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In recent years, ,“ Blockchain ” Once again, it has become a hot topic after dinner .“ Take blockchain as an important breakthrough in independent innovation of core technology ”“ Accelerate the development of blockchain technology and industrial innovation ”, For a time, blockchain has become a hot spot . Today, ,“ Blockchain ” Is coming into public view , Become finance 、 The focus of economic and social attention . As an Internet practitioner , In the face of this innovation , What needs attention and learning ？

In this article , You will learn the following ：

What is blockchain The principle of blockchain Features of blockchain Application scenarios of blockchain Blockchain development language and framework Suits the crowd ： Readers interested in blockchain

1. What is blockchain

—— Blockchain  It is a rising trading service platform 
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stay Wikipedia On , Blockchain is compared to a distributed database technology , Continuous growth by maintaining the chain structure of data blocks 、 Data records that cannot be tampered with . On Baidu Encyclopedia , Blockchain is distributed data storage 、 Point to point transmission 、 Consensus mechanism 、 New application mode of computer technology such as encryption algorithm . Blockchain （Blockchain）, It's an important concept of bitcoin , It's essentially a decentralized database , And as the underlying technology of bitcoin , It is a series of data blocks associated with cryptography methods , Each data block contains a batch of bitcoin network transaction information , Used to verify the validity of its information （ Anti-counterfeiting ） And generate the next block [1] .

Simply speaking , The concept of blockchain can be understood from both narrow and broad levels . Narrowly , Blockchain is a chained data structure based on blocks , In the block, the digital summary is used to verify the previous transaction history , It is suitable for the requirements of tamper proof and scalability in the scenario of Distributed Accounting . In broad sense , Blockchain also refers to Distributed Accounting Technology Based on blockchain structure , Including distributed consensus 、 Privacy and security protection 、 Point to point communication technology 、 Network protocol 、 Smart contracts, etc .

—— Blockchain Can we change the way we solve problems , We'll see .
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2. The development of blockchain

“ In the past 20 many years , The Internet enables individuals and organizations to conduct business and social activities more effectively .  However, the basic pattern of transactions between individuals and organizations has not changed .
Blockchain  It can bring more openness and efficiency to those processes , Just as we expected in the Internet age .”
                                                       —Arvind Krishna, Senior VP, IBM Research
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Understand the past , To better control the future , So what is the development process of blockchain in its past and present life ？

• 2008 year 10 month 31 Japan , Nakamoto sent an email to all members of a cryptography mailing list , The title is “ The currency ： Point to point e-cash system ”（Bitcoin:A Peer-to-Peer Electronic Cash System）.

• 2008 year 11 month 16 Japan , Nakamoto announced the source code of bitcoin system .

• 2009 year 1 month 3 Japan , On a server in Helsinki, Finland , Nakamoto has generated the first bitcoin block on the Internet , The so-called bitcoin Genesis block （genesis block）. after , Nakamoto and several developers discuss ideas online , Continue to develop iterations . As the bitcoin network matures , His activities began to diminish , Bitcoin system has gradually entered the state of autonomous operation .

• 2010 year 7 month , The first bitcoin platform was established , The number of new users has soared , Price inflation .

• 2011 year 11 After month , Nakamoto no longer appears . He became an anonymous legend , No one knows who he is , He only left his own creation .

• 2011 year 2 month , For the first time, bitcoin price reached 1 dollar , Then with the pound 、 Brazilian real 、 Bolanzroti exchange trading platform opened .

• 2012 year , Shwebo （Ripple） Release , As a digital currency , Use blockchain to transfer foreign exchange of countries .

• 2013 year , Bitcoin skyrocketed . The U.S. Treasury Department issued regulations on personal management of virtual currency , Clarify the definition of virtual currency for the first time .

• 2014 year ," Blockchain 2.0” Become a term for decentralized blockchain databases . For this second generation programmable blockchain , Economists think it's a programming language , It allows users to write more sophisticated and intelligent protocols .

• 2015 year 12 month , NASDAQ used blockchain technology in individual stock dealers for the first time , Its partners Chain.com Nasdaq's blockchain technology-based trading platform was used for the first time when issuing shares to a private investor Linq, The platform is NASDAQ and Chain.com co-developed .

