ava区块链数字货币交易所平台源码,区块链网址导航

区块链技术是近年来最受欢迎的技术之一，它是一种分布式数据库技术，可以用来存储和分发数字货币、数据和任何其他数字资产。它的基础是一个共享的、可信任的、可验证的数据库，可以让用户在不需要中介的情况下安全地进行交易。

数字货币交易所平台是基于区块链技术开发的一种虚拟货币交易平台，它可以让用户以数字货币的形式进行购买和出售，以及进行投资和投机。数字货币交易所平台的优势在于它可以让用户在不需要第三方的情况下进行安全的交易操作，而且可以提供实时的价格报价，以及可以跨越国家和地区的交易服务。

区块链网址导航是一种基于区块链技术开发的网络服务，它可以帮助用户更快速地找到自己需要的信息。区块链网址导航可以提供用户丰富的信息资源，如区块链行业新闻、行情分析、投资指导等，以及可以让用户进行安全的数字货币交易的交易所平台等。此外，它还可以提供一些与区块链技术有关的技术文章、教程和讨论等内容，让用户可以更好地了解区块链技术。

数字货币投资是指投资者以数字货币的形式进行投资的活动，它是一种非常有前景的投资方式，因为数字货币市场的价格波动性较大，可以给投资者带来更高的收益。投资者可以通过数字货币交易所平台进行投资，也可以通过区块链网址导航寻找更多的投资机会，以获得更多的收益。除此之外，投资者还可以通过学习和了解区块链技术来提升自己的投资技能，以获得更多的投资收益。

请查看相关英文文档

❶ Blockchain --- Distributed Finance (DeFi)

DeFi is the abbreviation of decentralized finance, usually referring to Ethereum-based Digital assets and financial smart contracts, protocols, and distributed applications (DApps).

Simply put, DeFi is to move traditional finance to the blockchain network, but compared with traditional finance, it achieves decentralization through the blockchain, which means removing the role of the middleman, thus Reduces the huge costs caused by intermediate links.

What DeFi ultimately wants to achieve is the tokenization of assets, replacing traditional centralized financial institutions with smart contract functionality, allowing users to enjoy financial services at a lower cost, and improving the operation of the entire financial system. efficiency and reduce operating costs. At the same time, we will create a borderless financial system that is open to the world to create a new decentralized system that is open, transparent, and secure, so that everyone can trade freely.

With the rapid development of blockchain, DeFi application scenarios are constantly enriched, and the financial industry is one of the most promising industries.

Similar to a bank, users can deposit money and earn interest from other users who borrow their assets. However, in this case, the assets are digital and smart contracts connect lenders to borrowers, enforcing the terms of the loan and distributing interest. This all happens without trusting each other or a middleman bank. And, thanks to the transparency provided by blockchain, by cutting out middlemen, lenders can earn higher returns and gain a clearer understanding of risks.

Decentralized exchange, referred to as DEX, DEX is a cryptocurrency exchange that uses smart contracts to implement trading rules, execute transactions and securely handle funds when necessary. When trading with a DEX, there is no centralized exchange operator, no registration required, and no identity verification or withdrawal fees.

DEX can use the order book for transactions. For example, if you want to exchange 10 A for 15 B, then I will write it down. Then a while later another person came and said I wanted to exchange 15 B's for 10 A's. I said great, it was a perfect match. So, I generated a transaction on the chain to exchange your coins. At this time, the exchange rate is actually used as a reference for both parties to the transaction - it is recommended that you use this exchange rate to easily find a match. In this way, go to ChinaXinhua Exchange only matches the needs of both parties to the transaction and puts it on the chain. There is no problem of smart contracts reading off-chain exchange rate information.

This method has many flaws. No matter how user-friendly this DEX is, its efficiency must be very poor compared to centralized exchanges. First of all, it is difficult to find a match when currency prices fluctuate. Secondly, it is definitely difficult to find a match for small currencies. Then there should be no transaction delays. Small. But compared to central exchanges, it still has the only advantage-reliability.

DEX can also use AMM (automatic market maker) transactions, which calculate the exchange rate according to its own supply and demand relationship to ensure that the coins in your hand will not be shorted by others at a low price. The simplest way is to always ensure that the number of your A coins and B coins is a fixed value. In this way, even if you sell short, the loss will be limited, and the market will always adjust the price to an appropriate level - because anyway, if the exchange rate is low If the exchange rate is high, some people will buy it, and if the exchange rate is high, some people will sell it.

