Blockchain image

1.

If you want to understand the application of blockchain, you can refer to many books and opinions, such as illustrated blockchain, blockchain: reshaping the economy and the world, blueprint and guide of new economy, and articles of coin'an community, including a detailed understanding of the platform of coin'an community, with great strength

As the name suggests, blockchain is composed of block and chain. It is a new application mode of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and so on. It is a kind of chain data structure that combines data blocks in order according to the time sequence, and it is a secure and reliable distributed account book that can not be tampered with and forged by means of cryptography

in 2008, in his paper bitcoin: a peer-to-peer e-cash system published by Nakamoto, he first proposed the idea of blockchain and encrypted digital currency. Starting from bitcoin, blockchain has become the underlying technology of various digital currencies

Second, the working principle of blockchain:

1. The basic concepts include: (1) transaction: one operation will change the account status once, such as adding a record 2) Block: records the transaction and status data within a specified time, which is a consensus and preservation of the current account status 3) Chain: it is composed of a series of blocks in chronological order, which is the log record of the whole state change. If you understand the working concept of blockchain, it is not difficult to understand its working principle. Suppose there is a distributed data logbook, which can only be added, not deleted or changed. Its structure is a linear chain formed by a series of "blocks" (which is also the source of the name of "blockchain"), and new data must be put into a new block to be added, The maintenance node can propose a new block, but it must go through a certain consensus mechanism to reach an agreement on the final selected block

2. Take bitcoin as an example to see the working principle of blockchain

the block of bitcoin is divided into block head and block body

Core advantages and characteristics of blockchain

1. The verification, accounting, storage, maintenance and transmission of decentralized blockchain data are all based on distributed system structure. There is no centralized hardware or management organization, and the rights and obligations of any node are equal, The data blocks in the system are jointly maintained by the nodes with maintenance function in the whole system. 2. The open and transparent system is open. In addition to the private information of all parties to the transaction is encrypted, the data of the blockchain is open to all. Anyone can query the blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent. 3. Security blockchain uses consensus based specifications and Protocols (such as a set of open and transparent algorithms) to enable all nodes in the whole system to exchange data freely and safely in a de trusted environment, so that the trust in "people" is changed into the trust in machines, and any human intervention does not work. 4. Information cannot be tampered with. Once the information is verified and added to the blockchain, it will be stored permanently. Unless more than 51% (almost impossible) nodes in the system can be controlled at the same time, the modification of the database on a single node is invalid. Therefore, the data stability and reliability of the blockchain are extremely high. 5. Anonymity because the exchange between nodes follows a fixed algorithm, and its data interaction does not need trust (the program rules in the blockchain will judge whether the activity is effective or not). Therefore, the counterparties do not need to let the counterparties generate their own trust by disclosing their identities, which is very helpful for credit accumulation

At present, the most popular classification of blockchain is to divide blockchain into public blockchain, private blockchain and consortium blockchain according to different participants

1. Public chain: anyone can participate in the use and maintenance, and can obtain the effective confirmation of the blockchain. Public chain is the earliest blockchain and the most widely used blockchain at present, such as bitcoin blockchain. The information is completely public

if the licensing mechanism is introced, it includes private chain and alliance chain. 2. Private chain: a company or indivial only uses the blockchain technology, enjoys the exclusive write permission of the blockchain, and does not disclose the information. At present, conservative giants (traditional finance) want to experiment with private blockchain, and the application procts of private blockchain are still groping. 3. Alliance chain: it is a blockchain between the public chain and the existing chain, which is jointly controlled by multiple organizations. The use of the chain is managed with authority, which can be controlled by the manager, and also open to others according to the manager's wishes. In addition, according to the different use scenarios and purposes of blockchain, it can be divided into currency chain for the purpose of digital currency, property chain for the purpose of recording property rights, and crowdfunding chain for the purpose of crowdfunding

