Craig Wright backtracks on claim he'd prove he is bitcoin creator

Australian tech entrepreneur Craig Wright, who earlier this week said he would provide "extraordinary proof" that he was the creator of digital currency bitcoin, will not provide any further evidence, according to a post on his blog on Thursday.

Although Wright did not renege on his claim to be Satoshi Nakamoto - the name, assumed to be pseudonymous, of the person or group who created the web-based currency in 2008 - the U-turn was taken by many bitcoin experts as confirmation of their suspicions that the claims were false.

"I believed that I could do this. I believed that I could put the years of anonymity and hiding behind me," Wright wrote. "But, as the events of this week unfolded and I prepared to publish the proof of access to the earliest keys, I broke. I do not have the courage. I cannot."

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Bitcoin is a web-based "cryptocurrency" that enables users to move money across the world quickly and anonymously without the need for third-party verification. Various attempts have been made to identify its elusive creator, but Wright's claims stood out due to the high-profile endorsements they received.

Lead bitcoin developer Gavin Andresen and bitcoin consultant Jon Matonis both wrote blogs on Monday endorsing Wright's claims, saying they had been shown proof by Wright that he was Nakamoto. Wright said on Thursday that Andresen and Matonis had not been deceived, but "that the world will never believe that now".

"I think he's significantly less likely to be Satoshi than any other person that's been suggested," another lead bitcoin developer, Peter Todd, told Reuters, referring to others who have been suspected of being bitcoin's creator.

"Plain fishy"

After coming under pressure to provide more credible evidence that he was bitcoin's creator, Wright had blogged on Monday that he would provide "independently verifiable documents and evidence" that would back up his claims. The post could no longer be found on his blog site.

"The possibility that Wright is Satoshi will always exist, but given the amount of evidence calling that into doubt, I think one would be foolish to give that possibility much weight," said Jerry Brito, executive director of Washington, D.C.-based digital currency advocacy group Coin Center.

"He's provided no cryptographic evidence verifiable by the public, and many of his answers sound plain fishy... Today's statement on his blog only further tarnishes his credibility."

Wright's representatives declined to give any comments on his decision to back away from providing further evidence, but said he was still their client. They believed he was still in London, where he has been living for the past few months.

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Interviews with some who had done business with Wright in Australia in December, when reports by Wired and Gizmodo that he could be Nakamoto first emerged, and an inspection of documents published by the two tech news websites, painted a complex picture of Wright.

They pointed to a smart but sometimes abrasive figure facing growing legal and financial problems at least in part caused by his involvement with bitcoin.

Each bitcoin is currently worth around $447, making the 15 million or so in circulation worth a total of around $7 billion.

Wright said his failure to produce better evidence would cause "great damage to those that had supported" him, in particular Matonis and Andresen.

"I can only say I'm sorry. And goodbye," Wright wrote.