The concept of Bitcoin (Bitcoin) was first proposed by Nakamoto in 2009, according to Satoshi Nakamoto's idea of ​​designing open source software and building a P2P network. Bitcoin is a P2P digital currency. Point-to-point transmission means a decentralized payment system. Unlike most currencies, Bitcoin does not rely on specific currency institutions to issue. It is based on specific algorithms and generated by a large number of calculations. The Bitcoin economy uses a distributed database of multiple nodes in the entire P2P network to confirm and record all transactions. And the use of cryptography design to ensure the security of the various aspects of currency circulation. P2P decentralization features and algorithms itself can ensure that can not be manipulated through the large number of bitcoin to manipulate the currency value. The cryptographic design allows bitcoin to be transferred or paid only by the real owner. This also ensures the anonymity of currency ownership and liquidity transactions. The biggest difference between Bitcoin and other virtual currencies is that their total number is very limited and they are extremely scarce. The currency system had no more than 10.5 million in 4 years, and the total amount will be permanently limited to 21 million.