A bitcoin ATM machine is shown at a restaurant in San Diego, California September 18, 2014. The device enables the user to convert cash to bitcoins via a QR code transfer to an application on their mobile device. REUTERS/Mike Blake (UNITED STATES - Tags: SOCIETY BUSINESS SCIENCE TECHNOLOGY) 

A U.S. bank note is inserted into a bitcoin ATM machine at a restaurant in San Diego, California September 18, 2014. The device enables the user to convert cash to bitcoins via a QR code transfer to an application on their mobile device. REUTERS/Mike Blake (UNITED STATES - Tags: SOCIETY BUSINESS SCIENCE TECHNOLOGY) 

A mobile device is shown after cash was converted to bitcoins from a Bitcoin ATM machine (shown in the background) at a restaurant in San Diego, California September 18, 2014. The bitcoin ATM ingests cash enabling the user to convert their money to bitcoins via a QR code transfer to an application on their mobile device. REUTERS/Mike Blake (UNITED STATES - Tags: SOCIETY BUSINESS SCIENCE TECHNOLOGY) 

Bitcoin Merchant CEO Steven Michael explains how a bitcoin ATM machine differs from a normal ATM machine at a restaurant in San Diego, California September 18, 2014. The device enables the user to convert cash to bitcoins via a QR code transfer to an application on their mobile device. REUTERS/Mike Blake (UNITED STATES - Tags: SOCIETY BUSINESS SCIENCE TECHNOLOGY) 

Bitcoin Merchant CEO Steven Michaels poses for a photo in San Diego, California September 18, 2014. His company installs bitcoin ATM machines that enable customers to convert cash to bitcoins via a QR code transfer to an application on their mobile device. REUTERS/Mike Blake (UNITED STATES - Tags: SOCIETY BUSINESS SCIENCE TECHNOLOGY PROFILE) 

A view of Romania's first bitcoin ATM is seen in downtown Bucharest June 27, 2014. In a well-lit office with red window frames in downtown Bucharest, Romania's first bitcoin ATM attracts many who until it opened in May had to buy or sell the digital currency face-to-face or through wire transfers. The interest in bitcoin in Romania stands out in a region where national currencies are widely seen as poor substitutes for the euro. Tech-savvy and still deeply distrustful of officialdom 25 years after the end of communism, many Romanians are unfazed by warnings about the cryptocurrency. Picture taken June 27, 2014. To match Feature ROMANIA-BITCOIN/ REUTERS/Bogdan Cristel (ROMANIA - Tags: BUSINESS SOCIETY SCIENCE TECHNOLOGY) 

The logo of Bitcoin (virtual currency) is pictured on a door in an illustration picture taken at La Maison du Bitcoin in Paris July 11, 2014. REUTERS/Benoit Tessier (FRANCE - Tags: BUSINESS) 

A Bitcoin (virtual currency) paper wallet with QR codes and coins are seen in an illustration picture taken at La Maison du Bitcoin in Paris July 11, 2014. French police dismantled an illegal Bitcoin exchange and seized 388 virtual currency units worth some 200,000 euros ($272,800) in the first such operation in Europe a public prosecutor said on Monday. REUTERS/Benoit Tessier (FRANCE - Tags: BUSINESS) 

Bitcoin (virtual currency) coins are seen in an illustration picture taken at La Maison du Bitcoin in Paris July 11, 2014. French police dismantled an illegal Bitcoin exchange and seized 388 virtual currency units worth some 200,000 euros ($272,800) in the first such operation in Europe a public prosecutor said on Monday. REUTERS/Benoit Tessier (FRANCE - Tags: BUSINESS) 

A Bitcoin (virtual currency) paper wallet printer is seen in an illustration picture taken at La Maison du Bitcoin in Paris July 11, 2014. French police dismantled an illegal Bitcoin exchange and seized 388 virtual currency units worth some 200,000 euros ($272,800) in the first such operation in Europe, a public prosecutor said on Monday. REUTERS/Benoit Tessier (FRANCE - Tags: BUSINESS) 