• 2016 year 1 month 20 Japan ,China The digital currency seminar of the people's Bank of China announced that the research on digital currency has achieved phased results . The meeting affirmed the value of digital currency in reducing the issuance of traditional currency , And said the central bank is exploring the issue of digital currency .

• 2016 year 12 month 20 Japan , Digital currency union —— China FinTech Digital currency union and FinTech The Institute was officially prepared for establishment .

Now blockchain technology may bring about a second revolution in the Internet , Take the Internet from “ Information internet ” Zonal “ Value Internet ”. In contrast to blockchain , It was found that , It was originally figuratively called “ information superhighway ” The Internet of is dealing with “ Information ”, What blockchain can handle is “ value ”.

Change is about to happen , The future has to . Once again, we are at the beginning of the revolution —— The revolution of value Internet , And to understand the future of the value Internet , We need to understand what blockchain technology is first .

 Blockchain , Perhaps the most promising and divergent technological and economic trend of the moment . It brings to the digital world “ The expression of value ” and “ Value transfer ” Two new basic functions .
 Its potential is emerging , But now it is in the stage of hazy and savage growth .
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3. Principle and characteristics

Blockchain  Technology has great potential to transform the business network with multi-party participation , So as to significantly reduce costs and risks , And carry out business model innovation .
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3.1 Basic concepts

To have a general understanding of blockchain , You can start with the following concepts ：

• transaction （Transaction）： An operation on the ledger , Cause a change in the status of the ledger , If you add a transfer record ;

• block （Block）： Record all transactions and status results occurred in a period of time , It is a consensus on the current ledger status ;

• chain （Chain）： The blocks are connected in series according to the sequence of occurrence , It is a log record of changes in the status of the whole ledger . If the blockchain system is regarded as a state machine , Then each transaction means a state change ; Generated blocks , It is the consensus of participants on the result of state change caused by transaction .

• dig （Mining） Refers to the formation of new blocks by calculation , It is the process that supporters of transactions use their own computer hardware to do mathematical calculations for the network, confirm transactions and improve security . Take bitcoin for example ： Trading supporters （ The miners ） Run bitcoin software on the computer and constantly calculate the complex cryptographic problems provided by the software to ensure the transaction . As a reward for their service , Miners can get the handling fee included in the transaction they confirm , And the newly created bitcoin .

• Pair equality network （Peer-to-Peer Network） By allowing a single node to interact directly with other nodes , So as to realize that the whole system operates like an organized collective . Take bitcoin for example ： The network is built in such a way —— Each user is disseminating transactions from other users . And it's important , Banks or other financial institutions are not required as third parties .

• Hash hash (Hash) It is a classic technology in cryptography , Enter a string of any length through Hash Algorithm , Convert to a fixed length output consisting of letters and numbers .

• digital signature （Digital Signature） It's a mathematical mechanism that allows people to prove their ownership .

• Private key （Private Key） It is a confidential data block that proves that you have the right to consume electronic money from a specific wallet , It is realized by digital signature .

• Dual consumption refers to the user's attempt to illegally pay electronic money to two different payees at the same time , Is one of the biggest risks of e-money .

3.2 The basic principle

The goal of blockchain is to achieve a distributed data record ledger , This account book only allows you to add 、 Deletion is not allowed . The basic structure at the bottom of the ledger is a linear linked list . The linked list consists of “ block ” In series , Record the hash of the leading block in the subsequent block （Hash） value . A block （ And the transactions in the block ） Is it legal , A quick check can be made by calculating the hash value . Nodes in the network can propose to add a new block , However, the block must be confirmed through consensus mechanism . The following figure shows the problems of the consumption system based on third-party institutions , This is also the background of bitcoin . How does blockchain technology trade ？ The following describes the principle of blockchain with the transaction and circulation process of bitcoin . Blockchain technology is the basic technology of bitcoin , Highly transparent 、 De centralization 、 To trust 、 No tampering 、 Anonymity, etc . These properties embody the concept of distributed autonomy , It has gradually been widely concerned by financial institutions with innovative consciousness . So-called DAC（Distributed Autonomous Corporation, Distributed autonomous institutions ）, Is to adopt a series of open and fair rules , An organization that operates autonomously without intervention and management . These rules often appear in the form of open source software , Everyone can get an indefinite form of return by means of payment , Share the proceeds , Participate in the growth of the system . such as , The currency 、 Nasdaq's new platform and other applications are typical DAC.

