Blockchain school 28

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. Remember that in zamby community, there are courses based on erc20 protocol in zamby school section

3. Let's talk about the social or economic significance of blockchain. In fact, many of the previous technologies were devoted to "proctivity". For example, artificial intelligence is a kind of progress in proctivity. The blockchain, which has greatly improved the proction relations, is committed to the proction relations. So why do you say that
because the so-called proction relationship is actually how to do business between people and business partners. And these things, originally, are in the cognitive process between people, and there is no special program to program or quantify it
for example, if you and I are good friends now, we can do business. If someone stirs up our relationship and we are not good friends, we will not do business. Even if we can make money in business, we will not do business because there is no trust between us
as for blockchain, it is actually because the data is authenticated by all nodes and backed up at the same time, so my data is as real as possible and can't be tampered with. In this case, if you believe my data, you can make a program on this basis, and then use the data to make what kind of business contract, what kind of service, what kind of service, and what kind of service, what kind of service, what kind of service, what kind of service, what kind of service, what kind of service, what kind of service, etc This "proction relationship" of commercial cooperation is programmed. In this way, we believe in the data and the program compiled by the algorithm. Because you believe in the data and the program, you can develop all kinds of apps in the program. These apps are the proction relations and what business to do. This is: blockchain is actually a reconstruction of "proction relationship".

4.

Blockchain is a new technology, not a disguised form of MLM. It is just claimed by many MLM organizations as "blockchain". In fact, there is no technology. It's just a practice of MLM under the name of "blockchain". The state has issued several announcements to crack down on this kind of MLM. The following is the Xinhua news report on MLM of blockchain:

blockchain is not equal to virtual currency, but also has security risks. Behind the popularity, there is exaggeration with "ulterior motives". Only by removing the flashiness, can the blockchain return to its real application value

invest 80000 yuan, change to 800000 yuan after three months? Shenzhen police cracked a huge fund-raising fraud. Under the guise of blockchain concept and 10 times income, thousands of investors were deeply involved in the case, involving up to 307 million yuan. Under the "veil of mystery" of the blockchain, the illegal elements have taken advantage of their own tricks, and the blockchain has become a "signboard" of economic crimes such as fraud and pyramid selling

why is the blockchain repeatedly "misused" by illegal activities such as pyramid selling fraud? In addition to "unknown", what is the "function" of blockchain technology itself? Since the beginning of this year, with the increase of supervision and the cooling of currency speculation, new opportunities have been brought to the development of blockchain. How about the implementation of blockchain commercial "application" The reporter of outlook news weekly recently concted an investigation

when the three-month "capital release period" promised by the trading platform expired and the staff began to "kick" in the QQ group, Tang Haiyan, who lives in Bao'an District of Shenzhen City, realized that she might have been cheated

previously, Tang Haiyan invested 80000 yuan to buy a virtual currency called "ordinary silver coin" under the introction of her classmates“ The other side said that this currency is the most advanced blockchain technology at present, with Tibetan tea as collateral. He also showed me the "technical white paper". I didn't understand blockchain, so I didn't read it carefully. "

although she doesn't know about blockchain and virtual currency, the high investment income makes Tang Haiyan full of expectations. She told reporters that companies issuing "ordinary silver coins" will regularly split the virtual currency according to the ratio of 1:10, which means that each split will make the value of "ordinary silver coins" in the hands of investors expand 10 times. As long as after a split, her investment of 80000 yuan is equivalent to the purchase of 800000 yuan worth of "ordinary silver coins", which can be sold on the trading platform to obtain huge profits

according to the rules of the trading platform, the newly purchased "ordinary silver coin" cannot be traded immediately, and it must be frozen on the platform for three months before it can enter the "release period". However, after three months, not only did Tang Haiyan not wait for the assets to double, but the 80000 yuan frozen on the platform could not be used for trading

"other investors began to question the authenticity of this investment in QQ group. As a result, the staff of the company kicked these investors out one by one, which made me feel bad." She said

The fact also proves Tang HaiYan's intuition. At the end of March 2018, Shenzhen police detected a huge fund-raising fraud, with the amount of fraud funds as high as 307 million yuan. In this case, Shenzhen Puyin blockchain Group Co., Ltd. involved in the case issued virtual currency in the mode of "blockchain + Tibetan tea" to obtain public deposits. Tang Haiyan was one of the thousands of victims

Shenzhen police investigation found that the company claimed that investors could buy and sell "ordinary silver coins" on the virtual trading platform "jucoin net" to earn a price difference

