Bitcoin is a cryptocurrency and worldwide payment system.[8]:3
It is the first decentralized digital currency, as the system works without a central bank or single administrator.[8]:1[9] The network is peer-to-peer and transactions take place between users directly through the use of cryptography, without an intermediary.[8]:4
These transactions are verified by network nodes 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[10] and released as open-source software in 2009.[11]
Bitcoin
Bitcoin logo.svg
Prevailing bitcoin logo
ISO 4217
Code XBT[a]
Denominations
Subunit
1⁄1000 millibitcoin[1]
1⁄100000000 satoshi[4]
Symbol ₿[b]
satoshi[4] sat
Coins Unspent outputs of transactions[3]:ch. 5
Demographics
Date of introduction 3 January 2009; 8 years ago
User(s) Worldwide
Issuance
Administration Decentralized[5][6]
Valuation
Supply growth 12.5 bitcoins per block (approximately every ten minutes) until mid 2020,[7] and then afterwards 6.25 bitcoins per block for 4 years until next halving. This halving continues until 2110–40, when 21 million bitcoins will have been issued.
^ Unofficial.
^ The symbol was encoded in Unicode version 10.0 at position U+20BF ₿ BITCOIN SIGN in the Currency Symbols block in June 2017.[2]
File:Bitcoin explained in 3 minutes.webmPlay media
Bitcoin explained in 3 minutes
Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies,[12] products, and services. As of February 2015, over 100,000 merchants and vendors accepted bitcoin as payment.[13] 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.[14]