used to verify the validity of the 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.

❹ How to get started with blockchain. These knowledge are not difficult to learn.

1. To learn blockchain knowledge, first learn the necessary concepts of blockchain knowledge.

2. [Blockchain]

The English name blockchain is the underlying technology of Bitcoin and a decentralized accounting method.

3. [Block and Chain]

Block refers to the information block that records transaction information. Each block contains three main factors: The ID of the block, the odd number of the transaction, and the ID of the previous block.

The Bitcoin system generates a block approximately every 10 minutes. Each block contains the ID of the previous block, making the blocks form a complete transaction chain. The longest one isThe only master blockchain.

4. [Bitcoin]

Bitcoin is a practical application of blockchain technology. It is a peer-to-peer electronic cash payment system. It was first used as Virtual currency exists. Japan has recognized the legality of Bitcoin and can use Bitcoin for shopping.

5. [Satoshi Nakamoto]

The legendary founder of Bitcoin published a paper on a peer-to-peer electronic cash system in 2008, marking the The birth of Bitcoin.

6. [Digital Currency]

It is completely different from the Q coins and other virtual currencies we use to play games in real life. For example, in Japan, although Bitcoin is a digital currency , but it can already be used to purchase goods in real scenarios.

7. [PoW]

A type of consensus mechanism, also known as proof of work. Bitcoin currently uses this consensus mechanism. It is relatively simple and easy to reach consensus, but consumes huge amounts of energy and is prone to bifurcation.

8. [PoS]

A type of consensus mechanism, also known as proof of equity. People with greater equity have a greater probability of becoming bookkeepers, but bookkeeping Human ones are not necessarily professional, don’t consume much energy, and are prone to split ends.

9. [DpoS]

On the basis of PoS, the bookkeepers are changed from unprofessional to professionals, like the EOS we are familiar with. In this consensus method, holders jointly select 21 nodes and 100 reserve nodes to connect the EOS constitution to reach a consensus, and jointly incubate the ecology on EOS.

10. [Public key and private key]

In the world of blockchain, the public key is equivalent to the bank account number, and the private key is equivalent to the bank account number + withdrawal password. The private key is essentially an array of 32 bytes. The private key can generate the public key and address, but this behavior is irreversible, so it is crucial to keep the private key. Losing the private key is equivalent to losing money. And it can never be found back.

11. [Hash value]

It can be simply thought of as a set of data that is closely arranged together. No item in the data can be changed, otherwise The calculated consequences will be very different.

12. [Smart Contract]

It is a promise in digital form. Both parties involved can execute these promised agreements on the consumer network without artificial restrictions. .

13. [Credit Consensus]

Based onThe characteristics of blockchain are that it is a distributed accounting method that cannot be tampered with and is irreversible. It is a trust mechanism that allows many people to form a trust based on digital algorithms.

14. [Public chain and private chain]

Public chain refers to a blockchain that can be participated in by people around the world and can be read, and is open to everyone , while the private chain is only in the hands of an organization and is only open to individuals or entities.

Blockchain is currently a hot topic. Many traditional large enterprises and venture capital are actively participating in the layout and investment of the blockchain industry. As the general public, we must master the necessary blockchain knowledge. , helps us judge and analyze real-world information and protect our investments.

❺ How to define blockchain and what are the application scenarios of blockchain?

Nowadays, many people think that blockchain is a universal technology that can do anything. It is somewhat different. Blockchain technology is a myth!
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, people 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 U.S. dollars, which has skyrocketed by more than a thousand times. From this,It has benefited a large number of local tycoons. At present, the virtual currency generated by blockchain technology is gradually entering into everyone's life. Many people have joined the ranks of currency speculation. People often hear people say that if you buy the right coin a hundred times, a bicycle will become a sports car, and one coin will make you tender. Model, you can imagine how attractive it is.

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 to identify them 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 during the real-time solidification process. 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-signing will also focus on building a smart contract platform based on blockchain technology. Jin Hongzhou said that data storage and certification are only based on The relatively superficial application of blockchain technology is the first step to realize the implementation of 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 understand the actual performance of blockchain technology, thereby stimulating 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 are endless——This is especially true for those groups 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 a paper titled "Project Jasper: Is a Distributed Batch Payment System Feasible?" the author observed that "Proof-of-work systems are not suitable for such large transaction processing systems because they assume that all transactions in the system are There is a need for openness and observability to a certain extent.”

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 that will touch individual employees and functional roles are expected to gradually appear in small businesses in the near future.among enterprises.

