Introduction to blockchains

A blockchain is a distributed database or ledger that maintains an ever-growing list of data records in opposition to tampering and revision. It provides immutable data storage over a distributed network and supports a large number of encrypted and coded interactions, which improves the reliability of the entire network interaction system and reduces the need for trust. Even if some nodes in the blockchain are hacked and fail, the system can run as usual. (In such a scenario, users are enabled to form a distributed peer -to peer (P2P) network in which they could interact with each other in an efficient manner without a trusted intermediary). In addition to being famous for decentralization, blockchain has shown other significant characteristics during its development, such as reliability, anonymity, transparency, auditability and programming. According to the different degree of openness and coverage, the current blockchain can be classified into three categories: public blockchain, consortium blockchain and private blockchain. In this process, the evolution of blockchain has gone through three processes: blockchain 1.0, 2.0 and 3.0. Blockchain 1.0, known as digital currency stage, is strongly related with the decentralization and payment of cryptocurrencies. Blockchain 2.0, known as digital finance stage, introduces economic, financial and market applications by programming far from simple currency transactions. Among them, the most significant features of blockchain 2.0 are the introduction and application of smart contracts. Blockchain 3.0, known as digital society stage, provides decentralized solutions for a variety of industries beyond just financial scene.