The man alleged to be "Dread Pirate Roberts," the founder and operator of the Silk Road—an online marketplace where bitcoins were traded for a range of goods and services, including drugs — was arrested by the FBI in San Francisco this week. The criminal complaint, provides many details about how the site and its users relied on widespread anonymity technology, including Tor and Bitcoin.
The increased attention on this technology is a good reminder about how important it is not to blame these tools for the actions of a small portion of their users. The public wouldn't tolerate a campaign to malign the car because of its utility as a getaway vehicle for bank robbers; we must apply the same critical thinking to essential privacy-preserving technology.
In certain parts of the complaint, even the federal agent behind the investigation and the Justice Department attorney in charge of the case acknowledge this. In describing how Tor was required to access the Silk Road (the site was configured as a Tor hidden service), they state that "Tor has known legitimate uses". Similarly, "Bitcoins are not illegal in and of themselves and have known legitimate uses."
Elsewhere the complaint goes astray. For example, it asserts that the suspect's efforts to "'hide the identities of those that run Silk Road' reflect his awareness of the illegal nature of the Silk Road enterprise." Of course, that explanation overlooks the countless lawful reasons why a person would want to engage in anonymous speech—and in the process hide the identities of those behind the technical infrastructure—that don't involve breaking the law.
Similarly, the complaint's description of the bitcoin "tumbler" that the Silk Road employed to obscure the parties involved in each transaction is alarmingly limited. According to the complaint, "the only function served by such 'tumblers' is to assist with the laundering of criminal proceeds." Really, the purpose of a tumbler is to attempt to make a bitcoin transaction as anonymous and private as cash. Certainly one can take issue with Silk Road's use of the technology in particular. It's incredibly dangerous, though, to say that anonymous currency—whether bitcoins or traditional cash—is only of interest to drug dealers or money launderers.
It's essential that the use of encryption, anonymization techniques, and other privacy practices is not deemed a suspicious activity. Rather, it must be recognized as an essential element for practicing freedom of speech in a digital environment.
In some ways, the complaint provides encouragement to those who depend on this technology to engage in speech privately and anonymously. After all, it was human error, and the chance discovery of nine fake ID cards in a routine package inspection at the border, that led to the final round of investigation. This year's revelations about the NSA's subverting certain cryptographic technologies have definitely heightened fears in the security community. Although there are still some unanswered questions about the investigation, it's a small relief that, for now, those fears weren't confirmed by the criminal complaint.
The point remains, however, that relegating these technologies by associating them only with their criminal use threatens to undermine their ability to enable important, lawful speech.
Unfortunately, we've witnessed that sort of demonization of technology before. We've seen it in attempts to target peer-to-peer protocols because they can be used for copyright infringement; in the outrageous stacking of penalties that can result in decades of possible prison time for violations of the Computer Fraud and Abuse Act; in the original "Crypto Wars" of the 1990s and their reprise today; and in many other places besides.
The allegations against the Silk Road are serious, and may get even more so as the case progresses to formal charges and a trial. But if the government puts undue weight on the suspect's use of technology, instead of the actual crimes of which he is accused, the public will be worse off for it.