Through this simple method, a market can be obtained that can automatically adjust according to supply and demand without obtaining exchange rate information from outside the chain. Of course, the weakness of this thing is also obvious - if the initial exchange rate is not close to the market exchange rate, you will suffer a lot of losses. Moreover, there are “gratuitous losses” in AMM.

Stablecoins are tokens designed to maintain a specific value, often pegged to fiat currencies such as the U.S. dollar.

For example, DAI is a stablecoin pegged to the U.S. dollar and collateralized by digital assets on the Ethereum (ETH) chain. Its issuance is realized through a lending smart contract: everyone can mortgage a certain amount of ETH (Ethereum) in exchange for DAI anchored 1:1 with the US dollar. Here, DAI takes the form of over-collateralization. For each DAI, $1.50 of Ethereum is locked in the MakerDAO smart contract as collateral.

If you pledge Ether worth $150, you can only get $100 worth of DAI. Then, it is written in this smart contract that if you return the $100 DAI within a certain period of time and pay part of the interest, then you can get back your mortgaged Ethereum.

But there is a problem here - the price of Ethereum will change. Moreover, the price changes of virtual currencies are quite drastic. What if Ethereum plummets? Then Ethereum, which was originally worth 150 US dollars, may instantly be less than 100 US dollars. At this time, the mortgaged assets are not as much as the assets I loaned out, and the price of DAI will be impossible.Then anchor it to the U.S. dollar, because everyone can see: DAI is not worth that much money anymore.

How to solve this problem? The role of over-collateralization is revealed - no matter how much the price of Ethereum fluctuates, it will still take some time to fall from $150 to $100. And this gives room for asset liquidation: First of all, we stipulate that the collateral must not be less than 150% of the loan, that is, it does not matter if Ethereum rises, but once it falls, you must immediately cover your position to 150%, otherwise your collateral Smart contracts that will enter liquidation.

Used to install DeFi virtual assets, which can be used for transfers, etc.

The asset management tool (also called the Kanban) is a wallet scanning service that allows you to view wallet details and history.

The three most important asset management tools are Debank, Zerion and Zapper.

Generally speaking, there will be many mining opportunities in the market, which is also an opportunity for everyone to manage their finances and make money. At this time, a robot that does asset management or provides financial services will come forward and say, I am here to help you make money. As long as you give me the money, I will go to the market to find money-making opportunities. Help you make money.

YFI is one of the most important financial management tools.

Robots in the blockchain world are all managed in a decentralized manner, that is to say, there is no clear definition of who they belong to. In this case, if the robot malfunctions, who should we hold responsible? What should be done? Who is responsible for the losses? In this case, an insurance robot is needed, which is specifically designed to insure other robots.

Robots in the blockchain world are decentralized, open and transparent, and execute automatically. How should these robots be upgraded and maintained? How to ensure the decentralization of robots?

Generally, many people negotiate around the same robot and vote to decide how to let the robot upgrade and provide services. The DAO robot is a robot that helps these people and robots form a decentralized governance relationship.

SpecializedGate provides an asset price robot. For example, when the little C robot just gave an example receives a Bitcoin, it needs to know how much a Bitcoin is worth. Otherwise, there is no way to calculate how much loan should be given to Xiao Ming. At this time, the oracle robot will run to Little C, enter a price, and tell Little C that Bitcoin is now worth $10,000.

Ethereum is a blockchain network that maintains a shared ledger of digital value. Almost all DeFi applications (called smart contracts or Dapps) are built on the Ethereum blockchain, consisting of In place of a central authority, the network’s participants control the issuance of the network’s native cryptocurrency, ether (ETH), in a decentralized manner.

DeFi ranking published by defipulse, which tracks the real-time value locked in global DeFi smart contracts.

MakerDAO is the undoubted leader in the field of DeFi. MakerDAO is to DeFi what Bitmain is to the mining industry.

Founded in 2014, MakerDAO is an automated mortgage loan platform on Ethereum and is also the provider of the stable currency Dai. MakerDAO is a decentralized derivative financial system built on Ethereum. It adopts a dual-currency model, one is the stable currency Dai, and the other is the equity token and management token MKR. Dai was launched on the mainnet in December 2017. Through the dual-currency mechanism, MakerDAO enables the entire decentralized pledge loan system to operate.

