In essence, blockchain is a distributed and decentralized network database system. All node maintainers jointly manage, transmit and synchronize the data, store the data in block and chain structure, and use cryptography to guarantee the security of transmission and access, which can realize a technical system where data is stored consistently and cannot be manipulated or changed.
A lot of people know that the concept of blockchain is derived from Bitcoin. However, Bitcoin is not the same as blockchain. Blockchain is the technical foundation behind Bitcoin. Essentially, blockchain is a collection of distributed data storage, peer-to-peer transmission (P2P), consensus mechanism (used to maintain the operation and fairness of blockchain system, and provide incentives to the blockchain maintainers), encryption algorithm and other existing collective application model of computer technology. It is a serial transaction record (or block) of content concatenated and protected by cryptography. Each block contains the encrypted hash, timestamp, and transaction data of the previous block.
To put it simply, blockchain is a distributed database, where all node maintainers jointly manage, transmit, and synchronize this data. As it is not a traditional centralized database, it is difficult to tamper with the data arbitrarily.