Bitcoin is a decentralized digital currency, without a central bank or single administrator, that can be sent from user to user on the peer-to-peer bitcoin network without the need for intermediaries. 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 under 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. As of February 2015, over 100,000 merchants and vendors accepted bitcoin as payment. 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.

As the first and most well-known cryptocurrency, bitcoin has been involved in many controversies and remains a controversial topic of discussion. Proponents of bitcoin say that it is a fast, efficient, and secure form of payment with a large potential market; opponents say that it is highly volatile and prone to hacks. The U.

S. Commodity Futures Trading Commission has classified bitcoin as a commodity, but not as a security.

As of May 2018, the total value of all existing bitcoins exceeded 100 billion US dollars, with millions of dollars worth of bitcoins exchanged daily.