Bitcoin is a cryptocurrency and a digital payment system, invented by an unknown programmer, or a group of programmers, under the name satoNakamoto.It was released as open-source software in 2009.
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. Since the system works without a central repository or single administrator, bitcoin is called the first decentralized digital currency.
The unit of account of the bitcoin system is bitcoin. As of 2014, symbols used to represent bitcoin are BTC,[note 1] XBT,[note 2] and ₿ (U+20BF, BitcoinSign.svg).[note 3][33]:2 Small amounts of bitcoin used as alternative units are millibitcoin (mBTC),[1] microbitcoin (µBTC, sometimes referred to as bit), and satoshi. Named in homage to bitcoin's creator, a satoshi is the smallest amount within bitcoin representing 0.00000001 bitcoin, one hundred millionth of a bitcoin.[9] A millibitcoin equals to 0.001 bitcoin, one thousandth of a bitcoin.[34] One microbitcoin equals to 0.000001 bitcoin, one millionth of a bitcoin.
General use:ccording to research produced by Cambridge University in 2017, there are between 2.9 million and 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin. The number of users has grown significantly since 2013, when there were 0.3 to 1.3 million users.