3.3 Basic characteristics

1. De centralization

Decentralization is the most basic feature of blockchain , Blockchain no longer relies on centralized institutions , The distributed recording of data is realized 、 Store and update . All nodes in the blockchain network , All have bookkeeping rights , Can be bookkept , This can avoid the disadvantages of operation centralization .

In the life , Such as Taobao shopping , Actually, your money is managed and stored by institutions such as Alipay. . Transfer accounts 、 Subtract from our account balance when consuming , Add when collecting money . Your personal information is also in Alipay's data. , These are all centralized , All around this third party, this center .

But if Alipay's servers are damaged , Being attacked leads to data loss , Then our records will be destroyed , Transaction cannot be queried 、 In a special period , Will be seized at any time 、 frozen 、 Unable to trade 、 Or data destruction due to natural disasters , The funds you have in Alipay can't be recovered. . Or another common problem ： Disclosure of personal information . This is the disadvantage of centralization .

However, the transaction mode supported by blockchain technology is different , Buyers and sellers can trade directly , No need to use any third-party payment platform , At the same time, there is no need to worry about the leakage of other information . The decentralized processing method should be simpler and more convenient , When there is too much centralized transaction data , Decentralized treatment will also save a lot of resources , Make the whole transaction autonomous and simple , And eliminate the risk of centralized control .

2. Global circulation

Blockchain assets are first based on the Internet , Wherever there is the Internet , The transfer and circulation of blockchain assets can be carried out . Compared with the centralized way , The transfer fee of blockchain assets circulating around the world is very low , For example, the handling charge for early transfer of bitcoin is 0.0001BTC, Compared with traditional transfer , Blockchain assets also arrive very quickly . Usually a few minutes to 1 It will arrive in an hour .

3. anonymity Anonymity is one of the most basic features of bitcoin . The anonymity of blockchain is based on the algorithm to address by address , Instead of trading with personal identity information . The anonymity of blockchain means that others cannot know how many blockchain assets you have , Who did the transfer with . such , Only transfer records can be found on the blockchain network , But I don't know who's behind the address , But once you know who the corresponding person behind this address is , You can also find all the relevant transfer records and assets .

4. Open and transparent

The blockchain system is open and transparent , Except that the private information of the parties to the transaction is encrypted , The data is transparent to the nodes of the whole network , That is, anyone or participating nodes can query blockchain data records or develop relevant applications through public interfaces , This is also the basis for the blockchain system to be trusted . Block chain data records and operating rules can be reviewed by the entire network node 、 trace , It has a high degree of transparency .

5. No tampering

Once the information of the blockchain system has been verified and added to the blockchain , You get permanent storage , You cannot change ( Systems such as private blockchain with special change requirements are excluded ). Unless you can simultaneously control the system over 51% The node of , Otherwise, changes to the database on a single node are invalid , Therefore, the data stability and reliability of blockchain are extremely high . The unidirectionality of hash algorithm is one of the basic technologies to ensure the non tamperability of blockchain network .

6. traceability

Its mechanism is to set that the following block has the hash value of the previous block , Like a hook , Only by identifying the previous hash value can it be hung up , So as to form a complete and traceable chain . Another good feature of traceability is to facilitate data query , Because this block is uniquely identified . For example, you need to query a record in the database , There are many algorithms to block to find , In the blockchain, the time node is used to define and find the blocks in the time period before addressing , This is more convenient .

7. Autonomy

The blockchain adopts consensus based specifications and protocols （ For example, an open and transparent algorithm ） So that all nodes in the whole system can exchange data freely and safely in a de trusted environment , Make right “ people ” Instead of trust in machines , Any artificial intervention doesn't work .

Blockchain Shared account book technology realizes the disintermediation of bilateral transactions involving multiple parties in a distributed environment . Share account books and network records , Traceability , Tamper proof is final . So as to ensure safety , Increase of efficiency , cost reduction .

