In a narrow sense, blockchain is a chain data structure that combines data blocks in chronological order, and a tamper proof and forgeable distributed ledger guaranteed by cryptography.

Broadly speaking, blockchain technology is a new distributed infrastructure and computing method that uses block chain data structure to verify and store data, uses distributed node consensus algorithm to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses intelligent contract composed of automatic script code to program and operate data.

What is a blockchain? From the perspective of science and technology, blockchain involves many scientific and technological issues such as mathematics, cryptography, Internet and computer programming. From the perspective of application, in short, blockchain is a distributed shared ledger and database, which has the characteristics of decentralization, non tampering, leaving traces in the whole process, traceability, collective maintenance, openness and transparency. These characteristics ensure the "honesty" and "transparency" of the blockchain and lay a foundation for the creation of trust in the blockchain. The rich application scenarios of blockchain are basically based on blockchain, which can solve the problem of information asymmetry and realize cooperative trust and concerted action among multiple subjects.

Blockchain is a new application mode of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism and encryption algorithm. Blockchain is an important concept of bitcoin. In essence, it is a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks associated with cryptographic methods. Each data block contains a batch of information of bitcoin network transactions to verify the effectiveness of its information (anti-counterfeiting) And generate the next block.

In fact, the word blockchain does not appear in the original English version of bitcoin white paper, but the chain of blocks. In the Chinese translation of the earliest bitcoin white paper, the chain of blocks was translated into blockchain. This is the earliest time when the Chinese word "blockchain" appeared.

The state Internet Information Office issued the regulations on the management of blockchain information services on January 10, 2019, which will take effect from February 15, 2019.