Blockchain ledger Download
for example, if you are a woman, every time your boyfriend says something disgusting to you or promises to buy something for you, you immediately record it and send it to you and all his friends, classmates, colleagues, as well as various groups and circles of friends, so that he can no longer resist. This is called blockchain
the core advantage of blockchain technology is decentralization, which can realize point-to-point transaction, coordination and cooperation based on decentralized credit in a distributed system without mutual trust by means of data encryption, time stamp, distributed consensus and economic incentive, so as to solve the high cost and low cost of centralized institutions Low efficiency and data storage insecurity provide solutions
the application fields of blockchain include digital currency, token, finance, anti-counterfeiting traceability, privacy protection, supply chain, entertainment, etc. with the popularity of blockchain and bitcoin, many related top domain names have been registered, which has a great impact on the domain name instry.
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 />}
}
taking bitcoin as an example, it does not have an entity form, but exists in a special account book. All bitcoin transactions are recorded in the ledger. Through the transaction records, we can calculate the number of bitcoins owned by each user. If a person owns bitcoin, it means that he can find the relevant transaction records in the ledger
the ledger mentioned here is a software that we can download from bitcoin's official website, and the underlying technology used in this software is blockchain. In order to facilitate understanding, we usually say that blockchain is the ledger
the reason why blockchain is used as the underlying technology of ledger is to realize the feature of digital currency decentralization. It can be said that the starting point of a series of problems and solutions of digital currency comes from decentralization
2. Blockchain is a technology to ensure the safe use of digital currency. As we all know, blockchain technology has the characteristics of encryption and non tampering, which can rece the probability of errors in the use of digital currency to 0. Because digital currency requires higher encryption, it must be supported by blockchain technology. At present, not only many instries in China are using blockchain technology, but also many foreign countries are actively using blockchain technology.
blockchain is the big ledger of bitcoin network, and each block is equivalent to a page in the ledger. What information is recorded in the "account book"? At present, each block of bitcoin mainly records data such as block head, transaction details, transaction counter and block size
"block header" contains all information except transaction information, mainly including the hash value of the previous block header, which is used to ensure that blocks are connected in sequence; Time stamp: record the generation time of the block; Random number: that is, the answer to the arithmetic problem of PK for all miners in the whole network; Difficulty target: score the difficulty coefficient of the arithmetic problem
"transaction details" records in detail the transferor, income party, amount and digital signature of the transferor of each transaction, which is the main content of each block
"transaction counter" describes the number of transactions contained in each block
"block size" refers to the size of each block data. Currently, each block is limited to 1MB, which does not rule out the possibility of expansion in the future.
Ledger is a book with a certain format and several account pages. Based on the accounting documents, it records all economic business in chronological order and classification, which is what we usually call the ledger. Blockchain represents a unique data record format. Blockchain is "block + Chain". The so-called block is the meaning of data block. Each block is connected by a certain mark to form a chain
Super ledger
hyperledger (Chinese name is super ledger, collectively referred to as hyperledger) is an open source project launched by Linux foundation in 2015 to promote blockchain digital technology and transaction verification. The goal of hyperledger is to enable members to work together to build an open platform to meet the needs of various users from different instries, while greatly simplifying the business process. The founding members of hyperedge include IBM, Intel, Cisco and other large companies. By the end of this book, more than 183 organizations and companies have joined hyperedge, and they are growing rapidly
at the beginning of hyperledger project, Linux foundation has received a number of different code bases, including IBM code base (inspired by Ethereum to a certain extent), Dah (bits of proof bitcoin code base) and sockstream code base (an extension of bitcoin code base). In addition, there are digital asset and ripple contributions. With the development of the instry, a single project has been unable to meet the needs of the business, so hyperledger has graally developed from a single project into a project group. At present, hyperledger is not a specific technology, but a set of blockchain technology frameworks. Up to now, the hyperledger project team contains 9 formal projects and more than 50 moles related to these formal projects
the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system
Hyperledger is an open source project launched by Linux foundation in 2015 to promote blockchain digital technology and transaction verification. It is composed of 30 initial enterprise members (including IBM, Accenture, Intel, J.P. Morgan, R3, Dah, DTCC, Fujitsu, Hitachi, swift, Cisco, etc.). The goal is to let members work together to build an open platform, meet various user cases from different instries, and simplify business processes