|
A cryptocurrency (or crypto currency) is a medium of exchange using cryptography to secure the transactions and to control the creation of new units. Cryptocurrencies are a subset of alternative currencies, or specifically of digital currencies. Bitcoin became the first decentralized cryptocurrency in 2009. Since then, numerous cryptocurrencies have been created. These are frequently called ''altcoins'', as a blend of ''bitcoin alternative''.〔〔 Cryptocurrencies use decentralized control as opposed to centralized electronic money/centralized banking systems. The decentralized control is related to the use of bitcoin's block chain transaction database in the role of a distributed ledger. ==Overview== Decentralized cryptocurrency is produced by the entire cryptocurrency system collectively, at a rate which is defined when the system is created and which is publicly known. In centralized banking and economic systems such as the Federal Reserve System, corporate boards or governments control the supply of currency by printing units of fiat money or demanding additions to digital banking ledgers. However, companies or governments cannot produce units of cryptocurrency and as such, have not so far provided backing for other firms, banks or corporate entities which hold asset value measured in a decentralized cryptocurrency. The underlying technical system upon which decentralized cryptocurrencies are based was created by the group or individual known as Satoshi Nakamoto.〔(Bitcoin-block-signing History ), http://blockchain.info, 2 March 2014〕〔(Deflation and Banking ), http://www.econlib.org, 19 December 2006〕〔(Bitcoin Creation Mechanism ), https://en.bitcoin.it, 12 January 2014〕 , hundreds of cryptocurrency specifications exist; most are similar to and derived from the first fully implemented decentralized cryptocurrency, bitcoin.〔(Listing of active coins ), http://cryptocoincharts.info, 27 February 2014〕〔(another authentication protocol forked from P.O.S. ), https://en.bitcoin.it, 7 June 2013〕 Within cryptocurrency systems the safety, integrity and balance of ledgers is maintained by a community of mutually distrustful parties referred to as miners: members of the general public using their computers to help validate and timestamp transactions adding them to the ledger in accordance with a particular timestamping scheme. The security of cryptocurrency ledgers is based on the assumption that the majority of miners are honestly trying to maintain the ledger, having financial incentive to do so. Most cryptocurrencies are designed to gradually decrease production of currency, placing an ultimate cap on the total amount of currency that will ever be in circulation. This can mimic the scarcity (and value) of precious metals and avoid hyperinflation.〔〔(How Cryptocurrencies Could Upend Banks' Monetary Role ), American Banker, 26 May 2013〕 Compared with ordinary currencies held by financial institutions or kept as cash on hand, cryptocurrencies are less susceptible to seizure by law enforcement.〔〔(The FBI's Plan For The Millions Worth Of Bitcoins Seized From Silk Road ), Forbes, 4 October 2013〕 Existing cryptocurrencies are all pseudo-anonymous, though additions such as Zerocoin and its distributed laundry feature have been suggested, which would allow for true anonymity.〔('Zerocoin' Add-on For Bitcoin Could Make It Truly Anonymous And Untraceable ), Forbes, 26 May 2013〕〔(This is Huge: Gold 2.0 - Can code and competition build a better Bitcoin? ), New Bitcoin World, 26 May 2013〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cryptocurrency」の詳細全文を読む スポンサード リンク
|