It's important to link blocks in blockchain
blockchain refers to the technical solution of collective maintenance of a reliable database through centralization and distrust in the past, and it is a technical way for the whole people to participate in bookkeeping. Previous bookkeeping methods were all centralized and needed centralized intermediary, whether it was traditional government, financial institutions, notarization institutions or emerging e-commerce platform and online payment platform
in economic hypothesis, information is sufficient. In fact, it is precisely because of insufficient information that there are very large intermediaries. The existence of intermediaries increases the transaction cost and raises the transaction threshold. In essence, blockchain technology is a large-scale collaboration tool. It makes direct value transfer possible by using pure technology for the first time, and continues the trend of Internet decentralization and disintermediation. Disintermediated blockchain technology will greatly subvert the information intermediary instry
blockchain technology is the basic technology for building bitcoin data structure and encrypted transmission of transaction information, which realizes the issue and transaction of bitcoin. The core of blockchain technology is that all the current participating nodes jointly maintain the transaction and database, so that the transaction is based on the principle of cryptography rather than trust, so that any agreed parties can directly carry out payment transactions without the participation of a third party
technically, a block is a data structure for recording transactions, reflecting the capital flow of a transaction. In the system, the transaction blocks are connected to form a main chain, and all the nodes participating in the calculation record the main chain or part of the main chain
a block contains the following three parts: transaction information, hash formed by the previous block and random number. Transaction information is the task data carried by the block, including the private keys of both parties, the number of transactions, the digital signature of electronic currency, etc; The hash hash formed by the previous block is used to connect the blocks and realize the sequence of past transactions; Random number is the core of the transaction. All nodes compete to calculate the answer of the random number. The node that gets the answer the fastest generates a new block and broadcasts it to all nodes for updating, so as to complete a transaction.
Public chain, also known as "public chain", refers to the blockchain that anyone in the world can enter the system at any time to read data, send confirmatory transactions and compete for bookkeeping. The public chain is generally considered to be "completely decentralized", because no indivial or institution can control or tamper with the reading and writing of data in it. In terms of application, blockchain public chain mainly includes bitcoin, Ethereum, super ledger, most counterfeit currencies and smart contracts. The ancestor of blockchain public chain is bitcoin blockchain, which has the following characteristics:
1, open source code
upload the code to GitHub, and everyone can get complete blockchain data by downloading, Accept the test of the public
2, complete decentralization
anyone can become a node, each node is open, everyone can participate in the calculation of the blockchain, any node is not permanent, but phased, and any center is not mandatory for nodes. Anyone can read and send transactions, and transactions can be effectively confirmed on the blockchain. Anyone can participate in the consensus process. The consensus process determines whether a block can be added to the blockchain and the exact current state. Everyone can get financial reward from it, which is proportional to their contribution to the consensus process. These public chains are generally considered to be "completely decentralized"
3. Developing decentralized applications
through this public chain, developers can easily develop centralized applications. Public chain can protect the rights and interests of users from the influence of program developers
According to experts, blockchain can be understood as a distributed public ledger, which is connected by various blocks into a chain. In the traditional bookkeeping system, the bookkeeping right is controlled by the central server
on the "account book" of blockchain, every point in the chain can record information on it, forming a point-to-point accounting system. Therefore, blockchain technology is considered as a decentralized technology
For example, in a village of 100 people, Zhang San bought a cow from Li Si and paid him 10000 yuan. In the past, he had to rely on Zhao Liu, a middleman, to transfer his 10000 yuan to Li Siwith the blockchain system, Zhang San can directly record his 10000 yuan to Li Si's account book, and the transaction information will be transmitted to the whole village, that is, the whole blockchain system, so that other 98 people can see the information. The whole transaction process is recorded by the system, which has the advantage of traceability to prevent the loss of Zhao Liu's account book or Li Si's denial of account
extended data
in 2008, Nakamoto first proposed the concept of blockchain. In the following years, blockchain became the core component of electronic currency bitcoin: as a public account book for all transactions. By using peer-to-peer network and distributed timestamp server, the blockchain database can be managed independently
the blockchain invented for bitcoin makes it the first digital currency to solve the problem of repeated consumption. The design of bitcoin has become a source of inspiration for other applications
blockchain is composed of a series of blocks generated by cryptographic algorithm. Each block is filled with transaction records, and the blocks are connected in sequence to form a chain structure, which is the blockchain ledger
taking bitcoin as an example, when miners generate new blocks, they need to calculate the new hash value and random number according to the hash value, new transaction block and random number of the previous block. In other words, each block is generated on the basis of the previous block data, which ensures the uniqueness of the blockchain data
because subtle changes in transaction records will completely change the result of hash value, miners can't cheat when competing for computing power. Each miner must wait until the previous block is generated before starting to calculate the qualified random number according to the data of the previous block, which ensures the fairness of mining.