NEW YORK--Federal prosecutors have charged a cryptocurrency expert with violating economic sanctions against North Korea by presenting at a conference there this year after the U.S. government denied his request to travel to Pyongyang.

Virgil Griffith, 36, was awaiting a federal court appearance Friday in Los Angeles, a day after he was arrested at Los Angeles International Airport.

Griffith is an American citizen but lives in Singapore. Messages were sent to Griffith's defense attorney seeking comment.

Federal prosecutors said Griffith secured a visa through “a (North Korean) diplomatic mission facility” in Manhattan for 100 euros and then traveled to the country through China in April.

A request for comment was sent to North Korea’s United Nations mission in New York.

At the conference, Griffith talked about how North Korea could use cryptocurrency to “achieve independence from the global banking system,” according to a criminal complaint.

The conference was attended by 100 people, prosecutors said, including several who appeared to work for the North Korean government.

The criminal complaint says Griffith showed the FBI photographs of himself in North Korea and provided agents with propaganda from the country. It said Griffith planned to facilitate the exchange of cryptocurrency between North and South Korea and encouraged other U.S. citizens to attend the same conference next year.

“Griffith announced his intention to renounce his U.S. citizenship and began researching how to purchase citizenship from other countries,” the U.S. Attorney’s Office in Manhattan said in a news release.

Prosecutors say another person involved in the alleged conspiracy was to be brought to New York and arrested. That person is not named in the criminal complaint against Griffith.

The U.S. attorney in Manhattan, Geoffrey Berman, said Griffith “provided highly technical information to North Korea, knowing that this information could be used to help North Korea launder money and evade sanctions.”

Griffith has contributed to the hacker magazine 2600, which tweeted Friday that Griffith’s arrest amounted to “an attack on all of us.”

“I kept warning him it was a trap,” the magazine’s editor, Emmanuel Goldstein said in a separate Twitter post, adding Griffith “insisted on” speaking to the FBI without a lawyer. “What’s ironic is that afterwards, he was convinced they totally got where he was coming from.”

The U.S. and the U.N. Security Council have imposed increasingly tight sanctions on North Korea in recent years to try to rein in its nuclear and ballistic missile programs. Pyongyang says it wants the U.S. to get the sanctions lifted and provide security guarantees before North Korea will abandon its advancing nuclear arsenal; the U.S. has said the North has to take substantial steps toward denuclearization before the sanctions will come off.

The U.S. government amended sanctions against North Korea in 2018 to prohibit “a U.S. person, wherever located” from exporting technology to North Korea. Prosecutors said Griffith acknowledged that his presentation amounted to a transfer of technical knowledge to conference attendees.

A self-described former hacker who went on to get a doctorate in computer science, Griffith became something of a tech-world enfant terrible in the early 2000s. He told The New York Times in 2008 that he considered himself a “disruptive technologist.”

In 2007, he created WikiScanner, a tool that aimed to unmask people who anonymously edited entries in Wikipedia, the crowdsourced online encyclopedia. WikiScanner essentially could determine the business, institutions or government agencies that owned the computers from which some edits were made.

It quickly identified businesses that had sabotaged competitors' entries and government agencies that had rewritten history, among other findings.

"I am quite pleased to see the mainstream media enjoying the public-relations disaster fireworks as I am," Griffiths told The Associated Press in 2007. (Wikipedia creator Jimmy Wales, for his part, said he welcomed WikiScanner as a tool of transparency.)

Four years earlier, as a college student at the University of Alabama, Griffith and a student at another university were about to tell a hacker conference about purported security flaws in a widely used campus debit card system when the manufacturer sued the two. They had posted online about ways to exploit the alleged flaws to get free vending-machine sodas, laundry machine use and more.

A judge barred the students from discussing the card-swiping system. In a settlement a few months later, they apologized to the company, promised to never actually build a transaction-processing device and agreed to complete 40 hours of community service.