33 blockchain

1.

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

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

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

< H2 > [popular explanation]

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

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

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

< H2 > [elements]

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

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

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

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

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

< H2 > [Characteristics]

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

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

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

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

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

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

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

2. In my opinion, wangchain technology is OK. They were established in early 2016. The instry includes more than ten instries including finance, energy, agriculture, medical care, ecation, etc., with a total of hundreds of customers. Their ability to get the recognition of so many customers also shows their ability.

3. Blockchain is a technology, but it is not a single technology, but the result of the integration of a variety of technologies, including cryptography, mathematics, economics, network science and so on. You can think of it as a distributed shared accounting technology, or as a database, but the database is jointly maintained by all nodes in the chain, and each node has an account book. Because the account books of all nodes are consistent, different nodes can trust each other, and there is no doubt about the data, so we all say that the blockchain has realized trust technically. For detailed professional technology, you can consult some professional technology companies, such as Jinbo technology, which focuses on the development of blockchain related procts, professional R & D team and perfect after-sales service, and you can consult by telephone.

4.

-- for the above data sources and analysis, please refer to analysis report on market outlook and investment strategic planning of China's blockchain instry of foresight Instry Research Institute

the research process of instry technology is constantly advancing

in recent years, the research process of global blockchain technology has accelerated, and the number of instry patent applications has increased rapidly. According to sopat statistics, from 2014 to 2018, the number of global blockchain patents continued to rise, and by 2018, the number of global blockchain patent applications had reached 2966. Among them, the number of patents in China's blockchain in 2018 accounted for 33.33% of the total number of patents in 2014, and increased to 82.1% in 2018

however, despite the continuous development and innovation of global blockchain technology in recent years, there is no universal evaluation standard and system to specify the technical performance, efficiency, scalability, security and other issues of blockchain. On the whole, blockchain technology needs further breakthrough

China's blockchain technology tends to serve applications

in terms of technology, the core of China's blockchain technology is to serve physical applications, while the US blockchain technology is still solving the potential problems of blockchain, which leads to the domestic focus on alliance chain applications, We hope to optimize the blockchain technology to meet the requirements of high concurrency applications; Foreign countries focus on the application of public chain, and carry out the optimization and innovation of core technology according to the characteristics of public chain. In terms of application, domestic blockchain focuses on the application of service instry and tends to be "non currency blockchain"; Most of the U.S. is a public chain, which tends to the circulation of digital assets

5. Blockchain is a decentralized distributed ledger system, which can be used to register and issue digital assets, property rights certificates, points, etc., and transfer, pay and trade in a point-to-point manner. Compared with the traditional centralized ledger system, blockchain system has the advantages of complete disclosure, tamper proof, multiple payment prevention, and does not rely on any trusted third party
e to the high network delay in peer-to-peer network, the transaction order observed by each node can not be completely consistent. Therefore, the blockchain system needs to design a mechanism to reach a consensus on the sequence of transactions that occur in the same time. This algorithm to reach consensus on the order of transactions in a time window is called consensus mechanism
-- chainknow

6. This is determined by your programming level. At present, the level of domestic programmers is basically a pyramid structure, and most of them are middle-level programmers. From this point of view, it is basically impossible for most people to learn functional programming. One of the most important reasons for choosing go is that a middle-level programmer can write very good go code. The main reason is that go language is very simple, features are very few, and the official class library is very rich. Most programmers can easily start to develop it. Chain33 blockchain developer platform, a well-known domestic open source project, is completely completed by go. There are many mature blockchain technologies in China, such as micro three cloud, etc., which will not be repeated here.

7. In order not to let you control the sovereignty, if you hold two companies, what you say is in charge, if you say it is expensive, if you say it is cheap, it is cheap

8. At present, it is in the early stage, and the application of blockchain technology is still vigorously supported by policies. The SMIC blockchain service platform launched by Changsha high tech Zone also solicits enterprises to go on the chain, which is a blockchain + public service mode.

9. In a simple explanation, 51% attack is also called majority attack. It means that malicious miners control more than 50% of the hash rate of the blockchain network, and then attack the network and take over the blockchain network, so that criminals can reverse transactions, stop payment or prevent new transactions from being confirmed
for more information about 51% attacks, you can learn about them on the password finance network,