Concerns over how to police the Darknet - Key issues for the 2015 Parliament

What is the darknet?

The vast majority of web pages are invisible to most casual internet users. This part of the web is known as the ‘deep web'.

In contrast to the open web, it consists of web pages that cannot be found by popular search engines like Google. They are mainly standard personal or corporate web pages such as photo collections or intranet pages.

However a very small part of the deep web consists of websites which allow their operators to conceal their identity if they wish to, using sophisticated anonymity systems.

This is what is commonly referred to as the ‘darknet'.  

How can website operators conceal their identity?

Most internet users who wish to hide their identity take simple measures, such as using pseudonyms on social media sites. Only a small proportion use sophisticated anonymity systems that offer stronger protection.

The most popular of these is called ‘Tor', with an estimated 2.5 million users daily worldwide. Most Tor users simply use it to browse the open web without revealing who they are. It is used for a variety of reasons, such as to circumvent censorship, to carry out under cover undercover online surveillance, or for peer-to-peer file sharing.

However, Tor also enables users to publish anonymous web services via ‘Tor Hidden Services' or THS. Most of the current debate on the ‘darknet' is concentrated around THS.

How does Tor work and who uses it?

A global network of approximately 6,000 computers provided by volunteers forms the ‘Tor Network'. Users can download free software onto their computer to access the Tor Network.

The Tor network uses a multi-layered system of encryption, and relays information in such a way that it is difficult for any one part of the system to link communication partners.

Thus no single entity (including Internet Service Providers and Tor Project Inc., which maintains the Tor Network) knows about a Tor user's online behaviour, such as which websites they have visited.

Tor Project Inc. states that about 1.5% of traffic on the Tor Network is from users accessing the THS; the bulk of traffic is users accessing the open web.

What is Tor Hidden Services used for?

It is difficult to give an accurate overview of what THS are used for, as there is no central record and many addresses only exist for a short time. THS is most well-known for criminal markets.

Until it was closed down by the FBI in September 2013, Silk Road was the most prominent of these. It allowed users to sell and buy illegal drugs and other commodities in a format similar to that of eBay. Several other illegal markets rapidly took its place after its shutdown.

THS is also used for the online viewing and distribution of indecent images of children, although it should be noted that in 2013, the Internet Watch Foundation took action on only 36 THS domains for containing such material, compared to 1,624 domains on the open web.

THS also allows whistle-blowers to share information with the media and advocacy groups.

For example, the New Yorker Strongbox is a THS that allows informants to share messages and files anonymously with reporters of the American magazine The New Yorker.

What challenges does THS present to law enforcement agencies?

There are situations where LEAs wish to find out about the online behaviour of a Tor user, or identify users of specific THS sites.

It is not publicly known what the extent of LEAs' capability is or what methods they employ. Tor has some technical limitations which may make it possible to de-anonymise Tor users.

However, this requires significant resources and a high level of expertise. Alternatively, sometimes users make simple oversights, allowing them to be identified by non-technical means.

For example in the 2013 Silk Road crackdown, the suspect was identified as the Silk Road operator based on his activities on the open web, including posts about Silk Road on discussion forums, where he registered using his real name and email address.

What is the future of the darknet? 

Tor Project Inc. plans to make Tor faster, easier to use and to increase its capacity. In response to public concerns about privacy, more people may start to use strong anonymity protection systems like Tor.

Also, organisations involved in providing browser and operating system software are increasing the level of privacy and anonymity they offer to their users.

For example, the non-profit organisation Mozilla Foundation, which offers the popular Firefox internet browser, has recently announced its collaboration with Tor Project Inc. on a project evaluating the use of Tor with Firefox on a larger scale.

While some Governments (such as the Chinese) have attempted to block access to Tor altogether, this has proved technically challenging: in the case of China, Tor Project Inc. developed ways of circumventing the block.

Some have argued for a Tor without THS. However, computer experts argue that any legislative attempt to preclude THS from being available in the UK over Tor would be technologically infeasible.