Blockchain is a peer-to-peer network system for creating and storing vast transaction data in the form of blockchains, through technologies such as cryptography and consensus mechanisms.

Each block contains the encrypted hash of the previous block, a corresponding timestamp, and transaction data. This design makes the content of the block difficult to tamper with. The distributed ledger formed by blockchain technology allows two parties to effectively record transactions and verify them permanently.

At present, the largest application of blockchain technology is digital currency, such as the invention of Bitcoin. The essence of payment is "the amount of money reduced from account A is increased to account B". If people have a public ledger that records all transactions of all accounts to date, then for any account, people can calculate the current amount of money it has. The blockchain is precisely the public ledger designed for this purpose, which preserves all transaction records. In the Bitcoin system, the Bitcoin address is equivalent to the account, and the number of Bitcoins is equivalent to the amount of money.

Blockchain originated from Bitcoin. Satoshi Nakamoto proposed the concept of "blockchain" in 2008 in "Bitcoin: A Peer-to-Peer Electronic Cash System," describing the architectural concept of an electronic cash system based on P2P network technology, encryption technology, timestamp technology, blockchain technology, etc. On January 3, 2009, the first block with a sequence number of 0, known as the "Genesis Block," was born, marking the birth of Bitcoin. A few days later, on January 9, 2009, the block with a sequence number of 1 appeared and connected to the Genesis Block with a sequence number of 0, forming a chain, which marked the birth of the blockchain.