Introduction to blockchain 3
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.
At the beginning of self-learning blockchain related knowledge, we can adopt the "bottom-up" method, that is, through reading books, reading white papers , we can check the information , and then summarize and connect these knowledge , and integrate them into a relatively complete knowledge system so I went to the bookstore and bought a of the Analects of Confucius. I read it from the beginning to the end and found that there were too many details and insights in it, which could not be transmitted through any interpretation. Actually, I spent a lot of time and read a lot of interpretation before. I really want to abandon the essence and pursue the end. I have to work hard it's the same in every field. When you don't understand it, you will have a kind of inexplicable fear of it, thinking that it is high and unattainable. In order to step into these fields quickly, you will look for a lot of so-called "interpretation" and "news" around it 2. technical perspective Basic Stage: 1. Blockchain Development Guide - author Shentu Qingchun: the author's research on the bottom layer of rendant bitcoin is very in-depth, and the explanation is very easy to understand 2. Blockchain technology guide - author Zou Jun: as the first domestic book to explain blockchain from a technical perspective, it is worth reading. Since its publication in 2016, it has been consistently evaluated well 3. Principles, design and application of blockchain by Yang Baohua and Chen Chang: as the CTO of Zhigui, Chen Chang remembers that the previous ink chain was based on hyperledger fabric, so this book has a thorough explanation of hyperledger related open source procts 3. Blockchain world is divided into two parts. The first part comprehensively reviews the birth, growth and graal development of blockchain in 2008 through full and accurate information, introces in detail the originality of blockchain technology, the scientific mechanism and the artistic logic, and introces the application characteristics of blockchain through more than ten instry scenarios such as finance, anti-counterfeiting and medical treatment. In the second part, combined with the spirit of G20 summit and the 13th five year plan, the author explores the combination of blockchain and digital economy, as well as the author's views and suggestions on the development trend of the instry
1. Blockchain links
as the name suggests, blockchain is a chain composed of blocks. Each block is divided into block head and block body (including transaction data). The block head includes the prevhash value (also known as hash value) of the previous block used to realize the block link and the random number (nonce) used to calculate the mining difficulty. The hash value of the previous block is actually the hash value of the head of the previous block, and the random number calculation rule determines which miner can obtain the right to record the block
2. Consensus mechanism
blockchain is accompanied by the birth of bitcoin, which is the basic technology architecture of bitcoin. Blockchain can be understood as an Internet-based decentralized accounting system. A decentralized digital currency system like bitcoin requires the consistency of accounting of honest nodes without a central node, which needs blockchain to complete. Therefore, the core of blockchain technology is a consensus mechanism to reach a consensus on the legitimacy of transactions between indivials without mutual trust without central control
there are four main types of consensus mechanisms in blockchain: pow, POS, dpos and distributed consistency algorithm
3. Unlocking script
script is an important technology to realize automatic verification and contract execution on blockchain. Every output of every transaction does not point to an address in the strict sense, but to a script. A script is like a set of rules that constrain how the receiver can spend the asset locked on the output
the validation of transactions also depends on scripts. At present, it depends on two kinds of scripts: Lock script and unlock script. Locking script is a condition added to the output transaction, which is realized by a script language and located in the output of the transaction. The unlocking script corresponds to the locking script. Only when the conditions required by the locking script are met can the assets corresponding to the script be spent, which is located in the input of the transaction. Many flexible conditions can be expressed by script language. Interpretation script is similar to the "virtual machine" in our programming field, which runs in every node of the blockchain network in a distributed way
4. Transaction rules
blockchain transaction is not only the basic unit of a block, but also the actual effective content recorded by the blockchain. A blockchain transaction can be a transfer, or the deployment of smart contracts and other transactions
as far as bitcoin is concerned, a transaction refers to a single payment transfer. The transaction rules are as follows:
1) the input and output of the transaction cannot be empty
2) for each input of a transaction, if its corresponding utxo output can be found in the current transaction pool, the transaction will be rejected. Because the current transaction pool is the transaction not recorded in the blockchain, and each input of the transaction should come from the confirmed utxo. If it is found in the current trading pool, it is Shuanghua trading
3) for each input in a transaction, the corresponding output must be utxo
4) each input unlocking script must verify the compliance of the transaction together with the corresponding output locking script
5. Transaction priority
the priority of blockchain transaction is determined by the blockchain protocol rules. For bitcoin, the priority of a transaction to be included in a block is determined by the time when the transaction is broadcast to the network and the amount of the transaction. With the increase of transaction broadcast time on the network and the increase of transaction chain age, the priority of transaction will be improved and eventually be included by the block. For Ethereum, the priority of the transaction is also related to the transaction fee that the publisher is willing to pay. The higher the transaction fee that the publisher is willing to pay, the higher the priority that the transaction is included in the block
6. Merkle proof
the original application of Merkle proof is bitcoin, which was described and created by Satoshi Nakamoto in 2009. Bitcoin blockchain uses Merkle proof to store transactions in each block. So that the transaction can not be tampered with, but also easy to verify whether the transaction is included in a specific block
7. RLP
RLP (recursive length prefix) is one of the main encoding methods of object serialization in Ethereum. Its purpose is to encode the sequence of arbitrary nested binary data.
