How does PhotoDNA spot online child pornography?

by | Aug 17, 2015 | Federal Crimes

Anyone who’s shopped for a pair of shoes or anything else online and then found multiple ads for similar products popping up at them for weeks afterward realizes that on some level, their Internet activity is being monitored. This is generally done by way of programs and not by humans. However, it’s important for people to be aware that if something illegal like child porn is being viewed online, law enforcement may find out.

In fact, Microsoft has created a tool called PhotoDNA for the purpose of fighting the online transmission of child pornography. It’s been estimated that some 720,000 illegal images may be uploaded on any given day. The company began work on the tool six years ago in partnership with the National Center of Missing and Exploited Children, and has been perfecting it since then.

While PhotoDNA has been used by law enforcement agencies, it is now being made available to those who own websites. In addition to helping prevent the transmission of pornographic images of children, it protects website owners from unwittingly having illegal images uploaded to their sites and to protect visitors to their site from seeing these images. It’s been used on search engine sites like Google and Bing, email systems like, social media sites and instant messaging services.

PhotoDNA, which is a cloud-based system, works via a hash reference system that compares images to those of illegal images and spots matches. It’s become so advanced that even illegal images that have been altered can be spotted.

This technology allows far more images to be “viewed” than humans could do. However, it also means that it may catch images that people view accidentally, that viewers may not realize are illegal or that are viewed by someone with access to their computer or mobile device.

The legal ramifications for possessing child pornography can be severe and the impact on your life permanently. If you are charged with possessing or sharing child pornography, regardless of the circumstances, it’s essential to seek experienced legal guidance immediately.

Source: BetaNews, “Microsoft PhotoDNA helps websites weed out illegal child porn and abuse images,” Mark Wilson, accessed Aug. 17, 2015