For those seeking stealth and anonymity online, a radio device known as ProxyHam was a highly anticipated new tool set to debut at the DefCon hacker conference next month. Now it's just staged its own disappearing act.

Late Friday, the Twitter feed for Rhino Security, the consultancy run by the project's creator Ben Caudill, announced that Caudill's talk was being pulled from the DefCon line-up, and that the ProxyHam project was being called off. "Effective immediately, we are halting further dev on #proxyham and will not be releasing any further details or source for the device," the message read. "Existing #proxyham units will be disposed of and no longer be made available at [DefCon]"

Just a couple weeks earlier, Caudill had enthusiastically described ProxyHam to WIRED as "that last-ditch effort to remain anonymous and keep yourself safe.” The $200 open-source, dictionary-sized networking device, which Caudill had said Rhino Security would be selling to DefCon attendees at cost, used a 900 megahertz radio to connect to an antenna dongle on a computer as far as 2.5 miles away. The result would be that an anonymous user could plant the ProxyHam in a library or coffee shop, then use that location's Wi-fi via ProxyHam's radio connection from the comfort and safety of their home. Any investigator who traced the connection would only find the ProxyHam's IP address—not the user's. “The KGB isn’t kicking in your door,” Caudill told WIRED last month. “They’re kicking in the door of the library 2.5 miles away.”

In a phone call today, Caudill said he couldn't offer any explanation for the project's sudden demise, and that he didn't expect ProxyHam to be resurrected any time soon. "I can't say much, which is unfortunate," he said. "It’s frustrating for me and for the team as a whole."

Caudill did say that it wasn't DefCon's choice to cancel his talk. He called the conference organizers Thursday night to tell them he couldn't present the research. Nor was it his employer who forced him to cancel it: He runs his own company.

Over the weekend, some followers of the project speculated that the FCC had barred Caudill from selling the device because it violated laws that control the use of radio spectrum. But Caudill denied that explanation, too, saying that ProxyHam's radio output remained below 1 watt, the legal limit. "We had no contact or issue with the FCC throughout the project," he said.

In fact, it seems much more likely that Caudill has been issued some sort of gag order. Did he have a run-in with law enforcement? "No comment," Caudill responded.

Online anonymity tools certainly aren't illegal. Tools like VPNs have allowed users to obscure their IP addresses for years. The anonymity software Tor is even funded by the U.S. government. But it's possible that secretly planting a ProxyHam on someone else's network might be interpreted as unauthorized access under America's draconian and vague Computer Fraud and Abuse Act.

If WIRED learns more about the project's shutdown or law enforcement action against ProxyHam, we'll provide an update here. Caudill himself, meanwhile, isn't offering hints. "There's no more information I can provide," he concludes cryptically. "It is what it is."