Dai is anchored 1:1 to the US dollar. Like other stablecoins, Dai also experiences price fluctuations. Unlike other stablecoins, Dai obtains value through over-collateralized encrypted digital currencies. Centralized stablecoins such as USDT, TrueUSD and GUSD have 1 USD of fiat currency as reserves behind every 1 USD of tokens issued, while 1 Dai is backed by more than 1 USD of digital assets as reserves.

Unlike USDT, TrueUSD, etc., Dai’s operating mechanism is open and transparent, which is also one of Dai’s advantages. Not only is Dai itself transparent, but the value fluctuation and quantity of Ethereum, the collateral used in exchange for Dai, are also transparent and publicly visible.

CompoundThe agreement creates a loan platform without an intermediary, where the borrower obtains benefits and the lender pays interest. (First Class Note: Usually we call the party who deposits tokens into the lending pool a borrower, and the party who borrows tokens from the lending pool is called a lender.)

Compound’s new ERC-20 token is referred to as cToken. , making it easier for users to perform lending operations. For example, cDAI and DAI exchange is supported, and DAI holders can lend tokens to cDAI users. Not all wallets support exchange, but in Eidoo wallet, users can easily exchange cDAI for DAI, thus lending DAI in exchange for interest. Today, Compound supports a total of 8 cTokens, with total locked assets equivalent to approximately US$200 million: cDAI, cETH, cUSDC, cBAT, cWBTC, cSAI, cREP, and cZRX.

Borrowers can withdraw tokens from Compound at any time, and interest is calculated automatically and instantly. If you withdraw coins through a non-custodial wallet like Eidoo, no intermediary is needed (because Ethereum’s decentralized protocol can do it).

Lenders must lock tokens as collateral and obtain 50-75% of the credit based on the strength of the underlying assets.

The Compound protocol also has 10% interest as a reserve, and the remaining 90% interest goes to the borrower. No fees, no protocol tokens. The credit market based on Ethereum forms a truly decentralized liquidity pool to issue and obtain loans in an unintermediary, autonomous and fast way.

Synthetix is ​​a synthetic asset issuance protocol based on Ethereum. Synthetix currently supports the issuance of synthetic assets including fiat currencies, cryptocurrencies, and commodities. Among them, the main legal currencies are the US dollar (sUSD), the euro (sEUR), and the Japanese yen (sJPY), but currently sUSD is the main currency. In terms of cryptocurrencies, there are Bitcoin (sBTC) and Ethereum (sETH). In addition, there are also inverse cryptoassets, such as iBTC. When the price of BTC falls, the price of iBTC rises, thereby making a profit. In terms of commodities, gold (sXAU) and silver (sXAG) are currently the main commodities.

Transactions on Synthetix are conducted in a decentralized manner and do not require the existence of counterparties, and there is no need to worry about liquidity and slippage issues. Trades on its exchange are executed through smart contracts and are trades on smart contracts rather than order book trades. Each of these has its own unique trading experience and some advantages.

Synthetix and other asset issuance agreementsSimilarly, asset mortgages are also required for issuance. For example, to generate dai in the MakerDAO protocol, ETH needs to be mortgaged. Synthetix is ​​similar, but it stakes its native token SNX. Users can issue synthetic assets simply by locking a certain amount of SNX in their smart contracts. Among them, its pledge rate is very high, which is 750% of its issued assets. Only when it reaches the target threshold of 750% can it have the opportunity to obtain rewards for transaction fees and new SNX tokens.

TVL is the total locked value of each DeFi protocol, the higher the better.

Dex is the trading volume, the higher the better.

The number of active addresses represents the number of DeFi users on Ethereum, the more, the better.

The lower the handling fee, the better.

As an infrastructure, Ethereum’s market value can be very high, but when it comes to its ratio to DeFi’s market value, the lower the market value of Ethereum, the better, and the higher it is, the better it is. The more mature.

Reference link:
https://zhuanlan.hu.com/p/206910261
https://zhuanlan.hu.com/p/ 366412971
https://zhuanlan.hu.com/p/377856331
https://www.hu.com/question/324838085/answer/1526607416

If something is wrong , please point it out, thank you~

❷ Where is the useful website navigation?

