Craig Wright
Craig Wright says he can no longer publish proof that he is bitcoin creator Satoshi NakamotoBBC

Self-claimed 'bitcoin creator' Craig Wright has admitted he cannot publish proof that he invented the cryptocurrency. The Australian entrepreneur previously said he would move bitcoins from one of the earliest address blocks, coins believed to be owned by its pseudonymous creator Satoshi Nakamoto.

But on 5 May, a day after Wright said he would provide "extraordinary proof" to back up his claim of being Nakamoto, he deleted every post on his blog and replaced the site with a single message.

Entitled 'I'm sorry', the post said Wright originally believed he "could put the years of anonymity and hiding behind me."

But, as events over the last week unfolded and he prepared to publish the proof bitcoin fans have demanded since the currency launched in 2009, Wright "broke", saying: "I do not have the courage. I cannot."

The post goes on: "When the rumours began, my qualifications and character were attacked. When those allegations were proven false, new allegations have already begun. I know now that I am not strong enough for this."

Weakness

Wright promised to move some of the first bitcoins ever created, evidence to satisfy all but the most hardened sceptic that he is Satoshi Nakamoto – or is at least one of several people attached to the name. It was hoped weight would move coins from 'block 9' by using a private key thought by the bitcoin community to belong to (and only be known by) Nakamoto.

But, in an act of "weakness", Wright has gone back on his promise. "I know that this weakness will cause great damage to those that have supported me, and particularly to [senior Bitcoin Foundation members] Jon Matonis and Gavin Andresen. I can only hope that their honour and credibility is not irreparably tainted by my actions,. They were not deceived, but I know that the world will never believe that now. I can only say I'm sorry. And Goodbye."

Matonis, founding director of the Bitcoin Foundation, tweeted after Wright published his final blog post, saying: "There won't be an on-chain signing from early bitcoin blocks, but there also won't be another Satoshi."

Wright revealed his claimed identity on 2 May to the BBC, The Economist and GQ, but the claim was met by immediate scepticism. He said he would be "posting a series of piece that will lay the foundation for the extraordinary claim [which will include] transferring bitcoin from an early block."