A Bitcoin (virtual currency) mining machine and a paper wallet with QR codes are seen in an illustration picture taken at La Maison du Bitcoin in Paris July 11, 2014. French police dismantled an illegal Bitcoin exchange and seized 388 virtual currency units worth some 200,000 euros ($272,800) in the first such operation in Europe, a public prosecutor said on Monday. REUTERS/Benoit Tessier (FRANCE - Tags: BUSINESS) 

A bitcoin sticker is seen in the window of Locali Conscious Convenience store, where one of Southern California's first two bitcoin-to-cash ATMs began operating today, in Venice, Los Angeles, California, June 21, 2014. The $15,000 ZenBox bitcoin ATMs are managed by Santa Monica company ExpressCoin, and were built by Robocoin. REUTERS/Lucy Nicholson (UNITED STATES - Tags: BUSINESS SCIENCE TECHNOLOGY) 

Zenbox CEO Cailen D. Sullivan talks to store customers about bitcoin as he sits next to one of Southern California's first two bitcoin-to-cash ATMs which began operating today, in Locali Conscious Convenience store in Venice, Los Angeles, California, June 21, 2014. The $15,000 ZenBox bitcoin ATMs are managed by Santa Monica company ExpressCoin, and were built by Robocoin. REUTERS/Lucy Nicholson (UNITED STATES - Tags: BUSINESS SCIENCE TECHNOLOGY) 

One of Southern California's first two bitcoin-to-cash ATMs which began operating today, is seen in Locali Conscious Convenience store in Venice, Los Angeles, California, June 21, 2014. The $15,000 ZenBox bitcoin ATMs are managed by Santa Monica company ExpressCoin, and were built by Robocoin. REUTERS/Lucy Nicholson (UNITED STATES - Tags: BUSINESS) 

Dana Byerlee, 33, of Santa Monica, buys bitcoins at one of Southern California's first two bitcoin-to-cash ATMs which began operating today, in Locali Conscious Convenience store in Venice, Los Angeles, California, June 21, 2014. The $15,000 ZenBox bitcoin ATMs are managed by Santa Monica company ExpressCoin, and were built by Robocoin. REUTERS/Lucy Nicholson (UNITED STATES - Tags: BUSINESS SCIENCE TECHNOLOGY) 

Dana Byerlee, 33, of Santa Monica, prepares to use one of Southern California's first two bitcoin-to-cash ATMs which began operating today, in Locali Conscious Convenience store in Venice, Los Angeles, California, June 21, 2014. The $15,000 ZenBox bitcoin ATMs are managed by Santa Monica company ExpressCoin, and were built by Robocoin. REUTERS/Lucy Nicholson (UNITED STATES - Tags: BUSINESS SCIENCE TECHNOLOGY) 

Dana Byerlee, 33, of Santa Monica, buys bitcoins at one of Southern California's first two bitcoin-to-cash ATMs which began operating today, in Locali Conscious Convenience store in Venice, Los Angeles, California, June 21, 2014. The $15,000 ZenBox bitcoin ATMs are managed by Santa Monica company ExpressCoin, and were built by Robocoin. REUTERS/Lucy Nicholson (UNITED STATES - Tags: BUSINESS) 

Bitcoin ATM receipts lie on a table inside Locali Conscious Convenience store, where one of Southern California's first two bitcoin-to-cash ATMs began operating today, in Venice, Los Angeles, California, June 21, 2014. The $15,000 ZenBox bitcoin ATMs are managed by Santa Monica company ExpressCoin, and were built by Robocoin. REUTERS/Lucy Nicholson (UNITED STATES - Tags: BUSINESS SCIENCE TECHNOLOGY) 

A Bitcoin sign is seen in a window in Toronto, May 8, 2014. REUTERS/Mark Blinch (CANADA - Tags: BUSINESS LOGO) 

A Bitcoin Teller Machine is seen in Toronto, May 8, 2014. REUTERS/Mark Blinch (CANADA - Tags: BUSINESS) 

A "Bitcoin Decentral" sign is seen in front of the CN Tower in Toronto, May 8, 2014. REUTERS/Mark Blinch (CANADA - Tags: BUSINESS) 

