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『一』What is blockchain

Blockchain is a new application model of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm, etc. It It is an underlying application technology of Bitcoin. Traditional information storage and exchange will go through a server, that is, a database, and all information can be found or modified in this database.
There are three types of blockchain: public chain, alliance chain, and private chain.
1. Public chain: It is composed freely by everyone who participates in it. Anyone can enter or exit at any time without any restrictions, but the information during your entry or exit will be known or recorded by the participants. .
2. Alliance chain: It is formed by multiple individuals or groups, and the participating people or groups are designated in advance or can only enter after being reviewed later. It has a certain access mechanism. , the writing and reading permissions of its information can also be determined by the person or group formed.
3. Private chain: It is equivalent to an individual or a certain unit using blockchain technology to store information. Only he has the authority to write information, and he can decide not to disclose the information to the public.

『二』What kind of blockchain does the alliance chain belong to?

The alliance chain is still essentially a private chain. The alliance chain is still essentially a kind of private chain. The private chain is larger than the private chain developed by a single small organization, but not as large as the public chain. It can be understood that it is a blockchain between the private chain and the public chain. A consortium blockchain is a blockchain whose consensus process is controlled by pre-selected nodes; for example, imagine a consortium of 15 financial institutions, each running a node and requiring each block to be valid. It has been confirmed by 10 institutions (2/3 confirmed). The blockchain may allow everyone to read it, or it may only be limited to participants, or it may take a hybrid route, such as the root hash of the block and its API (application programming interface) that are made public, and the API allows outsiders to use it. Make a limited number of queries and obtain information about the blockchain status. These blockchains can be considered “partially decentralized.” Characteristics of the alliance chain 1. Partial decentralization is different from the public chain. The alliance chain is only owned by the members within the alliance to a certain extent, and it is easy to reach a consensus because after all, the number of nodes in the alliance chain is very limited. of. 2. Strong controllability: Once the blockchain is formed, the public chain cannot be tampered with. This is mainly due to the fact that there are generally a large number of nodes in the public chain. For example, there are too many nodes in Bitcoin, and it is almost impossible to tamper with the block data. , and the alliance chain, as long as the majority of all institutions reach a consensus, the block data can be changed. 3. Data will not be made public by default. Unlike public chains, the data of the alliance chain is only accessible to institutions and users in the alliance. 4. The transaction speed is very fast. Like the private chain, the alliance chain is still a private chain in nature. Therefore, due to its small number of nodes, it is easy to reach consensus and the transaction speed is natural.It's much faster. There are currently many alliance chains in application. The more well-known ones are: 1. R3 Blockchain Alliance. The R3 Blockchain Alliance was established in September 2015. At present, more than 40 international banking organizations have joined, and its members Almost all over the world. R3CEV is a well-known alliance chain 2. Hyperledger Hyperledger was launched by the Linux Foundation in 2015. 3. Russian Blockchain Shenqiao Chain Alliance (Russian version R3).

『三』Consortium Blockchain

                                                                                                                                                                                   Both run N nodes. The data of the alliance chain only allows different institutions in the system to read, write and trade. The PKI-based identity management system, transaction or proposal initiation is implemented through digital certificates, and consensus is reached through joint signature verification by the participants, so no work is required. There is no proof of quantity (POW) and there is no digital currency (token), which improves the efficiency of transaction completion and saves a lot of computing costs (computing hardware investment and electricity energy consumption). Normally, nodes participating in the alliance chain will be divided into different read and write permissions, which can support more than 1,000 data writes per second.

『四』What is blockchain? If you understand these 9 questions, you will understand

What is blockchain? If you understand these 9 questions, you will understand
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. While you are still using your mobile phone to play games, others are already using their mobile phones to make money every month! 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 as an atomic bomb or as nuclear power to generate electricity. Similarly, blockchain can be used as an industryThe management of life factors may make society more stable, or it may be used by bad people 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 method. 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, the connection between international singers and ordinary people had 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, write songs for the international singer, or purchase Tokens to obtain dividend rights from distribution proceeds, etc., and enjoy records. Proceeds from distribution and downloads.
7.TrustIt 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 cause 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

『五』 Chain classification of blockchain

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Two days ago, a friend asked a lot of questions about the blockchain on WeChat. One of the questions was how to classify the chain of the blockchain. Blockchain can currently be divided into four categories: public chain, private chain, alliance chain and side chain. Beijing Muqi Mobile Technology Co., Ltd., a professional blockchain outsourcing development company, welcomes discussions for cooperation. The following will help you understand the characteristics of these blockchain chains and how to apply them. I hope it will be helpful to you.

1. Public chain - everyone can participate

Public chain means that anyone can read it, anyone can send transactions, and transactions can be effectively confirmed A blockchain in which anyone can participate in the consensus process.

