区块链v18棱镜协议,区块链是什么意思?

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『一』Does blockchain change 10 cases of existing business?

This article introduces the current 10 main usage scenarios of blockchain:

(1 ) Tracking products in the global supply chain;

is a typical usage scenario of blockchain technology in security traceability. It can promote information tracking, query, verification and anti-counterfeiting of commodity circulation, and can significantly improve the efficiency of some links. However, the role of the blockchain can only be reflected in the chain, but it cannot cover the parts operated by people below the chain.

(2) Guarantee 3D printing quality and tracking;

(3) Create personalized and lifelong “one-stop” medical records;

Blockchain healthcare can track anyone’s complete medical history, such as medications , illnesses, injuries, and transactions across health systems, physicians, pharmacies, and health plans, and empowering patients to control their own data. Blockchain can also transfer insurance payments: smart contracts can automatically trigger insurance provisions when a clinic confirms a patient has received treatment, and prevent fraudulent or inaccurate claims. Some startups, such as the UK's Medicalchain, blockchain company Gem, MIT and other companies and universities are experimenting with this use.

(4) Simplify trade logistics;

Traditional trade involves complex import and export procedures, and all participants in the entire chain require a large number of paper documents to interact, resulting in high communication costs. Blockchain can optimize this system. Maersk and IBM have created a platform that integrates services such as liner, warehouse, freight forwarding, ports, customs, exporters, importers and trade finance banks into the trade ecosystem, on a data exchange platform running on the blockchain interoperate.

(5) Facilitate and secure customs trade;

Blockchain has been tested in many customs departments, including the United Kingdom, South Korea, Singapore, Costa Rica, Mexico, Peru and the 15-nation East African Group. In 2017, U.S. Customs developed 14 use cases for blockchain, which are currently being tested and evaluated. Blockchain will be particularly useful for the UK: when the UK leaves the EU customs union, its number of customs declarations will increase from 55 million to over 250 million (non-EU trade plus EU trade, which previously did not require customs documents), which is currently the case with UK software The program cannot fully handle it. Blockchain can help: It can trace the origins of products and help determine the origin and appropriate tariffs for goods, such as those destined to join the European Union’s tariff package. For the UK’s 28 border agencies, imported products such as food, safety and intellectual property compliance need to be analyzed, and blockchain projects can be shared securely and transparently in real time.

(6) Prevent voting fraud and protect voter identities;

Blockchain security and identity protection features can reduce fraud and encourage voters to believe their votes are anonymous,

increase turnout and make elections more immediate . Using the technology, voters can scan their thumbs with their smartphones and cast their ballots during their Election Day commute. If everyone votes via the blockchain, no one can vote twice. Voting records are inviolable and every voteThe voting booth will record the ID of each ballot in real time.

(7) Launch crop insurance for farmers;

Crop insurance customized to specific farmer needs is often very expensive, and blockchain technology can reduce costs by determining trigger conditions and automating execution. For example, farmers can insure against extreme weather. If extreme weather affects a harvest, a blockchain-based insurance contract would immediately recognize this and pay the farmer’s claim.

Establishing a network of energy producers and users;

Decades ago, some companies introduced smart grids to provide intermediary services for energy producers and demanders. Now, blockchain can optimize smart grids and provide energy producers and consumers with a regional intermediary energy trading platform. TenneT and Brooklyn-based startup LO3 Energy are both trying this business.

(9) Create smart cities that can operate independently;

Blockchain can now amplify the impact of Douyou IoT on city operations. For example, Dubai has a pilot project to implement blockchain in city services. Dubai plans to use blockchain for more than 100 million annual government documents by 2020, including all visa applications, bill payments and license renewals.

(10) Automatic payment to the exporter when the goods arrive at the foreign buyer;

Blockchain changes the information asymmetry in existing international trade by allowing both parties to the transaction to access the same data and real-time digital files question. There is no need to store multiple copies of the same document across different databases for different entities. When goods arrive marked by sensors connected to the smart contract, a transfer of money from the buyer to the seller is automatically triggered.

2. Ten major problems currently faced by the blockchain industry and their analysis

2.1. Is the data on the blockchain really immutable?

Can one of the core features of blockchain, "anti-tampering", really be realized? And is "tamper-proof" really beneficial?

The report pointed out that the blockchain is not completely immutable and gave three weaknesses of the blockchain:

(2) It may be hacked, and 51% of the chain is controlled by people who want to tamper with the results.

(3) The "garbage of garbage" problem has existed for centuries. The value of a blockchain depends on the data on the chain, and data entered into the blockchain may be inaccurate or fraudulent. One solution is to use sensors instead of manually entering data.

The so-called "51% attack" is to take advantage of computing power to cancel payment transactions that have already occurred. If someone masters more than 50% of the computing power, he can find the random numbers needed to mine the block faster than others, so he actually has the absolute and effective right to decide which block. From a technical level, a 51% attack is achievable, but the cost is very high for the earliest cryptocurrencies such as BTC. They have built a huge network, which is why BTC’s network has remained stable for 10 years. reason. But with other counterfeit currencies, the risk is greater.

In addition, there is no direct benefit for the attacker to simply launch a 51% attack, and it must be linked to specific short selling and false recharge. Specifically, itOften it is a double spend on a certain transaction. The attacker stops attacking once. Continuous attacks are costly and will stop once successful; second, the community can issue an emergency pudding and add checkpoints to the blockchain. The community urgently agreed that the attacker’s blockchain was invalid. Therefore, there are many ways to deal with the 51% attack, and it will not be the end of the world for a blockchain.

2.2. Who owns and maintains the blockchain? And who asked about the appearance?

Responsible for problems and losses?

Since the blockchain is a decentralized user community, who will maintain it? Shouldn’t it require human adjustment and maintenance just like a website?

For permissioned chains, such as alliance chains and private chains, there is no need for incentives such as tokens to motivate people to manage, there is a manager who manages the entire network. Since there are fewer users in the network, coordination costs are relatively low. However, such networks are susceptible to security challenges, and as the number of network users increases, coordination costs will increase.

For consortium chains and private chains, since they are still very centralized organizations, the verification nodes are identified by the organization itself, so the management model is not very different from traditional centralized institutions. However, for public chains, there is no leader who coordinates the entire network system, and only relies on token incentives to coordinate different interest groups, which undoubtedly increases the instability of the entire ecosystem. At present, the development of the blockchain industry is in a very early stage. In addition to the relatively mature decentralized governance of BTC, in the governance of public chains such as ETH and EOS, the founder development team plays a very core role and is the "rules" of the public chain. "Maker", although the entire ecosystem has achieved partial decentralization, the founders still play a pivotal role in the direction of strategic development. Therefore, the author believes that the decentralization of blockchain can only be an ultimate goal that is constantly approaching. From the birth of the project to its maturity, its degree of decentralization should continue to increase, as shown in the figure below. In the early stages of project development, the founder and his development team play an absolute guiding role in the entire ecosystem. As the project ecosystem matures and the number of participants continues to increase, the original development team should gradually weaken its guiding role. The entire network maintenance needs to be decided jointly by all developers and users in the ecosystem. As for the final network problems, they can only be borne by all participants.

