“That was a big theme of the whole conference,” said Jerry Brito, director of the technology policy program at the Mercatus Center at George Mason University. Brito said businesses exchanging Bitcoins were coming to terms with the fact that they would now need to get licensed as money transmitters in 48 U.S. states, a process requiring in-person interviews in each state, thanks to FinCEN’s guidance.

“Everything I’m telling you, I’ve learned over the past couple of months as I’m racing to learn,” said Brito, who attended the Bitcoin Conference in San Jose. “I think that’s what the Bitcoin community is doing too.”

Charlie Shrem, chief executive of Bitcoin transfer firm BitInstant.com, told the conference about the importance of
complying with the new rules.

“You have to know your customer,” he told the audience, according to a video posted on the Internet. “Whether or not you agree with the laws or not, you’ve got to follow them.”

The FinCEN statement means companies that exchange Bitcoins for hard currency must now hire full-time compliance officers to verify the identities of users, especially those looking to transfer Bitcoins out of the digital world and back into dollars or other hard currencies. Estimates vary on how much it costs to get compliant, but licensing and registration fees alone can total in the tens of thousands of dollars, an added heavy cost for small startup businesses.

Brito said the Bitcoin community is also trying to increase its contact with law enforcement and regulators. The Bitcoin Foundation, a Bitcoin advocacy group made up of Bitcoin-related business owners and software programmers, is looking to hire a full-time lawyer based in Washington to make its case to regulators and lawmakers.

Some members of the community are declining to discuss regulation. Jon Matonis, the Bitcoin Foundation’s secretary who is identified on the group’s website as one of two spokesmen for press inquiries, told Reuters: “I am electing to take a brief break from commenting on issues such as this.”

U.S. law enforcement officials are looking first and foremost to unmask criminals operating in cyberspace and arrest them, wherever they may be in the world, and they’re looking to digital currency businesses to help.

Ed Lowery, special agent in charge of the U.S. Secret Service’s criminal investigative division, said the agency is working “aggressively with our international partners” to pursue cyber crime and the companies that permit the misuse of digital currencies. He declined to comment specifically on Bitcoin.

Liberty Reserve has not been the only recent target for the authorities. The Tokyo-based firm Mt. Gox, the world’s largest exchanger of U.S. dollars with Bitcoins, had two accounts held by its U.S. subsidiary seized this month by agents from the Department of Homeland Security on the grounds that it was operating a money transmitting business without a license.

Mt. Gox on Thursday announced it would require all of its users accounts to be verified before allowing them to perform any more deposits or withdrawals. Its founder declined to comment for this story.

Other companies are simply trying to avoid having to comply with U.S. rules by keeping away from the country. Following FinCEN’s statement, two digital currency firms structured similarly to Liberty Reserve – Russia-based WebMoney and Panama-based Perfect Money – restricted access to their services from inside the United States.