I have used many navigation software and websites in the workplace for twenty years, but in the current mobile Internet era, almost all we need are resources and There are only a few tools that I think are easy to use after being accumulated. Of course, you must first clarify your own needs. No. 1: hao123 Website: www.hao123.com Introduction: Needless to say, this is the navigation I first used. Although I use it less now, I still use it sometimes because it is easy to open. No. 2: Xigua Navigation Website: www.xgnav.com Introduction: Xigua Navigation is a website navigation website that collects high-quality websites and resources from the entire network. Timely collection of URLs and content classified as webmaster, ACG, server, wordpress, designer, blockchain, product manager, programmer, medicine, cross-border e-commerce, front-end, metaverse, etc. If you are looking for websites and resources, come to Xigua Navigation. No. 3: Cool Site Navigation Website: www.coolzhanweb.com Introduction: Kuzhan Navigation is a Chinese online navigation that collects high-quality websites and resources from the entire network. It includes asmr, film and television, gmail, bt, American dramas, temporary mailboxes, 2D, cloud text messages, code reception, oil monkey scripts, network disks, etc. Classified URLs and content make your online life simpler and more exciting. To surf the Internet, start with Cool Station Navigation.

❸ What is avax coin, a new force in the currency circle?

Avalanche (AVAX), formerly known as AVa/AVA, is an open source platform used to launch highly decentralized applications, new financial primitives and New interoperable blockchain. Utilizing a breakthrough consensus protocol framework, a smart contract platform that can confirm transactions in one second, supports everything in the Ethereum development kit, making millions of full block producers possible.

Avalanche was co-founded by Cornell University professor and IC3 co-founder Emin Gön Sirer, computer scholar Kevin Sekniqi, and Ted Yin, the first author of the HotStuff consensus on the Facebook Libra protocol.

The Avalanche-led Avalanche blockchain platform is a digital payment and computing platform based on the revolutionary consensus algorithm AVAlanche. This consensus enables the distributed ledger to achieve a high degree of decentralization, high concurrency processing and fast confirmation of transactions, while also achieving historical record deletion and chain governance.

The core of the AVA blockchain platform is a unified, interoperable infrastructure that enables anyone to build a blockchain network or Issue assets on the blockchain.

❹ What are the blockchain system development platforms?

How many stages are blockchains divided into?

There are 1.0, 2.0, and 3.0 blockchains. The digital currency based on Bitcoin is Blockchain 1.0; the smart contract platform based on Ethernet is Blockchain 2.0; the application scenarios and platforms of high-performance blockchain are Blockchain 3.0. A simple summary is that 1.0 is mining and currency speculation; 2.0 is ICO and currency issuance; 3.0 is the implementation of the project. Real implementation projects are still far away from us. Most projects use the 2.0 stage as the entry point for industry solutions. The combination of blockchain and industry allows blockchain to be applied in a certain industry.

What is a qualified blockchain project?

Potential blockchain projects have different evaluation standards and different periods. The explosion of digital currencies in 2017 was mainly due to the promotion of ICO and Ethereum smart contracts. In the past, projects that could meet these two conditions were considered good. Now the measurement standard for projects is:

(1) There are application scenarios. The project itself has a team, goals, and real-life scenario applications.Because some teams or companies are not suitable for blockchain applications, it is relatively blunt to establish a connection between the two.

(2) Multiple parties participating in the blockchain can generate transactions

(3) The blockchain has a large number of communities and users. To sum up, good blockchain projects can be put into practice.

For details, please refer to the case of Henan Keduoduo Information Technology Co., Ltd.

❺ Blockchain Technology

Background: After the birth of Bitcoin, it was discovered that the technology was very advanced, and blockchain technology was discovered. Bitcoin and blockchain technology were discovered at the same time.

1.1 The purpose of the birth of Bitcoin:

①Currency transactions have records, that is, ledgers;

②The disadvantages of centralized institution accounting - it can be tampered with; Yi Chaofa

Bitcoin solves the first problem: anti-tampering - hash function

1.2 hash function (encryption method)

① Function: convert any A string of length, converted to a fixed-length (sha256) output. The output is also called a hash value.

② Features: It is difficult to find two different x and y such that h(x)=h(y).

③Application: md5 file encryption

1.3 Blockchain

①Definition

Block: Split the general ledger into zones Block storage

Blockchain: On each block, add a block header. It records the hash value of the parent block. By storing the hash value of the parent block in each block, all blocks are connected in order to form a blockchain.

②How does the blockchain prevent transaction records from being tampered with?

