The secretive businessman had on Monday identified himself as the creator of the digital currency following years of speculation about who invented it.
Australian entrepreneur Craig Wright today said he would not provide further proof to back up his claim that he created Bitcoin, saying he was "not strong enough" for the public scrutiny.
"I believed that I could do this. I believed that I could put the years of anonymity and hiding behind me," read a statement posted on his website.
"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."
Wright said his "qualifications and character were attacked" and he was "not strong enough".
"I know that this weakness will cause great damage to those that have supported me," he said.
A representative of the Outside Organisation, a public relations firm that has worked with Wright, said the statement was "legitimate" but declined to comment further.
The secretive businessman had on Monday identified himself as the creator of the digital currency following years of speculation about who invented it.
Wright had presented proof that only the true creator of Bitcoin could have provided, the BBC said.
It posted a video of him demonstrating the signing of a message with the public key associated with the first transaction ever done on Bitcoin following its 2009 launch.
These keys had to be created by Satoshi Nakamoto, the pseudonym used at the time by the currency's creator, the broadcaster said.
But The Economist was more sceptical, saying there were still a number of steps to go through in order to verify the claim and "important questions remain".