Figure: Schematic diagram of the relationship between the degree of centralization and development stages of blockchain projects

2.3. Are smart contracts really smart?

The second reason why smart contracts are not yet that smart is that their entries can be manipulated by evil actors, such as contracting parties or miners who add transaction records to the blockchain's ledger of past transactions. One study showed that 3.4% of ETH smart contracts are vulnerable to hackers.

Smart contracts can indeed optimize many intermediate programs, but judging from current industry practice, they are far from being called smart. A qualified smart contract should include all possible scenarios. Because the core essence of smart contracts is "to make the most just ruling even in the darkest environment."

The difference between Ethereum and Bitcoin is that EthereumThe platform is Turing complete, and more types of contracts with more complex terms can be implemented through this platform. Of course, the cost of this is that the complex contract content makes it more difficult to analyze. Typically, complexity is directly proportional to the probability of a vulnerability; the higher the complexity, the greater the probability of a vulnerability.

Regarding the concept "code is law" proposed by Ethereum, however, the code has attracted hacker attacks due to its own vulnerabilities, so it is not enough to form the authority of "law". Therefore, it needs the trust and endorsement of the government, lawyers, courts and other intermediary institutions. Compared with coordination, the current contract seems too rough.

2.4. Is there identity theft on the blockchain?

3% of social media accounts are fake, so can fake accounts be created on the blockchain? Can identities on the blockchain be stolen?

Blockchain can create a personal database for users whose data cannot be tampered with, but how to meet the user's "tampering" needs? This may be a paradox in the development of blockchain technology. Regarding user needs, we may need to start from the perspective of on-chain standards and authority management.

2.5. Can blockchains be connected to each other?

One blockchain records the data of an entity or user in one way, while another blockchain records the same data of the same entity or user in another way. In a fragmented system, multiple account books are not connected to each other, which will form a world of "operational islands", or "data islands". Users need to register for multiple systems at the same time to conduct transactions with different people for different purposes.

In view of the value transfer needs of different chains, cross-chain technology is the key, which can effectively connect different alliance chains or private chains, and promote the outward expansion and connection of blockchains. The current mainstream cross-chain technologies include Notary schemes, Sidechains/relays, Hash-locking, Distributed private key control, etc.

2.6. How does the blockchain connect to off-chain databases?

If one party's data and documents are off-chain, and the other party's data and documents are on-chain, can the two parties interact? In the company's database, can half of the company's data on the blockchain interact with the other half of the data?

These challenges are well known and are being addressed. For example, the same queries and analysis can be run in on-chain and off-chain databases. The risk is that data brought from on-chain to off-chain is no longer immutable, and researchers recognize that data security and aggregating, transforming and optimizing on-chain and off-chain data sets are significant challenges.

2.7. Can blockchain facilitate money laundering?

Money laundering is a huge global problem, amounting to 1-2 trillion US dollars, accounting for approximately 2% - 5% of the total global GDP. Banks and authorities are fighting back, spending about $8 billion a year to combat corruption. Banks around the world require KYCverify.

Due to the anonymous nature of the blockchain, especially the emergence of anonymous coins, BTC has been criticized by many people as a tool for money laundering. However, the anonymity of BTC is only anonymity on the chain. The interaction between people and the chain, and the interaction between BTC and legal currency will leave traces. It is not as "lawless" as many media have promoted. Each BTC transaction requires the transfer of a corresponding address, and the transaction records of the address can be queried. In addition, the exchange of BTC and legal currency is conducted off-chain and cannot escape supervision. If the actual identity of any party in the transaction is exposed, it will be difficult for all participants in the transaction to escape recourse.

2.8. Will the blockchain consume all the energy in the world?

BTC has an amazing energy demand. Operating Bitcoin for one year requires the energy consumption of Ireland for one year. Because BTC’s POW consensus mechanism requires miners to mine for transaction verification. There are concerns that as the network increases and the value of BTC rises, energy demand will grow rapidly. In fact, miners themselves have incentives to prevent this from happening, and the scalability of the blockchain is limited by availability, energy costs, and the miners' own financial resources. The current alternative is the POS consensus mechanism. The POS mechanism selects validators based on the number of currency holders.

In fact, it can be seen that except for the early batch of cryptocurrencies headed by BTC, the vast majority of current blockchain projects have taken into account the disadvantages of POW and are constantly innovating consensus mechanisms to avoid excessive consumption of energy. Therefore, blockchain is not enough to cause such a huge consumption of energy.

2.9. Will blockchain take our jobs?

Regarding blockchain, if people can trade directly with each other, what impact will blockchain have on intermediaries such as banks and lawyers? Blockchain is unlikely to be a job killer; it will, like any technology, change the nature of work by changing companies’ business and revenue models.

When artificial intelligence becomes popular, people will continue to ask questions like this. On the one hand, we enjoy the convenience that technology brings us, but on the other hand, we are worried that technology will replace us. The biggest challenge of blockchain is not the technology itself, but changing the traditional profit distribution model. Blockchain technology can remove certain intermediary links, break the monopoly of many resources by centralized institutions, and thus change the interest pattern. This is also the most revolutionary point of blockchain.

2.10． Is the United States lagging behind in the development of the blockchain industry?

Globally, the blockchain industry in the United States is still in its infancy. Deloitte surveyed 1,053 executives in financial services, healthcare, technology industries, telecommunications, manufacturing and other industries in 2018. According to the survey, only 14% of American respondents believe that blockchain is used in their production, compared with 49% in China, 48% in Mexico, 40% in the United Kingdom, and 36% in Canada. Plans are also lagging: 41% of U.S. companies plan to invest $1 million or more in blockchain, compared with 85% in China, 74% in Canada, 72% in the United Kingdom, and 65% in Mexico.

According to Silicon Valley CaveAccording to the "White Paper on the Development of Blockchain in China and the United States" released by the China Securities Regulatory Commission, in terms of the number of ICOs, North America is comparable to Asia. In terms of the amount of financing, North America is far ahead with 7.85 billion. Therefore, the United States, as a major country in North America, is not lagging behind at all. On the contrary, it is still leading in many aspects.

《Harnessing Blockchain for American Business and Prosperity》

http://forex.hexun.com/2018-06-17/193222543.html

https://jiahao..com/s? id=1606478434369770769&wfr=spider&for=pc

Introduction to Tianjige: Tianjige (LD Research) was established on July 2, 2018. It is a company dedicated to exploring the unknown of science and technology, taking human development as the driving force, and taking "BASE Research for Solving Real" Problems" as the purpose of the research institute.