. In fact, the change of its trading price is that the company used investors' investment funds for behind the scenes operation, and once raised the price of "ordinary silver coin" from 0.5 yuan to 10 yuan, so that investors can taste some sweetness. When a large number of investors entered the market, the company continued to cash out through malicious manipulation of the price trend of "ordinary silver coin", which eventually led to the worthlessness of "ordinary silver coin" in the hands of investors

since 2018, engaging in fraud and pyramid selling under the banner of blockchain has become a common "routine" in new criminal tactics. In April 2018, Jinan police dropped a pyramid selling Gang under the guise of "western development", "national poverty alleviation", "original stocks", "blockchain" and "e-commerce", arrested more than 10 major suspects, frozen more than 100 accounts involved, and seized more than 300 million yuan of funds involved

according to Jinan police, huileyi e-commerce company designed a fake virtual disk on the Internet on the ground that the country is vigorously developing the big data instry, and released a variety of virtual currencies such as "precious currency" and "precious currency"

under the guise of giving away, they presented a certain amount of virtual currency to the New MLM staff, with the price of tens of yuan each. Then, through artificial manipulation, they appreciated the virtual currency all the way to more than 100 yuan or even hundreds of yuan, attracting people who did not know the truth to join. Finally, they "cut leeks" through the periodic fluctuation of the so-called "devaluation" of virtual currency, Finally, the purpose of seeking illegal interests is achieved

in Xi'an, a few days ago, the local police successfully cracked a huge network pyramid selling case under the banner of blockchain. According to the police, the suspect, Zheng Mou, has paid a high salary to the 9 network members, such as Zhang and Lee. Since March 28, 2018, he has gathered pyramid selling and network pyramid selling as a means to sell the virtual Datang coins at the consumption era network platform at the price of 3 yuan each, and manipulate the appreciation rate; p>

at the same time, promotion meetings were held in many cities at home and abroad to attract members. According to the development of members, 28 level agents were set up. In just 18 days, the gang developed more than 13000 registered members. At present, it has been found that the case involves 31 provinces, cities and autonomous regions in China, and the fund involved is as high as 86 million yuan

according to Tencent's 2017 pyramid selling situation awareness white paper released by Tencent security joint laboratory, in recent years, all kinds of overseas capital disk, virtual currency and ICO (initial public offering token financing of blockchain project) projects have emerged in an endless stream, which hide many risks such as illegal issuance, untrue projects, cross-border money laundering, fraud and pyramid selling, As a result, a large number of funds flow overseas. Once the market collapses, runs away or loses contact, investors often have no way to complain and the losses are difficult to recover. For example, Baichuan coin, mark coin, beta coin, dark coin, etc

the reporter of lookout Newsweek interviewed in Guangdong, Shandong, Shanghai and other places and learned that most people know that the concept of blockchain is very popular, but they "don't know where it is", and there are different opinions on the specific functions of blockchain: some people think it is used for "investment and financing", "buying and selling currency", while others think it is "a major invention of the same magnitude as the steam engine", Some entrepreneurs are even more eager to seize this "once-in-a-lifetime opportunity to get rich."

many people in the instry said that it is precisely because people have many misunderstandings about blockchain that criminals have opportunities to fish in troubled waters and mislead investors

First, blockchain is not equal to virtual currency. By the end of last year, the number of domestic ICO participants and the total volume of transactions have doubled, a large number of digital currency exchanges have fled overseas, and the agent investment mode has involved more ordinary people in high-risk investment

in many instries, we media and celebrities form interest alliances with issuers and digital exchanges to endorse and create public opinion for the "air currency" project. In December last year, nine departments including the people's Bank of China identified ICO as "suspected of illegal fund-raising, financial fraud, pyramid selling and other illegal and criminal activities"

in the interview, many people told our reporter that the existence of token has built a set of rights and interests mechanism for the development of blockchain technology, which is indispensable for stimulating the prosperity of blockchain applications“ The market practice in the past five years has proved that blockchain applications without equity mechanism are just like market economy without computers connected to the Internet and money, with greatly reced application scenarios and development speed. " An investor in Shanghai said

in fact, the token represented by bitcoin is only one of the earliest procts to verify the blockchain technology, and the two can not be equated, and the existence of token has obviously negative effects on the development of blockchain

Xiao Wei, chief engineer of network blockchain, told this reporter that the myth of ICO's sudden wealth shakes the R & D concentration of blockchain technical talents, and the myth of "sudden wealth" with hundreds of times of return tests the patience of blockchain technical R & D talents“ Many of the "comrades in arms" in the circle who used to do research and development of blockchain technology have gone to issue coins, and now few of them can insist on doing research and development and application of technology. "

