UK Edition
Dark web browser Tor is overwhelmingly used for crime, says study
There is an "overwhelming" amount of illicit and illegal content on the dark web, a new study shows.
That statement might seem self-evident. But the Tor browser was created to protect the anonymity of vulnerable people online. It is a web browser just like Google Chrome or Internet Explorer, but it masks the identity of who is browsing and what they're looking at.
In the first study of its kind, researchers at King's College London found that 57 per cent of the sites designed for Tor - known as .onion sites - facilitate criminal activity, including drugs, illicit finance, and extreme pornography. These are the sites that are often called the dark web or deep web.
The findings are not unexpected - if anything that figure is lower than expected. Tor has been associated with child pornography, gun trading and murder long before now.
"We expected something along these lines," said Thomas Rid, professor of Security Studies at King's College London and co-author of the study. "Previous studies have established that it's a pretty nasty place."
But the study claims to be the first representative map of the content available on Tor.
To collect the data Rid and Daniel Moore, a research student at King's College, developed a "crawler bot" that scraped Tor sites - also known as .onion sites - that can only be viewed using a Tor browser. It is possible to use regular sites on a Tor browser, but these weren't included in the research.
It found 5,205 live websites, and managed to classify the content of 2,723 of those.
After categorising the content, Rid and Moore found 1,547 of the sites contained illicit and illegal material.
"More than 50 per cent of what's hosted there is illegal and illegitimate," said Rid. "Other studies put that figure even higher, but we applied a very conservative classification."
Notably, they did not look at the traffic patterns on Tor.
Tor offers anonymous browsing to people across the world. Users in countries with strict censorship laws, like China or Iran, can use it to access mainstream sites - like Facebook - securely. Rid and Moore found that the vast majority of material on Tor was not just illegal in places like China or Iran, but in more liberal jurisdictions too.
The sites included marketplaces for drugs, fire arms and weapons, and explicit, illegal pornography. The study found a "near-absence" of Islamic extremist sites on Tor.
"Militants and extremists don't seem to find the Tor hidden services infrastructure very useful. So there are few jihadis and militants in the darknet," said Rid. "It's used for criminal services, fraud, extreme, illegal pornography, cyber attacks and computer crime."
What next for the dark web?
Rid and Moore commend Tor for offering vulnerable people access to anonymous browsing. But they said Tor needs to work harder to encourage its community to build a safe and legitimate browsing experience.
"The developers made Tor for a different purpose - they wanted security, not crime. It's up to them to change the direction," said Rid. "It's up to them to have a sensible discussion about ways to reduce crime, to get more legitimate users in."
Facebook has a site on Tor, but it is unclear how many people actually use it. ProPublica became the first major news site to launch on the browser at the beginning of this year. Rid doesn't think it is inconceivable that mainstream websites could have a presence on Tor.
Crypto tools like Tor have been crucial for maintaining the safety of activists, media, military and law enforcement, and regular people.
If the draft Investigatory Powers Bill is passed in the UK, Tor could become more popular. The Bill in its current state requires that communications service providers store the metadata of users for 12 months. In Tor that metadata is not attached to individuals, but is anonymised.
"There are sites on the dark net that are used for all sorts of purposes," said Rid. "There are search engines, news sites, drop sites - for publications like WikiLeaks, ProPublica and the New Yorker - discussion forums and password protected forums."
Tor's example will no doubt be used in the encryption debate that is circulating around the snoopers' charter, according to Rid and Moore.
"Tor's ugly example should loom large in technology debates," Rid and Moore conclude. "The line between utopia and dystopia can be disturbingly thin."
A spokesman for the Tor Project, said: "The researchers seem to make conclusory statements about the value of onion services [the Tor network] that lie outside the scope of their research results.
"Onion services are a tool with unique security properties used for a wide range of purposes." These include self authenticated sites, end-to-end encryption and anonymity when browsing.
Moore and Rid admit they might not have accessed all material available on Tor.
"You can never be sure that you actually access all of the dark web," said Rid. "It's more consistent and thorough than previous studies, but you have to be cautious. It's always possible that we missed sites because of the way the system's designed." They included everything that it would be reasonable for an average user to find.
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