Facebook will be the first company outside of Microsoft to roll out the Redmond company’s PhotoDNA technology — a move that the companies are describing as a big step in the fight against child pornography, given the social network’s large user base and its potential to prompt other online services to follow suit.

PhotoDNA, developed in conjunction with Dartmouth College, derives what amounts to a digital fingerprint from photographs to be able to find and identify other versions of the same images online. Microsoft previously donated to PhotoDNA to the National Center for Missing & Exploited Children.

“We hope that Facebook’s adoption of PhotoDNA serves as a springboard for other online service providers to take advantage of the opportunity available through NCMEC’s PhotoDNA program and, in fact, we know that others are exploring the possibility right now,” writes Bill Harmon, an associate general counsel in Microsoft’s Digital Crimes Unit, in a post this morning.

Harmon notes that Microsoft has implemented PhotoDNA in Bing and SkyDrive, identifying “horrific images on our services that we would have never found otherwise.” He adds, “To date, we have evaluated more than two billion images on our services using the PhotoDNA signatures provided by NCMEC, leading to the identification of more than 1,000 matches on SkyDrive and 1,500 matches through Bing’s image search indexing.”

Facebook will hold a live event at noon Pacific on Friday to talk about the PhotoDNA rollout. (Note: Day corrected since original post.)

Microsoft is a minority shareholder in Facebook. More in this New York Times post this morning. Here’s a Microsoft graphic showing how the technology works.

Like what you're reading? Subscribe to GeekWire's free newsletters to catch every headline

Job Listings on GeekWork

Find more jobs on GeekWork. Employers, post a job here.