Xu zewei, Secretary of the Party committee of Beijing Internet Finance Instry Association, said that under the background of China's ban on ICO, many domestic start-ups promoting blockchain applications are "selling dog meat with sheep's pawn" and financing through concept packaging of worthless tokens“ ICO has polluted the good atmosphere of innovation and entrepreneurship, and created a kind of speculative proct. Many young people are not thinking about entrepreneurship, but are thinking about issuing money, which makes us have the illusion of getting rich overnight. "

at present, more and more people in the instry begin to think about whether the development of blockchain must rely on the issuance of tokens to achieve incentives. Guo Dagang, Secretary General of Beijing Internet Finance Instry Association, told this reporter that the so-called incentive mechanism is only the theoretical basis for the project party to issue tokens for itself. Huo Xuewen, director of Beijing Municipal Bureau of financial work, also believes that if blockchain does not get rid of the dilemma of issuing currency, it will never find a legal landing mechanism

secondly, blockchain is not omnipotent and its security is at risk. Blockchain is generally considered to achieve three functions:

first, the data stored on the blockchain can not be tampered or forged, and the data has high credibility and credibility; Second, the whole process of the transaction can be traced, which can achieve accurate responsibility tracking; Third, the embedded smart contract in the blockchain can be executed automatically based on the contract, so as to improve work efficiency and rece the risk of default. It is generally believed that blockchain has broad application prospects in finance, logistics, trade and other fields

in fact, blockchain is not omnipotent, and its function has many limitations. It is generally believed that, according to the characteristics of cryptography, in order to tamper or falsify in the blockchain, more than 51% of the nodes need to be controlled in theory. When there are enough nodes in the blockchain, it is difficult to tamper with the trust creation mechanism widely participated by the public

However, in reality, digital currency exchanges are frequently attacked or even stolen. On June 20, 2018, bithumb exchange of South Korea announced on its official website that the exchange had been attacked by hackers and stolen 35 billion won, about 32 million US dollars of cryptocurrency

Ji Xinhua, known as the first generation of "hackers" in China, said that the blockchain will continue to face attacks, and the process of uploading data to the blockchain is prone to information leakage. Some people in the instry worry that once the super computing power of quantum computing is realized, it will also have a direct impact on the blockchain

Zhao Yao, a special researcher of the Institute of finance of the Chinese Academy of Social Sciences, told this reporter that the academic community has confirmed as early as 2013 that the blockchain is not perfect and there are many "cheating" strategies. As long as there are enough economic incentives, controlling attacks of more than 51% nodes does not only exist in theory

Zeng Guang, Secretary General of Shenzhen Internet Finance Association, said that the blockchain technology itself does not have the ability to do so

5. There should be no big blockchain meeting in Beijing on October 27. However, there was a science and Technology Finance Conference on blockchain in Shanghai on October 27 and 28

the participating enterprises or teams include Wanda, decent, sesame credit, latte finance, bitcoin China, etc.

6. Blockchain is a term in the field of information technology. In essence, it is a shared database. The data or information stored in it is characterized by "unforgeability", "trace in the whole process", "traceability", "openness and transparency" and "collective maintenance". Based on these characteristics, blockchain technology has laid a solid "trust" foundation, created a reliable "cooperation" mechanism, and has broad application prospects
response time: December 28, 2020. Please refer to the official website of Ping An Bank for the latest business changes
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7. There is no specific measure. But we can choose from several aspects:
1 those who have many excellent tutors
2 those who have cultivated many excellent students
3 who only do training, but not others
4 who have done it for a long time.

8.

As we all know, blockchain is the proct of recent years, but the market for blockchain related courses can be said to be multifarious, fengmaolingjiao, each has its own merits, here, do a statistics, study, discuss and exchange together

mining mean? What did the miners do

10. What is the application of blockchain? What changes will blockchain bring

11. Blockchain will become the basic internet protocol, similar to TCP / IP and HTTP

12. What is Ethereum? Why is it the representative of blockchain 2.0? He is the founder of Ethereum and the real big man in the blockchain instry

14. What is a smart contract

15. What is Ethereum smart contract

V God said that the token system of Ethereum

17. Machines need the certificate more than people

18. What is the standard of erc20 certificate

19. The Dao crowdfunding event and Ethereum bifurcation

20. How to design Tongzheng? How to express assets

21. Classification of token (list of categories)

22. Technology and components of Ethereum smart contract

23. Erc721 standard and encryption cat

24. Ethereum account (external account and contract account)

25. Four features of blockchain

26. What is blockchain 3.0 like

What is EOS? What is the difference between EOS, bitcoin and Ethereum

The consensus mechanism and block generation of EOS

29. Daniel laremo (BM): the main developer of EOS

30. A map to understand what EOS is

31. The "Impossible Triangle" of blockchain

32. What is the application of blockchain (decentralized application)

33. How to recover the stolen EOS key

the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system

9. Sponge school is suitable for zero foundation learning. I had no experience in development before. I took a full-time class for one and a half months there, and now I have successfully changed my career.