# BTC By [Untitled](https://paragraph.com/@0x4d9f004242ea41b460c94469382d88d46b84cc5f) · 2023-02-25 --- **Bitcoin** ([abbreviation](https://en.wikipedia.org/wiki/ISO_4217#Cryptocurrencies): **BTC**[\[a\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-BTCcode-16) or **XBT**[\[b\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-XBTcode-17); [sign](https://en.wikipedia.org/wiki/Currency_symbol): **₿**) is a [protocol](https://en.wikipedia.org/wiki/Communication_protocol) which implements a [highly available](https://en.wikipedia.org/wiki/High_availability), public, permanent, and decentralized [ledger](https://en.wikipedia.org/wiki/Ledger). In order to add to the ledger, a user must prove they control an entry in the ledger. The protocol specifies that the entry indicates an amount of a token, **bitcoin** with a minuscule b. The user can update the ledger, assigning some of their bitcoin to another entry in the ledger. Because the token has characteristics of money, it can be thought of as a [digital currency](https://en.wikipedia.org/wiki/Digital_currency).[\[10\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-18) Bitcoin transactions are verified by network [nodes](https://en.wikipedia.org/wiki/Node_\(networking\)) through [cryptography](https://en.wikipedia.org/wiki/Cryptography) and recorded in a public [distributed ledger](https://en.wikipedia.org/wiki/Distributed_ledger) called a [blockchain](https://en.wikipedia.org/wiki/Blockchain). The [cryptocurrency](https://en.wikipedia.org/wiki/Cryptocurrency) was invented in 2008 by an unknown person or group of people using the name [Satoshi Nakamoto](https://en.wikipedia.org/wiki/Satoshi_Nakamoto).[\[11\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-whoissn-19) The currency began use in 2009,[\[12\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-NY2011-20) when its implementation was released as [open-source software](https://en.wikipedia.org/wiki/Open-source_software).[\[7\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-Antonopoulos2014-12): ch. 1  The word "_bitcoin_" was defined in a [white paper](https://en.wikipedia.org/wiki/White_paper) published on October 31, 2008.[\[3\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-paper-6)[\[13\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-ageofcr-21) It is a [compound](https://en.wikipedia.org/wiki/Compound_\(linguistics\)) of the words [_bit_](https://en.wikipedia.org/wiki/Bit) and [_coin_](https://en.wikipedia.org/wiki/Coin).[\[14\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-btox-22) Bitcoin is legal in seven of the top ten world economies by GDP in 2022.[\[15\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-auto3-23)[\[16\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-auto2-24) The Library of Congress reports that, as of November 2021, nine countries have fully banned bitcoin use, while a further forty-two have implicitly banned it.[\[17\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-25) A few governments have used bitcoin in some capacity. [El Salvador has adopted Bitcoin](https://en.wikipedia.org/wiki/Bitcoin_in_El_Salvador) as legal tender, although use by merchants remains low. [Ukraine](https://en.wikipedia.org/wiki/Ukraine) has accepted cryptocurrency donations to fund the resistance to the [2022 Russian invasion](https://en.wikipedia.org/wiki/2022_Russian_invasion_of_Ukraine). [Iran](https://en.wikipedia.org/wiki/Iran) has used bitcoin to bypass [sanctions](https://en.wikipedia.org/wiki/Sanctions_against_Iran). In the United States, there is "no intention" to ban Bitcoin.[\[18\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-26) Bitcoin has been described as an [economic bubble](https://en.wikipedia.org/wiki/Economic_bubble) by at least eight recipients of the [Nobel Memorial Prize in Economic Sciences](https://en.wikipedia.org/wiki/Nobel_Memorial_Prize_in_Economic_Sciences).[\[19\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-4Nobels-27) The [environmental impact of bitcoin](https://en.wikipedia.org/wiki/Environmental_impact_of_bitcoin) is worth noting.[\[20\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-28) Its [proof-of-work](https://en.wikipedia.org/wiki/Proof-of-work) algorithm for [bitcoin mining](https://en.wikipedia.org/wiki/Bitcoin_mining) is designed to be computationally difficult, which requires the consumption of increasing quantities of electricity, the generation of which has contributed to [climate change](https://en.wikipedia.org/wiki/Climate_change).[\[21\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-29)[\[22\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-30) According to the [University of Cambridge](https://en.wikipedia.org/wiki/University_of_Cambridge), bitcoin has emitted an estimated 200 million metric tonnes of carbon dioxide since its launch, [\[23\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-31) or about 0.04% of all carbon dioxide released since 2009.[\[24\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-32) However, bitcoin miners have an economic incentive to use the cheapest forms of energy.[\[25\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-33)[\[26\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-34) [Renewable energy](https://en.wikipedia.org/wiki/Renewable_energy) is the cheapest form of energy over time,[\[27\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-35) so it is in a Bitcoin miner's economic interest to use the cheaper [renewable energy](https://en.wikipedia.org/wiki/Renewable_energy) when possible.[\[28\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-36) The UNESCO World Heritage Site, [Virunga National Park](https://en.wikipedia.org/wiki/Virunga_National_Park), in eastern Congo, Africa pays for its operations, using a profitable Bitcoin mining operation powered by the Park's hydroelectric plant.[\[29\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-37) Oil and gas giant Exxon mines Bitcoin using the natural gas flared by oil mining operations to generate their electricity.[\[30\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-38) Mining Bitcoin this way makes use of an otherwise "monumental waste of a valuable natural resource".[\[31\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-39) Still other miners reduce their overall energy bill by using the heat generated by their computers to heat their homes,[\[32\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-40) or [hot tubs](https://en.wikipedia.org/wiki/Hot_tub).[\[33\]](https://en.wikipedia.org/wiki/Bitcoin#cite_note-41) --- *Originally published on [Untitled](https://paragraph.com/@0x4d9f004242ea41b460c94469382d88d46b84cc5f/btc)*