A pan-European drive to use the financial system to fight online child abuse has succeeded in reducing sales of child abuse material using conventional payment systems – but research suggests that abusers have been driven underground, turning to anonymiser technologies to evade law enforcement, and bitcoin to pay for material.

Experts from the European Financial Coalition Against Commercial Sexual Exploitation Online (EFC) report that images and videos of child abuse have become a currency in their own right, with abusers expected to provide new material in exchange for access.

The fight against online child abuse is also struggling in the face of increased use of live-streaming to share video of abuse. Live-streamed material is more difficult to discover once the stream has ended, and requires rapid action from law enforcement authorities to combat.

“Rather than a success, the phenomenon is getting harder to tackle, with all this material going underground”, says Tania Anguelova, the EFC’s project officer.

“It is getting harder and harder to find this material in the open web … and more and more challenging to identify the offenders,” she added.

The EFC, which includes tech firms such as Microsoft and Google, financial companies including Visa and Mastercard, and child protection organisations including INHOPE and the International Centre for Missing and Exploited children, was formed in 2012 with the aim of cracking down on people who exploit children for money.

Its report, the first since 2013, finds that conventional payment systems are declining in popularity. They were used in a little under 10% of the 5,236 URLs suspected of commercial distribution of child abuse material that were catalogued over 2013.

Of those, 266 accepted payment through money transfer services, 135 through credit card companies and 102 through digital wallet operators. The British anti-abuse Internet Watch Foundation suggest that SMS payments are also being used.

“A proactive approach by reputable companies, a number of regulations, compliance programmes and preventative work appear to have been effective in reducing the number of sites able to process payments,” the EFC report concludes.

But commercial abusers have moved to other payment methods in order to continue operating. Much of the evidence is still anecdotal, notes the report, but law enforcement and financial experts have expressed concern that commercial exploitation of child abuse material is “moving to a new unregulated, unbanked digital economy”.

It cites IWF research that found 22 sites exclusively taking bitcoin in exchange for child abuse material in 2014, and 37 accepting it overall. The organisation first discovered bitcoin being taken for child abuse material back in June 2013.

Some organisations have also turned to using child abuse material as currency. “A worrying phenomenon is the fact that the new material is sometimes considered a currency itself. And this is another big phenomenon which we need to find a way to tackle properly,” said Anguelova.

The other major technological trend cited by the coalition is the rise in the live-streaming of child abuse for payment. “[It] is no longer an emerging trend but an established reality. It is of particular concern in the context of emerging markets due to internet adoption there,” the report states.

A recent operation led by the National Crime Agency in the UK resulted in a paedophile ring, which streamed live sexual abuse of children as young as six, being dismantled, says the EFC paper. In some cases the victims’ parents were involved.

“Fifteen victims in the Philippines aged between six and 15 were rescued, 29 people were arrested, including 11 in the Philippines. 12 countries were involved in the arrest of individuals who had been paying for the live abuse of children.

“Over £37,500 was identified as having been paid for the live abuse of children by the customer network. Three other ongoing investigations have identified 733 suspects.”

Dismantling such rings is difficult, because the real-time monitoring of streams is legally and technically challenging, with users adopting layers of anonymity and many broadcasts password-protected.

As a result, the best approach as identified by the report is using the financial system to identify suspicious transactions in order to follow the money back to the abuser, and prioritising the identification of individuals who have access to children.