A group of researchers at University of Limerick have teamed up with the Federal Police of Brazil to tackle the distribution of child pornography on the dark web.
Brazilian ministry of justice, Sergio Moro, has hailed the innovative collaboration between the researchers at UL and Brazilian law enforcement, which has sought to make police operations more efficient.
The research, recently published in the Nature’s Scientific Reports journal, details the results of applying network analysis to assess the effectiveness of Operation Darknet – a Brazilian Federal Police crackdown on one of largest paedophile online forums hidden by the Tor browser.
The police operation, carried out between 2014 and 2016, led to the arrest and identification of 182 users – 170 of which were distributors – and the rescue of six children. Of over 10,000 users, 766 were sharing content.
The team of researchers from the Mathematics Applications Consortium for Science and Industry (MACSI) and the Centre for Social Issues Research, both based at UL, subsequently investigated how effective the operation was in disrupting the distribution of the content.
The research team, which included a Federal Police Officer from Brazil, used the analysis to suggest the best ways to target individuals to maximise the effect of this disruption.
“Network analysis has previously been applied to drug trafficking networks and terrorist networks to identify structural weaknesses and key figures in these illicit networks,” explained Dr Pádraig MacCarron, a postdoctoral researcher at the Centre for Social Issues Research and MACSI who worked with Dr Bruno da Cunha, Kleber A. Oliveira and Professor James Gleeson on the research.
“The dark web network in this study however, was much more dense – as in there were more connections between users than normal - making it more difficult to breakdown using traditional network methods. It was found that the 60% of those core 766 distributors would need to be removed to completely fragment the network. This makes the network highly robust.
“The approach was then taken to try to disrupt the most content shared. Ten of those distributors each had their content viewed more than 100,000 times. This contributed to almost one third of the total views. Of those ten distributors, eight of them were arrested. Of the twenty arrested who had received the most views, they provided 39% of the content. The best the police could have achieved with twenty arrests would have been a reduction of 43%.
“Initially the police investigation was highly effective, quickly arresting those responsible for more than half the content provided. However, subsequent targets were less optimally selected, so that the total arrests reduced the posts by 58% of a possible 92%. This analysis hopes to help lead to more efficient police interventions,” he added.
The team believe the collaboration to be a first between Brazilian law enforcement and Irish mathematicians. Brazilian ministry of justice, Sergio Moro, mentioned the UL research in a recent interview, outlining that “one should invest in intelligence methods to enrich police work” and that “the publication is an index of the quality of the scientific know-how of the Brazilian Federal Police”.
The research was partly funded by Science Foundation Ireland and by the European Research Council.
The study - Assessing police topological efficiency in a major sting operation on the dark web by Bruno Requião da Cunha, Pádraig MacCarron, Jean Fernando Passold, Luiz Walmocyr dos Santos Jr., Kleber A. Oliveira and James P. Gleeson - is online: https://www.nature.com/articles/s41598-019-56704-4