More than 80% of so-called dark net" internet traffic is generated by visits to websites offering child-abuse material, according to a study of Tor "hidden services" websites conducted at the University of Portsmouth. Researcher Dr Gareth Owen analysed traffic to sites using Tor's technology to hide their addresses from search engines over a six-month period, in an attempt to understand what kind of sites were most popular. He presented his findings at the Chaos Computer Congress in Germany, with Wired reporting on the research's conclusion that while sites with paedophile material represent just 2% of the estimated 45,000 hidden services websites online at any one time, they account for 83% of visits to these sites once automated "botnet" traffic is removed from calculations. The study focuses on websites using Tor's technology to hide themselves, rather than the surfing habits of individual internet users using Tor's anonymising features. The latter are not spending 84% of their time visiting child-abuse websites. "Before we did this study, it was certainly my view that the dark net is a good thing, but it's hampering the rights of children and creating a place where paedophiles can act with impunity," Owen told Wired, while describing the scale of traffic to these sites as "a huge shock". The study found that less than a sixth of hidden services sites that were online in March when the research started were still online in September when it concluded, suggesting a short average lifetime for these websites.