区块链程序教程pdf,区块链 程序

区块链是一种分布式数据库，它可以用来存储和管理数据，以及创建和管理虚拟货币。它是一种新型的技术，它可以让用户安全地存储、管理和交易数字资产，而无需任何中介机构。本文将介绍区块链程序教程pdf中的三个关键词：区块链节点、智能合约和去中心化应用程序（dApp）。

区块链节点是区块链网络的基础结构，它是一种可以访问、存储和传输区块链数据的计算机节点。一个区块链网络可以由数百万个节点组成，这些节点负责存储、校验和传输数据，以确保区块链网络的安全性和可靠性。节点可以是个人用户，也可以是企业用户，甚至是政府机构。

智能合约是一种可以在区块链上运行的自动执行程序。它可以让用户在区块链上安全地执行交易，而不需要任何中介机构。智能合约可以用来处理交易、存储数据、发布代币等，并且可以根据特定的条件自动执行。智能合约可以让交易更加安全、可靠和高效，因此它被认为是区块链技术的重要组成部分。

去中心化应用程序（dApp）是一种基于区块链技术的应用程序，它可以在区块链上运行，并且可以让用户安全地存储、管理和交易数字资产。dApp可以让用户实现去中心化交易，而不需要任何中介机构，这可以大大提高交易的安全性和可靠性。dApp还可以让用户创建和发布新的应用程序，以实现更多的功能，例如金融服务、智能合约等。

总之，区块链程序教程pdf中的三个关键词：区块链节点、智能合约和去中心化应用程序（dApp），都是区块链技术的重要组成部分，它们可以让用户安全地存储、管理和交易数字资产，而无需任何中介机构。未来，区块链技术将在更多领域得到广泛应用，发挥着越来越重要的作用。

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㈠ How enterprises can build their own blockchain

Hello, thank you for the invitation!

How can enterprises build their own blockchain?

With the popularity of various currency transactions, the development of the exchange industry has been driven. So as a novice who wants to cross industries, how to establish a blockchain exchange development company? Chainsoft Network summarizes the following points for you.

Please click to enter the picture description

1. Determine the operating scope of the exchange development company

Determine the company's The scope of operations is very important, as it determines whether the company has the potential to be profitable. Relevant laws and regulations vary from region to region every day, so the first step is to understand the local laws and regulations, and obtain the necessary licenses and approvals to open a Bitcoin exchange according to your scope of operations, to avoid violating local laws and regulations, and bring To cause unnecessary trouble.

2. Check the country’s regulations and compliance requirements

Almost all governments require entities involved in currency exchange businesses to comply with Know Your Customer (KYC) norms. KYC is the process by which businesses verify the identities of their customers through government-issued ID cards or passports. The main purpose here is to prevent money laundering. Make sure to comply with your country’s KYC norms and integrate suitable customer verification procedures in your exchange.

3. Work with a bank or payment processor

You need to work with a bank or payment provider to process payments via fiat currency. You can choose a trustworthy bank with extensive online facilities.

4. Create liquidity on your exchange

Any exchange needs liquidity to operate successfully. Customers are hesitant to place an order or even deposit funds unless they see complete order and trading activity. New trading naturally encounters liquidity issues.

5. Ensure high-level security of trading and customer data

Any exchange development company needs top-notch security to ensure exchange operators and traders’ funds are maintained Safety. This should also apply to your customers’ private data, including their KYC details and bank account information. The Gox breach, a security flaw that went unnoticed for years, resulted in the theft of nearly 1% of all Bitcoins in circulation at the time. According to Chainsoft Network, one-third of all Bitcoin exchanges were hacked between 2009 and 2019. Therefore security must be your top priority in trading.

6. Establish customer support channels

Finally, customer support is another important component of a successful exchange. Staff are needed to approve KYC requests, answer customer complaints, process deposits and withdraw fiat currency, etc. A fast customer support mechanism ensures that your customers start trading from the day they sign up and generate revenue for your exchange.

I hope this helps you solve related problems. For more details, please feel free to consult and discuss!

㈡ How to quickly get started with blockchain

Currently, there are not many videos on the market for systematically learning blockchain, and it is still relatively rare to learn blockchain by yourself. You can sign up for a class. Dark Horse Programmers has newly opened a blockchain course. The teacher uses easy-to-understand teaching methods and explains the technology in simple and easy-to-understand terms. You can definitely learn it. Source: AreaTV. If you want to understand blockchain and watch video tutorials, come here!

㈢ What are the tutorials on blockchain technology?

