BITCOIN OF CRYPTOCURRENCY BY WIKIPEDIA

Bitcoin is a cryptocurrency and worldwide payment system.[9]:3 It is the first decentralized digital currency, as the system works without a central bank or single administrator.[9]:1[10] The network is peer-to-peer and transactions take place between users directly, without an intermediary.[9]:4 These transactions are verified by network nodes through the use of 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[11] and released as open-source software in 2009.[12]

Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies,[13] products, and services. As of February 2015, over 100,000 merchants and vendors accepted bitcoin as payment.[14] Research produced by the University of Cambridge estimates that in 2017, there are 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin.[15]

Units
The unit of account of the bitcoin system is bitcoin. Ticker symbols used to represent bitcoin are BTC[a] and XBT.[b] Its Unicode character is ₿.[25]:2 Small amounts of bitcoin used as alternative units are millibitcoin (mBTC)[1], bit (ƀ)[26][better source needed][3][better source needed] and satoshi (sat). Named in homage to bitcoin's creator, a satoshi is the smallest amount within bitcoin representing 0.00000001 bitcoins, one hundred millionth of a bitcoin.[4] A bit equals 0.000001 bitcoins, one millionth of a bitcoin or 100 satoshis. A millibitcoin equals 0.001 bitcoins, one thousandth of a bitcoin or 100,000 satoshis.[27]