Bitcoin[a] (?) is a cryptocurrency invented in 2008 by an unknown person or group of people using the name Satoshi Nakamoto.[13] The currency began use in 2009[14] when its implementation was released as open-source software.[6]:ch. 1
Bitcoin
₿))[a]Ticker symbolBTC, XBT[b]Precision10?8Subunits ??1?1000millibitcoin??1?100000000satoshi[2]DevelopmentOriginal author(s)Satoshi NakamotoWhite paper"Bitcoin: A Peer-to-Peer Electronic Cash System"[4]Implementation(s)Bitcoin CoreInitial release0.1.0 / 9 January 2009 (12 years ago)Latest release0.21.0 / 15 January 2021 (40 days ago)[3]Development statusActiveWebsitebitcoin.orgLedgerLedger start3 January 2009 (12 years ago)Timestamping schemeProof-of-work (partial hash inversion)Hash functionSHA-256Issuance scheduleDecentralized (block reward)
Initially ?50 per block, halved every 210,000 blocks[7]Block reward?6.25[c]Block time10 minutesBlock explorerwww.blockchain.com/explorerCirculating supply?18,355,100 (as of 1 May 2020)Supply limit?21,000,000[5][d]
- ^ The symbol was encoded in Unicode version 10.0 at position U+20BF ? BITCOIN SIGN in the Currency Symbols block in June 2017.[1]
- ^ Compatible with ISO 4217.
- ^ May 2020 to approximately 2024, halved approximately every four years
- ^ The supply will approach, but never reach, ?21 million. Issuance will permanently halt c.?2140 at ?20,999,999.9769.[6]:ch. 8
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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.[7] Transactions are verified by network nodes through cryptography 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.[15] Research produced by the University of Cambridge estimated that in 2017, there were 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin.[16]
Bitcoin has been criticized for its use in illegal transactions, the large amount of electricity used by miners, price volatility, and thefts from exchanges.[citation needed] Some economists, including several Nobel laureates, have characterized it as a speculative bubble at various times. Bitcoin has also been used as an investment, although several regulatory agencies have issued investor alerts about bitcoin.[17][18