After the blockchain is formed, tampering with any transaction will cause the hash value of the transaction block to be different from that of its sub-blocks. , tampering was discovered.

Even if you continue to tamper with the hash value in the sub-block header, the hash value in the sub-block will be different from that in the grandchild block, and the tampering will be discovered.

1.4 The essence of blockchain

①The essence of Bitcoin and blockchain: a big ledger visible to everyone, only recording transactions .

②Core technology: Through cryptographic hash function + data structure, it ensures that the ledger records cannot be tampered with.

③Core function: Create trust. Fiat currency relies on government credibility, and Bitcoin relies on technology.

1.5 How to trade

①Trade,You need an account and password, corresponding to the public key and private key

Private key: a string of 256-bit binary numbers. No application is required to obtain it, and you don’t even need a computer. You can generate the private key by tossing a coin 256 times.

The address is converted from the private key. The address cannot reverse the private key.

The address is the identity, which represents the ID in the Bitcoin world.

After an address is generated, it can only be known by everyone if it enters the blockchain ledger.

②Digital signature technology

Signature function sign (Zhang San’s private key, transfer information: Zhang San transfers 10 yuan to Li Si) = signature of this transfer

< p> Verify Korean verify (Zhang San’s address, transfer information: Zhang San transfers 10 yuan to Li Si, signature of this transfer) = True

Zhang San uses his own signature function sign() The private key signs this transaction.

Anyone can verify whether the signature was issued by Zhang San himself who holds Zhang San's private key by verifying the Korean vertify(). It returns true, otherwise it returns false.

sign() and verify() are cryptographically guaranteed not to be cracked. ·

③Complete the transaction

Zhang San will provide the transfer information and signature to the entire network. Under the premise that the account has a balance, after verifying that the signature is true, it will be recorded in the blockchain ledger. Once recorded, Zhang San's account will be reduced by 10 yuan, and Li Si's account will be increased by 10 yuan.

Supports one-to-one, one-to-many, many-to-one, and many-to-many transactions.

In the Bitcoin world, private keys are everything! ! !

1.6 Centralized Accounting

① Advantages of Centralized Accounting:

a. No matter which center keeps accounts, don’t worry too much

< p> b. Centralized accounting, high efficiency

②Disadvantages of centralized accounting:

a Denial of service attack

b Stop service after getting tired

p>

c Central institutions are vulnerable to attacks. For example, destroying servers and networks, committing self-intrusion, legal termination, government intervention, etc.

All attempts at confidential currencies with centralized institutions in history have failed.

Bitcoin solves the second problem: how to decentralize

1.7 Decentralized accounting

①Decentralization: Everyone can keep accounts. Everyone can insureKeep a complete ledger.

Anyone can download open source programs, participate in the P2P network, monitor transactions sent around the world, become an accounting node, and participate in accounting.

② Decentralized accounting process

After someone initiates a transaction, it is broadcast to the entire network.

Each accounting node continues to monitor and continue transactions across the entire network. When a new transaction is received and the accuracy is verified, it is put into the transaction pool and continues to be propagated to other nodes.

Due to network propagation, the transactions of different accounting nodes at the same time are not necessarily the same.

Every 10 minutes, one person is selected from all accounting nodes in a certain way, and his transaction pool is used as the next block and broadcast to the entire network.

Other nodes delete the transactions that have been recorded in their own transaction pool based on the transactions in the latest block, continue accounting, and wait for the next selection.

③ Features of decentralized accounting

A block is generated every 10 minutes, but not all transactions within these 10 minutes can be recorded.

The accounting node that obtains the accounting rights will be rewarded with 50 Bitcoins. After every 210,000 blocks (approximately 4 years), the reward is halved. The total amount is about 21 million, and it is expected to be mined in 2040.

Recording the reward of a block is also the only way to issue Bitcoin.

④ How to allocate accounting rights: POW (proof of work) method

Compete for accounting rights by calculating mathematical problems on several accounting points.

Find a random number that makes the following inequality true:

There is no other solution except traversing the random numbers starting from 0 and trying your luck. The process of solving the problem is also called mining.

Whoever solves the problem correctly first will get the accounting rights.

If a certain accounting node finds the solution first, it will announce it to the entire network. After other nodes verify that it is correct, a new round of calculation will start again after the new block. This method is called POW.

⑤ Difficulty adjustment

The generation time of each block is not exactly 10 minutes

As Bitcoin develops, the computing power of the entire network does not increase.

