Law enforcement agencies will have free access to a new tool developed by Microsoft used to identify, track down and rescue victims of sexual abuse and child pornography. Microsoft and Facebook currently use the software, PhotoDNA, to find, delete and report child pornography online, Information Week reports. PhotoDNA, codeveloped by Microsoft and Dartmouth College professor Hany Farid, identifies images using mathematical “signatures” even if the images have been altered, enabling law enforcement officers to find child porn online and track down and prosecute the creators of the images. The software includes the signatures of 15,000 “worst of the worst” images. Microsoft’s Digital Crimes Unit released the software and integrated it in to other law enforcement software packages.