4. Application scenarios

Blockchain There is a distinction between public chain and federal chain . In enterprise commercial applications , The federation chain is a more fitting choice .
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Blockchain （Blockchain） It is a kind of orderly connection of data blocks , And ensure that it cannot be tampered with by means of cryptography 、 An unforgeable distributed ledger （ database ） technology . Popular said , Blockchain technology can realize the openness and transparency of all data information in the system without third-party endorsement 、 No tampering 、 Don't falsify 、 Traceability . As an underlying protocol or technical solution, blockchain can effectively solve the problem of trust , Realize the free transmission of value , In digital currency 、 Transaction settlement of financial assets 、 Digital Government 、 There are broad prospects in the fields of deposit certificate anti-counterfeiting data services .

1. Digital currency

After experiencing physical 、 noble metal 、 After banknotes and other forms , Digital currency has become the development direction of the digital economy era . Compared with real money , Digital currency has easy to carry storage 、 Low circulation cost 、 Easy to use 、 Easy to prevent counterfeiting and manage 、 Breaking regional restrictions , Better integration of resources and other characteristics .

Bitcoin technology realizes that there is no need for third-party transit or arbitration , An e-cash system in which both parties can transfer money directly to each other .2019 year 6 Internet giants in June Facebook Released its cryptocurrency Libra currency （Libra） white paper . Whether it's bitcoin or Libra, The underlying technology it relies on is blockchain technology .

Our country is back in 2014 The development of central bank digital currency began in . China's digital currency DC/EP Adopt a two-tier operation system ： The central bank does not issue digital currency directly to the public , Instead, the central bank cashes the digital currency to various commercial banks or other legal operating institutions , These institutions will exchange it for the public to use .2019 year 8 At the beginning of , The central bank held a videoconference on the work of the second half of the year , The meeting called for accelerating the research and development of national legal digital currency . 　　 2. Financial asset transaction settlement

Blockchain technology naturally has financial attributes , It's revolutionizing the financial industry . Payment and settlement , Under the blockchain distributed ledger system , Multiple market participants jointly maintain and synchronize a copy in real time “ General ledger ”, The payment that can only be completed in two or three days can be completed in just a few minutes 、 Liquidation 、 Settlement task , It reduces the complexity and cost of cross-border transactions . meanwhile , The underlying encryption technology of blockchain ensures that participants cannot tamper with account books , Ensure transparent and secure transactions , Regulators can easily track transactions on the chain , Quickly locate the flow of high-risk funds .

Securities issuance and trading , The traditional stock issuance process is long 、 The high cost 、 It's complicated , Blockchain technology can weaken the role of underwriting institutions , Help all parties to establish a fast and accurate information exchange and sharing channel , The issuer handles the issuance by itself through the smart contract , The supervision department shall uniformly review and check , Investors can also bypass intermediaries for direct operations . Digital bills and supply chain finance , Blockchain technology can effectively solve the financing difficulties of small and medium-sized enterprises . At present, it is difficult for supply chain finance to benefit small and medium-sized enterprises in the upper reaches of the industrial chain , There is often no direct trade with core enterprises , It is difficult for financial institutions to evaluate their credit qualifications . Based on blockchain Technology , You can build an alliance chain network , Covering core enterprises 、 Upstream and downstream suppliers 、 Financial institutions, etc , Core enterprises issue accounts receivable vouchers to their suppliers , After the bill is digitized and linked, it can flow between suppliers , Each level of supplier can realize the corresponding amount of financing with the digital bill .

3. Digital Government

Blockchain can make data run , Greatly streamline the process . The distributed technology of blockchain enables government departments to concentrate on one chain , All processes deliver smart contracts , As long as the clerk passes the identity authentication and electronic signature in one department , Smart contracts can be processed and circulated automatically , Complete all subsequent approvals and signatures in sequence .

Blockchain invoice is the earliest application of blockchain technology in China . The tax department launched blockchain electronic invoice “ Tax chain ” platform , Tax department 、 Billing party 、 The ticket recipient joins through a unique digital identity “ Tax chain ” The Internet , True realization “ A transaction is an invoice ”“ Invoice is reimbursement ”—— Seconds 、 Minute level reimbursement is recorded , Greatly reduce the cost of tax collection and management , Effectively solve data tampering 、 One vote over reporting 、 Tax evasion and tax evasion .

Poverty alleviation is another landing application of blockchain technology . Make use of the openness and transparency of blockchain technology 、 It can be traced back to 、 It can't be tampered with , Realize the transparent use of poverty alleviation funds 、 Precise delivery and efficient management .

