Bitcoin
| Bitcoin | |
|---|---|
Prevailing bitcoin logo
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| ISO 4217 | |
| Code | XBT |
| Denominations | |
| Subunit | |
| 10−3 | millibitcoin |
| 10−6 | microbitcoin, bit |
| 10−8 | satoshi |
| Symbol | BTC, XBT, (B͈̎), Ƀ |
| millibitcoin | mBTC |
| microbitcoin, bit | μBTC |
| Coins | Unspent outputs of transactions denominated in any multiple of satoshis |
| Demographics | |
| Date of introduction | 3 January 2009 |
| User(s) | Worldwide |
| Issuance | |
| Administration | Decentralized |
| Valuation | |
| Supply growth | 12.5 bitcoins per block (approximately every ten minutes) until mid 2020, 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. |
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Bitcoin is both a and an electronic payment system invented by an unidentified programmer, or group of programmers, under the name of Satoshi Nakamoto. Bitcoin was introduced on 31 October 2008 to a cryptography mailing list, and released as open-source software in 2009. The identity of Nakamoto remains unknown, though many have claimed to know it. 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 the blockchain, which uses bitcoin as its unit of account. Since the system works without a central repository or single administrator, the U.S. Treasury categorizes bitcoin as a decentralized virtual currency. Bitcoin is often called the first cryptocurrency, although prior systems existed, and it is more correctly described as the first decentralized digital currency. Bitcoin is the largest of its kind in terms of total market value.
Bitcoins are created as a reward in a competition in which users offer their computing power to verify and record bitcoin transactions into the blockchain. This activity is referred to as mining and successful miners are rewarded with transaction fees and newly created bitcoins. Besides being obtained by mining, bitcoins can be exchanged for other currencies, products, and services. When sending bitcoins, users can pay an optional transaction fee to the miners. This may expedite the transaction being confirmed.
As of February 2015, over 100,000 merchants and vendors accept bitcoin as payment. Instead of a 2–3% fee typically imposed by credit card processors, merchants accepting bitcoins often pay fees of 0% to less than 2% of the total purchase. Despite the fourfold increase in the number of merchants accepting bitcoin in 2014, the cryptocurrency did not have much momentum in retail transactions. The European Banking Authority and other sources have warned that bitcoin users are not protected by refund rights or chargebacks.
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Wikipedia