Tracers in the Dark: The Global Hunt for the Crime Lords of Cryptocurrency

by Andy Greenberg

A panel of appellate judges considered the argument—and rejected it. In a nine-page opinion, they explained their ruling, setting down a precedent that spelled out in glaring terms exactly how far from private they determined Bitcoin’s transactions to be. “Every Bitcoin user has access to the public Bitcoin blockchain and can see every Bitcoin address and its respective transfers. Due to this publicity, it is possible to determine the identities of Bitcoin address owners by analyzing the blockchain,” the ruling read. “There is no intrusion into a constitutionally protected area because there is no constitutional privacy interest in the information on the blockchain.” A search requires a warrant, the American judicial system has long held, only if that search enters into a domain where the defendant has a “reasonable expectation of privacy.” The judges’ ruling argued that no such expectation should have existed here: The HSI agent wasn’t caught in the Welcome to Video dragnet because IRS agents had violated his privacy. He was caught, the judges concluded, because he had mistakenly believed his Bitcoin transactions to have ever been private in the first place.