4. Deposit certificate anti-counterfeiting

The blockchain can prove the existence of a file or digital content at a specific time through hash timestamp , Coupled with its public 、 No tampering 、 Traceability and other characteristics are judicial authentication 、 Proof of identity 、 Protection of property rights 、 Anti counterfeiting and traceability provide a perfect solution .

In the field of intellectual property , Through the digital signature of blockchain technology and the certificate stored on the chain, the text can be 、 picture 、 Audio and video, etc , Create and execute transactions through smart contracts , Let the creator regain the pricing power , Preserve data in real time and form evidence chain , At the same time, it covers the confirmation of rights 、 Trading and rights protection . In the field of anti-counterfeiting and traceability , Through supply chain tracking, blockchain technology can be widely used in food and medicine 、 agriculture products 、 liquor 、 Luxury goods and other fields .

5. Data services

Blockchain technology will greatly optimize the existing big data applications , It plays a great role in data circulation and sharing . The Internet of the future 、 Artificial intelligence 、 The Internet of things will produce massive data , Existing centralized data storage （ Calculation mode ） Will face great challenges , Edge storage based on blockchain technology （ Calculation ） It is expected to become a future solution .

also , The tamper proof and traceability mechanism of blockchain for data ensures the authenticity and high quality of data , This becomes big data 、 Deep learning 、 Artificial intelligence is the basis of all data applications . Last , Blockchain can realize multi-party collaborative data computing on the premise of protecting data privacy , Hope to solve “ Data monopoly ” and “ data silos ” problem , Realize the value of data circulation .

For the current development stage of blockchain , In order to meet the development and application needs of general business users , Many traditional cloud service providers began to deploy their own BaaS（“ Blockchain as a service ”） Solution . The combination of blockchain and cloud computing will effectively reduce the deployment cost of enterprise blockchain , Promote the implementation of blockchain application scenarios . In the future, blockchain technology will be used in charity 、 insurance 、 energy 、 logistics 、 Internet of things and many other fields play an important role .

 The difficulty and breakthrough of blockchain technology lies in how to apply it innovatively to all walks of life , Serve economic and social development .
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5. Blockchain development language

5.1 Common development languages

Privacy and secrets are important ： Anyone's ID And behavior patterns , stay blockchain The network should not be clarified by unauthorized people through studying the account books . Any business logic and transaction parameters on the network should not be accessed by anyone other than the custodian .

1.JAVA development language （ Future money ）

Definition :Java Is an object-oriented programming language , Not only absorbed c++ Advantages of language , Also abandoned in c++、 The difficulty of multiple inheritance is difficult to understand in concepts such as pointers , therefore Java The language has two powerful and easy-to-use features . As a representative of static object-oriented programming language ,Java Language perfectly realizes the object-oriented theory , Allow programmers to program complex programs in an elegant way of thinking .

Java It's characterized by simplicity 、 object-oriented 、 Distributed 、 robust 、 Security 、 Platform independence and portability 、 Multithreading and dynamic .Java Can write desktop applications 、Web Applications 、 Distributed and embedded system applications .

2.C++ development language （ The currency 、 Just pass 、 Shwebo ripple）

Definition :c++ yes C Inheritance of language , It can be C The process of language programming , It can also be an abstract data type , As a feature of object-based programming , It can also undertake the inheritance and polymorphism of object-oriented programming .c++ Good at object-oriented programming , It can also perform process based programming , therefore c++ It's the size of the problem .

3.GO development language （ The etheric fang 、IBM）

Definition :Go It's a new language , Parallel , garbage collection , Fast compiled languages . It has the following characteristics :

It can compile a large program on the computer Go The program takes a few seconds .Go Provides a software construction model , Make dependency analysis easier , And avoid most c The beginning of style , Including files and Libraries .Go It's a statically typed language , Its type system has no hierarchy . therefore , Users don't need to spend time defining relationships between types , This makes them lighter than typical object-oriented languages .Go Is a complete garbage collection language , Provide basic support for concurrent execution and communication . According to its design , It provides a method for the construction of system software on multi-core machines .

