Australian entrepreneur Craig Wright has publicly identified himself as Bitcoin
creator Satoshi Nakamoto.
His admission ends years of speculation about who came up with the original
ideas underlying the digital cash system.
Mr Wright has provided technical proof to back up his claim using coins known
to be owned by Bitcoin's creator.
Prominent members of the Bitcoin community and its core development team have
also confirmed Mr Wright's claim.
Signed blocks
Mr Wright has revealed his identity to three media organisations - the BBC, the
Economist and GQ.
At the meeting with the BBC, Mr Wright digitally signed messages using
cryptographic keys created during the early days of Bitcoin's development. The
keys are inextricably linked to blocks of bitcoins known to have been created
or "mined" by Satoshi Nakamoto.
"These are the blocks used to send 10 bitcoins to Hal Finney in January [2009]
as the first bitcoin transaction," said Mr Wright during his demonstration.
Renowned cryptographer Hal Finney was one of the engineers who helped turn Mr
Wright's ideas into the Bitcoin protocol, he said.
"I was the main part of it, but other people helped me," he said.
Mr Wright said he planned to release information that would allow others to
cryptographically verify that he is Satoshi Nakamoto.
Soon after Mr Wright went public, Gavin Andresen, chief scientist at the
Bitcoin Foundation, published a blog backing his claim.
"I believe Craig Steven Wright is the person who invented Bitcoin," he wrote.
Jon Matonis, an economist and one of the founding directors of the Bitcoin
Foundation, said he was convinced that Mr Wright was who he claimed to be.
"During the London proof sessions, I had the opportunity to review the relevant
data along three distinct lines: cryptographic, social, and technical," he
said.
"It is my firm belief that Craig Wright satisfies all three categories."
How Bitcoin works
Bitcoin is often referred to as a new kind of currency.
But 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 new Bitcoins are produced each
day.
There are currently about 15 million Bitcoins 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.
They operate like privately run bank accounts - with the proviso that if the
data is lost, so are the Bitcoins owned.
'I want to work'
By going public, Mr Wright hopes to put an end to press speculation about the
identity of Satoshi Nakamoto. The New Yorker, Fast Company, Newsweek and many
other media organisations have all conducted long investigations seeking
Bitcoin's creator and named many different people as candidates.
In December 2015, two magazines, Wired and Gizmodo, named Mr Wright as a
candidate after receiving documents believed to be stolen from him that
revealed his involvement with the project.
Soon after these stories were published, authorities in Australia raided the
home of Mr Wright. The Australian Taxation Office said the raid was linked to a
long-running investigation into tax payments rather than Bitcoin.
Questioned about this raid, Mr Wright said he was cooperating fully with the
ATO.
"We have lawyers negotiating with them over how much I have to pay," he said.
The stories in December have led to many more journalists and others pursuing
him and people he knows, he said.
"There are lots of stories out there that have been made up and I don't like it
hurting those people I care about," he said. "I don't want any of them to be
impacted by this."
"I have not done this because it is what I wanted. It's not because of my
choice," he said, adding that he had no plans to become the figurehead for
bitcoins.
"I really do not want to be the public face of anything," he said, expressing
regret that he had been forced to reveal his identity.
"I would rather not do it," he said. "I want to work, I want to keep doing what
I want to do. I don't want money. I don't want fame. I don't want adoration. I
just want to be left alone."
Bitcoins are now accepted as payment for a vast variety of goods and services -
everything from international money transfers to ransoms for data encrypted by
computer viruses. There are currently about 15.5 million bitcoins in
circulation. Each one is worth about $449 ( 306).
Satoshi Nakamoto is believed to have amassed about one million Bitcoins which
would give him a net worth, if all were converted to cash, of about $450m.