The public chain adopts the proof-of-work mechanism (POW), proof-of-stake mechanism (POS), and share authorization proof mechanism (DPOS), and combines economic rewards and encrypted digital verification. And establish a principle that the economic rewards that each person can obtain are proportional to the workload. These blockchains are often considered to be completely decentralized.

Features:

1. Open source. Since the operating rules of the entire system are open and transparent, this system is an open source system; 2. Protect users from the influence of developers. In the public chain, program developers There is no right to interfere with users, so the blockchain can protect users who use the programs they develop; 3. The access threshold is low and anyone with sufficient technical ability can access it, that is, as long as there is a computer that can be connected to the Internet, it will be enough Conditions of access; 4. All data is public by default, although all associated participants hide their true identities. This phenomenon is very common. They generate their own security through their public nature, where every participant can see all account balances and all their transaction activity.

Case: There are many familiar figures in the public chain: BTC, ETH, EOS, AE, ADA, etc.

2. Private chain - rights are in the hands of a few people

A private chain 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. Relevant applications include database management, auditing, and even a company. Although in some cases it is desirable to have public auditability, in many cases public readability is not necessary.

Features:

1. Fast transaction speed. The transaction speed of a private chain can be faster than any other blockchain, or even close to not being a blockchain. the speed of a conventional database. This is because even a small number of nodes have a high degree of trust, and each node does not need to verify a transaction. 2. Good privacy, giving better privacy protection The private chain makes the data privacy policy on that blockchain exactly the same as in another database; there is no need to deal with access permissions and use all the old methods, but at least it says , this data is not publicly available to anyone with an internet connection. 3. Low transaction costs. Transaction costs are significantly reduced or even zero. Transactions can be carried out completely free or at least very cheaply on the private chain. If one entity controlled and processed all transactions, they would no longer need to charge fees for their work.

Case: The Linux Foundation, R3CEV Corda platform, and Gem Health network’s Hyperledger project are either developing or using private chains.

3. Alliance chain - partial decentralization

The degree of openness and decentralization of the alliance chain is limited. The participants are screened out in advance or designated directly. The read permission of the database may be public, or it may be limited to the participants of the system like the write permission.

Features:

1. Low transaction costs. Transactions only need to be verified by a few trusted high-computing nodes without the need for confirmation by the entire network; 2. Nodes are easy to connect. If something goes wrong Problems, the consortium chain can be quickly fixed through manual intervention, and allows the use of consensus algorithms to reduce block times, thereby completing transactions faster; 3. Flexible, if necessary, the consortium or company running the private blockchain can be easily modified The rules of the blockchain, restoring transactions, modifying balances, etc.

Case: Ripple has established an alliance chain for international remittances between Japan and South Korea and inter-bank remittances in Japan. At the same time, Xunlei Link, which has been popular for a while, is also a semi-open alliance chain.

4. Side chain - extended protocol

Strictly speaking, "side chain" is not a blockchain itself, but can be understood as an extension of the blockchain. Protocol. The early "side chain" was to solve the limitations of Bitcoin blockchain technology. Side chains are like pathways that connect different blockchains to each other to achieve the expansion of the blockchain. Side chains Completely independent of the Bitcoin blockchain, but the two ledgers can "interoperate" and interact.

Features:

1. Independence, side chain The advantage of the architecture is that the code and data are independent, which does not increase the burden on the main chain and avoid excessive data expansion. The side chain has an independent blockchain, an independent trustee or witness, and an independent node network, that is, a The blocks generated by the side chain will only be broadcast among all nodes where the side chain is installed. 2. Flexibility. All blockchain parameters of the side chain can be customized, such as block intervals and block rewards. , the whereabouts of transaction fees, etc., advanced users can also modify the consensus algorithm.

Case: LSK, RDN, ARDR and other currencies use side chain technology.

For the current In the entire digital currency field, this year may still be a competition for underlying public chain projects. The reason is that the current public chain as the infrastructure of the blockchain still has obvious shortcomings, and it is still unable to achieve true security, reliability and efficiency. This is also It obviously restricts the development of the entire blockchain industry.

How does "Lu" explain blockchain in a popular way?

"Blockchain technology is considered to be the next generation technology after steam engines, electricity, and the Internet. The next generation of disruptive core technologies. If steam engines release people's productivity, electricity solves people's basic living needs, and the Internet completely changes the way information is transmitted, then blockchain, as a machine that builds trust, will likely completely change the way value is transmitted in the entire human society. ”

I have just come into contact with the blockchain. There are too many basic knowledge that need to be understood and known. Don’t worry, today I will give you some popular science.some knowledge. Today, let’s first take a look at what public chains, private chains, alliance chains, and side chains are.