This article comes from Babbitt

Related questions and answers: What are the uses of blockchain technology in the business field?

What are the uses of blockchain technology in the business field?

In recent years, due to the virtual digital With currency speculation booming, blockchain, as its underlying technology, has also begun to receive widespread attention. Blockchain has the characteristics of decentralization, trustlessness, collective maintenance, and reliable storage. It is currently widely used in the field of virtual currency.

Since the birth of Bitcoin, more than 1,600 virtual currencies have appeared in the world, and a huge industrial chain ecosystem has been formed around the generation, storage, and trading of virtual currencies. But overall, the industry is still in its infancy and is still far away from the real value use area. The core of the blockchain economy lies in the reconstruction of business logic and organizational forms, so it is necessary to obtain practical examples in multiple industries to demonstrate its value. This article will explore the business models used by blockchain in various industries from the perspective of combining blockchain with industry needs.

First of all, the core of blockchain is to solve the problem of credit:

Credit is the foundation of all commercial activities and finance. The United States has implemented trusted identification since 2011, while China has implemented a real-name system to achieve supervised information dissemination. The significance of blockchain is that it has established decentralized trust from a technical level for the first time and realized a completely distributed credit system.

Secondly, blockchain solves the problem of value exchange:

Traditional networks can achieve point-to-point transmission of information, but cannot achieve point-to-point transmission of value. Because information is allowed to be copied, and value must be authentic and unique, it is necessary to rely on a centralized organization to achieve value transfer. Blockchain perfectly solves this problem and provides a method to realize point-to-point transfer of value. During the value transfer process, accounting is realized by the network without relying on a centralized institution. Therefore, blockchain is expected to become a new financialIntegrated infrastructure will become the cornerstone of the future value Internet.

The use of blockchain

There are currently two main modes of blockchain use:

1) Native blockchain use: directly based on decentralized blockchain technology to realize value Transfer and transaction use, such as digital currency;

2) "Blockchain+" model: combine traditional scenarios with the underlying protocol of the blockchain to improve efficiency and reduce costs. It is expected that the use of blockchain in various industries will be dominated by the second model.

Blockchain has five core attributes, namely: transaction attributes (value attributes), certificate attributes, trust attributes, intelligence attributes, and traceability attributes. The above core attributes are combined with the needs of the industry to solve the industry's pain points and become the business model used by blockchain in various industries.

Blockchain + Bank

1. Cross-border payment

Cross-border payment is a pain point that has long plagued the banking industry. Traditional cross-border payment methods include two major categories: one is online payment, including electronic account payment and international credit card payment, which is suitable for small retail amounts; the other is the bank remittance model, which is suitable for large-amount transactions; both have payment cycles Long, high fees, low transaction transparency and other issues. Especially in recent years, with the rise of cross-border e-commerce, convenient, fast, safe and low-cost cross-border payment has become an urgent need for the industry.

The role of blockchain:

The characteristics of blockchain are deintermediation and open and transparent transactions. There is no third-party payment institution to join, which shortens the payment cycle, reduces fees, and increases transaction transparency. For example, in December 2017, China Merchants Bank teamed up with Wing Lung Bank and Wing Lung Shenzhen Branch to successfully implement cross-border RMB remittances between the three parties using blockchain technology. Its clearing process is safe, efficient and fast, greatly improving customer experience.

2. Supply chain finance

The pain points in this field are the long financing cycle and high costs. Centered on the core enterprise system of the supply chain, it is difficult for third-party credit enhancement institutions to authenticate the authenticity of various relevant vouchers in the supply chain, resulting in long manual review times and high financing costs.

The role of blockchain:

Blockchain introduces consensus mechanism, existence proof, non-tampering, traceability and other features into supply chain finance, and does not require third-party credit enhancement agencies to authenticate various relevant credentials in the supply chain. authenticity, thereby reducing financing costs and shortening the financing cycle. For example, in April 2017, the listed company Yijian and IBM China Research jointly launched the blockchain supply chain financial service system "Yijian Block". The system focuses on pharmaceutical scenarios and currently has more than 30 pharmaceutical distribution companies. Successfully registered in the "Yijian Block", as of the end of July, the number of transactions had been close to 8,000, and the total investment amount exceeded 100 million yuan.

3. Digital Bills

The pain point of the digital bill industry lies in the long-term problems of "false bills" and "one vote selling many", which have brought risks to the bill financing business of the banking industry.

The role of blockchain:

The existence proof and non-tampering characteristics of blockchain effectively solve the problem of false digital bills; at the same time, blockchain solves the double-spending problem and can avoid&q"One ticket sells many". For example, Shenzhen Blockchain Financial Services Co., Ltd. issues ticket chain products to provide ticket financing services based on blockchain to solve the ticket financing needs of small, medium and micro enterprises. Cooperative banks include Ganzhou Bank and Guiyang Bank , Suzhou Bank, Shizuishan Bank, Langfang Bank, Wuhai Bank, Jilin Jiutai Rural Commercial Bank, Yaodu Rural Commercial Bank, Shenzhen Rural Industrial Bank, Weifang Bank, Zhongyuan Bank, etc. In addition, Zheshang Bank, Jingdong Finance, Hang Seng Electronics , HNA, etc. are also verifying blockchain digital bill services.

Blockchain + Securities

1. Asset Securitization

Asset securitization uses future income as a guarantee to obtain current financing. The The pain points in the field are: there are many participating entities, many operating links, low transaction transparency, information asymmetry, and the authenticity of the underlying assets cannot be guaranteed.

The role of blockchain:

Blockchain introduces existence to asset securitization With attributes such as proof of authenticity, non-tamperability, and consensus mechanism, it can monitor the true status of assets in real time and solve the problem of trust in underlying assets by all parties in the transaction chain. Various assets such as equity, bonds, bills, income certificates, warehouse receipts, etc. It can be integrated into the blockchain and become a digital asset on the chain, improving the efficiency of asset circulation and reducing costs. For example, in May 2017, Internet Finance and partners including Baiqian Leasing, Huaneng Trust, etc. jointly issued a blockchain The asset securitization ABS project supported by technology has an issuance scale of 424 million yuan.

Blockchain + Insurance

1. Insurance business

There is information asymmetry in the insurance industry and a lack of trust between customers and insurance institutions Problems such as: It is difficult for users to choose insurance products that suit them, and insurance institutions face the risk of insurance fraud.

The role of blockchain:

The decentralization, openness, transparency, and traceability of blockchain, Establish a good communication channel between insurance institutions and users; insurance subject information is managed uniformly on the blockchain and cannot be tampered with, helping insurance institutions avoid the risk of fraudulent insurance; at the same time, smart contracts can improve work efficiency and reduce costs. For example, France Insurance giant AXA is using the Ethereum public blockchain to provide automatic flight delay compensation for air passengers. If the flight is delayed for more than 2 hours, the "smart contract" insurance product will automatically pay the claim to the passenger.

