Canadian police have uncovered a huge online child pornography file sharing network with content amounting to 1.2 petabytes of data, which is four times more than the total amount of data stored by the US Library of Congress.

The child pornography ring could consist of up to 7,500 users in 100 countries, and the police have decided to go after the operators of a data centre the material was seized from.

The amount of child pornography seized is so great that the police had to purchase additional storage hardware in order to store and analyse the data (to understand the relative size of a petabyte, read this).

"What we are alleging is occurring is that there are individuals and organisations that are profiting from the storage and the exchange of child sexual exploitation material," Scott Tod, Deputy Commissioner of the Ontario Provincial Police (OPP), told Vice Motherboard at a defence conference in late February.

"They store it and they provide a secure website that you can log into, much like people do with illegal online gaming sites."

Much of the details surrounding this investigation are still unclear as the investigation is ongoing, and the police have yet to decide whom or how many people should be charged.

However, if the police do go after the data centre, it will set a new precedent that the hosts of information are responsible for what their users upload.

This would be similar to the ongoing case against internet entrepreneur Kim Dotcom, who maintains that he is not responsible for users deciding to upload pirated films to Megaupload storage lockers, which were then shared with users all over the world.

A data centre based in Ontario, Canada

The police have said that the file-sharing service was traced back to a data centre company based in Ontario, Canada which has "millions of dollars in profits", and that is where the data was seized.

In fact, the amount of child pornography seized is so great that the police had to purchase additional storage hardware in order to store and analyse the data.

The police also had to develop password-cracking software able to cycle through 500,000 possibilities per second in order to sift through the huge pile of approximately 1.5 million compressed, password-protected RAR files.

"This is the first investigation of this scale, to my knowledge—in North America, if not worldwide," Tod said.

Out of the 7,500 unique IP addresses identified when the data was seized, the police have identified that 2,200 of the users are in the US, 843 are in Germany, 534 are in Japan, 457 are in Russia, 394 in Canada, 380 in the UK and 374 in France.

Project Spade

"We're not making any assumptions of how many are actually criminally guilty at this time, or criminally responsible. But we're certainly a size of information that's being traded that we know is illegal material of volumes that we've never seen before," Tod said.

Before this, the largest child pornography investigation in the world was Project Spade – an operation started by Toronto Police Service in October 2010 that eventually covered over 50 countries and equated to 142 terabytes of child pornography.

Over 2,300 people were caught purchasing naked images of teenaged boys. Almost 350 people were arrested for sharing pornographic videos by mail and the internet, and 386 children are believed to have been rescued.

The implications from this child pornography bust continue to this day – in the UK, the Independent Police Complaints Commission (IPCC) is currently investigating whether North Wales Police took sufficient action against 12 individuals named by Canadian authorities that were believed to have bought videos of naked children.