The man who claimed to have invented Bitcoin says he doesn't have the 'courage' to provide proof

Craig Wright, the Australian man who explosively - and dubiously - claimed to have invented bitcoin says that he will not be providing any further proof of his claims.

In a statement posted to his website, Wright said that as he prepared to provide "proof" of his access to the earliest bitcoin that would verify his identity, he broke down. "I do not have the courage. I cannot," he wrote. "I know now that I am not strong enough to this."

The identity of the inventor (or inventors) of bitcoin is one of the enduring mysteries of the tech sphere. There have been multiple attempts to track down its mysterious creator, known only by the pseudonym Satoshi Nakamoto, but none have been conclusive; indeed, some have been positively disastrous.

Craig Wright entered the running last year when allegedly leaked documents supplied to Wired and Gizmodo suggested he might have hand in the the creation of the digital currency, although doubts remained.

Wright didn't comment at the time, but in the last week finally came forward to claim to have invented bitcoin.

His claim was initially bolstered by the support of Gavin Andresen, a leading developer in the bitcoin community who worked closely with Nakomoto during the cryptocurrency's earliest days to develop its software. Andresen had met with Wright, and became convinced he was telling the truth: "After spending time with him I am convinced beyond a reasonable doubt: Craig Wright is Satoshi."

But very significant doubts have since been poured on Wrights claims - namely the lack of any clear independently verifiable proof. It'd be technically simple for him to prove his claims (or at least, prove ownership of bitcoin that once belonged to Satoshi Nakomoto) by signing a message with the encryption key associated with the "genesis block," the first block of bitcoin ever mined. But Wright failed to do so.

He had promised to provide more evidence for his claims, writing that "over the coming days, I will be hosting a series of pieces that will lay the foundations for this extraordinary claim." But this is no longer the case.

"I'm sorry," the message on Wright's website reads. "I believed that I could do this. I believed that I could put the years of anonymity and hiding behind me. 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."

This about-face is certain to be taken by doubters as proof that Wright is lying - that he was called on his bluff, could not provide the evidence people are demanding, and is trying to save face. (It's also possible that Wright's website has been hacked, but there has so far been no evidence of this.)