2 , Credit information management

The pain point in this field is that credit information agencies have limited data collection channels and a lack of data sharing, making it difficult to accurately characterize the credit status of individuals or institutions; in addition, there are also issues about how to protect user privacy during the data collection process. .

The role of blockchain:

Blockchain has the characteristics of trustlessness, consensus, and non-tampering. At the technical level, it ensures that limited and controllable credit data can be achieved on the basis of effectively protecting user privacy. Sharing and verification. For example, Ping An’s blockchain credit reporting business is now online. In addition, domestic startups such as Shanghai Juzhen, LinkEye, Bubi Blockchain, etc. are also conducting joint credit reporting and safe certificate deposits. Exploration.

As a basic technology, blockchain is used in many fieldsIt has great use value in industries that require distributed processing, point-to-point transactions, and rapid establishment of trust relationships. Its core is to solve the problem of credit and realize point-to-point transfer of value. Therefore, it is considered to be the cornerstone of the future value Internet.

The core of the blockchain business model is to use the innovative attributes introduced by the blockchain and combine it with traditional industry uses to realize the reconstruction of business logic in order to create new usage scenarios, or improve efficiency and reduce costs.

It is expected that the use of blockchain will first start in the pan-financial field that has high requirements for credit, efficiency, and security: the financial industry pays more attention to efficiency and security, and blockchain has a high degree of matching with its pain points, and can be used for Systematically solve trust issues, efficiency issues, default risks, etc. that exist in all aspects of financial services; blockchain’s attributes such as “transaction, certificate storage, and traceability” are more likely to generate value in the financial industry. At the same time, the market space in the financial industry is huge, and small progress can bring huge benefits.

Blockchain will also extend to all areas of social life: Blockchain solves problems such as the management, transaction, and transfer of digital assets, and therefore will play an important role in the wave of asset digitization, such as supply chain management, data Applications such as services, asset management, public services, and the Internet of Things are gradually being implemented in various fields, and "blockchain+" is becoming a reality.

『二』Zihang Shuobi: Newbies in the currency circle don’t even know what “blockchain” is

First of all, I believe that before everyone learns about blockchain, You’ve heard of Bitcoin first, right? Because we all know that the first people to hold Bitcoin made money!

But one point of view is wrong: What point of view? Many people believe that Bitcoin is the blockchain. In fact, Bitcoin is just a type of blockchain asset, and it is the earliest blockchain asset. The concept of blockchain comes from Bitcoin. The reason why Bitcoin can be so arrogant and exist independently without relying on any organizational structure is because the bottom layer is supported by blockchain technology.

Just like our mobile phones can run, the bottom layer is supported by Android or ios system. So what kind of technology is blockchain? Why is it so powerful? Can make Bitcoin so valuable! The English name of blockchain is block chain, and block means block. You can imagine that if you fall or bump into something, you may have bruises, right? The blocks in the blockchain contain some The data block of transaction information, something, may have a bruise, right? The block in the blockchain contains some data blocks of transaction information, and the chain in the blockchain connects the data blocks. , this is like a big ledger. Anyone who uses this blockchain ledger can directly query any transaction information arranged in order, and it is difficult to tamper with. So how does it do it?

Give a simple example using local materials: There are now a total of 100 readers who are linked through the Internet to form a blockchain network system. Please pay attention! We are not reading this article now, but a blockchain network system. In this system, I ask one of the people, say this person is called panda, to borrow 10 yuan, and then panda transfers the 10 yuan to me in the network system. Then my account or wallet increased by 10 yuan. As for panda, who lent money to Bibi, his account lost 10 yuan. After this transaction is completed, other people in our blockchain network system, after seeing it, will take a small notebook and record the matter. My account will increase by 10 yuan, and panda's account will decrease by 10 yuan.

That’s not right, then what are you doing when you are full and have nothing to do? Why should we record these small and medium-sized "bad things"? This is because the network system will pay wages to those who participate in recording. As long as she records it once, the system will automatically reward tokens that are common in this network system. As long as there is money, everyone is willing to do anything. In reality, there are actually countless individuals in a blockchain system. In other words, our group not only has only 13 people, but they don’t know each other yet, but they can all spread to each other on the system chain and record them in the blockchain in order. For this transaction in the network, if one day I want to default on the debt and no longer plan to pay back 10 yuan to panda, then I must convince more than 51% of the people in the blockchain network system to delete this record or tamper.

If it were replaced by real-world computing power, it would be almost impossible and would require huge costs. This is the characteristic of blockchain technology - decentralized collaboration, transaction data is difficult to tamper with, and transaction information is transparent and queryable. Its main function is to solve two problems that are difficult to solve on the Internet - one is trust and the other is value transfer.

The so-called trust, according to the above scenario, is that I may default on the loan and take the money and run away; the value transfer is: my borrowing account should increase by 10 yuan, while the panda account becomes -10 Yuan money exchange. Then we may have questions again, isn't Alipay and WeChat payment solved now? Wouldn’t it be enough to just confirm the account and transfer the money directly and send a red envelope? Yes, Alibaba and Tencent exist based on solving these two problems. but! Thinking about it from another perspective, if a mere blockchain technology can solve these two problems now, can huge and complex institutions like Alibaba and Tencent be abandoned?

Rebuilding a new network system to apply it to more fields is on the way.

Because, the final conclusion is: this technology builds the value of Bitcoin, then this technical logic can also be used in many other fields. Maybe one day you will be happy to discover - Huh? I am now using a product from a certain blockchain technology company! ? Just like many years ago, one day youUnknowingly, I started using QQ and started to learn how to surf the Internet, watch videos and play games. Having said that, what does it mean that Bitcoin is an early asset of the blockchain? Why does it add value? According to the scenario mentioned above, the so-called tokens are the tokens issued by the system to everyone in the group by participating in accounting. These tokens are blockchain assets. (The behavior of everyone participating in bookkeeping is commonly known as mining.) Bitcoin itself is the value token of the Bitcoin blockchain network system

Then why is it Will it add value? Because its quantity is limited, the number of issuances is determined at one time from the beginning of the establishment of the network system and will never be issued additionally.

So, in the future, the more people participate in accounting in a certain blockchain network, the number of people who get it will gradually decrease, and value-added will become inevitable. This is like Alibaba's early stocks. After the Alipay application is launched, the more people participate in using it, the more it is needed, and Alibaba's stocks will inevitably increase in value.

