Alexander Janssen, a Tor node operator located in Germany, has shut down his node after a second confrontation with police several months ago. Law enforcement agents entered Janssen's home, handcuffed him, and searched the premises. Janssen was informed that he was a suspect in a bomb threat investigation involving an Internet forum. He was then taken to the police barracks where he was interrogated. After Janssen was released, a German state security official informed him that the detainment was a misunderstanding.

Tor is an anonymizing proxy service that obscures the origin of users by relaying traffic through various nodes on the network. The destination server sees the IP address of the Tor exit node rather than the IP address of the user. Unfortunately, this has made Tor exit node operators the accidental targets of police investigations that involve the Internet activity of users who rely on Tor to hide their identity.

Janssen's situation is not unique. Tor exit nodes were seized by the German government last year during a child pornography investigation. Early this year, Janssen also became a suspect in a child pornography investigation as a result of traffic relayed by his Tor exit node. At the time, Janssen was able to resolve the problem with a lawyer, but it left him shaken.

His latest confrontation with German law enforcement agents was enough to convince him to give up. "I've shut down my Tor-server," wrote Janssen in a blog entry yesterday. "I can't do this anymore; my wife and I were scared to death. I'm at the end of my civil courage. I'll keep engaged in the Tor-project, but I won't run a server anymore."

Like the German government's recent law against hacking software that inadvertently criminalized many computer security tools, the country's attempts to harass Tor node operators reflect an unwillingness to distinguish between a legitimate technical service and criminal behavior.