BitCoin (BTC) is a point-to-point electronic currency system implemented by Satoshi Nakamoto based on cryptography distributed ledger technology.

In Internet trade, people used to rely on centralized financial institutions to complete the payment of an order. In this process, there are often many restrictions and data is not transparent, facing the risk of tampering. Bitcoin provides a decentralized electronic payment system through distributed ledger technology based on cryptography, realizing transparent and open transaction data storage, traceability and query. At the same time, anyone in the world can participate in it without any region or transaction amount limit.

To provide a decentralized, permissive payment system has long been expected by the public. Before the launch of Bitcoin, there were many different electronic money technologies and products in the world, the earliest origin comes from the issuer based "Ecash" protocol proposed by David Chom and Stefan Blanz. Then came the emergence of digital currencies based on "ecash" protocols, including Adam Baker's "Hashcash," Wei Dai's "B-Money," Nick Saab's "bit-Gold," And Hal Finney's "RPOW" developed on the "Hashcash" technology. In the past implementation, it is often difficult to solve the "Byzantine general problem", and the system faces the risk of centralization.

Bitcoin system solves the problem of consensus in distributed systems through Pow (Proof of work) algorithm, and the system security can be ensured by more than 51% honest computing power.