Of course, there are currently many projects applying blockchain technology, but most of them have not found a landing scenario. However, the more people believe that a project created using blockchain technology will be used in the future. If necessary, the price of the tokens of this project will be pushed up. Therefore, there are far more investment opportunities in blockchain assets than in the ordinary stock market. If you invest in a value project, then it may skyrocket like Bitcoin a few years ago, which skyrocketed from 130,000 per coin to a little over 40,000 now. In other words, you don’t need to consider any investment opportunities in other varieties. A few years ago, if you bought Bitcoin with your eyes closed and then ignored it and just went about your own business, the return on this investment would be 100 times in one year.

Profit! How much is that right? The opportunities in this industry are far more than these. Almost all currencies will have the opportunity to rise or fall sharply, but this range of rise and fall is not like the 10% daily limit in stocks. Blockchain assets disappear from trading around the world 24 hours a day, and It is T+0, and there is no limit on the increase or decrease. The price of any variety is completely affected by the limit on the increase or decrease and the pursuit of funds. Most varieties have experienced an increase of more than 100% throughout the year. High This kind of investment opportunity is also difficult to find in other markets.

The currency circle is like Tai Chi. Only when a person is in a state of tranquility can he feel the opponent's strength and intention in the push hand for the first time. What I felt at the time was that only by clearing myself could I receive information to the maximum extent and quickly, and make correct judgments and responses. The same is true in the currency circle.

This material is for learning reference only and does not constitute buying or selling advice. Buy and sell based on it at your own risk!

『三』Blockchain Technology

Background: After the birth of Bitcoin, I discovered that the technology was very advanced, and I discovered the blockchain.technology. Bitcoin and blockchain technology were discovered at the same time.

1.1 The purpose of the birth of Bitcoin:

①Currency transactions have records, that is, ledgers;

②The disadvantages of centralized institution accounting - it can be tampered with; Yi Chaofa

Bitcoin solves the first problem: anti-tampering - hash function

1.2 hash function (encryption method)

① Function: convert any A string of length, converted to a fixed-length (sha256) output. The output is also called a hash value.

② Features: It is difficult to find two different x and y such that h(x)=h(y).

③Application: md5 file encryption

1.3 Blockchain

①Definition

Block: Split the general ledger into zones Block storage

Blockchain: On each block, add a block header. It records the hash value of the parent block. By storing the hash value of the parent block in each block, all blocks are connected in order to form a blockchain.

②How does the blockchain prevent transaction records from being tampered with?

After the blockchain is formed, tampering with any transaction will cause the hash value of the transaction block to be different from that of its sub-blocks. , tampering was discovered.

Even if you continue to tamper with the hash value in the sub-block header, the hash value in the sub-block will be different from that in the grandchild block, and the tampering will be discovered.

1.4 The essence of blockchain

①The essence of Bitcoin and blockchain: a big ledger visible to everyone, only recording transactions .

②Core technology: Through cryptographic hash function + data structure, it ensures that the ledger records cannot be tampered with.

③Core function: Create trust. Fiat currency relies on government credibility, and Bitcoin relies on technology.

1.5 How to trade

①To conduct transactions, you need an account number and password, corresponding to the public key and private key

Private key: a string of 256-bit binary numbers , you don’t need to apply for it, you don’t even need a computer, you can generate the private key by tossing a coin 256 times

The address is converted from the private key. The address cannot reverse the private key.

The address is the identity, which represents the ID in the Bitcoin world.

After an address is generated, it can only be known by everyone if it enters the blockchain ledger.

②Digital signature technology

Signature function sign (Zhang San’s private key, transfer information: Zhang Sanzhuan10 yuan to Li Si) = signature of this transfer

Korean verification (Zhang San’s address, transfer information: Zhang San transferred 10 yuan to Li Si, signature of this transfer) = True

Zhang San uses his private key to sign this transaction through the signature function sign().

Anyone can verify whether the signature was issued by Zhang San himself who holds Zhang San's private key by verifying the Korean vertify(). It returns true, otherwise it returns false.

sign() and verify() are cryptographically guaranteed not to be cracked. ·

③Complete the transaction

Zhang San will provide the transfer information and signature to the entire network. Under the premise that the account has a balance, after verifying that the signature is true, it will be recorded in the blockchain ledger. Once recorded, Zhang San's account will be reduced by 10 yuan, and Li Si's account will be increased by 10 yuan.

Supports one-to-one, one-to-many, many-to-one, and many-to-many transactions.

In the Bitcoin world, private keys are everything! ! !

1.6 Centralized Accounting

① Advantages of Centralized Accounting:

a. No matter which center keeps accounts, don’t worry too much

< p> b. Centralized accounting, high efficiency

②Disadvantages of centralized accounting:

a Denial of service attack

b Stop service after getting tired

p>

c Central institutions are vulnerable to attacks. For example, destroying servers and networks, committing self-intrusion, legal termination, government intervention, etc.

All attempts at confidential currencies with centralized institutions in history have failed.

Bitcoin solves the second problem: how to decentralize

1.7 Decentralized accounting

①Decentralization: Everyone can keep accounts. Everyone can keep a complete ledger.

Anyone can download open source programs, participate in the P2P network, monitor transactions sent around the world, become an accounting node, and participate in accounting.

② Decentralized accounting process

After someone initiates a transaction, it is broadcast to the entire network.

Each accounting node continues to monitor and continue transactions across the entire network. When a new transaction is received and the accuracy is verified, it is put into the transaction pool and continues to be propagated to other nodes.

Due to network propagation, the transactions of different accounting nodes at the same time are not necessarily the same.

Every 10 minutes, one person is selected from all accounting nodes according to a certain method, and his transaction pool is used as the next block and broadcast to the entire network.

Other nodes delete the transactions that have been recorded in their own transaction pool based on the transactions in the latest block, continue accounting, and wait for the next selection.

③ Features of decentralized accounting

A block is generated every 10 minutes, but not all transactions within these 10 minutes can be recorded.

The accounting node that obtains the accounting rights will be rewarded with 50 Bitcoins. After every 210,000 blocks (approximately 4 years), the reward is halved. The total amount is about 21 million, and it is expected to be mined in 2040.

Recording the reward of a block is also the only way to issue Bitcoin.

④ How to allocate accounting rights: POW (proof of work) method

Compete for accounting rights by calculating mathematical problems on several accounting points.

Find a random number that makes the following inequality true:

There is no other solution except traversing the random numbers starting from 0 and trying your luck. The process of solving the problem is also called mining.

Whoever solves the problem correctly first will get the accounting rights.

If a certain accounting node finds the solution first, it will announce it to the entire network. After other nodes verify that it is correct, a new round of calculation will start again after the new block. This method is called POW.

⑤ Difficulty adjustment

The generation time of each block is not exactly 10 minutes

As Bitcoin develops, the computing power of the entire network does not increase.

