Craig Wright, who has claimed to be the inventor of Bitcoin, has reneged on a promise to present new “proof” to support his case.

The Australian entrpreneur had pledged to move some of the virtual currency from one of its early address blocks, an act many believe can only be done by the tech’s creator.

This would have addressed complaints that earlier evidence he had published online was misleading.

On his blog, Craig Wright said: “I believed that I could put 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.

“When the rumors 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.”

Craig Wright had earlier indicated that he would transfer some Bitcoins from “block 9” by using a private key thought to be known only to Satoshi Nakamoto, a pseudonym used by the person or team that designed the crypto-currency.

Satoshi Nakamato is known to have used the address in 2009 to send coins to a computer scientist.

Craig Wright had promised the “proof” in light of a growing backlash against one of his blogs.

On May 2, he posted what seemed to be evidence that he had Satoshi Nakamoto’s key by describing a process that led to the creation of a “digital signature”.

However, soon after, this was attacked by security researchers who linked the signature to an earlier Satoshi Bitcoin transaction that could be found via a search engine.

Craig Wright subsequently wrote that he was the victim of “false allegations” and would prove his case by both moving the coins and by sharing “independently verifiable documents”.

His claims had initially been bolstered by the fact that two senior members of the Bitcoin Foundation – an organization set up to protect and promote the virtual currency – had said they were convinced he was indeed behind the technology.

Bitcoin is often referred to as a new kind of currency.

It may be best to think of its units being virtual tokens rather than physical coins or notes.

However, like all currencies its value is determined by how much people are willing to exchange it for.

To process Bitcoin transactions, a procedure called “mining” must take place, which involves a computer solving a difficult mathematical problem with a 64-digit solution.

For each problem solved, one block of bitcoins is processed. In addition the miner is rewarded with new bitcoins.

This provides an incentive for people to provide computer processing power to solve the problems.

To compensate for the growing power of computer chips, the difficulty of the puzzles is adjusted to ensure a steady stream of several thousand new bitcoins a day. There are about 15 million bitcoins currently in existence.

To receive a bitcoin a user must have a Bitcoin address – a string of 27-34 letters and numbers – which acts as a kind of virtual post-box to and from which the bitcoins are sent.

Since there is no registry of these addresses, people can use them to protect their anonymity when making a transaction.

These addresses are in turn stored in Bitcoin wallets which are used to manage savings.

Bitcoin wallets operate like privately run bank accounts – with the proviso that if the data is lost, so are the bitcoins owned.