Go It's a compiler language , It combines the flexibility of interpretation language 、 The development efficiency of dynamic type language and the security of static type . It also intends to become a modern language that supports network and multi-core computing . To achieve these goals , Some language problems need to be solved : An expressive but lightweight type system 、 Concurrency and garbage collection mechanisms 、 Strict dependency rules, etc . These cannot be solved by libraries or tools , So create .

4.Solidity development language （ The etheric fang ）

Definition :Solidity Is in Ethereum virtual machine (EVM) High level language for smart contracts running on . Its grammar is close to Javascript, It's an object-oriented language . But when it comes to taking the Internet as a real thing , It's very different .

5.2 Development framework

What framework is used to develop blockchain ？ The goal is to adapt to the needs of different scenarios , Blockchain applications always need to be modified many times in actual use , To meet the needs of a specific business , So the architecture for customizing the private blockchain system appears , Using these frameworks can easily customize the blockchain system suitable for the enterprise's own business needs .

1. Bitcoin architecture

The currency （Bitcoin） As the ancestor of blockchain , In the big family of blockchain, it has the influence of lifting heavy as light . It has the following characteristics ：

Money can be sold without a central authority ; You can pay without an intermediary ; Maintain user anonymity ; The transaction cannot be cancelled .

2. Ethereum Architecture

The etheric fang （Ethereum） Our goal is to provide a blockchain with Turing complete language , In this language, contracts can be created to write arbitrary state transition functions . Users simply use a few lines of code to implement logic , You can create a blockchain based application , And applied to scenarios other than currencies . Ethereum is beyond the function of bitcoin , There are also the following design objectives ：

Turing's complete contract language ; Built in persistent state storage .

3.Fabric framework

Fabric By IBM and DAH Led the development of a blockchain framework , Is one of the project members of super ledger . Its function is similar to Ethereum , It is also a distributed smart contract platform . But unlike Ethereum and bitcoin , It was a framework from the beginning , Not a public chain , There are no built-in tokens （Token）.

As a blockchain framework ,Fabric A loosely coupled design , The consensus mechanism 、 Authentication and other components are modular , So that it can easily select the corresponding module according to the application scenario in the application process . besides ,Fabric Container technology is also used , The smart contract code （Chaincode） Put it in Docker Run in , Thus, the smart contract can be written in almost any high-level language .

Here is Fabric Some design goals of ： Modular design 、 Components are replaceable ; To run on Docker Smart contract ;

4.Onchain DNA framework

Onchain DNA（Onchain Distributed Networks Architecture）, It can support the public chain at the same time 、 League chain 、 Different application types and scenarios such as private chain , And quickly integrate with the business system .

Onchain DNA The key design objectives are as follows ： Underlying support for a variety of digital assets ; Turing's complete smart contract and persistent state ; Cross chain interoperability ; The finality of the transaction .

5.Corda framework

Corda from Java and Kotlin Development , And in its various functions, it fully depends on Java, For example, smart contracts 、 Data access interface, etc .Corda The key design goal of is ： There is no global ledger ; By a notary public （Notaries） To solve the multiple payment problem of transactions ; Only the participants and notaries of the transaction can see the transaction . So Corda All transactions will not be broadcast to the whole network , And all nodes communicate directly , No, P2P The Internet . This leads to the fact that its network scale will be limited to a smaller scale , Cannot form a large-scale alliance chain , The applicable business scenarios are relatively narrow .

The business value of blockchain technology lies in improving process transparency 、 Data credibility 、 Authors efficiency .

6. Reference resources

Blockchain Baidu Encyclopedia baike.baidu.com/item/%E5%8C… What is blockchain ？ Super detailed , After reading it, you can learn without a teacher ！c.biancheng.net/view/1884.h… Five application scenarios of blockchain technology www.qstheory.cn/llwx/2019-1… Seven application scenarios of blockchain blog.csdn.net/u010199413/… Five characteristics of blockchain www.jianshu.com/p/67cf0855f… Six characteristics of blockchain www.jianshu.com/p/2533090b1… Quickly understand bitcoin / The principle of blockchain blog.csdn.net/dog250/arti… Blockchain ： origin 、 Principle and Application blog.csdn.net/jasonwang19… What development language does blockchain technology use www.toutiao.com/a6527824301… What framework is used to develop blockchain ？ www.sohu.com/a/283233206… Blockchain Technology （Blockchain） brief introduction static.runoob.com/download/ib…