In order to cope with changes in computing power, the difficulty will be increased or decreased every 2016 blocks (about 2 weeks), so that the average time for each block to be generated is 10 minutes.

#欧易OKEx# #BTC[超话]# #digital currency#

『四』 Tutorial on getting started with blockchain

However, there are few simple and easy-to-understand introductory articles. What exactly blockchain is and what makes it special is rarely explained.
Next, I will try to write a best-understood blockchain tutorial. After all, it is not difficult. The core concept is very simple and can be explained clearly in a few sentences. I hope that after reading this article, you will not only understand the blockchain, but also understand what mining is, why mining is getting more and more difficult, and other issues.
It should be noted that I am not an expert in this area. Although I have been paying attention to it for a long time, my detailed understanding of blockchain started at the beginning of this year. You are welcome to correct any errors or inaccuracies in the article.
1. The essence of blockchain
What is blockchain? In a word, it is a special distributed database.
First, the districtThe main function of the blockchain is to store information. Any information that needs to be saved can be written to the blockchain and read from it, so it is a database.
Secondly, anyone can set up a server, join the blockchain network, and become a node. In the world of blockchain, there is no central node. Every node is equal and stores the entire database. You can write/read data to any node, because all nodes will eventually be synchronized to ensure that the blockchain is consistent.
2. The biggest features of blockchain
Distributed databases are not a new invention, and there have been such products on the market for a long time. However, blockchain has a revolutionary feature.
Blockchain has no administrator, it is completely centerless. Other databases have administrators, but blockchain does not. If one wanted to add auditing to the blockchain, it would not be possible because it is designed to prevent the emergence of a central authority.
It is precisely because it is unmanageable that blockchain can be uncontrollable. Otherwise, once big companies and large groups control the management, they will control the entire platform, and other users will have to take orders from them.
However, without an administrator, everyone can write data into it. How can we ensure that the data is trustworthy? What if it is modified by a bad person? Please read on, this is the wonderful thing about blockchain place.
3. Block
Blockchain is composed of blocks. Blocks are much like database records. Every time data is written, a block is created.
Each block contains two parts.
Head: records the characteristic values ​​of the current block
Body: actual data
The block header contains multiple characteristic values ​​of the current block.
Generation time
Hash of the actual data (i.e. block body)
Hash of the previous block
...
Here, you need to understand what a hash is , which is necessary to understand blockchain.
The so-called hashing means that the computer can calculate a characteristic value of the same length for any content. The hash length of the blockchain is 256 bits, which means that no matter what the original content is, a 256-bit binary number will be calculated in the end. And it can be guaranteed that as long as the original content is different, the corresponding hash must be different.
For example, the hash of the string 123 is (hexadecimal), which is 256 bits when converted to binary, and only 123 can get this hash. (Theoretically, it is possible for other strings to get this hash, but the probability is extremely low and can be approximated as impossible.)
Therefore, there are two important inferences.
Corollary 1: The hash of each block is different, and the block can be identified by the hash.
Corollary 2: If the content of the block changes, its hash will definitely change.
4. The non-modifiable nature of Hash
Blocks and hashes have a one-to-one correspondence, and the hash of each block is calculated based on the block header (Head). That is to say, the characteristic values ​​​​of the block header are connected together in order to form a very long string, and then the hash is calculated on this string.
Hash = SHA256 (block header)
The above is the calculation formula of block hash. SHA256 is the hash algorithm of the blockchain. Note that this formula only contains the block header and not the block body. In other words, the hash is uniquely determined by the block header.
As mentioned before, the block header contains a lot of content, including the hash of the current block body. , and the hash of the previous block. This means that if the content of the current block body changes, or the hash of the previous block changes, it will definitely cause the hash of the current block to change.
This point has great significance for blockchain. If someone modifies a block, the hash of the block changes. In order for subsequent blocks to still be connected to it (because the next block contains the hash of the previous block), the person must modify all subsequent blocks in sequence, otherwise the modified block will be removed from the blockchain . Due to the reasons mentioned later, hash calculation is very time-consuming, and it is almost impossible to modify multiple blocks in a short period of time, unless someone controls more than 51% of the computing power of the entire network.
It is through this linkage mechanism that the blockchain ensures its own reliability. Once the data is written, it cannot be tampered with. This is just like history, what happened happened, and it can’t be changed from now on.
Each block is connected to the previous block, which is where the name blockchain comes from.
5. Mining
Since synchronization between nodes must be ensured, the adding speed of new blocks cannot be too fast. Just imagine, you have just synchronized a block and are preparing to generate the next block based on it, but at this time, another node generates a new block, and you have to give up half of the calculations and synchronize again. Because each block can only be followed by one block, you can only generate the next block after the latest block. So, you have no choice but to sync as soon as you hear the signal.
So, the inventor of the blockchain, Satoshi Nakamoto (this is a pseudonym, his true identity is still unknown), deliberately made it difficult to add new blocks. His design is that on average, the entire network can generate a new block every 10 minutes, which is only six per hour.
This output speed is not achieved through commands, but by deliberately setting up massive calculations. In other words, only through an extremely large amount of calculations can the effective hash of the current block be obtained and the new block added to the blockchain. Because the amount of calculation is too large, it cannot be done quickly.
This process is called mining, because the difficulty of calculating a valid hash is like finding a grain of sand that meets the conditions among the sand in the world. The machine that calculates hashes is called a mining machine, and the person who operates the mining machine is called a miner.
6. Difficulty coefficient
After reading this, you may have a question. People say that mining is difficult, but isn’t mining just about using a computer to calculate a hash? This is the strength of computers. How could it be? becomes difficult, why can’t it be calculated?
It turns out that not just any hash will do, only hashes that meet the conditions will be accepted by the blockchain. This condition is particularly harsh, causing most hashes to fail to meet the requirements and must be recalculated.
It turns out that the block header contains a difficulty coefficient (difficulty), which determines the difficulty of calculating the hash. For example, the difficulty coefficient of the 100,000th block is 14484.16236122.
The blockchain protocol stipulates that the target value (target) can be obtained by dividing the difficulty coefficient by a constant. Obviously, the greater the difficulty coefficient, the smaller the target value.
The validity of the hash is closely related to the target value. Only hashes smaller than the target value are valid, otherwise the hash is invalid and must be recalculated. Since the target value is very small, the chance that the hash is smaller than this value is extremely slim. It may be calculated 1 billion times before it is considered a hit. This is the fundamental reason why mining is so slow.
As mentioned earlier, the hash of the current block is uniquely determined by the block header. If the hash of the same block needs to be calculated repeatedly, it means that the block header must keep changing, otherwise it is impossible to calculate different hashes. All feature values ​​in the block header are fixed. In order to make the block header change, Satoshi Nakamoto deliberately added a random item called Nonce.
Nonce is a random value. The role of the miner is actually to guess the value of Nonce so that the hash of the block header can be smaller than the target value so that it can be written to the blockchain. Nonce is very difficult to guess. At present, we can only use trial and error one by one through exhaustive methods. According to the protocol, Nonce is a 32-bit binary value, which can reach a maximum of 2.147 billion. The Nonce value of the 100,000th block is 274148111. It can be understood that the miner started from 0 and calculated 274 million times before obtaining a valid Nonce value so that the calculated hash can meet the conditions.
If you are lucky, you may find Nonce in a while. If you are unlucky, you may have calculated it 2.147 billion times without finding the Nonce, that is, it is impossible to calculate a hash that meets the conditions for the current block body. At this time, the protocol allows miners to change the block body and start a new calculation.
7. Dynamic adjustment of difficulty coefficient
As mentioned in the previous section, mining is random, and there is no guarantee that a block will be produced in exactly ten minutes. Sometimes it can be calculated in one minute, and sometimes it may take several hours. No result. Overall, with the improvement of hardware equipment and the increase in the number of mining machines, the computing speed will definitely become faster and faster.
In order to keep the output rate constant at ten minutes, Satoshi Nakamoto also designed a dynamic adjustment mechanism for the difficulty coefficient. He stipulated that the difficulty factor should be adjusted every two weeks (2016 blocks). If the average block generation speed in these two weeks is 9 minutes, it means that it is 10% faster than the legal speed, so the next difficulty factor will be increased by 10%; if the average block generation speed is 11 minutes, it means WithIt is 10% slower than the legal speed, so the difficulty factor of the next step must be lowered by 10%.
The difficulty coefficient is adjusted higher and higher (the target value is getting smaller and smaller), which makes mining more and more difficult.
8. Forks of the blockchain
Even if the blockchain is reliable, there is still an unresolved problem: if two people write data to the blockchain at the same time, that is to say, two people write data to the blockchain at the same time. Blocks join because they are connected to the previous block, forming a fork. Which block should be adopted at this time?
The current rule is that new nodes always adopt the longest blockchain. If there is a fork in the blockchain, it will look at which branch is behind the fork to reach 6 new blocks first (called six confirmations). Based on a block calculation of 10 minutes, it can be confirmed in one hour.
Since the generation speed of new blocks is determined by computing power, this rule means that the branch with the most computing power is the authentic blockchain.
9. Summary
Blockchain, as an unmanaged distributed database, has been running for 8 years since 2009 without major problems. This proves it works.
However, in order to ensure the reliability of data, blockchain also has its own price. The first is efficiency. You have to wait at least ten minutes to write data to the blockchain. All nodes synchronize the data, which requires more time. The second is energy consumption. The generation of blocks requires miners to perform countless meaningless calculations. This is Very energy consuming.
Therefore, the applicable scenarios of blockchain are actually very limited.
There is no management authority that all members trust
The written data does not require real-time use
The benefits of mining can make up for its own costs
If the above conditions cannot be met, then the traditional database is Better solution.
Currently, the largest application scenario (and possibly the only application scenario) of blockchain is the cryptocurrency represented by Bitcoin.