The current underlying technology platforms of blockchain include Bitcoin blockchain, Ethereum, Hyperledger, Corda, and Chain wait. Dark Horse Programmer is going to open a related course in Shenzhen. I heard that this course has been developed for more than two years and is very valuable

㈣ Tutorial for 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 of all, the main function of 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 the administrator, everyone can write data into it. How can we ensure that the data is trustworthy? What should I do if it is modified by bad people? 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 blockThey are all connected to the previous block, which is also the origin of the name blockchain.
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, and 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? It becomes very difficult, why can’t it be calculated?
It turns out that not just any hash can be used, 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, and 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.This allows the hash of the block header to 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 It 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 consumingof.
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.

㈤ Tutorial for beginners in blockchain wool, a must-read tutorial for beginners in the currency circle

Explanation of terms:

Blockchain token

A new business model created based on blockchain technology, and token is the token of each project. We collectively call it "token" token as the project progresses

and implementation Application circulation generates value (this value depends on everyone’s consensus)

The blockchain is a bit like a huge, global and decentralized accounting book.

It is used to record how much currency one person sends to another person, and to track the balances of all accounts.

It is operated by thousands of people around the world who have special computers (we also call them miners ) for recording and maintenance.

Blocks in the blockchain are composed of many transaction records. These transactions are similar from wallets such as Imtoken, MetaMask, Exos, Mist, Geth, Parity, etc. The operation interface is sent out

2. Airdrop

Each project will airdrop a certain proportion of tokens as a benefit for the start of community construction, in order to allow more future users to participate , so airdrop is the most important part of the commercial application of blockchain (you can understand it as the previous Internet projects allowed everyone to take taxis, eat, etc. for free)

3. Wallet

Wallet Divided into 'light wallet', 'hardware wallet', 'Bitcoin wallet', 'Ethereum wallet', cold wallet, etc.

Blockchain technology solves different industry pain points in different fields, so the value generated is also great. Different

For example: Bitcoin has solved the problem of trust, so now its value is 50,000 yuan each

Ethereum has solved the problem of smart contracts, so it Now each one costs 4,000

Ripple solves the problem of cross-border payment, so it currently ranks third in market value

4. Pain points solved by the wallet

Traditional banks

When you register an account at a bank or exchange, these institutions will create a new account for you in their internal systems. The bank will closely track your personal information, record your account password, balance, transaction records and Have complete control over your funds. The bank will charge account management and service fees while providing you with services, such as helping you recover stolen credit card purchases. The bank allows you to use prepaid consumption methods such as checks or debit cards, and Check your balance online, reset your password, and replace your lost debit card. When you use a bank or exchange account to trade, the transaction amount and transfer address may be restricted by these institutions, and There is also an audit process. These restrictions will also charge you additional handling fees.

Virtual Currency Wallet

When you create an account in any wallet, the actual The above just generates a pair of digital strings with cryptographic meaning: the private key and the public key (address) of your account. The entire process of generating these keys occurs in the browser of your local computer or within your mobile phone. The wallet file is absolutely Your private key, password and any account information will not be forwarded, received or saved. There will be absolutely no handling fees charged for the wallet file. Simply put, you are just using this operation interface to interact directly with the blockchain network. If you Provide your public key (address) to others, and the other party will be able to send you tokens. If you provide your private key to others, then the other party will have complete control of your account and funds.

5 .Wallet Security

Please actively pay attention to the security of your account private key and password. Your private key may sometimes be stored in a mnemonic phrase, keystore file, UTC file, JSON file, or wallet. Files and other forms. Please remember that if you accidentally lose your private key or password, no one can recover them. If you enter your private key on a phishing website, they will steal all your funds. Do not trust or click on web links you see in email, Slack, Reddit, Twitter, etc. Make a good habit of manually entering the address to open the website, and do not open the website through links in emails or other channels. Send your private key Make backup copies of your private keys or passwords. It is best not to save them on your computer, handwrite or print them on paper. Save the backup of your private keys or passwords separately in a secure offline environment, if they are kept together with your computer. A fire or flood can easily destroy them all. Never store private keys in online network disks, photo albums with cloud synchronization and other online environments. If you really value your digital currency, then you should buy it A hardware wallet, the value of your assetsMore professional equipment must be used to protect it.