On May 28, Ma Huateng, CEO of Tencent, proposed the anti-counterfeiting method based on cloud integrated blockchain technology, which is far more efficient than traditional anti-counterfeiting methods. The future anti-counterfeiting verification scenario may only require users to use their mobile phones for simple scanning, and a large number of complete information based on different dimensions can be obtained

take Maotai liquor as an example:

distillery address, proction workshop, operation staff, inspector, delivery time, transportation vehicle information and driver information,

liquor year, raw material source, raw material supplier, storage warehouse number, raw material transportation vehicle and driver information,

all information can be accurately traced, permanently recorded and tampered with

the above information can be easily verified

2. Food safety issues as early as last November, Wal Mart has cooperated with IBM to track the source of food by using blockchain technology, so as to ensure the safety of food and increase the circulation of food to rece costs. For Wal Mart and other large supermarkets, it took a few days to investigate the source of problem food, After using this technology, only one item of proct information is needed to achieve accurate traceability, and important information such as food origin, inspector, supplier, logistics and transportation can quickly find problems in a few minutes. Currently, procts tracked by blockchain include packaging procts from the United States and pork from China

3. Information security

blockchain technology is promoting an information security technology revolution. (1) identity protection PKI is a common public key encryption technology in e-mail, message application, website and other communication applications. However, since the implementation of most PKI, the centralized trusted third party certification authority (CA) is used to issue, activate and store user certificates. Hackers can attack PKI to fake user identity or crack encrypted information

certcoin is the first PKI implementation of blockchain, which comes from MIT, removes the centralized authentication center, and uses blockchain as a distributed ledger for domain name and public key

pomcor company: blockchain PKI implementation path: keep the authentication center, and use blockchain to store the hash value of issued and activated certificates. Users can verify the authenticity of certificates through decentralized and transparent sources, and can also improve the network access performance through local authentication of secret key and signature based on blockchain

(2) data integrity protection

guardtime developed a secret key free signature architecture (Ksi) based on blockchain technology to replace the secret key based data authentication technology. Ksi stores the hash table of the original data and files on the blockchain, runs the hash algorithm to verify other copies, and compares the results with the data stored in the blockchain. Any data tampering will be found quickly because the original hash table is stored in millions of nodes

(3) key infrastructure protection

the "Achilles heel" of the Internet, DDoS has entered the TB era, DDoS is still the simplest weapon for hackers to bring down the big target with low cost, DNS service is the primary target for hackers to carry out large-scale destruction, but blockchain technology is expected to fundamentally solve the problem

The distributed storage of

blockchain makes hacker attacks lose focus. Nebulis is developing a distributed DNS system, which uses Ethereum blockchain and interstellar Internet file system (IPFs, the distributed substitute of HTTP) to register and resolve domain names. The biggest weakness of DNS is caching, which makes DDoS attacks possible. It is also the bane of the centralized government's censorship of social networks and manipulation of DNS registration. A highly transparent and distributed DNS system can effectively prevent any entity, including the government, from arbitrarily manipulating records

(1) digital currency: improve the convenience of currency issuance and use, such as bitcoin and Ethernet in foreign countries, and guorenbao in China

from the use of physical transactions, to physical currency and credit currency, and then to the rise of bitcoin network, more and more people are aware of the distributed ledger blockchain technology behind it, and graally apply it in many scenarios other than digital currency

(2) cross border payment and settlement: realize point-to-point transaction, rece intermediate fees

transfer and payment. At present, the most mature application of blockchain technology is payment and transfer. Blockchain technology can avoid complicated systems, save the process of inter-bank reconciliation and review, and accelerate the settlement speed; virtual currency can rece transaction costs without the intervention of clearing house. Different countries have different clearing proceres. It takes two or three days for a single remittance to arrive, which is inefficient and accounts for a large proportion of funds in transit. No longer through the third party, through the blockchain technology to form point-to-point payment. By eliminating the link of the third-party institutions, we can make full day payment, real-time payment, withdraw cash quickly and rece the hidden cost, which helps to avoid the capital risk. It is timely and convenient

(3) bills and supply chain financial business: rece human intervention, rece costs and operational risks

value transfer between point-to-point, control and verify physical bills or central system; Intermediaries will be eliminated and human intervention reced. With the improvement of efficiency, financing channels are more unblocked, risks are lower, and multiple parties benefit

(4) securities issuance and Trading: realize quasi real-time asset transfer, accelerate the speed of transaction clearing

the application of blockchain technology can make the process of securities trading more concise, transparent and fast, rece the plication of IT system, and improve the efficiency of market operation. For stocks, blockchain can eliminate paper and pen or electronic form records, rece human errors in trading, and improve the transparency and traceability of trading platform. Citigroup and Nasdaq cooperate to promote blockchain applications

(5) customer credit investigation and anti fraud: rece the cost of legal compliance, prevent financial crimes

the customer information and transaction records recorded in the blockchain help banks identify abnormal transactions and effectively prevent fraud. The technical characteristics of blockchain can change the existing credit reference system, and store the data of customers with bad records in the blockchain when the bank concts "know your customer" (KYC)

equity crowdfunding:

2.

