What is Bitcoin?

Bitcoin is a digital asset and a payment system invented by an unknown person or group of people under the name Satoshi Nakamoto and released as open-source software in 2009. Transactions are verified by network nodes through cryptography and recorded in a public dispersed ledger called a blockchain. 

The system is peer-to-peer, and transactions take place between users directly, without an intermediary. These transactions are verified by network nodes through the use of cryptography and recorded in a public distributed ledger called a blockchain. Bitcoin is unique in that there are a finite number of them: 21 million.