Bitcoin is the first worldwide decentralized crypto currency and digital payment system called digital currency, as the system works without a central repository or single administrator. The system is peer-to-peer, and transactions take place between users directly, without an intermediary. These transactions are verified by network nodes and recorded in a public distributed ledger called a blockchain.
Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies, products, and services. As of February 2015, over 100,000 merchants and vendors accepted bitcoin as payment. Bitcoin can also be held as an investment. According to research produced by Cambridge University in 2017, there are 2.9 to 5.8 million unique users using a crypto currency wallet, most of them using bitcoin.