The strict definition of blockchain refers to the distributed database technology that multiple nodes in peer-to-peer network jointly maintain a continuously growing list ledger constructed by time stamp and orderly record data blocks through consensus mechanism based on cryptography technology. This technical solution allows any number of nodes in the participating system to calculate and record all the information exchange data in the system in a period of time to a data block through cryptography algorithm, and generate the fingerprint of the data block for linking the next data block and checking. All participating nodes in the system jointly determine whether the record is true

blockchain is a technical solution similar to NoSQL (non relational database). It is not a specific technology, and can be implemented through many programming languages and architectures. There are many ways to realize blockchain, including pow (proof of work), POS (proof of stake), dpos (delegate proof of stake), etc

the concept of blockchain was first proposed in the paper "bitcoin: a peer-to-peer electronic cash system" by indivials (or groups) who call themselves Satoshi Nakamoto. Therefore, bitcoin can be regarded as the first application of blockchain in the field of financial payment

< H2 > [popular explanation]

no matter how big the system or how small the website is, there is a database behind it. So who will maintain this database? In general, who is responsible for the operation of the network or system, then who is responsible for the maintenance. If it is wechat database, it must be maintained by Tencent team, and Taobao database is maintained by Alibaba team. We must think that this way is natural, but blockchain technology is not

if we think of the database as a book, for example, Alipay is a typical account book. Any change of data is bookkeeping. We can think of database maintenance as a very simple way of accounting. In the world of blockchain, everyone in the blockchain system has the opportunity to participate in bookkeeping. The system will select the fastest and best bookkeeper in a period of time, maybe within ten seconds or ten minutes. The bookkeeper will record the changes of the database and the account book in a block. We can think of this block as a page. After the system confirms that the records are correct, the system will record the changes of the database and the account book in a block, It will link the fingerprint of the past account book to this paper, and then send this paper to everyone else in the whole system. Then, over and over again, the system will look for the next person with fast and good bookkeeping, and everyone else in the system will get a of the whole ledger. This means that everyone as like as two peas in the system is called Blockchain. It is also called distributed account technology. P>

as like as two peas (computer) have identical accounting books, and everyone has the same rights, they will not collapse e to the loss of contact or downtime of a single person. As like as two peas, the data is transparent and everyone can see what changes are in every account. Its very interesting feature is that the data can't be tampered with. Because the system will automatically compare, it will think that the same number of books with the largest number are real books, and a small number of books with different numbers are false books. In this case, it's meaningless for anyone to tamper with his own account book, because unless you can tamper with most nodes in the whole system. If there are only five or ten nodes in the whole system, it may be easy to do so. However, if there are tens of thousands or even hundreds of thousands of nodes and they are distributed in any corner of the Internet, unless someone can control most computers in the world, it is unlikely to tamper with such a large block chain

< H2 > [elements]

combined with the definition of blockchain, we think that we must have the following four elements to be called public blockchain technology. If we only have the first three elements, we will consider it as private blockchain Technology (private chain)

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

2, verifiable data structure (verifiable PKC system, non tampering database)

3, distributed consensus mechanism (Solving Byzantine general problem, solving double payment)

4 Game design of Nash equilibrium (cooperation is the strategy of evolutionary stability)

< H2 > [Characteristics]

combined with the definition of blockchain, blockchain will realize four main characteristics: decentralized, trustless, collective maintenance and reliable database. And the other two will be derived from the four characteristics  Features: open source  Privacy. If a system does not have these characteristics, it can not be regarded as an application based on blockchain technology