『五』What is the concept of blockchain

Literally understood, blockchain includes two concepts: block and chain. The blockchain itself is composed of blocks, and the network built by linking different nodes together is the blockchain. The main function of the blockchain is to store information. Any information that needs to be saved can be written to the blockchain or read from it.

Each block stores: some valid record or transaction; information involving the block; links to the previous block and the next block through the hash of each block - which can be thought of as a block The unique code of the fingerprint.

Each block therefore has a specific and immovable position within the chain, as each block contains information from the hash of the previous block. The entire chain is stored in every network node that makes up the blockchain, so an exact copy of the chain is stored among all network participants.

Uses

Essentially, blockchain can be used to store any type of information that must remain intact and be more secure than going through a middleman. ,dispersionand cheaper ways remain available. Additionally, since the stored information is encrypted, its confidentiality is guaranteed as only those with the encryption key can access it.

Using blockchain in healthcare. For example, health records can be consolidated and stored on the blockchain. This means that every patient's medical history is secure and, at the same time, available to every authorized doctor, regardless of the health center where the patient received treatment. Even the pharmaceutical industry could use this technology to authenticate medicines and prevent counterfeiting.

Blockchain is also very useful for managing digital assets and documents. The problem with digitization so far has been that everything is easily copied, but Blockchain allows you to record purchases, deeds, documents or any other type of online asset without it being counterfeited.

『Lu』 What exactly is blockchain? Which blockchains have physical applications

What is blockchain?

Official definition: Blockchain is a new application model of computer technology such as distributed data storage, point-to-point transmission consensus mechanism encryption algorithm, etc. The so-called consensus mechanism is a mathematical algorithm that establishes trust and obtains rights and interests between different nodes in the blockchain system.

Vernacular understanding: A block is to package all the data generated within a time period in chronological order. Generally, the length of a block is 10 minutes, which means that within 10 minutes, all the data on the Internet will The data is packed into a complete package, and this complete data package is called a block. The blockchain links these data packages in order to form a structure, and cryptographically ensures that it cannot be tampered with or forged to form a distribution. ledger, this is the blockchain.

It seems that everyone has a preliminary knowledge and understanding of the blockchain. So whether the blockchain has any practical application in daily life, the answer is yes, the current practical application There are mainly the following aspects. Of course, I may not know some of them. Friends are welcome to leave messages to add.

Financial Industry

Blockchain should be used the most in the financial industry.

For example, in May 2017, OMG (Omise Coin) announced that it would cooperate with Alipay to launch an e-wallet, integrating the "Alipay" payment solution into its own payment service suite to help local electronics in Thailand. Business merchants accept online payment transactions from Chinese tourists.

Another example is PPT, which is a financial transaction system for bills based on blockchain.

Gaming

The gambling industry entered the blockchain probably last year. Why does gambling favor blockchain? Because blockchain provides a relatively fair betting system. Why? It is relatively fair. As can be seen from the previous introduction, the blockchain cannot be tampered with or forged.

For example, WICC (WikiChain) can realize rich application scenarios such as asset issuance, betting applications, copyright traceability, mutual insurance, decentralized exchanges, and cross-border settlement.

For exampleThe STX (King of Fighters Coin) stox application is designed to provide the full functionality of a prediction market application without the need for any central server. Prediction markets require functions such as event planning, market production, providing information and analysis to traders, reporting event results, and of course collection and payment.

I believe that if the current lottery industry is built on the blockchain, people will become more and more enthusiastic about buying, because there are too many insider tips that make people give up.

Internet of Things

The Internet of Things still has many applications on the blockchain, because the traceability and immediacy of blocks are very suitable for this industry.