In order to cope with changes in computing power, the difficulty will be increased or decreased every 2016 blocks (about 2 weeks), so that the average time for each block to be generated is 10 minutes.

#欧易OKEx# #BTC[超话]# #digital currency#

❻ Please download the full text of "Blockchain Industry Dictionary" for free from Baidu Netdisk resources, thank you~

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Introduction : This is the world's first Chinese version of "Blockchain Dictionary". "Viking Capital" and "Jiazi Guangnian" systematically sorted out multiple concepts in the blockchain field, covering basic definitions, basic blockchain technology, digital currency and legal supervision. The dictionary was completed by the Viking Research Institute and Jiazi Think Tank, a research institute under Jiazi Guangnian, which took a month to complete!

❼ If your deposit or withdrawal is slow, please check the confirmation progress on the blockchain browser first

Blockchain browser:

1. BTC transfer progress inquiry (2 confirmations):

https://btc.com

2. BCC transfer progress inquiry ( 2 confirmations):

https://blockdozer.com

3. ETH transfer progress query (30 confirmations):

https: //etherscan.io

4. LTC transfer progress query (4 confirmations):

https://live.blockcypher.com

5. USDT transfer progress inquiry (2 confirmations):

https://omniexplorer.info

6. NEO transfer progress inquiry (5 confirmations):

https://www.antchain.xyz

7. IOTA transfer progress query (1 confirmation):

https://thetangle.org< br />
8. XLM transfer progress query (1 confirmation):

https://stellarchain.io

9. QTUM transfer progress query (6 1 confirmation):

https://qtumexplorer.io

10. BTS transfer progress query (1 confirmation):

https:/ /www.cryptofresh.com

11. HSR transfer progress query (10 confirmations):

http://explorer.h.cash

12. GXS transfer progress query (1 confirmation):

https://block.gxb.io

❽ What is blockchain mining What does it do? Detailed introduction to blockchain and virtual currency

When Bitcoin was first issued, people discovered that it was decentralized and not subject to any central control; it was completely open, except for the encryption of transaction information. The information of the entire system is highly transparent, and the technology is all open source; security, as long as you cannot control %51 of all nodes, you cannot modify the data arbitrarily, which makes it relatively safe; independence, the entire model and Bitcoin do not rely on any third party. All nodes verify and exchange data within the system without any intervention

Here we explain in detail what blockchain technology is. To put it bluntly, it is block + chain. So what is a "block"? What is a "chain" again?

A block is a ledger. Transaction accounting is completed by multiple nodes distributed in different places, and each node records a complete account, so they can all participate in supervising the legality of the transaction, and at the same time Can jointly testify for it

Each block contains the cryptographic hash of the previous block, the corresponding timestamp, and the transaction data (usually a hash value calculated using the Merkle tree algorithm) represents), this design makes the block content difficult to tamper with. The distributed ledgers connected by blockchain technology can effectively record transactions between two parties, and can permanently verify this transaction.

The function of the hash function h(): convert a string of any length into a fixed-length (for example, 256 bits) output. The output is also called a hash value. This output is irreversible

It is difficult to find two different x and y such that h(x) = h(y), that is, two different inputs, There will be different output. Theoretically, two different inputs may have different outputs, but this is almost impossible. For example, if an infinite space is mapped to a finite space, there must be a many-to-one situation. The theory exists, but there are no rules. It is guaranteed that you cannot find this result through any mathematical inference. Why is it 256 bits here? Isn't it longer? Because 256 bits are secure enough.

Split the ledger into blocks. For example, a piece of paper in a book is a block. Each block records transactions within a period of time, such as 10 minutes.

We divide Each piece of paper is likened to a block. A part of content is added to each block. We call it a block header, which records the hash value of the parent block. Each block stores the hash value of the parent block. , connect all blocks smoothly to form a blockchain

Record the hash value of block 1 to the block header of block 2, and so onThe block header of each block records the hash value of the parent block, and each block is linked in order. This is called a blockchain. The first block has no block header and is also called the genesis block

The blockchain is a ledger. Only when transactions occur in the ledger will the money in your account increase. If you need to make a transaction, you first need an account number and password. Just like your bank card has an account number and password, others can make a transfer to you. The account password on the block ledger is the public key and private key

Lao Wang (who already has a private key and a public key) wants to transfer 10 BTC to Zhang, which requires some operations