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 noted that “many governments will award project contracts to a certain supplier in the absence of fair competition. This allows companies with greater political resources to improperly win over competitors; or companies in the same industry Bids will be negotiated in advance between companies, ensuring that each company gets a share of the tender. 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 anything else that needs to be tracked. Transparency of financial processes. 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 internal affairs and The Ministry of 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 companies and governments. Of course, the key lies in implementation; and we should also look at all this with optimism, that is, although blockchain technology is often misunderstood, it is and will eventually find a direction in which it can exert its own energy!

< p> In layman's terms, the blockchain is like 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. Each node keeps accounts separately. The failure of one or two nodes will not affect the entire network.

How is this distributed network different from the distributed servers of Google Network? Google Network's distributed servers still belong to 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 relationship. You can just go offline and shut down if you want, but because of the currency rewards, there will always be someone who will turn on the machine as a new node to support the network.

After the popular and technical explanation, I hope you understand. So the first application scenario is finance. I put my money in Alipay. If Alipay doesn't recognize it one day, there's nothing you can do. butIt is placed on the blockchain. It is useless if one node does not recognize it, because other nodes still have my records. The second is the contract. Nowadays, contracts are made on paper and are easy to be faked. But if they are put on the blockchain, they cannot be faked.

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. .

Blockchain technology was first used in Bitcoin. Blockchain provides a reliable and trustworthy means of organizing data for cross-subject business scenarios. 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 you 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 on the InternetThe Internet is a place where data and information are exploding. If there is such a place, it will be like a magical treasure land.

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 protect the data of policyholders, in today’s Internet, data is value and wealth, so value protection and value transmission are the future development directions of the Internet. And blockchain technology can really do just that.

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.

❻ What is blockchain and how was it born?What are the types?

If you want to understand the blockchain, you must first understand the basic structure of the program. Everything we see on the Internet is constructed through computer language. There are many kinds of computer languages, but the most basic characters that make up the language are codes, and blockchain technology is a way of applying codes, which is different from traditional centralization. The difference between the models is that the blockchain has the characteristics of immutability, privacy, security, and consensus.

There are many application scenarios for blockchain. The most successful case so far is Bitcoin, followed by electronic invoices, cross-border payments, etc. Based on the interoperability of data, it is impossible to With characteristics such as tampering, it can also be used to save some important data. As long as this data uses blockchain technology as the underlying technology, it can never be destroyed and will be saved forever. No person or institution has the ability to modify or delete it. In addition, there are certain intersections between blockchain payment and education, medical care, credit reporting, automobiles, transportation and other fields. It is a technology, not a certain product, so there is only one type of it, but with the application As the scene changes, its role is also different. It can be integrated with existing scenes in almost any field and then derive other applications.

❼ [Thinking about blockchain from scratch] (10) Everyone is the ecology, and the ecology is everyone

2018 is destined to be an extraordinary year for blockchain content entrepreneurship. Especially in the past two months, various content platforms have emerged. In addition to Bihu, which has been publicly tested, there are also PRI, ONO, QUNQUN, Zhibi, etc. that are currently undergoing internal testing.

In Dayu WeChat, one platform has several partners joining the group, and they are all frantically recruiting new promotion platforms.

What is the magic power of blockchain that makes everyone so enthusiastic and popular?

Knifefish thought of a word, ecology.

1 Multiple identities, one person, one ecosystem

In any economy in the past, we generally had only one identity, the boss was the boss, the employees were employees, and the investors were investors. , the boundaries between the parties are clear and distinct.

But in the world of blockchain, identity characteristics and boundary consciousness are blurred and homogenized. We generally play multiple roles, unified into one, living in peace and harmony.

Taking Bihu as an example, Daoyu not only contributes content and is a producer, but also browses and likes other articles, and is also a consumer. At the same time, Daoyu invests his time and energy in his works on Bihu, which has a positive impact on Bihu. Ecologically speaking, he is also an investor and platform maintainer.

Therefore, from the perspective of the role and identity of the swordfish itself, the swordfish has the roles of producer, consumer, investor, etc., all of which are carried by the swordfish in a unified manner, co-prosperity and symbiosis, and become a self-contained entity.

The swordfish is aloneIn fact, it is an ecology, rather than being just a fixed role and a link in the previous production relations.

2 Convergence of interests, shared ecology for everyone

In the past various production relations, the interests of all parties were inconsistent. The interests between bosses and employees are inconsistent, the interests between the company and customers are inconsistent, the interests between the board of directors and management are inconsistent, and even the interests between employees are inconsistent, and so on.

Among these production relations, the most difficult thing to coordinate is the issue of interests.

People are all seeking profit. Since their interests are inconsistent with each other, it is naturally difficult to coexist.