For example, DATA is the concept of the Internet of Things. It is a decentralized p2p network. Data sources can connect to any node in the entire network, then publish data, and the network will immediately send it to subscribers. Achieve horizontal scalability through sharding pattern. This timeliness and accuracy are very important in IoT applications.

Game industry

For example, GTC (G coin) is a decentralized digital asset based on Ethereum erc20 issued by Game Global. G coin is committed to becoming a universal number in the global game industry. Monetary standards.

For example, MANA is a distributed shared virtual platform. On this platform, users can browse and discover content and interact with other people and entities. Users can also claim ownership of virtual territories through a blockchain-based land ledger. The territory is demarcated by rectangular coordinates (x, y), and its owner can decide the content published on the territory, including static 3D scenes to interactive systems such as games.

There are many other industries. The emperor did not list them one by one, but listed a few representative ones. What is the purpose? It shows that the blockchain is definitely not just a currency transaction, it is a real implementation project, and it is a product of the changes of the times with real practical uses.

The development of human society is actually like the blockchain, it is irreversible and unstoppable. As far as I feel, the blockchain will enter thousands of households sooner or later. Regardless of whether it is bull or bear, hold it in your hands. Value coins and Flush have started quoting digital currencies, which shows that society is accepting it step by step. The power of social development cannot be blocked by any country or person.

『撒』Illustration of what is blockchain

Blockchain is so popular that it has begun to affect my life. I don’t even want to understand it anymore. Let’s take a look today. What exactly is blockchain.

Structure of this article:

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

Blockchain technology was first developed by a group of researchers in 1991 to time-stamp digital documents so that these documents cannot be tampered with. From then on, it basically played no other role until 20In 2009, Satoshi Nakamoto used blockchain technology to create the digital cryptocurrency Bitcoin.

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

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

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

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

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

The third element contained in the block is the hash value of the previous block. This element allows links to be formed between blocks and makes the blockchain very secure.

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

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

But to prevent tampering, hashing is not enough
Because today’s computers are powerful enough and can calculate thousands of hashes per second.Hash value
In this way, you can completely tamper with a block and recalculate the hash value of other blocks, making your block legal again.

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

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

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

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

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

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

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

『8』What is blockchain and what is digital currency< /p>

Blockchain is an important concept of Bitcoin, which is essentially a decentralized database.
At the same time, as the underlying technology of Bitcoin, it is a series of data blocks generated using cryptographic methods. Each data block contains a batch of Bitcoin network transaction information, which is used to verify the validity of its information. (anti-counterfeiting) and generate the next block. Digital currency is an unregulated, digital currency that is usually issued and managed by developers and accepted and used by members of a specific virtual community. The European Banking Authority defines virtual currency as: a digital representation of value that is not issued by a central bank or authority and is not linked to a legal currency, but which, because it is accepted by the public, can be used as a means of payment or can be transferred, stored or traded electronically. .
The content of this article comes from: China Law Publishing House's "Complete Knowledge of Legal Life Common Sense Series"

『九』 What exactly is blockchain

What is blockchain ?
Blockchain is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithms. 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. It is essentially a decentralized database and serves as the underlying technology of Bitcoin. Blockchain is a series of data blocks generated using cryptographic methods. Each data block contains information about a Bitcoin network transaction and is used to verify the validity of its information (anti-counterfeiting) and generate the next block.
Blockchain was born from Satoshi Nakamoto’s Bitcoin. Since 2009, various Bitcoin-like digital currencies have appeared, all based on public blockchains.
The current situation of digital currencies is that a hundred flowers are blooming. Here are some common ones: bitcoin, litecoin, dogecoin, dashcoin. In addition to currency applications, there are also various derivative applications, such as Ethereum, Asch and other underlying application development platforms, as well as NXT , SIA, BitShares, MaidSafe, Ripple and other industry applications.
On January 20, 2016, the People’s Bank of China Digital Currency Seminar announced that it had achieved phased results in digital currency research. The meeting affirmed that digital currencies are reducing traditionalThe value of currency issuance and other aspects, and said that the central bank is exploring the issuance of digital currency. The expression of the People’s Bank of China’s Digital Currency Seminar has greatly enhanced the confidence of the digital currency industry. This is the first time that the five central bank ministries and commissions have expressed a clear attitude towards digital currencies since they issued a notice on preventing Bitcoin risks on December 5, 2013. [4]
On December 20, 2016, the Digital Currency Alliance - China FinTech Digital Currency Alliance and FinTech Research Institute were officially established, with Huobi being one of the co-initiators. [5]
Some areas where blockchain can be used are:
▪ Smart contracts
▪ Securities trading
▪ E-commerce
▪ Internet of Things
▪ Social communication
▪ File storage
▪ Proof of existence
▪ Identity verification
▪ Equity crowdfunding
We can compare the development of blockchain to the development of the Internet itself , something called finance-internet will be formed on the Internet in the future, and this thing is based on blockchain, and its precursor is bitcoin, that is, traditional finance starts from private chains and industry chains (local area network), and the bitcoin series starts from public chains (Wide Area Network), they all express the same concept - digital assets (Digital Asset), and finally converge to an intermediate balance point.
The evolution of blockchain is:
▪ Blockchain 1.0 - digital currency
▪ Blockchain 2.0 - digital assets and smart contracts
▪ Blockchain 3.0 ——The implementation of distributed applications in various industries
Blockchain is divided into three categories, which is introduced in detail in the book "Blockchain: Defining the New Pattern of Future Finance and Economics" [2] issued by Currency,< br />Hybrid blockchains and private blockchains can be considered as broad private chains:
Public Blockchains (PublicBlockChains)
Public blockchains refer to: any individual or group in the world Transactions can be sent and effectively confirmed by the blockchain, and anyone can participate in its consensus process. The public blockchain is the earliest blockchain and the most widely used blockchain. The virtual digital currencies of all major bitcoins series are based on the public blockchain. There is only one blockchain corresponding to this currency in the world. .
Consortium (Industry) Blockchain (ConsortiumBlockChains)
Industry Blockchain: Multiple pre-selected nodes are designated within a certain group as bookkeepers, and the generation of each block is jointly performed by all pre-selected nodes. decide (preselect nodeParticipate in the consensus process), other access nodes can participate in transactions, but do not participate in the accounting process (essentially still managed accounting, but become distributed accounting, how many pre-selected nodes, how to determine the accountant of each block becomes The main risk point of the blockchain), anyone else can conduct limited queries through the open API of the blockchain.
Private Blockchain (privateBlockChains)
Private Blockchain: Only uses the general ledger technology of the blockchain for accounting. It can be a company or an individual, and has exclusive access to the writing of the blockchain. With access permissions, this chain is not much different from other distributed storage solutions. (Dec2015) Conservative giants (traditional finance) all want to experiment with private blockchains, while public chain applications such as Bitcoin have been industrialized, and private chain application products are still being explored.