It is proved that Lao Wang himself issued the transfer signature function Sign (Lao Wang’s private key + Transfer information: Lao Wang transferred 10 BTC to Zhang San) = signature of this special account
The verification is that Lao Wang himself issued the transfer verification function Verify (Lao Wang’s address + Transfer details: Lao Wang transferred 10 BTC to Zhang San) + Signature of this transfer) = true
Once the transfer is recorded in the block, no one can change it. Zhang San will increase it by 10 BTC, and Lao Wang will decrease it by 10 BTC accordingly. The entire operation is automatic, such as your wallet The app will help you do this. The app knows your private key, you tell the wallet the transaction content, the wallet signature is announced to the entire network, and it waits for others to verify the transaction

Centralized accounting The efficiency will be higher. Banks, governments or Alipay will keep accounts for you, which is very reliable, because they can't touch your money unless they have your private key

There are some disadvantages in centralized accounting< /p>

In decentralization, everyone can keep accounts, and everyone can keep a complete ledger. Anyone can download open source programs, participate in Bitcoin's p2p network, monitor transactions sent from all over the world, become an accounting node, and participate in accounting. Suppose Xiaoyi releases a transaction and broadcasts it to the entire network, and accounting node A listens. When this transaction arrives, A verifies that the transaction bit is true and puts it into the transaction pool to continue to spread to other nodes. Because it is spread through the network, the transaction pools of different accounting nodes are not necessarily the same at the same time. Every 10 minutes, from all accounting nodes Among the nodes, select one according to a certain method. After verifying that the transaction of this node is true, then compare the transaction records in the transaction pool of this selected node with the transaction records in the transaction pool of your own (A) node. The comparison is completed. After that, the transactions recorded by the selected accounting nodes will be deleted from the transaction pool, and the other accounting nodes will continue to record and wait for the next selection. There is a cycle every 10 minutes. During this 10 minutes, all accounting nodes will record accounts normally. , 10 minutes later, a node will be selected to use the transactions in its transaction pool as a new block. This block comes from the transaction pool of an accounting node I randomly selected among all the accounting nodes, and the cycle continues

Transactions are notOnce it is recorded, it is completed. Only when the transaction becomes a certain block, the transaction is truly completed. This is a complete accounting process of decentralization. Your transaction will not be recorded immediately because the p2p network propagation takes time. If the node of the selected block has not received your transaction, the transaction will be not done. A block is generated every 10 minutes, but not all transactions within 10 minutes can be recorded. 10 minutes is just an average value

Due to the characteristics of decentralized accounting, accounting nodes with accounting rights will receive a 50BTC reward every ten minutes, which is about the same for every 210,000 blocks. In 4 years, the reward is halved. Bitcoin has been halved twice since its issuance. Then a new block is generated every ten minutes. The reward for this accounting node is 10.5 BTC. If it is halved every 4 years, the total number of BTC can be calculated. The amount is approximately 21 million, and it is expected to be mined in 2040. Recording the reward of a block is also the only way to issue Bitcoin. When BTC is mined, the only income that the accounting node can obtain is the transaction fee.

Accounting nodes compete for accounting rights through questions,

Find a certain random number that makes the equation invalid
SHA256 hash function (random number + parent block hash value + Transactions in the transaction pool) A certain specified value)
There is no other solution except traversing the random numbers starting from 0 and trying luck. The process of solving the problem is also called mining, so the accounting node that solves this problem is also called mining. It’s called a miner. The faster you traverse random numbers, the greater the possibility of getting the accounting rights. This traversal speed is called computing power by mine bosses. In order to obtain this computing power, mine bosses will Purchase more mining machines with higher computing power

Whoever solves the problem correctly first will get the accounting rights. Accounting node A is the first to find the solution, which is announced to the entire network. After other nodes verify that it is correct, node A obtains the block, gains 12.5 BTC, and restarts a new round of calculation after the new block. This method is called (POW) allocating accounting rights

It usually takes about 10 minutes to solve this random number. 10 is not absolute, because the process of solving this problem is a process of luck. In response to changes in computing power in the future, Bitcoin will increase or decrease the difficulty every 2016 blocks, about two weeks, so that the average block generation time is ten minutes

Each block contains The encrypted hash of the previous block, the corresponding timestamp, and the transaction data (usually represented by a hash value calculated by the Merkle tree algorithm) are included. This design makes the block content difficult to tamper with. The distributed ledgers connected by blockchain technology can effectively record transactions between two parties, and can permanently verify this transaction.

