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A cryptocurrency (or crypto currency) is a medium of exchange using cryptography to secure the transactions and to control the creation of new units.[1] Cryptocurrencies are a subset of alternative currencies or specifically of digital currencies. The first cryptocurrency to be created was Bitcoin in 2009.[dubious ] Since then, numerous cryptocurrencies have been created. A feature that is typical in cryptocurrency is decentralized control, distinct from a centralized electronic money system such as PayPal. Another common feature is that transactions are publicly recorded in a ledger. An example is Bitcoin, where all transactions are recorded in the block chain.


Cryptocurrency is produced by the entire cryptocurrency system collectively, at a rate which is prior defined and publicly known. In centralized banking and economic systems such as the Federal Reserve System, governments control the supply of currency by printing units of fiat money or demanding additions to digital banking ledgers. However, governments cannot produce units of cryptocurrency and as such, governments cannot provide backing for firms, banks or corporate entities which hold asset value measured in a decentralized cryptocurrency. The underlying technical system upon which all cryptocurrencies are now based was created by the group or individual known as Satoshi Nakamoto.[2][3][4]

Hundreds of cryptocurrency specifications now exist; most are similar to and derived from the first fully implemented cryptocurrency, Bitcoin.[dubious ][5][6] 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.[7]

The security of cryptocurrency ledgers is based on the assumption that the majority of miners are honestly trying to maintain the ledger.

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.[1][8] Compared with ordinary currencies held by financial institutions or kept as cash on hand, cryptocurrencies are less susceptible to seizure by law enforcement.[1][9][not in citation given] Existing cryptocurrencies are all pseudo-anonymous, though additions such as Zerocoin and its distributed laundry[10] feature have been suggested, which would allow for anonymity.[11][12][13]


The first cryptocurrency, Bitcoin, was created in 2009 by pseudonymous developer Satoshi Nakamoto. It used SHA-256, a cryptographic hash function, as its proof-of-work scheme.[14][15][16] In April 2011, Namecoin was created as an attempt at forming a decentralized DNS, which would make internet censorship very difficult. Soon after, in October 2011, Litecoin was released. It was the first successful cryptocurrency to use scrypt as its hash function instead of SHA-256. Another notable cryptocurrency, Peercoin was the first to use a proof-of-work/proof-of-stake hybrid.[17] Many other cryptocurrencies have been created though few have been successful, as they have brought little in the way of technical innovation. On 6 August 2014, the UK announced its Treasury had been commissioned to do a study of cryptocurrencies, and what role, if any, they can play in the UK economy. The study was also to report on whether regulation should be considered.[18]


Central bank representatives have stated that the adoption of cryptocurrencies such as Bitcoin pose a significant challenge to central banks' ability to influence the price of credit for the whole economy, they've also stated that as trade using cryptocurrencies become more popular, there is bound to be a loss of consumer confidence in fiat currencies. Gareth Murphy, a senior central banking officer has stated "widespread use [of cryptocurrency] would also make it more difficult for statistical agencies to gather data on economic activity, which are used by governments to steer the economy". He cautioned that virtual currencies pose a new challenge to central banks' control over the important functions of monetary and exchange rate policy.[19]

Jordan Kelley, founder of Robocoin launched the first Bitcoin ATM in the United States on February 20, 2014. The kiosk installed in Austin, Texas is similar to bank ATMs but has scanners to read government-issued identification such as a driver's license or a passport to confirm users' identities.[20]

The Dogecoin Foundation, a charitable organization centered around Dogecoin and co-founded by Dogecoin co-creator Jackson Palmer, donated more than $30,000 worth of Dogecoin to help fund the Jamaican bobsled team's trip to the 2014 Olympic games in Sochi, Russia.[21] The growing community around Dogecoin is looking to cement its charitable credentials by raising funds to sponsor service dogs for children with special needs.[22]


Cryptocurrencies are legal in all countries except Iceland, due primarily to Iceland's freeze on foreign exchange.[23] Controversy over the misuse of cryptocurrency has also led to restrictions in certain countries – regulators in China banned the handling of Bitcoins by financial institutions during an extremely fast adoption period in early 2014.[24] In Russia, though cryptocurrencies are perfectly legal, it is illegal to actually purchase goods with any currency other than the Russian ruble.[25]

On March 25, 2014 the IRS ruled that Bitcoin will be treated as property for tax purposes as opposed to currency. This means Bitcoin will be subject to capital gains tax. One benefit of this ruling is that it clarifies the legality of Bitcoin. No longer do investors need to worry that investments in or profit made from Bitcoins are illegal or how to report them to the IRS.[26]

Some cryptocurrency have legal issues such as Coinye, an altcoin that used, without permission, rapper Kanye West as its logo. This altcoin has been compared to the popular Dogecoin. Upon hearing of the release of Coinye, originally called Coinye West, attorneys for Kanye West sent a cease and desist letter to the email operator of Coinye, whose name remains unknown. The letter stated that Coinye was willful trademark infringement, unfair competition, cyberpiracy, and dilution and instructed Coinye to stop using the likeness and name of Kanye West.[27]