『撒』 What 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 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 make will be added based on cryptographic principles.It is encrypted into a string of characters that the receiver 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 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 be executed automatically, 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. 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 It's a series like refuting rumors and so on.These legends combine the expectations, imaginations and speculations of later generations and become "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 that there are more than 4,900 types of digital currencies, 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 significantly reduce tax collection and management costs, and effectively solve data tampering, over-reporting of one ticket, and theft.Tax evasion and other issues.

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 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.Function

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 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 of the improvements are at the bottom of the system, and users cannot directly see that they have benefited from the use of blockchain; some applications are still in pilot mode, and users have not yet experienced them.test. 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.

『8』 Blockchain Alliance Chain (3) Understanding Fabric

Fabric is the core blockchain framework launched by the Hyperledger Alliance. It is suitable for complex enterprises and between enterprises. Build an alliance chain. According to the goals of the Hyperledger Alliance, Fabric is built as a modular basic alliance chain framework that supports pluggable components. ;

Unlike Ethereum-based Quorum, Fabric only considered inter-enterprise applications from the beginning. Its unique channel concept connects enterprises in different subnets according to different business purposes. Each subnet corresponds to a channel, and each channel has its own independent blockchain. Quorum obviously has only one public network (all enterprise nodes join it), and private business between enterprises is completed through Private Manager.

The simplest way to understand channel is to analogize it to a Topic provided by a message service. In fact, Fabic was first implemented based on Kafka's distributed message service.

In the Fabric network, an enterprise can have one or more nodes join the entire alliance chain; an enterprise can join 1 or more Channels (subnets); a node can join 1 or more channels. Each channel forms a subnet, so Fabric is a network composed of subnets.

So how does Fabric realize the execution and completion of smart contracts?What about putting the business on the chain (recording the transaction results in the blockchain)?

Unlike other frameworks, Fabric divides the entire process into three stages:

Business endorsement stage: The endorsement node sent by the customer's request completes the business calculation through smart contracts (but does not update the status), and completes the endorsement; returns the endorsement result to the client.

Business sorting phase: The client sends the endorsement results to the ordering node (orderer) through the Channel. The ordering node completes the sorting of transactions, packages them into blocks, and finally distributes them to all connected The node of the channel.

Business verification and writing to the ledger stage: Through the Gossip network, all Channel nodes will receive the new block. The nodes will verify each transaction in the block to determine whether it is valid: valid will be followed by In the new world state, invalid ones will be marked as "invalid" and the world state will not be updated, but the entire block will be completely added to the ledger (including invalid transactions).

Based on the above description, Fabric nodes can actually be divided into , ordinary nodes and Order nodes:

Peer, ordinary nodes, complete endorsement (including execution of contracts only) and Verification.

orderer, sorting node, completes sorting.

The Fabric network that joins the orderer node can be described as follows:

Each Channel defines all nodes belonging to the channel, but it is not necessary that all nodes are connected to the Orderer Nodes (private data or transactions can be spread between nodes through gossip protocol communication).

In the blockchain, consensus is the basis of the blockchain. Different from the public chain, the consensus of the alliance chain requires that all transactions added to the ledger are deterministic and final, that is, there cannot be forks, the order between blocks is certain, and there is only one chain. In Fabric, this objective requirement is realized by sorting. All transactions will be submitted to the orderer node to obtain a determined order, and finally packaged into blocks and entered into the ledger. Fabric supports the implementation of ordering services based on Raft starting from 1.4.1, which can be considered as the implementation of consensus based on Raft.

The RAFT-based sorting service has better distribution and simpler configuration than the early Kafka. It is a commonly used consensus algorithm in alliance chains. Quorum uses RAFT as the consensus layer by default. . Simply put, RAFT is a leader and follower model. All nodes joining the RAFT network have a leader at any time. Only this leader has the right to decide the order of transactions and package them into blocks. Other nodes can only submit transactions as followers. and sync block.

Based on the FAFT network, each enterprise can have one or more nodes participating in the Orderer. In Frabric, the network connection between enterprises can be changed into the following form:

Users of blockchain are called EOA (External of Account) in Ethereum, and the carrier of EOA is a wallet. Let's use this concept to see how Fabric implements users and initiates transactions. EOA in Fabric is a certificate (x.509) issued by the CA center. A Certificate represents an Identity (this is still very different from Ethereum. An EOA in Ethereum is actually a hash address). The channels that EOA can participate in And the authorized operations are determined by the MSP (Membership Service Provider) of the channel (as shown below).

Note: Certificate is a common method of verifying identity in cryptography; certificate contains personal information, public key and signature of the CA that issued the certificate. The verifier only needs to have the CA's certificate (including the CA's public key) to verify whether the signature is correct and whether the content of the certificate has been tampered with. Simply put, through CA and Certificate, we can obtain a verifiable identity and trust chain.