ANXBTC bitcoin exchange Chief Executive Ken Lo poses with Hong Kong's first bitcoin ATM during a demonstration in Hong Kong March 13, 2014. The territory's first bitcoin retail store was opened in February. REUTERS/Bobby Yip (CHINA - Tags: BUSINESS SCIENCE TECHNOLOGY) 

A smartphone with a QR code is seen in front of Hong Kong's first bitcoin ATM during a demonstration at a bitcoin exchange in Hong Kong March 13, 2014. The territory's first bitcoin retail store was opened in February. REUTERS/Bobby Yip (CHINA - Tags: BUSINESS SCIENCE TECHNOLOGY) 

The screen of a Bitcoin machine is seen at the Old Shoreditch Station Cafe and Bar in east London March 7, 2014. Britain's first machine for dispensing digital currency opened for business in a cafe near London's "Silicon roundabout" tech hub in east London on Friday, offering customers the ability to exchange bank notes for bitcoins. REUTERS/Andrew Winning (BRITAIN - Tags: SOCIETY BUSINESS) 

A customer sits near a Bitcoin machine at the Old Shoreditch Station Cafe and Bar in east London March 7, 2014. Britain's first machine for dispensing digital currency opened for business in a cafe near London's "Silicon roundabout" tech hub in east London on Friday, offering customers the ability to exchange bank notes for bitcoins. REUTERS/Andrew Winning (BRITAIN - Tags: SOCIETY BUSINESS) 

A man widely believed to be Bitcoin currency founder Satoshi Nakamoto, also known as Dorian Nakamoto, is surrounded by reporters as he leaves his home in Temple City, California March 6, 2014. REUTERS/David McNew (UNITED STATES - Tags: BUSINESS TPX IMAGES OF THE DAY) 

Satoshi Nakamoto, also known as Dorian Nakamoto, is surrounded by reporters as he leaves his home in Temple City, California, March 6, 2014. The reclusive Japanese American man, thought to be the father of Bitcoin, emerged from his Southern California home and denied any involvement with the digital currency, before leading reporters on a car chase leading to the headquarters of the Associated Press. Bitcoin is a digital currency that, unlike conventional money, is bought and sold on a peer-to-peer network independent of central control. Its value soared last year, and the total worth of bitcoins minted is now about $7 billion. REUTERS/David McNew (UNITED STATES - Tags: BUSINESS TPX IMAGES OF THE DAY) 

A man widely believed to be Bitcoin currency founder Satoshi Nakamoto, also known as Dorian Nakamoto, is surrounded by reporters as he leaves his home in Temple City, California March 6, 2014. REUTERS/David McNew (UNITED STATES - Tags: BUSINESS TPX IMAGES OF THE DAY HEADSHOT) 

A general view of the home (in blue) of Autumn Radtke, chief executive of First Meta Pte Ltd, in Singapore March 6, 2014. Singapore police are investigating the apparent suicide of the 28-year-old American woman who ran a small exchange in the Asian city state trading virtual currencies. REUTERS/Edgar Su (SINGAPORE - Tags: OBITUARY SOCIETY) 

Chrysanthemum flowers are seen, at the place where residents say the body of Autumn Radtke, chief executive of First Meta Pte Ltd, was found, on the second floor of a public housing estate in Singapore March 6, 2014. A cleaner said the flowers were offered by residents after the incident. Singapore police are investigating the apparent suicide of the 28-year-old American woman who ran a small exchange in the Asian city state trading virtual currencies. REUTERS/Edgar Su (SINGAPORE - Tags: OBITUARY SOCIETY) 

Mark Karpeles (2nd L), chief executive of Mt. Gox, attends a news conference at the Tokyo District Court in Tokyo February 28, 2014. Mt. Gox, once the world's biggest bitcoin exchange, filed for bankruptcy protection on Friday, saying it may have lost all of its investors' virtual coins due to hacking into its faulty computer system. Karpeles, bowing in contrition and wearing a suit instead of his customary T-shirt, apologised in Japanese at a news conference for the company's collapse, blaming "a weakness in our system." REUTERS/Yuya Shino (JAPAN - Tags: CRIME LAW BUSINESS TPX IMAGES OF THE DAY) 