Decentralized: there is no centralized hardware or management organization in the whole network. The rights and obligations of any node are equal, and the damage or loss of any node will not affect the operation of the whole system. Therefore, it can also be considered that the blockchain system has excellent robustness

trustworthiness: there is no need to trust each other when participating in the data exchange between each node in the whole system. The operation rules of the whole system are open and transparent, and all data contents are also open. Therefore, within the specified rule range and time range of the system, nodes cannot and cannot cheat other nodes

collective maintenance: the data blocks in the system are maintained by all the nodes with maintenance function in the whole system, and these nodes with maintenance function can be participated by anyone

reliable database: the whole system will enable each participating node to obtain a of the complete database in the form of sub databases. Unless more than 51% of the nodes in the whole system can be controlled at the same time, the modification of the database on a single node is invalid, and the data content on other nodes cannot be affected. Therefore, the more nodes and computing power in the system, the higher the data security in the system

Open Source: since the operation rules of the whole system must be open and transparent, the whole system must be open source for the program

Privacy Protection: since there is no need to trust each other between nodes, there is no need to disclose the identity between nodes, and the privacy of each participating node in the system is protected

3. Basically, the principle is the same. Take baopin.com as an example, baopin.com's video blockchain authentication is actually DAPP. First, it takes a screenshot of the video's key frames per minute, then transcodes it into a string of unique numbers, and then uploads and records it into the Ethereum blockchain.

4. Blockchain is "efficient and inefficient", "decentralized". Blockchain short video is to put the original short video on the blockchain for authentication, proving that it is original.

