On its twentieth anniversary, the UK’s Internet Watch Foundation—propped up by Microsoft’s PhotoDNA tech—is urging Web companies to use its list of digital fingerprints to help prevent the upload, sharing, and storage of child abuse sex images online.

The IWF hash list of the underlying code associated with child abuse images was distributed to Google, Facebook, and Twitter in August 2015. It is compiled by analysts at the charity, who have the gruelling task of sifting through photos and videos showing children being sexually abused. Every eight minutes they identify a new webpage containing horrendous images.

To date, 125,583 hashes have be added to the list—more than 3,000 of which involved the abuse of babies and toddlers.