Mark Karpeles, chief executive of Mt. Gox, attends a news conference at the Tokyo District Court in Tokyo February 28, 2014. Mt. Gox, once the world's biggest bitcoin exchange, filed for bankruptcy protection on Friday, saying it may have lost all of its investors' virtual coins due to hacking into its faulty computer system. Karpeles, bowing in contrition and wearing a suit instead of his customary T-shirt, apologised in Japanese at a news conference for the company's collapse, blaming "a weakness in our system." REUTERS/Yuya Shino (JAPAN - Tags: CRIME LAW BUSINESS) 

Mark Karpeles (L), chief executive of Mt. Gox, leaves in a taxi after a news conference at the Tokyo District Court in Tokyo February 28, 2014. Mt. Gox, once the world's biggest bitcoin exchange, filed for bankruptcy protection on Friday, saying it may have lost all of its investors' virtual coins due to hacking into its faulty computer system. Karpeles, bowing in contrition and wearing a suit instead of his customary T-shirt, apologised in Japanese at a news conference for the company's collapse, blaming "a weakness in our system." REUTERS/Yuya Shino (JAPAN - Tags: CRIME LAW BUSINESS) 

Protester Aaron holds a placard during a demonstration against Mt. Gox, in front of the building where the digital marketplace operator is housed, in Tokyo February 25, 2014. The website of Mt. Gox appears to be taken down, shortly after six major Bitcoin exchanges released a joint statement distancing themselves from the troubled Tokyo-based bitcoin exchange. Tokyo-based Mt. Gox was a founding member and one of the three elected industry representatives on the board of the Bitcoin Foundation. REUTERS/Toru Hanai (JAPAN - Tags: BUSINESS CIVIL UNREST SCIENCE TECHNOLOGY) 

Kolin Burges (R), a self-styled cryptocurrency trader and former software engineer from London, holds a placard to protest against Mt. Gox, as photographers take photos of him in front of the building where the digital marketplace operator was formerly housed in Tokyo February 26, 2014. Japanese authorities are looking into the abrupt closure of Mt. Gox, the top government spokesman said on Wednesday in Tokyo's first official reaction to the turmoil at what was the world's biggest exchange for bitcoin virtual currency. REUTERS/Toru Hanai (JAPAN - Tags: BUSINESS SCIENCE TECHNOLOGY CIVIL UNREST) 

Kolin Burges, a self-styled cryptocurrency trader and former software engineer who came from London, holds a placard to protest against Mt. Gox, in front of the building where the digital marketplace operator is housed in Tokyo February 25, 2014. The website of Mt. Gox appears to be taken down, shortly after six major Bitcoin exchanges released a joint statement distancing themselves from the troubled Tokyo-based bitcoin exchange. Tokyo-based Mt. Gox was a founding member and one of the three elected industry representatives on the board of the Bitcoin Foundation. REUTERS/Toru Hanai (JAPAN - Tags: BUSINESS CIVIL UNREST SCIENCE TECHNOLOGY) 

(L-R) ANXBTC bitcoin exchange Chief Operations Officer Dave Chapman, Chief Executive Ken Lo and Chief Technology Officer Hugh Madden pose with a bitcoin sign outside Hong Kong's first bitcoin retail store during its opening, in Hong Kong February 28, 2014. REUTERS/Bobby Yip (CHINA - Tags: BUSINESS) 

A smartphone display shows the average bitcoin exchange rates against the U.S. dollar, British sterling pound, and the euro during a media opportunity at the Tokyo Bitcoin weekly meeting at a restaurant in Tokyo February 27, 2014. Any regulation of the bitcoin crypto-currency should involve international cooperation to avoid loopholes, Japanese vice finance minister Jiro Aichi said on Thursday. Commenting on the closure this week of Tokyo-based Mt. Gox, once the world's biggest exchange for the bitcoin virtual currency, Aichi said the ministry would respond to the problems "if necessary", after finding out exactly what happened. REUTERS/Yuya Shino (JAPAN - Tags: BUSINESS SCIENCE TECHNOLOGY POLITICS) 

