(This is a comprehensive and in-depth book on blockchain technology. This book focuses on the implementation principle, consensus mechanism, application scenarios and future development direction of blockchain. This book has 5 chapters, the main content is: from the development process and principles of Bitcoin and blockchain, introduce the origin and successful application of blockchain; from blockchain and traditional industries, artificial intelligence, finance, big data, etc. The combination of various aspects describes the huge technological changes that blockchain can bring to people; introduces the main application scenarios and corresponding cases of blockchain technology, including proof of existence, smart contracts, supply chains, identity verification, asset transactions, market Forecasting, e-commerce, logistics, file storage, medical care, etc.; introduce the current successful blockchain technology practice projects from the aspects of principle, technological innovation, development, etc., including Ethereum, Notary Link, BitShares, Ripple, Hyperledger; from the blockchain network The evolution of itself, the Internet of Things, the Internet, etc., depicts the future blueprint of blockchain technology - building a next-generation Internet based on credit.)