Bitcoin’s founder’s identity was in question in a London court on Tuesday, where a trial could end the mystery.

Craig Wright, an Australian computer scientist, said in the High Court that he was “Satoshi Nakamoto,” the name used by the creator of bitcoin.

Wright has said for a long time that he is Nakamoto. A nonprofit group of tech and crypto companies is trying to show he is lying. The trial began on Monday and will last a month, before a judge decides later.

“Wright’s claim is a lie, based on a fake story and fake documents,” lawyer Jonathan Hough said for the Crypto Open Patent Alliance (COPA) at the start of the trial. “He has made more fake documents and excuses when his lies were found out.”

The trial is not only about who made bitcoin, but also who owns the rights to it.

Wright has used his claim to sue developers who want to keep working on the open-source technology, the alliance says in their lawsuit. The judge’s decision will affect three other lawsuits that Wright has filed because he says he has the rights to bitcoin.

“Wright has tried to ruin developers, sent them letters to sue them, and has sued them a lot, all based on the false claim that he made bitcoin,” the alliance said in a statement on Monday.

Bitcoin started in 2008, during the financial crisis. A paper by someone or a group using the name Nakamoto explained how digital money could be sent around the world without banks or countries. Nakamoto disappeared three years later.

People have guessed who Nakamoto is for years and some names came up when Wright said he was Nakamoto in 2016, but then he went away, saying he was too scared to prove it.

Wright said in court on Tuesday that he made the technology and the name, which he said was from his love of Japan. He said the name was from the philosopher Tominaga Nakamoto and Satoshi David, a character in a book about J.P. Morgan, and a Pokemon.

He said he used a fake name to keep his privacy.

“This let me work on my project and keep the attention on bitcoin’s innovation and future, not on me,” he said.

Defense lawyer Anthony Grabiner said the alliance did not have any evidence that Wright was not Nakamoto, and only tried to make his documents look bad.

He said, “No one else has said they are Satoshi, even though Dr. Wright’s claim is very famous. If Dr. Wright was not Satoshi, the real Satoshi would have come out to say so.”

Wright made some bitcoin fans believe him by using Nakamoto’s secret bitcoin keys, but other crypto experts said he was wrong. Many people in the crypto world do not believe him, but he has won in court.

In 2021, he won a case in Florida against the family of a dead business partner who said they should get half of the 1.1 million bitcoin, worth about 37.7 billion pounds ($47.5 billion) today.

Wright and other experts said in court that he had the bitcoin. His lawyers said he worked with his dead friend David Kleiman, but not on making or running bitcoin.

All bitcoin deals are public, so bitcoin users have asked Wright to move some coins to show he has them. Wright seems to have never done that, even though he said he would show he had the money.

In the trial in London, Hough and Wright argued a lot about the documents that Wright said proved his story.

Hough said the first paper on bitcoin was made on OpenOffice software and that both sides agreed that Wright gave a version made on LaTeX software, which was not there when the paper was made.

Hough said the numbers on the paper that were not in line showed it was fake.

Wright said, “That paper would be perfect if I faked it.” He will talk in court for five more days.