In a recent blog posting, a German operator of a Tor anonymous proxy server revealed that he was arrested by German police officers at the end of July. Although he was released shortly afterwards, information about the arrest had been kept quiet until his lawyers were able to get the charges dropped.

Tor Project

Tor is a privacy tool designed to allow users to communicate and browse anonymously on the Internet. It's endorsed by the Electronic Frontier Foundation and other civil liberties groups as a method for whistle blowers and human rights workers to communicate with journalists. Tor provides anonymous Web-browsing software to hundreds of thousands of users around the world, according to its developers. The largest numbers of users are in the United States, the European Union and China.

The police were investigating a bomb threat posted to an online forum for German police officers. The police traced one of the objectionable posts on the forum to the IP address for Janssen's server. Up until his arrest, Alex Janssen's Tor server carried more than 40GB of random strangers' Internet traffic each day.

Showing up at his house at midnight on a Sunday night, police cuffed and arrested him in front of his wife and seized his equipment. In a display of both bitter irony and incompetence, the police did not take or shutdown the Tor server responsible for the traffic they were interested in, which was located in a different city, more than 500km away.

Janssen's attempts to explain what Tor is to the police officers initially fell on deaf ears. After being interrogated for hours, someone from the city of Düsseldorf's equivalent of the Department of Homeland Security showed up and admitted to Janssen that they'd made a mistake. He was released shortly after.

Germany is clearly not going out of its way to make computer security researchers and activists feel too welcome. Germany recently passed a law that "renders the creation and distribution of software illegal that could be used by someone to break into a computer system or could be used to prepare a break in. This includes port scanners like nmap, security scanners like nessus [as well as] proof of concept exploits."

Back in summer 2006, German authorities conducted a simultaneous raid of seven different data centers, seizing 10 Tor servers in the process. Agents took the servers believing them to be related to a child porn investigation. Furthermore, in 2003 a German court ordered the developers of the Jap anonymity system, a completely different project than Tor, to create a back-door in their system to be used in national security investigations.

This event does raise some interesting legal questions. If 40GB of other people's Internet traffic flows through your own home network, can authorities, be they the RIAA or FBI, reasonably link anything that has been tracked to your computer's IP address to you?

Does setting up a Tor server give you the ultimate plausible deniability card? "No officer, that BitTorrent downloadwasn't mine. It was from one of the thousands of people who route their Internet traffic through the anonymizing sever on my home network."

The ability to have a believable claim to plausible deniability is something that some of us have been attempting to get for a while by having an open wireless access point at home. And 40GB of Internet traffic from perfect strangers may be more significant in the eyes of a court than the possibility of one or two of your neighbors connecting to your wireless network. All of this, for now, remains theoretical. No Tor-related case has made it to the courts.. but it's just a matter of time until one does.