Different from traditional stored data, each node of the blockchain stores data according toThe blockchain structure stores complete data. Each node of the blockchain is independent and has equal status. It relies on the consensus mechanism to ensure the consistency of storage. Traditional distributed storage generally synchronizes data to other backup nodes through a central node. .

Mahjong is a traditional Chinese blockchain project. A group of four miners work together. The miner who first collides with the correct hash value of 13 numbers can obtain the accounting rights and be rewarded.

Many people say that blockchain is a scam and Bitcoin is a scam. This may be a scam, but this technology has been widely recognized and applied. The cryptography knowledge involved in blockchain can only be used by ordinary people. Even if you don’t understand it, the most important thing is to look at the problem from a relatively rational perspective. Don’t let the wind be the rain.

There is something incredible about this technology. It maintains absolute order without a center or supervision. This is the trust that only needs to be established by everyone’s consensus. Bitcoin created this consensus, and in the blockchain In the world everyone is fair and equal.

❾ "Blockchain Project Development Guide" pdf download and read online, seek Baidu Netdisk cloud resources

"Blockchain Project Development Guide" (Narayan Prussia Narayan Prusty) e-book network disk download for free online reading

Resource link:

Link: https://pan..com/s/16X1h2dUsvOqdsNfJA9f0jQ Extraction code: qcqe< /p>

Book title: Blockchain Project Development Guide

Author: Narayan Prusty

Translator: Zhu Xuantong

Douban score: 5.7

Publisher: Machinery Industry Press

Publishing year: 2017-12-8

Number of pages: 198

Introduction:

Blockchain is one of the most disruptive emerging information technologies in the past decade. It is establishing trust, arbitration and recording of human transaction processes in a new way. Base. This book has 9 chapters in total. It first introduces basic concepts such as decentralized applications and DApps, and then explains popular DApps such as Bitcoin, Ethereum, and Hyperledger accordingly. Secondly, based on the analysis of the working principle of Ethereum, the writing method of smart contracts is introduced, and the application method of web3.js is introduced. Then use the above knowledge to create specific applications such as wallet services, smart contract deployment platforms, betting apps, enterprise-level smart contracts, and alliance blockchains.

About the author:

Author: (India) Narayan Prusti Translator: Zhu Xuantong Translator: Yan Ying Translator: Dong Ning

Narayan Prusti, who created an MP3 search engine at the age of 18, is a multi-tasking developer with a focus on blockchain and JavaScript, tend to use Ethereum, Bitcoin, Super Classification, IPFS, etc. to build decentralized applications. The scalable applications he writes are widely used in startups, enterprises and government departments in India, Singapore, the United States and other countries. Narayan Prusty currently works for the Emirates National Bank’s blockchain enterprise in Dubai. He is the author of "Learning ECMAScript 6" and "Modern JavaScript Applications". Zhu Xuantong holds a master's degree from Tsinghua University and is a doctoral candidate at the Institute of Quantitative and Technical Economics of the Chinese Academy of Social Sciences, focusing on technical economics and management research. Has extensive working experience in government and international organizations. Yan Ying, Ph.D. from Fudan University, is a researcher in charge of Microsoft Research Asia and the head of Coco Blockchain China. She focuses on research on blockchain technology, big data analysis, databases and cloud computing. Dong Ning is the CEO of ChainNova, the director of the Financial Technology Research Center of the New Generation Information Technology Institute of Peking University, the former head of IT economics for IBM Greater China, and the founder of the IBM blockchain community.

❿ When will Baidu launch the blockchain product "Du Universe"

It is reported that the network's new blockchain product-"Du Universe", It will be launched on the official website at 10:00 on June 8, and its APP version will be launched on June 13.

In the space rule setting of "Universe", the planet's gravity, the volume of aggregated elements, and the mass of the planet are positively correlated. When the mass of the planet reaches a certain level, it can be "unlocked" "More mysterious features.

According to the official website of “Du Universe”, this blockchain product has not yet been fully formed. The official website also revealed that 100 elements will be “airdropped” on the first day of product release.

This blockchain product of the Internet covers many fashionable elements such as "blockchain games", "uniqueness", "interstellar travel", "decrypting the unknown", etc., which has given rise to the wave of blockchain. The "curious players" have more room for imagination.