Blockchain file

1.

blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies. Blockchain is an important concept of bitcoin,

in essence, it is a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of information of bitcoin network transactions, Used to verify the validity of its information (anti-counterfeiting) and generate the next block

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most blockchain public chains are limited by scalability. The biggest feature of blockchain technology is decentralization, which requires that all accounts in the network need to deal with the accounting process. Distributed accounting has high security, low misoperation rate, political neutrality and correctness

however, blockchain technology embraces these features at the same time, sacrificing scalability, unable to meet the personalized supervision, and slightly insufficient in protecting data privacy. Moreover, with the increase of the number of ledger, the interaction delay will increase exponentially, that is to say, the more ledger in the blockchain network, the higher the delay

2.

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

on December 2, 2019, the word was selected into the top ten catchwords of "biting words" in 2019

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Application of blockchain Finance:

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

3. const SHA256 = require(crypto-js/SHA256);< br />class Block{
constructor(index,timestamp,data,previousHash='&# 39;)< br />{
this.index=index;< br />this.timestamp=timestamp;< br />this.data=data;< br />this.previousHash=previousHash;< br />$this.hash=this.calculateHash();< br />}

calculateHash(){
return SHA256(this,index+this.previousHash+this.timestamp+JSON.stringify(this.data)).tostring();< br />}
}
class Blockchain{
constructor(){
this.chain=[this.createGenesisBlock()];<
}
/ / create a generated information block
creategenesis block() {
return new block (0, & quot; 01/01/2019",& quot; Genesis block", 0);
/ / the date is the user's data. In fact, it is the hash value obtained by adding several values together. Here, the information is encrypted and the picture is encrypted. Then the data is still stored in the database, but all the data are hash values. To get this data, you must know the hash value of the previous data block. Then, if the hacker needs to crack all the nodes, the hash value is decrypted, Then all the blocks from the first node to the last node can be decrypted to get the real data. So the security of data stored in the blockchain depends on whether the data is encrypted. If the plaintext is not encrypted, then it is not a blockchain
}
/ / get the last block
getlatesblock() {
return this.chain [this.chain. Length-1]
}
/ / create block
addblock (newblock) {
newblock. Previoushash = this. Getlatesblock(). Hash< br />newBlock.hash=newBlock.calculateHash();< br />this.chain.push(newBlock);< br />}
}

4. How to store information on the blockchain: call the API provided by the blockchain platform

generally, the blockchain platform will provide corresponding interfaces, such as RPC, json-rpc, HTTP, etc. of course, the platforms are not the same, and the degree of friendliness is different

some companies specializing in API, such as blockcypher, can provide friendly calling interfaces, and it is not very convenient to write answers on the mobile phone, Search below

as for the storage content, add a point: in addition to the conventional cloud storage, file entities on the file hash record chain also have blockchain based storage schemes, such as IPFs, storej and so on

5. mining often mentioned in the field of blockchain is actually proof of work (POW)< Br > the so-called workload proof is used to confirm that you have done a certain amount of work. The whole process of monitoring work is usually extremely inefficient, and it is a very efficient way to prove that the corresponding workload has been completed through the certification of the work results< Mining is a process of processing transactions by consuming computing resources, ensuring network security and keeping everyone's information synchronized in the network< This process is called "mining" because it is similar to gold panning, because it is also a new temporary mechanism< However, unlike gold panning, mining provides rewards for services that ensure the safe operation of payment networks. What is the principle of mining< Br > anyone can become a miner by running software on specialized hardware< Br > the mining software monitors the transaction broadcast through the network and performs appropriate tasks to process and confirm these transactions< Br > miners can earn transaction fees paid by users to speed up transaction processing and issue new coins according to fixed formula after completing these tasks. New transactions need to be included in a block with mathematical workload proof to be confirmed< This kind of proof is difficult to generate because it can only be generated by trying billions of calculations per second< Br > miners need to run these calculations before their blocks are accepted and rewarded. As more people start mining, the difficulty of finding effective blocks will be automatically increased by the network to ensure that the average time to find a block remains at 10 minutes< Br > therefore, the competition for mining is very fierce, and no indivial miner can control the content contained in the block chain.

6. If people dig with shovels, they can't move when they reach the rock layer. The situation varies from place to place. In some places, the rock layer is on the surface, and in some places, it is tens of meters or even deeper
if you dig by machine, you can dig to a very deep place. Some mines are 2000 meters underground
if it's drilling, the current deep drilling in the mainland can reach a depth of more than ten kilometers. The deeper the drilling depth is, the higher the requirements for technology and equipment are. Further down, it is not impossible to dig, but limited by technology and equipment.

7. You are right. The spring tide will come soon. Give me some time. In addition, it's not good to participate in the blockchain project. Let's have a look

8. All move within 8 hundred miles!