There have been very few arrests in the United States related to cryptocurrency. This is primarily due to the difficulty of tracking cryptocurrency payments. The arrests that have been made are all on charges of using cryptocurrency to launder money. The most notable case was the arrest of Charlie Shrem, the CEO of BitInstant, a Bitcoin exchange backed by the Winklevoss twins.[28]

Florida has taken a firm stance against money laundering through Bitcoin with its recent arrest of three money launderers. The launderers were purportedly using the website to launder hundreds of thousands of dollars worth in Bitcoin. They were apprehended after an undercover agent asked to purchase Bitcoin with the intent of buying stolen credit cards online.[29]

Though not directly related to cryptocurrency, Ross Ulbricht was arrested in October 2013 for allegedly running an illegal drug trafficking website, the Silk Road, that used Bitcoin as the only payment option. Ulbricht was arrested on charges of alleged murder-for-hire and narcotics trafficking violations and accused of being the founder and chief operator "Dread Pirate Roberts".


On August 6, 2013 Magistrate Judge Amos Mazzant of the Eastern District of Texas federal court ruled that because cryptocurrency (expressly Bitcoin) can be used as money (it can be used to purchase goods and services, pay for individual living expenses, and exchanged for conventional currencies), it is a currency or form of money. This ruling allowed for the SEC to have jurisdiction over cases of securities fraud involving cryptocurrency.[30]

GBL, a Chinese Bitcoin trading platform suddenly shut down, and up to $5 million worth of Bitcoin disappeared with it.[31] Subscribers were unable to log into the Chinese Bitcoin platform on October 26, 2013.

In February 2014 cryptocurrency made national headlines due to the world's largest Bitcoin exchange, Mt. Gox, declaring bankruptcy. The company stated that it had lost nearly $473 million of their customer's Bitcoins likely due to theft. This was equivalent to approximately 750,000 Bitcoin, or about 7% of all the Bitcoins in existence. Due to this crisis, among other news, the price of a Bitcoin fell from a high of about $1,160 in December to under $400 in February.[32]


To not need a trusted third party to timestamp transactions added to the blockchain ledger cryptocurrencies use various timestamping schemes.

Proof-of-work schemes[edit]

The first timestamping scheme invented was the proof-of-work scheme. The most widely used proof-of-work schemes are based on SHA-256, which was introduced by Bitcoin, and scrypt, which is used by currencies such as Litecoin.[17] The latter now dominates over the world of cryptocurrencies, with at least 480 confirmed implementations.[33]

Some other hashing algorithms that are used for proof-of-work include Blake, scrypt, SHA-3, and X11.

Proof-of-stake and combined schemes[edit]

Some cryptocurrencies, such as Peercoin, use a combined proof-of-work/proof-of-stake scheme,[17][34] while others such as Nxt[35] exclusively use proof-of-stake.

List of cryptocurrencies[edit]

This is a list of some of the well-known cryptocurrencies. There were more than 530 cryptocurrencies available for trade in online markets as of 7 November 2014 but only 10 of them had market capitalizations over $10 million.[36]

ReleaseCurrencySymbolFounderHash AlgorithmTimestamping
2009Bitcoin[nt 1]BTC[37][38]Satoshi Nakamoto[nt 2][39]SHA-256d[40][41]POW[41][42]
2011Namecoin[nt 3]NMCVincent Durham[43][44]SHA-256POW
2011[41]Litecoin[nt 4]LTCCharles Lee[39]scrypt[41]POW
2012[41]PeercoinPPCSunny King
SHA-256[46]POW & POS
2013Ripple[nt 5][47][48][49]XRP[49]Chris Larsen &
Jed McCaleb[50]
2013MastercoinMSCJ. R. Willett [52]SHA-256d[53]N/A
2013PrimecoinXPMSunny King
2013Dogecoin[nt 6]DOGEJackson Palmer
& Billy Markus[55]
2014[57]Darkcoin[nt 7]DRKEvan Duffield &
Kyle Hagan[58]
X11POW & POS[nt 8]
2014AuroracoinAURBaldur Odinsson


  1. ^ The first decentralized ledger currency.
  2. ^ It is not known whether the name "Satoshi Nakamoto" is real or a pseudonym, or whether it represents one person or a group of people.
  3. ^ A cryptocurrency that also acts as an alternative, decentralized DNS.
  4. ^ The first successful scrypt cryptocurrency.
  5. ^ A unique cryptocurrency based on peer to peer debt transfer. The term Ripple can also refer to both the digital currency (also known as XRP), or to the payment network on which it and other digital currencies can be traded.
  6. ^ A cryptocurrency based on an internet meme.
  7. ^ A cryptocurrency that adds privacy to transactions through a decentralized coin-mixing system called Darksend.
  8. ^ Via Masternodes containing 1000 DRK as "Proof of Service". Through an automated voting mechanism, one Masternode is selected per block and receives 20% of mining rewards.


See also[edit]


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  3. ^ Deflation and Banking,, 19 December 2006
  4. ^ Bitcoin Creation Mechanism,, 12 January 2014
  5. ^ Listing of active coins,, 27 February 2014
  6. ^ another authentication protocol forked from P.O.S.,, 7 June 2013
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  11. ^ 'Zerocoin' Add-on For Bitcoin Could Make It Truly Anonymous And Untraceable, Forbes, 26 May 2013
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