The National Center for Missing & Exploited Children is a child protection organization, who operates the CyberTipline – an online reporting system for all types of online child sexual abuse. They offer numerous resources and assistance to victims and survivors of child sexual abuse.
"Take It Down works by assigning a unique digital fingerprint, called a hash value, to nude, partially nude, or sexually explicit images or videos of people under the age of 18. Online platforms can use hash values to detect these images or videos on their services and remove this content. This all happens without the image or video ever leaving your device or anyone viewing it. Only the hash value will be provided to NCMEC."