US, South Korea officials trace bitcoin transactions to take down massive child porn site

Officials have seized approximately eight terabytes of child sexual exploitation videos and arrested more than 300 people worldwide associated with the site, the US Justice Department said.

US and South Korean law enforcement officials have taken down the largest darknet child pornography website, the US Justice Department announced today. Officials seized approximately eight terabytes of child sexual exploitation videos and arrested more than 300 people worldwide associated with the site. They also rescued dozens of minor victims who, the DOJ says, were being actively abused by the users of the site. 

A federal grand jury in the US District of Columbia indicted Jong Woo Son, a 23-year-old South Korean national, for his operation of the site Welcome to Video, the largest child sexual exploitation market by volume of content. The nine-count indictment against Son was unsealed Wednesday, along with a parallel civil forfeiture action. 

Son is currently in custody serving a sentence in South Korea, where he was already charged and convicted for operating the site. 

Welcome To Video, according to the DOJ, was among the first Darknet websites to monetize child exploitation videos using bitcoin. Each user received a unique bitcoin address when theycreated an account on the site.  

By tracing of bitcoin transactions, IRS Criminal Investigation (IRS-CI) special agents were able to identify the site administrator and ultimately track down the website server's physical location in South Korea. The government agencies involved using software from the firm Chainalysis, the company said, to analyze the blockchain transactions and map out contributors and users of the site.

Chainalysis has a history with working with the federal government, previously helping to dismantle the now-defunct BTC-e cryptocurrency exchange through which ransomware gangs laundered money.

An analysis of the Welcome To Video server showed the website had more than one million bitcoin addresses, signifying that the site had capacity for at least one million users. 

Agents from the US, South Korea and the UK arrested Son and seized the server in March 2018. Additionally, agents have arrested and charged 337 site users across 24 US states and 11 other countries. 

The National Center for Missing and Exploited Children (NCMEC) is currently analyzing more than 250,000 unique videos seized from the site's server. As many as 45 percent of the videos already analyzed contain new images that have not been previously known to exist.

At least 23 minor victims residing in the United States, Spain and the United Kingdom, who were being actively abused by the users of the site, have been rescued due to this operation, the DOJ said. 

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