Hidden websites that run under the cover of anonymity in the so-called “dark net” -- corners of the Internet that allow people to conceal their identity online -- generate an overwhelming majority of their traffic through content related to child pornography, according to a six-month-long study. 

The study, conducted by Gareth Owen, a computer science researcher at the University of Portsmouth in the UK, examined online traffic to sites hidden on the Tor network, a system that is designed to allow users to surf the Internet anonymously so their activities and location cannot be discovered. The study revealed that forums to discuss and trade illegal drugs and smuggled goods formed the largest categories of sites hidden on Tor. But, sites that get the maximum number of visits are those related to child pornography, Wired reported.

According to the study, more than four out of five visits to Tor hidden sites were linked to online destinations with content related to pedophilia, which is over five times as many as any other categories of content that researchers found in the study. The findings are expected to question supporters of the “dark net,” who defend the concept claiming that it is crucial to protect users’ privacy.

“Before we did this study, it was certainly my view that the dark net is a good thing,” Wired quoted Owen as saying. “But it’s hampering the rights of children and creating a place where pedophiles can act with impunity.”

Over a period of six months, Owen and his team of researchers identified about 80,000 hidden sites on Tor, and most of them did not stay online for a long time. Although the number of sites containing images of child abuse is small, the traffic they generated -- about 75 percent of all visits observed in the study -- outnumbered that of other sites. However, Owen said that it is yet to be concluded that actual users were behind all the visits to pedophilia sites.

“It's not as quite as straightforward as it looks. It might look like there are lots of people visiting these sites but it is difficult to conclude that from this information,” BBC News quoted Owen as saying. “What proportion are people and which are something else? We simply don't know.”

Meanwhile, Roger Dingledine, one of the original developers of Tor, also questioned the methodology of the study, claiming it only examined longstanding sites for their content.

Here is a statement by Dingledine about Owen’s study:

Dr. Owen's data shows that there's a lot of churn in hidden services, so nearly all of the sites were gone by the time he did these scans. His graphs only show data about the sites that were still up many months later: so his data could either show a lot of people visiting abuse-related hidden services, or it could simply show that abuse-related hidden services are more long-lived than others. We can't tell from the data... Without knowing how many sites disappeared before he got around to looking at them, it's impossible to know what percentage of fetches went to abuse sites... There are important uses for hidden services, such as when human rights activists use them to access Facebook or to blog anonymously. These uses for hidden services are new and have great potential.