Inconsistency of interests is the root of many problems in the company. Therefore, the resulting internal and external conflicts have caused a huge consumption of resources, and many companies have been destroyed due to this.

In such a production relationship, an organization (company) is like a fragile fishing net. Each party pulls one end and pulls it toward itself. As long as one party is too strong, it will inevitably cause an imbalance and the fishing net will break.

But in the blockchain ecosystem, no matter which party you are on, or whether you are involved in multiple parties, everyone’s interests are naturally the same. Everyone will be prosperous and everyone will suffer. Everyone’s energy is positive, and their hearts are They all want to make this ecosystem bigger and stronger.

For example, Bihu, in this ecosystem, whether it is the platform, content generators, or consumers, everyone wants to increase the value of the KEY in their hands, and they all want to contribute more to the Bihu ecosystem. Make some contribution.

This is not to say that everyone becomes noble as soon as they join the blockchain, but that everyone’s interests have converged and they all want to make money by expanding the ecosystem.

3 Complete closed loop, self-operating ecology

Self-motivating. There is no need for other external stimulus intervention. Incentives can be completed within the ecosystem. You work, OK, and the system will send you rewards (tokens). Everything is executed automatically. Tokens are generated by the system and require no additional payment.

Self-organizing. The blockchain efficiently organizes all participants in the ecosystem through smart contracts, consensus mechanisms, TOKEN, etc., forming a self-contained system without external force or external demands. All parties within the organization perform their respective duties and work together to build and maintain the ecosystem.

Self-running. All operations are completed within the system, and the maintainers of the ecosystem, whether miners, nodes, etc., do it on their own and voluntarily. No one forces it, and there is no need for external intervention.

Since the birth of Bitcoin, it has been operating safely for 9 years, and its lifespan has exceeded that of many enterprises. The most awesome thing is that Bitcoin has not established any special maintenance organization, has not hired a single employee, and has not paid 1 cent of operating expenses. This is unprecedented in human history.This is a bullish scene that has never appeared in history. Bitcoin’s current market value is more than 100 billion US dollars, exceeding the market value of most listed companies.

Therefore, in the blockchain ecosystem, all incentives, organizations, and operations do not require external force and can be completed within the system.

This is completely different from the previous production relations. The previous incentives, organization and operation had to rely on external forces, such as manpower, power, money, punishment, etc. outside the system.

4 Consensus co-construction, everyone is the ecosystem

Consensus is the core competitiveness of the blockchain and one of the greatest values. It is precisely because of the consensus that we come together, gather in a project, gather in the blockchain system, and form an ecosystem together.

In this system, everyone is the ecology, the ecology is everyone, and every participant is a part of the ecological co-construction. In this ecosystem, it is truly everyone for one and one for everyone.

Unlike previous production relations, everyone is in a tense superior-subordinate relationship and a competitive relationship. Everyone is in danger and wants to maximize their own interests. It is usually a zero-sum game.

In the everyone-to-people ecosystem of the blockchain, it is not that human nature has changed and everyone is no longer selfish, but that the environment has changed, the system has changed, and the ecology has changed. Individuals naturally change with the general environment and ecology.

Everyone still pursues maximization of interests, but this is based on the maximization of ecological interests and the interests of everyone's mutual prosperity.

In the governance system, the blockchain increases the cost of people doing evil, reduces the possibility of people doing evil, and at the same time increases the interests of people doing good. This decrease and increase complete the ecological innovation. , fundamentally changed the previous model of production relations.

In this way, everyone is in the game, coexisting and prospering with each other, forming a complete and upward ecology.

In such an ecosystem, no one will come out to cause trouble or cause trouble for you.

❽ 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 aA 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 the administrator, everyone can write data into it. How can we ensure that the data is trustworthy? What should I do if it is modified by bad people? 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 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 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 each blockThe hashes are 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 exactly the strength of computers, how come it becomes so difficult and it can’t be calculated for so long?
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 it 2.147 billion times without finding the Nonce, that is, it is impossible to calculate a hash that meets the conditions for the current block body. 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 subsequent difficulty factor must be increased by 10%;If the average generation speed is 11 minutes, it means that it is 10% slower than the legal speed, so the subsequent difficulty coefficient 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.

❾ What is blockchain? If you understand these 9 questions, you will understand

What is blockchain? If you understand these 9 questions, you will understand< br />What is blockchain? What can blockchain do? How to make money with blockchain? I believe that many netizens are confused when faced with this new term. So how can we better understand blockchain and make this new technology available to us? The author has collected nine very common questions from the Internet. I hope that after reading this article, you will have a clearer understanding of blockchain.

