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Voluntary Industry Initiatives

The National Center for Missing & Exploited Children®, pursuant to 18 U.S.C. § 2258C, partners with the Internet industry in voluntary initiatives to help reduce the proliferation of child pornography online, including the URL and Hash Value Sharing and PhotoDNA Initiatives. These valuable initiatives allow members of the online industry to take proactive steps to limit the accessibility of child pornography images on the Internet and protect child victims from being repeatedly victimized when images of their exploitation continue to circulate online.

To learn more about these initiatives, including how your company can get involved, contact

URL Initiative

NCMEC maintains a list of URLs for active Web pages containing apparent child pornography. By joining the URL Initiative, Electronic Service Providers are provided access to NCMEC's URL list which is updated daily.


PhotoDNA is an image matching technology developed by Microsoft Research in collaboration with Dartmouth College. It creates a unique signature for a digital image called a PhotoDNA signature. This signature, like a fingerprint, can be compared with the signatures of other images to find copies of that image. NCMEC and online service providers use PhotoDNA to help find, report and curtail the online circulation of some of the worst known images of child pornography. Major U.S. companies have implemented PhotoDNA, and the technology is helping them identify child pornography images on their servers that may have otherwise gone undetected.

Hash Value Sharing Initiative

Through the Hash Value Sharing Initiative, U.S. based Electronic Service Providers can partner with NCMEC to receive a list of MD5 hash values which represent the "worst of the worst" images of apparent child pornography.

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