5. Regular blockchain enterprises are not money, and blockchain traces the source to crack down on fake and inferior information
in the past two years, the word blockchain is very popular, and blockchain e-commerce will undoubtedly be the biggest wind outlet in the next decade. However, the instry is in chaos. Many people think that blockchain is money and have many misunderstandings about blockchain. So before we talk about blockchain, we should first talk about the idea of blockchain
blockchain is now understood by most people as "currency". There are too many coin cards in the coin circle, bitcoin and bitcoin. In fact, blockchain has nothing to do with currency. It is a technology, a business ecology and an idea. It is mainly applied in every field. It is extremely similar to the Internet. Talking about blockchain now is like the Internet 20 years ago. What did we talk about the Internet 20 years ago? When talking about its technical architecture, operating system, language, server and so on, it was said at that time that Internet e-commerce was deceptive, because many people had not been exposed to this aspect. In fact, many people have misunderstood blockchain, especially after being confused by the currency circle
When did jiuzero blockchain start? Jiuling started to investigate and prepare from 2016, and has about half a year to investigate all aspects of the blockchain. In 2017, it began to enter the field of blockchain. By 2020, it will be the fifth year. It has gained a lot of experience and achieved a lot in application. We've never played with coins, never engaged in ICO. In the first few years, we didn't make a lot of noise, that is, we should do a good job in technology, platform and browser, and apply them in traceability. We have done a good job in the application of traceability since 2017, and many procts have been launched; In 2018, more than 10000 procts will be applied in traceability. In 2019, it will be further promoted. This year, it will be further developed, and all procts will be opened up in the whole process of visualization. So at the beginning, we used it in the field of traceability. Since 2018, we have used it in the whole blockchain ecology, including blockchain traceability, blockchain invoice, sharing economy, supply chain finance, general points and other applications, as well as the platform technology services we built. We have entered this field in an all-round way, And relatively speaking, it is relatively mature and completely implemented
What's more, why is blockchain on fire now? Why does the development of blockchain reach the height of "thinking"? This is in line with the trend of the times
let's review the history of China's economic development in recent decades. The wealth of Chiang Kai Shek's time was concentrated on the local tyrants, evil gentry and warlords. Mao Zedong liberated most of the common people as peasants, and United most of them was more suitable for the situation of China at that time. Therefore, he defeated Chiang Kai Shek, overthrew the bureaucracy of the local tyrants, evil gentry and warlords, redistributed their wealth, developed the proctive forces again, and completely redistributed their revolution and distribution, Mao Zedong really realized serving the people and let the people live a good life. In the era of large collectives, people go to work in the countryside to earn points. According to the points you earn, how much food can you get. In Deng Xiaoping's time, I felt that this was not right. It might be that the efficiency was not high, and I ate a big pot of rice. Later, I started the reform and opening up. After the reform and opening up, the fields were divided into households according to the number of people. After that, the output increased a lot, which stimulated everyone's enthusiasm, increased the output and improved the efficiency. After the reform and opening up, commercial instrial enterprises began to develop
we can see that economic development is based on the needs of the times. China's reform and opening up has gone for decades, from the traditional economic era to the E-commerce Internet economy, and now the blockchain has come out, also because of the new problems of wealth distribution in the Internet era
in the Internet era, social wealth is highly concentrated on several platforms, such as Alibaba, Tencent, Internet, Jingdong, etc. the Internet e-commerce leaders have too strong a say in finance, resources, procts and other aspects. Social development has completely lost its balance. The uneven distribution of wealth has made the rich richer and the poor poorer. The instrial enterprises without money, including the whole of China, are now difficult to survive except for the monopolized central enterprises. At this time, there needs to be another revolution in business. The proctive forces must be redistributed and readjusted. It happens that blockchain is born to meet the needs of the era of transportation
the rules and mechanisms of blockchain are completely open and fair, can not be tampered with, and can not be decentralized. The oligarchs of institutions are removed to form a sharing economy for common development. Why does the government support blockchain so much? Because the government can fully enter the field of blockchain for supervision, and the privacy of citizens can be protected. Personal information in the Internet is not protected, and personal information in the blockchain is in their own hands. In the era of Internet e-commerce, oligarchs monopolize information resources. There are too many fake and shoddy procts and too many false information, so we have no way to distinguish them
at this time, the rule mechanism of decentralized supervision of blockchain emerges as the times require. Blockchain is not only a technology (it has made some improvement and promotion in the original Internet technology), but more importantly, it can solve the problems that cannot be solved by the Internet, traditional e-commerce and traditional ecology, such as traceability. Traceability in the Internet age can be falsified. A traceability source can be pasted anywhere, but the traceability of blockchain is different. The technology of blockchain is real. Everyone can participate together. Through distributed storage, everyone can get the data, and then all things can be traced, including procts and invoices, Including a person to send a message can be traced, stored, fidelity
the traceability of blockchain starts with raw materials, then proction and processing, then warehousing, sales, etc. every link should be visualized, with pictures, videos and words, which will leave traces of every link. Only in this way can we make everyone trust completely and be fair, open and transparent when there are too many fake and shoddy procts and lack of trust. In short, blockchain is to solve the problem that the Internet can not solve
when it comes to blockchain, bitcoin is the first thing that many people think of. In fact, bitcoin's contribution to the world is to put forward a rule and mechanism. Bitcoin itself has no value. It has no proct and no support. But its technology and concept are very good, because this technology can't be fake. The source code of this technology is open source and can be shared. Its technology uses the idea of blockchain
as soon as the rules and mechanisms of blockchain come out, they are sought after by everyone. However, in recent years, they have been confused by money. That kind of money is deceptive and runs counter to blockchain. On the contrary, it makes people distrust blockchain because they don't know enough about blockchain and think blockchain is money. Because if you want to understand a field, just like jiuzero blockchain has entered its fifth year, you are engaged in blockchain ecology, blockchain traceability, blockchain digital integration, blockchain technology development, blockchain browser development and so on every day. In this field, you are still learning constantly, because it is not easy to learn a field thoroughly. The reason why we have been very motivated in the past few years is because we know that it is a big trend and coming. Just like the Internet 20 years ago, many people don't believe, understand and turn a deaf ear to it. But ten years ago, Tencent, Alibaba, Huawei and other big enterprises got up. At the same time, now this opportunity is in front of us. Can we seize it? This is a question worth thinking about
finally, let's make it clear that blockchain has nothing to do with currency
for regular blockchain enterprises, the government has requirements and certification standards
standards: three basic requirements (patent, soft work, registered company in national blockchain Park, paid in registered capital, dedicated blockchain R & D funds), four landing application standards (blockchain browser, website, blockchain application scenarios, blockchain procts), five kinds of blockchain professionals (blockchain finance professionals, Blockchain digital professionals, blockchain credit management professionals, blockchain software development professionals, blockchain encryption technology professionals, and employees with bachelor degree or above who have been employed for more than one year) can get six basic subsidies
in the blockchain instry, there are at least tens of thousands of companies doing money and ICU. They all say that they are regular, but can they take out these certificates. The document points out that as long as the company has digital currency or ICO, it is not a blockchain company
under the background of this era, the ideas, rules and mechanisms, decentralized supervision and privacy distribution of blockchain can protect everyone's interests, redistribute proctivity assets, prevent the interests from being too concentrated on certain oligarchs and institutions, let everyone participate together, and let everyone exert their energy together to fight against counterfeiting, tax evasion, tax evasion, tax evasion, etc The real purpose of blockchain is to crack down on false transactions and create a conscientious ecosystem that can protect the interests of the people and provide hematopoietic function.