As shown in the picture above, fabric Zhongtong uses Wallet as the carrier of EOA. A Wallet can contain multiple Identities (x.509 certificate). Identity verifies correctness through the chain of trust provided by the CA.

  After verifying the identity, Fabric uses MSP to resolve in the blockchain network whether the identity represents a member of the organization and what role it has within the organization. For example, the channel will first verify whether the current user Identity is a valid identity, then check the enterprise and role it has through MSP, and finally determine whether the user has the right to perform operations.

It can be said that Fabric access control is completed through MSP. An MSP needs to be defined every time access control is required. For example, each channel defines an MSP, which specifies the access rights to resources within the channel range. MSP is an obscure concept in Fabric, and it is also the basis for providing secure access between enterprises.

As mentioned earlier, Fabric divides business processing and Internet access into three parts: endorsement, sorting, and adding to the ledger after verification.

Endorsement is the stage in which Fabric executes smart contracts. In Ethereum, smart contracts are executed in the EVM and are supported in multiple languages. In Fabric, smart contracts are called chaincode: A chaincode can be understood as a container of smart contracts, which can contain one or more smart contracts. It is not used in EVM. Chaincode is executed in JVM or NodeJS.

Client applications access the ledger through smart contracts. Each accessible smart contract is installed on a node accessible to the client and is defined in the channel. (Nodes with smart contracts are called endorsement nodes, nodes without smart contracts are called unsubmitted nodes, and submitting nodes only maintain ledgers)

The client application submits a transaction request, and the request reaches the endorsement node , the endorsement node will first verify the customer's signature to ensure that the customer's identity has the right to execute this transaction, then execute the smart contract (chaincode) mentioned in the transaction, and generate an endorsement response (or transaction proposal, trans-proposal). This endorsement response usually contains the world state's read set, write set, and the node's signature for this transaction. The main difference here from the Ethereum alliance chain is that the endorsement phase only simulates transactions and does not actually update the transaction results. The real update transaction is completed in the third phase. The endorsement node finally sends the generated endorsement response fanhui to the client, and the execution of the smart contract part ends.

Usually the execution of a transaction requires the signatures of multiple parties, so the client needs to send a transaction to multiple endorsement nodes, and the selection of these endorsement nodes needs to meet the requirements of the endorsement policy.

The picture below is a packageA schematic diagram of the network containing clients, endorsing nodes, and submitting nodes.

According to Fabric’s official reference document, the process of successful customer transactions can be described in the following figure.

As shown in the figure above, from 1 to 3, it is the endorsement stage, 4 is the sorting stage, and 4.1, 4, 2, 5 are the verification and submission stages. Refer to Frabic's node concept to learn more about the concept of transaction details.

Generally speaking, Fabric is more focused on inter-enterprise. Through the above, everyone can have a general understanding of the basic composition and concepts of Fabric. Fabric itself is not mysterious. It uses existing inter-enterprise technologies. For a better understanding, it is recommended to read Support for Distributed Messaging Systems and Enterprise Security Infrastructure (CA related). Compared with the Ethereum-based alliance chain implementation, Fabric's subnet concept is more adaptable to complex inter-enterprise applications, but its complex security considerations make operating costs very high. In addition, Fabric uses Certificate as user identity, which has great The limitations of Fabric will be changed in the new 2.0.

In the next article, we will take a look at Sawtooth, a blockchain framework provided by Inter.

Blockchain Alliance Chain (1) Understanding Ethereum

Blockchain Alliance Chain (2) Understanding Quotum

Blockchain Alliance Chain (3) Understanding Fabric

Alliance Chain of Blockchain (4) Understanding Sawtooth

『九』 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, blockchain funds are closely related to education and medical care.There is a certain overlap in the fields of medical treatment, credit reporting, automobiles, transportation, etc. It is a technology, not a certain product, so there is only one type of it, but as the application scenarios change, the roles it plays are also different. It can be integrated with existing scenarios in almost any field and then derive other applications.

『Shi』Blockchain-What is Blockchain? Jindian News can understand the 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 and uses a client written in Go language as the default client (i.e., the method of interacting with the Ethereum network, supporting otherclients in multiple languages).

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. Its original intention was to serve industrial production. IBM open sourced 44,000 lines of code, which is a great contribution and allows us to have The opportunity is so close to explore the principles of blockchain that are different from Bitcoin.

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 that are associated using cryptographic methods, eachEach data block contains the information of a Bitcoin network transaction, which is used to verify the validity of the information (anti-counterfeiting) and generate the next block
The evolution method of the blockchain is:
▪ Block Chain 1.0 - Digital Currency
▪ Blockchain 2.0 - Digital Assets and Smart Contracts
▪ Blockchain 3.0 - IFMChain, the blockchain officially links mobile terminals