A man checks the graph showing recent fluctuations on Bitcoin exchange rates against the U.S. dollar on his laptop during a media opportunity at the Tokyo Bitcoin weekly meeting at a restaurant in Tokyo February 27, 2014. Any regulation of the bitcoin crypto-currency should involve international cooperation to avoid loopholes, Japanese vice finance minister Jiro Aichi said on Thursday. Commenting on the closure this week of Tokyo-based Mt. Gox, once the world's biggest exchange for the bitcoin virtual currency, Aichi said the ministry would respond to the problems "if necessary", after finding out exactly what happened. REUTERS/Yuya Shino (JAPAN - Tags: BUSINESS POLITICS SCIENCE TECHNOLOGY) 

Tembusu Terminals' partners Peter Peh Sik Wee (2nd R) and Jarrod Luo (R) speak to the media before launching the first Bitcoin vending machine at a pub in Singapore February 27, 2014. According to Tembusu Terminals, this is the first Bitcoin vending machine in Asia. REUTERS/Edgar Su (SINGAPORE - Tags: BUSINESS SCIENCE TECHNOLOGY) 

Tembusu Terminals' Andras Kristof gestures as he speaks to the media after launching the first Bitcoin vending machine at a pub in Singapore February 27, 2014. According to Tembusu Terminals, this is the first Bitcoin vending machine in Asia. REUTERS/Edgar Su (SINGAPORE - Tags: BUSINESS SCIENCE TECHNOLOGY) 

The Liberty Teller bitcoin purchasing terminal is seen at South Station in Boston, Massachusetts, February 25, 2014. REUTERS/Dominick Reuter (UNITED STATES - Tags: BUSINESS) 

A customer inserts U.S. currency into the Liberty Teller bitcoin purchasing terminal at South Station in Boston, Massachusetts, February 25, 2014. REUTERS/Dominick Reuter (UNITED STATES - Tags: BUSINESS) 

Dave Mitchell (L) purchases bitcoin at the Liberty Teller kiosk as Liberty Teller co-founder Chris Yim looks on at South Station in Boston, Massachusetts, February 25, 2014. REUTERS/Dominick Reuter (UNITED STATES - Tags: BUSINESS) 

Bitcoin Foundation Vice Chairman Charlie Shrem exits the Manhattan Federal Courthouse in New York January 27, 2014. Shrem has been charged by U.S. prosecutors with conspiring to commit money laundering by helping to funnel cash to illicit online drugs bazaar Silk Road. Shrem, who was also charged with operating an unlicensed money transmitting business, appeared in U.S. District Court in Manhattan on Monday and was released on a $1 million bond. REUTERS/Lucas Jackson (UNITED STATES - Tags: CRIME LAW BUSINESS TPX IMAGES OF THE DAY) 

A customer uses the world's first ever permanent bitcoin ATM unveiled at a coffee shop in Vancouver, British Columbia October 29, 2013. The kiosk, built by Las Vegas RoboCoin and operated by local dealer Bitcoiniacs, will allow users to withdraw their bit coins in the form of Canadian dollars or deposit cash to buy more bitcoins. REUTERS/Andy Clark (CANADA - Tags: SOCIETY BUSINESS SCIENCE TECHNOLOGY) 

An employee of a bitcoin exchange company displays bitcoin vouchers, which are worth around HK$9 (US$1.15), in Hong Kong February 11, 2014. About 50,000 such vouchers were distributed as "lai see" or red packets during the Lunar New Year in the territory to promote the use of bitcoin. A retail store and an ATM machine for the digital currency is expected to be launched in the territory, according to the organizers of the event. REUTERS/Bobby Yip (CHINA - Tags: BUSINESS SCIENCE TECHNOLOGY) 

People sit inside the Bitcoin Embassy in Tel Aviv February 2, 2014. The sparely furnished property opened a few months ago to support a community of Bitcoin fanatics, perhaps the most active in the world, who are out to build just that - a next-generation trading system based on the digital currency. Picture taken February 2, 2014. REUTERS/Baz Ratner (ISRAEL - Tags: BUSINESS) 

