UK spooks to hunt down pedophiles on the 'dark net'

The unit will combine the investigatory expertise of the U.K.'s National Crime Agency (NCA) with those of the Government Communications Headquarters (GCHQ), the U.K's intelligence service. Together they will tackle the worst cases of child sexual exploitation online, the U.K. government said on Thursday.

"Persistent pedophiles are increasingly communicating on the so-called 'dark web', using ever more sophisticated techniques to disguise their identities and encrypt the horrific images of children that they are sharing with peers," the government said, adding that the new unit will develop high-tech capabilities to analyze vast volumes of child abuse imagery.

By the "dark web,", the U.K. means services such as Tor, short for The Onion Router.

The new unit will focus on the most prolific offenders, who inevitably leave behind 'digital footprints' in some form.

Tor is software designed to offer users better privacy when browsing the Internet by routing traffic through a network of worldwide servers in order to mask the user's location. While it is know to be used by pedophiles, the system is also widely used by a variety of people who don't want to reveal their real IP address while browsing the Internet. It is also used by people to access services that are blocked by governments in some countries. 

Tor is by far the most popular network of this type, though there are others that operate in a similar fashion, the U.K. government said. However, Tor remains a niche activity as users represent only 0.18 percent of the total number of Internet users in the U.K. and 0.26 percent of daily Internet users, it said, adding that "not all those using Tor will do so for criminal purposes."

Nevertheless, the U.K. government isn't too pleased with the abilities Tor gives its users.

"The so-called 'dark-net' is increasingly used by pedophiles to view sickening images. I want them to hear loud and clear, we are shining a light on the web's darkest corners; if you are thinking of offending there will be nowhere for you to hide," U.K. Prime Minister David Cameron said in a statement.

The spread of child abuse imagery is also being reduced by major tech companies like Facebook, Microsoft, Google, Twitter and Yahoo, who use digital fingerprint measures to track the hash value of child sex abuse images identified by the Internet Watch Foundation (IWF).

Since last year, Google and Microsoft have introduced a number of changes to their search functions, including algorithm changes to prevent images of child abuse material from appearing in their search results. "Google has seen a fivefold reduction in the number of searches for child abuse images since these changes were made," according to the U.K. government.

Hashing technology for videos has also been developed by Google, allowing known child abuse videos to be identified and blocked from being shared. The technology will be shared with industry partners and Yahoo will be the first one to pilot it.

Microsoft, Google and Mozilla have also committed to investigate the feasibility of implementing browser-level blocking restrictions designed to prevent people getting access to URLs of known child abuse material via Chrome, Firefox and Internet Explorer.

The U.K. measures were announced during the #WeProtect Children Online summit, which took place in London. A series of global commitments from over 30 countries to track down pedophiles was unveiled there. Countries will invest in law enforcement operations, similar to the U.K's and supported by a £50 million (about US$78 million) fund to prevent children experiencing violence and exploitation. The fund will be supported by UNICEF, governments and partners from civil society and the private sector.

Loek is Amsterdam Correspondent and covers online privacy, intellectual property, online payment issues as well as EU technology policy and regulation for the IDG News Service. Follow him on Twitter at @loekessers or email tips and comments to loek_essers@idg.com