1. Created by the US government
In the mid 1990s, US military researchers created a technology that allowed intelligence operatives to exchange information completely anonymously. They called it 'Tor', which stands for 'The Onion Router'.
As part of their strategy for secrecy, they released Tor into the public domain for anyone to use. Their reasoning was simple: the more people using the system, the harder it would be to separate the government's own messages from the general noise. You can't be anonymous on your own.
Tor spread widely and today, is a critical part of the so-called 'dark web': a network of untraceable online activity and hidden websites, of which Tor hosts approximately 30,000. And that anonymity has attracted a huge range of people; all who want to keep their activities hidden.
2. WATCH: How the dark web works
Watch the video to see how Paul Syverson from the US Naval Research Laboratory created Tor, and how it works.
3. CLICKABLE: Who uses the dark web, and why?
There are many legitimate uses for the dark web- but it also enables online criminal activity. Click on the images below to see how the dark web is used today.
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Images: Getty, PA and Thinkstock
4. Good or bad: The expert view
Despite the benefits that online anonymity can bring, would we better off without it?
Bruce Schneier, computer security expert
"Internet anonymity is vital for people living in countries where you can be arrested, tortured, and killed for the things you do online. This is why the US government was instrumental in developing the technology, and why the US State Department continued to fund Tor over the years."
Troels Oerting, former cyber-crime chief
"The Tor network hides criminals. I know it was not the intention, but that's the outcome and this [was] my job, to tell society what the trade-off is here. By having no possibility to penetrate it, criminals can continue their crimes on a global network. It's very, very difficult for the police to penetrate, so it's risk-free crime."
Jake Applebaum, The Tor Project
“There is often asserted certain narratives about anonymity and, of course, one of the narratives is that anonymity creates crime. So you hear about things like the Silk Road [a dark web marketplace that sold drugs and guns] and you hear, 'Oh, it's terrible, someone can do something illegal on the internet'. Well, welcome to the internet. It is a reflection of human society, where there is sometimes illegal behaviour.”
Dr. Joss Wright, Internet researcher
"We should not shy away from the negative uses of Tor any more than we should ignore its benefits. Preventing individuals from communicating without being tracked, watched, logged, and profiled, however, would be a huge blow to our society."
UK government concerns
In 2014, David Cameron announced plans for GCHQ to work alongside Britain's National Crime Agency in order to attack the dark web and root out criminal activity. He said, "The dark net is the next side of the problem, where paedophiles and perverts are sharing images, not using the normal parts of the internet that we all use."
The Parliamentary Office of Science and Technology
In a recent report on the dark net and anonymity, the Parliamentary Office of Science and Technology claimed "there is widespread agreement that banning online anonymity systems altogether is not seen as an acceptable policy option in the UK. Even if it were, there would be technical challenges. For example, when the Chinese government attempted to block access to Tor, Tor Project Inc. introduced secret entrance nodes to the Tor Network, called ‘bridges’, which are very difficult to block."