Bitcoin is a cryptocurrency, a form of electronic cash. It is the first decentralized digital currency: the system was designed to work without a central bank or single administrator.
Many economists and investors consider the bitcoin market to be a bubble. Bitcoin has also been criticized for its use in illegal transactions, its high electricity consumption, price volatility, and thefts from exchanges.
Bitcoins are sent from user to user on the peer-to-peer bitcoin network directly, without the need for intermediaries, though most transactions are made through a cryptocurrency exchange market. Transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a blockchain. Bitcoin was invented by an unknown person or group of people using the name Satoshi Nakamoto and released as open-source software in 2009.
Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies, products, and services. Research produced by the University of Cambridge estimates that in 2017, there were 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin.