6.

US $260 million is invested in virtual currency, while US $260 million is invested in investment and development. Because after Meitu announced its financial expenditure, it immediately made a reply to this matter, saying that this is the beginning of Meitu's layout of the blockchain, and the digital currency will appreciate in the future. As a company, Meitu naturally wants to develop and earn income, so it has to invest. Since the development prospect of digital currency is good, they will naturally invest

Third, the company also thinks that this is an investment< p> In addition to providing sufficient financial support for the development of blockchain, the chairman of Meitu company also said that because he is optimistic about the development of digital currency, he thinks that in the future, he will invest in digital currency in large quantities. As a profit-making company, Meitu needs sufficient funds to ensure its development. Therefore, investment income is also a way for the company to make profits. The development of digital currency is good, so we choose to invest in digital currency

(the picture is from the Internet, if there is any infringement, please contact the author to delete it)

7. In the future, blockchain will be applied to all aspects through technology. For example, if someone needs to modify the content of an entry, this behavior will be recorded on the blockchain and cannot be eliminated. In addition, the network also released a totem, which is also a blockchain, and is mainly used in the field of pictures to protect intellectual property rights. In fact, there are many application directions of blockchain, such as court judgments, tickets, blockchain tax tickets and so on. This is the trend in the future. It is not advisable to issue virtual currency through blockchain to speculate in currency.

8. Blockchain application fields:
1. Financial field. Blockchain has great potential application value in international exchange, letter of credit, equity registration, stock exchange and other financial fields. The application of blockchain technology in the financial instry can save the third-party intermediary link and realize the point-to-point direct docking, so as to greatly rece the cost and quickly complete the transaction payment< 2. Internet of things and logistics. Blockchain can also be naturally combined in the field of Internet of things and logistics. Through blockchain, we can rece logistics costs, trace the proction and delivery process of goods, and improve the efficiency of supply chain management. This field is considered as a promising application direction of blockchain

3. Public service. Blockchain is closely related to people's proction and life in public management, energy, transportation and other fields, but the centralization of these fields also brings some problems, which can be transformed by blockchain. The decentralized and fully distributed DNS service provided by the blockchain can realize domain name query and resolution through the point-to-point data transmission service between nodes in the network. It can be used to ensure that the operating system and firmware of an important infrastructure have not been tampered with. It can monitor the status and integrity of the software and detect bad tampering, And ensure that the data transmitted by the system using the Internet of things technology has not been tampered with< 4. Digital rights. Through blockchain technology, works can be authenticated to prove the existence of text, video, audio and other works, and ensure the authenticity and uniqueness of ownership. After the works are confirmed on the blockchain, the subsequent transactions will be recorded in real time to realize the full life cycle management of digital rights, and can also be used as a technical guarantee in judicial evidence collection. For example, mine labs, a start-up company in New York, developed a metadata protocol based on blockchain. This system called mediachain uses IPFs file system to realize right protection of digital works, mainly for right protection applications of digital pictures

5. Insurance. In terms of insurance claims, insurance institutions are responsible for fund collection, investment and claims settlement, and often have higher management and operation costs. Through the application of smart contract, there is no need for the applicant to apply or the insurance company to approve. As long as the claim conditions are triggered, the automatic claim settlement of the policy can be realized. A typical application case is lenderbot, which was launched by the blockchain enterprise stratumdeloitte and payment service provider lemonway in 2016. It allows people to register customized micro insurance procts through the chat function of Facebook messenger to insure the high value items exchanged between indivials, and the blockchain replaces the third party role in the loan contract< 6. Public welfare. The data stored on the blockchain is highly reliable and tamperable, which is naturally suitable for social public welfare scenarios. The relevant information in the public welfare process, such as donation project, collection details, fund flow, recipient feedback, etc., can be stored on the blockchain, and can be made transparent and public, which is convenient for social supervision.