Mock Bitcoins are displayed on a table in an illustration picture taken in Berlin January 7, 2014. European banking regulators warn consumers against hacking and other risks associated with online currencies like Bitcoin. It follows similar advisories from the Bank of France and the Chinese central bank - and adds pressure to calls for the sector to be regulated. REUTERS/Pawel Kopczynski (GERMANY - Tags: BUSINESS) 

A mock Bitcoin is displayed on a table in an illustration picture taken in Berlin January 7, 2014. European banking regulators warn consumers against hacking and other risks associated with online currencies like Bitcoin. It follows similar advisories from the Bank of France and the Chinese central bank - and adds pressure to calls for the sector to be regulated. REUTERS/Pawel Kopczynski (GERMANY - Tags: BUSINESS) 

Some of Bitcoin enthusiast Mike Caldwell's coins in this photo illustration at his office in Sandy, Utah, September 17, 2013. Bitcoins, touted by some experts as the future of money, gained in prominence during Europe's financial crisis as more people questioned the safety of holding their cash in the bank. Cameron and Tyler Winklevoss, currently making headlines with plans to launch a Bitcoin fund, said on Tuesday that they could see the digital currency becoming a country's official money. REUTERS/Jim Urquhart (UNITED STATES - Tags: BUSINESS SOCIETY) 

Bitcoin enthusiast Mike Caldwell poses at his office in Sandy, Utah, September 17, 2013. Caldwell produces physical coins Bitcoins, which have been around since 2008, and have become a form of electronic money that can be exchanged without using traditional banking or money transfer systems. Bitcoins, touted by some experts as the future of money, gained in prominence during Europe's financial crisis as more people questioned the safety of holding their cash in the bank. REUTERS/Jim Urquhart (UNITED STATES - Tags: BUSINESS SOCIETY) 

Bitcoins created by enthusiast Mike Caldwell are seen in a photo illustration at his office in Sandy, Utah, September 17, 2013. Caldwell produces physical coins Bitcoins, which have been around since 2008, are a form of electronic money that can be exchanged without using traditional banking or money transfer systems. REUTERS/Jim Urquhart (UNITED STATES - Tags: BUSINESS SOCIETY) 

One of Bitcoin enthusiast Mike Caldwell's coins in this photo illustration at his office in Sandy, Utah, September 17, 2013. Bitcoins, touted by some experts as the future of money, gained in prominence during Europe's financial crisis as more people questioned the safety of holding their cash in the bank. Cameron and Tyler Winklevoss, currently making headlines with plans to launch a Bitcoin fund, said on Tuesday that they could see the digital currency becoming a country's official money. REUTERS/Jim Urquhart (UNITED STATES - Tags: BUSINESS SOCIETY) 

A chain of block erupters used for Bitcoin mining is pictured at the Plug and Play Tech Center in Sunnyvale, California October 28, 2013. Since discovering digital currency Bitcoins a few months ago, Aaron Jackson-Wilde has paid about $2,000 for "rigs" powered by specialised computer chips which are designed to help operate and maintain the Bitcoin network - and, in return, generate a small reward in a process known as "Bitcoin mining". A form of electronic money independent of traditional banking, Bitcoins started circulating in 2009 and have since become the most prominent of several fledgling digital currencies. Picture taken October 28. To match Feature TECHNOLOGY-BITCOINS/ REUTERS/Stephen Lam (UNITED STATES - Tags: BUSINESS SCIENCE TECHNOLOGY) 

BITCOIN/ - Updates bitcoin price volatility chart. Diagram explaining how the Bitcoin economy works. (SIN06) 

BITCOIN-PRICE/ - Charts the Bitcoin to U.S. dollar rate. Daily close in the Mt. Gox exchange. (SIN11) 

BITCOIN/EXCHANGES - Charts the top 5 USD Bitcoin exchanges ranked by 30-day volume and value of bitcoins traded. (SIN07)