Blockchain is represented by graph
MACD is called the moving average of similarities and differences, which is developed from the double index moving average. The fast line dif is obtained by subtracting the slow index moving average (ema26) from the fast index moving average (ema12), and then 2 × Fast line dif-dif's 9-day weighted moving average (DEA) obtained MACD column. The significance of MACD is basically the same as that of double moving average, that is, the dispersion and aggregation of fast and slow moving average represent the current long short state and the possible development trend of stock price, but it is more convenient to read. When MACD turns from negative to positive, it's a buy signal. When MACD turns from positive to negative, it's a sell signal. When MACD changes from a large angle, it means that the gap between the fast moving average and the slow moving average widens very quickly, which represents the change of a market trend.
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)
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 robustnesstrustworthiness: 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
Blockchain is a term in the field of information technology. In essence, it is a shared database. The data or information stored in it is characterized by "unforgeability", "trace in the whole process", "traceability", "openness and transparency" and "collective maintenance". Based on these characteristics, blockchain technology has laid a solid "trust" foundation, created a reliable "cooperation" mechanism, and has broad application prospects
on January 10, 2019, the state Internet Information Office issued the regulations on the management of blockchain information services. In October 24, 2019, ring the eighteenth collective learning of the Central Political Bureau, general secretary Xi Jinping stressed that "block chain as an important breakthrough in core technology and independent innovation", "accelerating the development of block chain technology and instrial innovation". "Blockchain" has entered the public field of vision and become the focus of social attention
extended data:
related extension: blockchain financial application:
since 2016, the major financial giants have also carried out blockchain innovation projects to explore the possibility of applying blockchain technology in various financial scenarios. In particular, Puyin group took the lead in creating a "blockchain +" standard digital currency
standard digital currency refers to the process of assets identification, evaluation, right confirmation and insurance completed by a third party organization, which is written into the blockchain through careful digital algorithm to form the standard corresponding relationship between assets and digital currency, which is called standard digital currency
in order to realize the great leap forward development of blockchain finance, promote the new development of China's economy, accelerate the circulation of global assets, and realize the dream of rejuvenation that has been struggling for generations, Puyin group will hold the Guiyang strategic development ceremony of Puyin blockchain finance in Guizhou on December 9, 2016
the meeting will discuss the realization of digital circulation of assets by blockchain, the financial transaction mode of blockchain, and the application of blockchain services and social public instry. This conference will mark the beginning of the application of blockchain finance and the change and development of the new financial ecology
on June 1, 2020, Xinhua news agency was authorized to broadcast the "overall plan for the construction of Hainan free trade port" issued by the CPC Central Committee and the State Council, which will "actively participate in the formulation of international rules for cross-border data flow, and establish standards and rules for data rights confirmation, data trading, data security and blockchain finance" as one of the key tasks of Hainan free trade port before 2035
From the perspective of technology and architecture, I will tell you my understanding of blockchain in common language
what is blockchain? In a word, blockchain is a storage system. To be more specific, blockchain is a distributed storage system without an administrator and each node has all the data
What are the common storage systems like
as shown in the figure above, the bottom is data, and the top can write data. A space to store data, a software to manage data, provide an interface to write data, this is the storage system. For example, MySQL is the most common storage system
What are the problems of ordinary storage system? There are at least two common problems
the first is the problem of non high availability. There is a dangerous place for data. In technical terms, data is not highly available
The second problem is that there is only one write point. In technical terms, it is a single point of control
How do ordinary storage systems usually solve these two problems
in fact, MySQL can do a master-slave synchronization of al master, master-slave synchronization of al master, two nodes can be written at the same time. If you want to do a multi room multi live data center, in fact, multi room multi live data synchronization. What we should emphasize here is that multi-point writing often leads to the consistency problem of writing conflicts. Take MySQL as an example, suppose that the attribute of a table is self incrementing ID, then the data in the database is 1234 now. If one of the nodes writes and inserts a piece of data, it may become 5, and then these 5 pieces of data are synchronized to another master node, Before synchronization, if another write node inserts a piece of data, a piece of data with self incrementing ID of 5 will be generated. Then, after the generation, synchronize to another node, and the synchronized data will conflict with the two local 5's after it arrives, which will lead to synchronization failure and write consistency conflict. This problem will occur in the case of multi-point writing
how to ensure consistency in multi-point writing
the reform "Swan class" gives you more technical work
it is not a digital currency. If it is a digital currency, it is not very reliable. Now more than 80% of the newly born digital currencies are pyramid schemes. In fact, there is no practical value. These coins can not be compared with the old bitcoin, Ruitai coin and Laite coin.
Characteristics of blockchain
one of the four characteristics of blockchain: tamper proof
the most easily understood characteristic of blockchain is tamper proof
tamper proof is based on the unique account book of "block + Chain": the blocks with transactions are added to the end of the chain in time order. To modify the data in a block, you need to regenerate all blocks after it
one of the important roles of consensus mechanism is to make it almost impossible to modify a large number of blocks at high cost. Take the blockchain network (such as bitcoin and Ethereum) with workload proof as an example, only with 51% of computing power can all blocks be regenerated to tamper with data. However, the destruction of data is not in line with the self-interest of players with large computing power. This practical design enhances the reliability of data on the blockchain
generally, the transaction data in the blockchain ledger can not be "modified", it can only be "modified" through the new transactions that are approved. The process of correction will leave traces, which is why the blockchain can not be tampered with. Tampering refers to changing or misinterpreting by means of forgery
in today's common files and relational data, unless a special design is adopted, the system itself does not record modification traces. Blockchain ledger adopts a design different from that of files and databases. It draws on the design of ledger in reality, that is, to retain the traces of records. Therefore, we can not "modify" the account book without leaving traces, but can only "modify" the account book (see Figure 2)
Figure 6: bitcoin is centralized in the organization and logically centralized
when we imagine the future organization, the ideal prototype in our mind is often bitcoin organization: completely decentralized autonomous organization. But in practice, for the sake of efficiency and advancement, we will move closer to the centralized organization and finally find a suitable balance point
nowadays, in the blockchain projects that are created and issued through the smart contract of Ethereum and run in a community or ecological way, the ideal state of many projects is similar to the bitcoin organization, but the actual situation is between the completely decentralized organization and the traditional company
when we discuss the fourth feature of blockchain, which is decentralized self-organization, we are actually going out of the code world, involving human organization and collaboration. Now, various discussions and practical explorations have also revealed the significance of blockchain beyond technology: it may serve as an infrastructure to support human proction organization and collaborative change. This is another example of the complete isomorphism between blockchain and Internet. Internet is not only a technology, it has changed people's organization and collaboration
in general, Ethereum has brought blockchain into a new stage. When discussing Ethereum, if we want to summarize two key words, they are smart contract and token; If I can only say one, I will choose "Tong Zheng". I would rather look for its meaning from the history of the Internet and repeat the previous analogy: as a token of value, its role is similar to HTML. With HTML, what kind of website to build depends entirely on our imagination