blockchain technology has the following four ways to make money:
1. Hardware and infrastructure. A typical one is mining machinery proction and distribution chain, where you can make money by buying mining machinery and digging
2. The underlying platform of blockchain and common technologies, such as Ethereum and other public chains, and the privacy protocol nucypher, where you can make money by investing in its token, building applications on the chain, and providing services for users
3. Various vertical applications, such as supply chain traceability and Finance Based on blockchain, right confirmation and trading, can be used or invested to make money
Service facilities, such as digital asset exchange and wallet, media procts, etc., you can make money by making your own exchange
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type of blockchain
1. Public blockchain
refers to: any indivial or group in the world can send transactions, and the transactions can be effectively confirmed by the blockchain, Anyone can participate in its consensus process
public blockchain is the earliest and the most widely used blockchain. The virtual digital currencies of bitcoin series are all based on public blockchain, and there is only one corresponding blockchain in the world
2. Consortium block chains: multiple preselected nodes are designated as bookkeepers within a group, and the generation of each block is jointly determined by all preselected nodes (preselected nodes participate in the consensus process), and other access nodes can participate in the transaction
3. Private blockchain
private blockchain: it only uses the general ledger technology of blockchain for bookkeeping. It can be a company or an indivial, and only enjoys the write permission of the blockchain. This chain is not very different from other distributed storage schemes
the top and easiest thing to do is the application layer. I can see two or three such projects every day, accounting for more than 95% of the whole market. But such companies often write a lot of technical things in the white paper. In fact, they also write in vain. This is purely for the purpose of collecting pages, because they don't need to talk about technology at all
the second type is the intermediate operation level, such as quantum chain and ant. This kind of project is similar to the operation procere, called the basic chain, which is used to run the application. This category is relatively small, and the proportion has dropped to less than 5%
the third category is more downward extension and lower level, such as standard chain and arcblock. This kind is even less. It's good to see two or three in a month. And some of them are not necessarily true, because there is really nothing to write about, and all fields are occupied by others, so someone will go in this direction.
At present, there are not many videos on the market for systematic learning of blockchain, and self-learning of blockchain is still relatively rare. You can apply for classes. Black horse programmers will open a new blockchain discipline. Teachers will teach in an easy-to-understand way and explain in simple terms. You can certainly learn it. Source area video network, want to understand the blockchain, watch video tutorial here
blockchain is a decentralized distributed ledger database . The advantage of this distributed ledger is that buyers and sellers can trade directly without any intermediary. Everyone has a backup, even if you lose this, it will not be affected
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blockchain application field
1, financial field
blockchain has potential huge application value in international exchange, letter of credit, equity registration, stock exchange and other financial fields. The application of blockchain technology in the financial instry can save the third-party intermediary link and realize the point-to-point direct docking, so as to greatly rece the cost and quickly complete the transaction payment
2. The Internet of things and logistics
blockchain can also be naturally combined in the field of Internet of things and logistics. Through blockchain, we can rece logistics costs, trace the proction and delivery process of goods, and improve the efficiency of supply chain management. This field is considered as a promising application direction of blockchain
3. The data stored on the public welfare field
blockchain is highly reliable and tamperable, which is naturally suitable for social public welfare scenarios. The relevant information in the public welfare process, such as donation project, collection details, fund flow, recipient feedback, etc., can be stored on the blockchain, and can be made transparent and public, which is convenient for social supervision
4. In the field of insurance
in terms of insurance claims, insurance institutions are responsible for fund collection, investment and claims settlement, and often have higher management and operation costs. Through the application of smart contract, there is no need for the applicant to apply or the insurance company to approve. As long as the claim conditions are triggered, the automatic claim settlement of the policy can be realized
in a narrow sense, blockchain is a kind of chain data structure that combines data blocks in chronological order in a sequential way, and it can not be tampered with and forged by cryptography. In a broad sense, blockchain technology is a new distributed infrastructure and computing paradigm, which uses blockchain data structure to verify and store data, uses distributed node consensus algorithm to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses intelligent contract composed of automated script code to program and operate data
both eurocrowdfunding and Ethereum use blockchain technology.