Please pay attention to subsequent updates and follow the blockchain currency circle (www.qkl808.com) which will lead you on the road to financial freedom

< p>㈥ How to build a blockchain website

Websites are no longer mysterious and no longer a high-tech activity. Ordinary users can also easily build relatively professional websites. Let me briefly introduce to you some procedures and precautions for building a personal website.
1. Domain Name
If you want people to visit your website, a domain name is essential. The domain name should be as short as possible and as easy to remember as possible, such as the .top domain name. Of course, there are not many domain names that are easy to remember and have characteristics. You need to consider this yourself, as long as you feel that there is a certain pattern or it is easy for users to remember. That’s it.
2. Space
To build a website, you must have a space, which is a place to store the website. For individual users, it is recommended to purchase a virtual host. When purchasing a web host, look at its service, speed, response time, etc. Generally, you can choose a service provider with a certain reputation.
Note: Domain name and space are currently good choices for domestic service providers such as Alibaba Cloud, Western Digital, and China Data.
3. Website program
Of course, the website program should be ready-made, because individuals do not need to compile a website program from scratch, and they do not have the ability. Nowadays, there are ready-made website management systems on the Internet. There are many such systems. You can choose based on your own comprehensive trial.
When choosing a website program, its versatility and secondary development must also be taken into consideration. For those that are not very versatile and are not conducive to the second phase of development, although they are powerful, they are not recommended because it will be very troublesome when the website needs to be designed with personalized functions after it reaches a certain scale. In addition, try to choose asp (asp.net) for programs. PHP, JSP, etc. are not particularly popular in China. Try to choose asp.net between asp and asp.net. After all, it is based on the .net architecture and is the development trend.
4. Website Design
After selecting the website program, you need to design the website according to your own needs. Generally speaking, it is best if there are professional artists and programmers to make modifications. However, individual webmasters may not necessarily have this condition and can choose intelligent website building from service providers.

㈦ How to issue coins on Binance Chain

1. Enter the blockchain browser: https://bscscan.com/
2. Enter the contract address and search Target Contract
Both Code and Read Contract under this tab page do not need to be connected to the wallet, only Write Contract needs to be connected to the wallet.
3. Option Write Contract tab, connect to metamask wallet
Metamask wallet connectionAfter successful connection:
After clicking the Write button, the metamask wallet will pop up, prompting that BNB needs to be consumed. Just authorize and confirm the consumption of BNB.
After the execution is completed, the execution results can be queried on the blockchain browser.
After the currency issuance is completed, the contract must be open sourced and the contract code must be verified to completely match the ABI and bytecode. Therefore, you need to upload token-related information to the BSC blockchain browser, including: contract name, compiler version, license, constructor parameters, etc.
The following are the operation steps of the open source contract code:
1. After the currency issuance is completed, record the transaction hash of the contract:
Query the hash details on the BSC blockchain browser:
The contract address of the code is:
2. View the contract details on the BSC blockchain browser
Enter the contract details page and select the contract TAB
3. Click "Verify and Publish" to upload Coin information to the BSC blockchain browser
4. Select the relevant information when creating the contract and fill in the following form
I. The contract address is automatically brought out
II. Compiler type selection: If the contract code is composed of multiple files, choose: Solidity (Multi-Part files). If it is a single-file contract, choose: Solidity (Single file)
III. Compiler version: According to the contract code The compiler version is determined and must be consistent with the version when the contract code is compiled. The compiled version of this example contract is: pragma solidity ^0.6.12, so select V0.6.12+commit.27d51765
IIIV, license authorization type: The contract code is MIT authorization, just select MIT here. This place can actually take your pick.
5. After the above information is configured, upload the contract code file
Select all the files that make up the contract code and click "Click to Upload selected files"
Click "Click to Upload selected files" to upload the contract The code file is uploaded to the blockchain browser. The screenshot after uploading is as follows:
6. Continue to select the subsequent configuration information to complete the open source of the contract code
The parameters passed in the constructor are entered during contract deployment. Confirm that there are no Just ask a question.
This example does not call the contract class library, so the contract class library address does not need to be filled in.

What are the introductory books on blockchain?

"New Economic Blueprint and Introduction"

Published: 2016

Recommendation: This book is mainly for programmers. Combined with API programming, it tells you the principles and usage of cryptocurrency, and how to develop related software. For non-programmer readers, the first few chapters of this book are still applicable as an in-depth introduction to Bitcoin. (Book pdf download: https://quant.la/Download)

㈨ Please download the full text of "C# Blockchain Programming" for free from Baidu Netdisk resources, thank you~

"C# Download the latest complete collection of "Blockchain Programming" pdf on network disk:

Link: https://pan..com/s/1GndqzGQBBjI2jcwAF9umVQ

?pwd=78hr Extraction code: 78hr< /p>

Introduction: This is a tutorial book on blockchain programming. The author has been in the industry for 15 years, so he wrote this tutorial based on C#.