(CNN) - Federal authorities say they've busted a massive child porn ring, and they say it's one of the worst instances of internet child abuse they have ever investigated - and one of the most sophisticated.
Thumb drives, hard drives, and cameras are the kinds of technology exploited by cyber forensic investigators to uncover the members-only online bulletin board for child pornography called Dreamboard. Officials describe the images as "horrific".
"The board may have been the vehicle for the distribution of up to 123 terabytes of child pornography, which is roughly equivalent to nearly 16,000 DVDs," said Homeland Security Secretary Janet Napolitano.
Of the 72 people charged so far, 52 have been arrested in 14 countries, and the investigation is continuing. Officials say more than 600 Dreamboard members were required to post images every 50 days or risk expulsion. The more they posted the more access they got to material on the site.
"The payment system, if you will, would be a barter system. I'll show you mine, you show me yours," said Neil O'Callaghan of the Federal Cyber Crimes Center.
The government says members were encouraged to create porn, instructed to "keep the children 11 or younger". Some of the victims were just infants.
One part of the board mandated that children be in pain. "If the girl looks totally comfortable, she is not in distress, it does not belong in this section," said the posting.
"This is an encouragement of the torture of children for sexual gratification," said O'Callaghan.
The board told members how to mask their identities, and erase their internet footprints. It used encryption. Experts at the Immigration and Customs Enforcement Cyber Crimes Center that investigated the case, say the use of sophisticated passwords has made cracking porn cases more difficult, and ever-larger hard drives are making it harder to find evidence.
"The haystack was the size of my fist. Now the haystack is huge because - technology," said Federal Computer Forensic Agent Doug Skinner.
The Center for Missing and Exploited Children says it is significant that law enforcement was able to disrupt this ring, but the Center says the problem of child porn is vast and growing.