(1) The concept of blockchain
Bitcoin as the ancestor of blockchain was first proposed by Satoshi Nakamoto [12], and its operation is supported by blockchain technology, but there is no unified definition of blockchain in the academic community at this stage. Swan defines blockchain as a decentralized database that is open and transparent. This paper argues that blockchain can be simply understood as a trustworthy and over-capacity public ledger, where every node in the system can participate in bookkeeping, and each page of the ledger contains all the transaction information in the system that cannot be tampered with and destroyed within a certain period of time, and the generated data "password" is used to verify the validity of the information and link to the next page.
From a technical point of view, blockchain is a function of a variety of variables; From its structural level, the blockchain can be regarded as a "block" + "chain" that stores transaction information, blocks are created one by one by the individuals involved in bookkeeping in chronological order, and the chain covering all transaction history is formed by the new blockchain generated by connecting to the previous block.
(2) Three characteristics of blockchain
1.Decentralization, avoiding the intervention of third parties.
The blockchain adopts a distributed structure, does not rely on any central equipment or management agency, and distributed ledger enables the recognized information to be quickly recorded in the block; The distributed propagation of transaction information avoids the transmission of information to the first server, so as to improve the efficiency of information dissemination; Distributed storage allows each subject to obtain all transaction information, preventing data loss or tampering.
2.Trustlessness and anonymity behind data transparency.
The traditional Internet establishes a trust relationship through a reliable central institution or a third party, while blockchain technology uses mathematical principles and algorithms to make the operation of the system open and transparent, and users who join the system can see all the transaction records of the blockchain, a public ledger. Therefore, the two parties to the transaction do not need to know the real identity and credit status of the other party, and do not need to rely on the credit endorsement of a third-party authority, but only need to look at the public ledger and trust the common algorithm to establish trust.
3.De-risking to ensure the security and immutability of information.
When a new block is generated in the blockchain, the node that generates the block will propagate it to the network for verification, and after it is verified to be valid, a new block will be added to the blockchain, and each node will back up the new transaction data, and no node can tamper with the data. In fact, the hacker's investment in controlling 51% of the computing power is much higher than the income obtained after success, so the attack is meaningless, and in the case of a large enough number of nodes, the hacker is not able to control 51% of the nodes, so the blockchain ensures that the data is safe and effective. In addition, the blockchain uses asymmetric encryption and digital signature encryption technology, and the public key encrypts the information and only the corresponding private key can be opened, so as to ensure data security.
(3) The development status and application of blockchain
By the end of 2017, more than 20 countries around the world had invested in the development of blockchain-related industries. With the innovation of blockchain technology, blockchain has changed from 10 Blockchain to a programmable society30.According to the "Development of China's Blockchain Industry" issued by the Ministry of Industry and Information Technology, China's blockchain industry is currently in a stage of rapid development, with a significant increase in enterprises entering the blockchain, and the blockchain industry chain is gradually improving.
As the underlying technical support, blockchain technology can bring profound changes to various fields such as finance, economy, science and technology, and even politics. According to the characteristics of blockchain, there can be two types of applications: first, based on the characteristics of blockchain distributed ledger, identity verification, proof of stake, and intelligent assets can be developed; Second, based on the decentralization of blockchain, industries involved in value transmission can be reconstructed through blockchain technology, which can exclude some central institutions, such as third-party payment platforms.