Who is Satoshi Nakamoto?

That’s a question that’s loomed over Bitcoin long before it hit triple-digit exchange rates (one Bitcoin is worth more than $450). It was the appearance of Nakamoto’s white paper in 2008 that outlined how Bitcoin could work, which paved the way for the cryptocurrency to exist. As for Satoshi Nakamoto himself, or herself — the name was simply a pseudonym — journalists at outlets such as Wired, Newsweek and the New Yorker all tried their hands at pulling off Nakamoto’s mask, to limited success.

Now, a 45-year-old Australian named Craig Steven Wright has stepped forward to the Economist, BBC and GQ-UK magazine, and on his own blog attempting to set the record straight once and for all. “I was the main part of it, but other people helped me,” he told the BBC. Wired and Gizmodo have investigated Wright, and they came to the same conclusion: Wright played a critical role.

The BBC reports that Wright “provided technical proof to back up his claim.” The Economist took a more skeptical path. Wright possesses certain digital keys that only Nakamoto would have, the magazine said, but it said it did not have enough time to independently verify the key’s verisimilitude. “Our conclusion is that Mr Wright could well be Mr Nakamoto, but that important questions remain,” the Economist wrote. “Indeed, it may never be possible to establish beyond reasonable doubt who really created bitcoin.”

The open-source software for Bitcoin, which allows users to make online transactions anonymously and without going through banks or other financial institutions, was released in 2009. It started out more resembling monopoly money than real currency — people would trade the “coins” (really just lines of code) for favors or even give them away. But as the exotic system gained popularity, it gained value.

Now anyone — tech nerds, central-bank-averse Libertarians, criminals — can use Bitcoins for anything from ordering pizza to trafficking drugs. Their value fluctuates wildly.

The BBC quoted a blog post by Gavin Andresen, chief scientist at the Bitcoin Foundation, in support of the claim:

I believe Craig Steven Wright is the person who invented Bitcoin.

I was flown to London to meet Dr. Wright a couple of weeks ago, after an initial email conversation convinced me that there was a very good chance he was the same person I’d communicated with in 2010 and early 2011. After spending time with him I am convinced beyond a reasonable doubt: Craig Wright is Satoshi.

Part of that time was spent on a careful cryptographic verification of messages signed with keys that only Satoshi should possess. But even before I witnessed the keys signed and then verified on a clean computer that could not have been tampered with, I was reasonably certain I was sitting next to the Father of Bitcoin.

It also quoted Jon Matonis, an economist and one of the founding directors of the Bitcoin Foundation. “During the London proof sessions, I had the opportunity to review the relevant data along three distinct lines: cryptographic, social, and technical,” he told the BBC. “It is my firm belief that Craig Wright satisfies all three categories.”

If Wright is indeed the author of the paper, he’s not in it for the fame, he says — or even laying claim to the alleged $450 million worth of bitcoin in Satoshi Nakamoto’s account. It’s that the attention to his life after the Wired and Gizmodo profiles were starting to affect the people around him. “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 told the BBC. “I don’t want any of them to be impacted by this.”

“I have been staring at my screen for hours,” he wrote on his blog, “but I cannot summon the words to express the depth of my gratitude to those that have supported the bitcoin project from its inception – too many names to list. You have dedicated vast swathes of your time, committed your gifts, sacrificed relationships and REM sleep for years to an open source project that could have come to nothing. And yet still you fought. This incredible community’s passion and intellect and perseverance has taken my small contribution and nurtured it, enhanced it, breathed life into it. You have given the world a great gift. Thank you.

“Be assured,” he wrote,”just as you have worked, I have not been idle during these many years. Since those early days, after distancing myself from the public persona that was Satoshi, I have poured every measure of myself into research. I have been silent, but I have not been absent. I have been engaged with an exceptional group and look forward to sharing our remarkable work when they are ready.

“Satoshi is dead.

“But this is only the beginning.”

Wright — a former academic “nobody,” as Wired put it — had never before appeared on the public lists of any Nakamoto hunters, yet troves of leaked (or perhaps hacked) documents published by Wired and Gizmodo seemed to point to him in December.

Within hours of the two stories’ publication, Wright’s online presence had all but vanished, Gizmodo reported, and Australian authorities were raiding Wright’s suburban Sydney home.

In a statement to the Associated Press, Australian Federal Police said the searches were related to a tax investigation, not the recent articles linking Wright to Bitcoin.

The hill on which Wright has staked his flag are two of the earliest Bitcoin blocks. In the terminology of Bitcoin, a block can be thought of as a list of transactions — the actors in each transaction may be anonymous, but there’s a public record of where Bitcoins move, to keep everyone honest. String enough of these ledgers together, and you end up with Bitcoin’s famous blockchain. Each time a new Bitcoin batch is “mined,” computers add sequentially larger and larger numerical blocks to the end of the chain.

In coming forward, Wright needed to demonstrate that he had been involved with Bitcoin from the beginning. To do so, he showed the Economist and the other publications he had ownership of a very old Bitcoin block: the ninth block of transactions ever created. Wright demonstrated that he has the key — a specific string of numbers — to Block 9 to independent Bitcoin experts as well. (He outlines this on his blog, with a signature that includes Jean-Paul Sartre’s speech refusing the Nobel Prize — though, fair warning, it can be a bit inscrutable to the novice.)

Not only did he show control of Block 9, the Economist reports he has the key to the very first block, Block 1. The Economist was more skeptical of his ownership of Block 1, as Wright was less forthcoming with it than with his public Sartre signature — and it’s possible, in theory, for him to have feigned the demonstration. “Still, as far as we can tell he indeed seems to be in possession of the keys, at least for block 9,” the Economist wrote.

Complicating the issue is that Dave Kleiman — in whom Wright confided, according to emails obtained by Wired — and cryptologist Hal Finney, the first person to receive a transaction from Nakamoto, have passed away since Bitcoin launched. It’s possible, the Economist notes, Wright acquired the keys to bBocks 1 and 9 from one of those men.

This 2014 video by The Washington Post provides a basic guide to Bitcoin.