GCHQ: David Cameron’s ‘dark web’ announcement says nothing new

http://www.theguardian.com/uk-news/2014/dec/11/david-cameron-child-abuse-gchq-announcement

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In the months since the Edward Snowden revelations, GCHQ and its defenders have been keen to highlight the agency’s work in tackling those sharing images of child abuse online: so far this year more than 70 articles in the UK’s media have highlighted the agency’s work in this area.

Such is the backdrop of David Cameron’s announcement of a joint effort between GCHQ’s spies and the National Crime Agency to tackle child abuse on the so-called “dark web”, those parts of the internet beyond Google where anonymity tools let people browse in ways which are difficult to track, even for intelligence agencies.

Any news about heightened efforts to track down and prevent child abuse will doubtlessly be widely welcomed by the British public, and rightly so – but how much of what the prime minister announced is actually new?

GCHQ has for a long time worked both on its own and with UK police authorities to help tackle child abuse. As the UK’s codebreaking agency, its specialist skills have long been drawn upon to assist in breaking the encryption often used by offenders to attempt to keep their picture and video banks hidden.

As well as that practical action, the UK already has laws – passed largely as a response to online child abuse – making it an offence to refuse to decrypt files when requested by law enforcement agencies. Both UK law and practice has already been adapted to handle that aspect of child abuse sharing.

The other aspect of the cooperation which is effectively being presented by the prime minister as new is a focus on the “dark web”. Most frequently, the anonymisation service Tor – which is funded in large part by the US government – is presented as the villain of this piece, because while it is an essential tool for many activists in oppressive regimes across the world, the anonymity it can grant is also useful to terrorists and criminals.

The issue is that both intelligence agencies and law enforcement have long targeted Tor software and its users: both the NSA and GCHQ made extensive efforts to track users, partly through trying to break the system itself, and partly through aiming malware at Tor users. Similar efforts by the FBI earlier this year have proven instrumental in breaking down most of the dark web’s drug marketplaces – including the notorious Silk Road.

The third strand of the briefing from Number 10 concerns automated systems to help block images and videos of child abuse from YouTube and Google search results, and to help identify those sharing them.

Journalists were pointed towards work from the Internet Watch Foundation based on using digital fingerprints of images and videos – called hash values – to help automatically track down and block such content.

Again, however, such systems are well-established and in use by the internet giants. Google (which also runs YouTube) has one of the most sophisticated anti child-abuse systems on the planet, based on a similar system to the technology it uses to automatically remove content which violates copyright from its networks.

Once a particular image is identified unambiguously as being of child abuse, it is put into an automated scanner which identifies key features in its code, and then identifies and blocks all copies of that image from Google’s services and search results. Google also uses this information to identify users promulgating such content, and cooperates with law enforcement internationally. Other major online service providers have similar systems in place.

The end result is that it becomes difficult to see what, precisely, the prime minister announced. Both the police and GCHQ were already working to circumvent anonymity provided by Tor, working against child sex offenders’ use of encryption, and cooperating with each other. Technology companies already work to fingerprint such content and remove it.

What’s left could be as little as a new operational name for long-running work – plus a few good headlines for GCHQ, and the prime minister himself.