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New Research Reveals Disturbing Trends in Child Sexual Abuse Material Availability and Offender Behaviour on the Tor Network

Updated: Apr 12


A groundbreaking peer-reviewed article by an international research team published in the high-level journal, Nature Scientific Reports, sheds light on the alarming prevalence of individuals seeking child sexual abuse material (CSAM) on the Tor network.


An international team of researchers in Finland, the United States, and Spain has completed the first large-scale study of Tor users to discover their search behaviour and to understand how widely CSAM is available through the Tor network. The researchers also conducted an intercept survey to directly engage Tor users and discovered new ways to interfere with abusers’ activities.

The study found that one-fifth of onion domains share CSAM, and that CSAM is easily available on 21 out of the 26 most popular Tor search engines. Analysing 110 million search sessions from the search engine, the research team found that 11% seek CSAM, and offenders predominantly search for CSAM depicting children aged 12-16 years old.

The study aimed to find ways to address illegal and harmful behaviour on the Tor network. Besides staging an intervention, the study sought to provide assistance to users. In the study, the search engine identified searches for CSAM and directed users to answer a survey. Simply answering the survey already constitutes an intervention. Over the course of more than a year, users completed the survey a total of 11,470 times.

The findings reveal that 65% of the survey respondents were first exposed to CSAM when they were under 18 years old. Moreover, 48% of CSAM offenders said they want to stop using CSAM, some seek help, however 74% of help-seekers have not been able to receive help.

The article, titled “Investigating child sexual abuse material availability, searches, and users on the anonymous Tor network for a public health intervention strategy”, was published in the Scientific Reports journal on 3 April 2024. The researchers emphasise the urgent need for a public health approach to combat CSAM offending, stating that the spread of CSAM is a complex public health issue that requires a concerted global effort and commitment.

Juha Nurmi, a researcher at Tampere University’s Network and Information Security Group (NISEC), led the research and analysed the content available on onion websites and the search behaviour of Tor users. He was also the lead author of the research paper.

Protect Children, a leading child-rights NGO based in Helsinki, contributed to the research article, and is advocating for the findings to strengthen global commitments to tackle the epidemic of online child sexual abuse and exploitation.

“Protect Children is deeply concerned by the findings of this research,” said Nina Vaaranen-Valkonen, Executive Director and Psychotherapist at Protect Children. “We urge policymakers, law enforcement agencies, and civil society organisations to prioritise the prevention and intervention strategies necessary to combat CSAM and protect children from exploitation.”

Juha Nurmi, Arttu Paju, Billy Bob Brumley, Tegan Insoll, Anna K. Ovaska, Valeriia Soloveva, Nina Vaaranen-Valkonen, Mikko Aaltonen, and David Arroyo. “Investigating child sexual abuse material availability, searches, and users on the anonymous Tor network for a public health intervention strategy”. Scientific Reports, 2024.

The full research article is available in Nature: Scientific Reports


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