Nearly omnipotent blockchain technology
Simply put, blockchain is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithms. Its core is distributed data, and the result is "decentralization." Blockchain technology can be applied to many scenarios in our lives. Next, let’s take a look at the analysis of blockchain technology!
1. Technology is a double-edged sword. when youWhile others are still using their mobile phones to play games, they are already making money every month with their mobile phones! I want to try Jiaerwu Wuyi Wuba Lingyi Lacquer to make your mobile phone no longer a toy!
Just like nuclear energy is a physical technology, blockchain is an underlying technology at a technical level.
Nuclear energy can be used for atomic bombs and nuclear power generation. Similarly, blockchain can be used for the management of industries and life elements, which may make society more stable, or it may be used by bad guys as the fastest way to commit crimes. .
2. Talking about technical value apart from the application level is muddying the waters
As the underlying technology, blockchain has its application level and negotiation methods. Currently, some people talk about blockchain in terms of business models, some in terms of hardware, and some people talk about blockchain in terms of power distribution. It is gradually becoming clear in the market that blockchain is used in the design of technology combinations and business models, from hardware to software to business model to financial design and many other aspects. But not every blockchain can issue coins, and not every blockchain should issue coins.
3. Technology is decentralized, but the application is not necessarily
Blockchain technology is decentralized, but it can be decentralized or not in upper-layer applications. If it is applied to things, industries and projects that cannot be decentralized, it is not decentralized; if it is applied to things where everyone can participate universally and have equal authority, then it can be decentralized.
Including coins on the blockchain, if a country adopts legal digital currency, the coins on the blockchain can also be centralized. The blockchain that supports the operation of Bitcoin is decentralized, but the alliance chain usually has one or more enterprises as the core control alliance, which becomes centralization.
Technology itself and what kind of business and political ecology the technology can support are completely different things.
4. What kind of people use what kind of tools
As a powerful tool, blockchain is powerful not only because of technology, but also because many talented people have invested in it. field, causing the energy of this technology to be amplified. As for whether the power of blockchain benefits society or cuts leeks? It is possible to make the world more turbulent or to make society more harmonious and beautiful.
On the positive side, more kind-hearted people will come in and reach more consensus, and there will be more legislation, restrictions and norms at the national level, which will ultimately allow us to use this technology to give more people opportunities; on the negative side, In other words, it is possible that more greedy and unethical people will come in to divide the wealth, and it is even possible that people in some countries and regions will use this new technology to commit crimes and terrorism.
5. Blockchain promotes the globalization of civilians
Under the blockchain, the global connection space is closer. The 6-degree space will become 5 degrees or even 4 degrees in the future. Blockchain can inspire The growth of various communities. The globalization of interest groups will become inevitable, and there will be various international communities and summits in the future.
6. Blockchain facilitates co-creation
For example, in the past, international singers and ordinary peopleThe link between people has to go through several barriers, including record companies, agents, sales channels, etc. In the blockchain era, international singers publish their songs under blockchain technology. Everyone has the possibility to become a partner of an international singer. They may write songs for international singers, or they can purchase Tokens to obtain dividend rights from distribution proceeds, etc., and enjoy records. Proceeds from distribution and downloads.
7. Trust will become convenient and low-cost
The combined effect of artificial intelligence, big data and blockchain can resolve disputes at the factual level. The tamper-proof nature of the blockchain allows hundreds or even tens of thousands of machines to maintain the same data and encrypt it. Basic facts will be trustworthy. On this basis, the corresponding contracted and authorized information cannot be changed. Replace manual systems with machines, breaking the loopholes in manual operations, the possibility of cheating and even corruption, so that everyone's information can be confirmed to be authentic and trustworthy.
On this basis, if the trust level of the business system is good, trust between people will be enhanced in the process of implementing the designed system.
8． Interaction leads to creativity, and creativity generates income
Blockchain is a comprehensive ledger. Some exchanges are just ideas and creativity at the moment, but they may be the starting point of a certain career or even industry in the future. In the previous accounting system, there may not be value. However, under blockchain technology, values ​​that are not yet seen can be recorded. If this leads to products, creative people can benefit. Various human activities may be valuable, creative, and worthy of recording.
Extended from this, a better application of blockchain can record creative related models, introduction of business opportunities, etc., and put valuable things in an ecosystem. Blockchain can create new ones. A cooperative approach.
9. There will be more legal supporting facilities in the future
The world of blockchain is not a disorderly world. Technology will be used by people, and people are rational.
Records can resolve various factual disputes, and can also cause more issues such as authorization rights, patent and creative copyright management, and many other issues. In the future, there will be more legal supporting systems to not only standardize and manage service consumption and life, but also to avoid related risks and problems, and to avoid and combat crime