Facebook Adopted PhotoDNA to Against Child Pornography

Facebook is the first company to use a tool from Microsoft that identifies known images of child pornography and remove them from the social network.

The tool, called PhotoDNA, is software that analyzes images for certain characteristics and compares them to images in a reference database. Microsoft calls this process “robust hashing,” and an illicit image’s “hash value” can help authorities track and identify copies – altered or not – of child porn photos.



Microsoft said it has been testing PhotoDNA on Bing, Windows Live Skydrive and Hotmail for more than a year. Now, Facebook is deploying the technology across its entire social network, which has become one of the premier photo-sharing services.

Facebook will run PhotoDNA against all photos uploaded to the site, to block the distribution of these images of criminal exploitation. The technology will also better enable to report incidents to the National Center (for Missing and Exploited Children) and police, to allow them to take immediate action.

Facebook also said it is required by law to report images of child pornography to the NCMEC, which forwards the incident to the appropriate law enforcement agency. Facebook also works with INTERPOL and the International Centre for Missing and Exploited Children, the spokesperson said.



PhotoDNA has the power to quickly and accurately identify known child pornography images amongst Facebook’s billions of files shared online. In just one month, Facebook’s services host more than 30 billion pieces of shared content, including photos, Web links, news stories, blog posts and more. Identifying graphic child pornography in a sea of content like that is a daunting task, but PhotoDNA is helping to find the proverbial needle in a haystack.

Child pornography had been nearly eradicated in the 1980s. But the advent of the Internet opened up a new way – an easier, safer and more anonymous way – to transmit and share illegal content.

In 2009, Microsoft donated PhotoDNA to the NCMEC, which reviews thousands of images per week and assigns PhotoDNA signatures to known images of child abuse. The center then shares the signatures with Microsoft and services such as Facebook, which can then find illegal images and delete them. The technology can pluck out inappropriate images from a sea of billions in a very fast and very reliable way.

PhotoDNA was created by Microsoft Research and further developed by a Dartmouth College computer science professor. Microsoft hopes Facebook’s adoption of the tool will encourage more companies to use PhotoDNA. Law enforcement agencies already are able to download the tool from the NCMEC.