'Hash List' to Help Google, Facebook, More Remove Child Porn

Top tech titans have joined the U.K.'s Internet Watch Foundation (IWF) to help combat online child sexual abuse.

The IWF on Monday announced it will distribute a "hash list" of images to Web-based organizations to speed the identification and removal of the content worldwide.

Hashes, or digital fingerprints of an image, have been assessed by IWF analysts, and will be issued to members like Facebook, Google, Microsoft, Twitter, and Yahoo, to identify inappropriate images on their services.

Based on trained analysts' assessments, the IWF will automatically create three types of hashes: PhotoDNA (developed by partner Microsoft), MD5, and SHA-1. The digital fingerprints are available only for photos; the organization is developing video-hashing software.

Last month, Microsoft launched a cloud version of PhotoDNA. It is now available for free from the Azure Marketplace, allowing organizations to automatically detect child exploitation images on their services and report this illegal content to the National Center for Missing and Exploited Children and other law enforcement agencies.

By integrating the hash list into social networks and search programs, Web watchdogs and operators can prevent photos from being shared, stop abusive images from being uploaded to the Internet, and protect people from accidentally stumbling across such content.

"It means victims' images can be identified and removed more quickly, and we can prevent known child sexual abuse images from being uploaded to the Internet in the first place," IWF CEO Susie Hargreaves said in a statement.

A six-month project, the hash list is coming soon to all IWF members around the world.

"We were developing a service from scratch, which would be a complex and challenging task, but we knew that this could revolutionize the way in which we fight online child sexual abuse material," Harriet Lester, technical projects officer at IWF, wrote in a blog post.

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"The IWF Hash List could be a game-changer and really steps up the fight against child sexual abuse images online," Hargreaves said. "This is something we have work on with our members since … last December."

The Foundation removes around 500 URLs, each containing one to thousands of images of child sexual abuse material, every day. With the addition of the hash list, that number is expected to grow exponentially.

In 2013, Google launched a shareable database that makes it easier for organizations to report and remove images of child sexual abuse from larger portions of the Web.