pornography, allowing the companies to report the possessor to authorities. 133 Microsoft and
Dartmouth College developed PhotoDNA in 2009, which works by creating a “hash” or
fingerprint134 for each child pornography image in a database. 135 When PhotoDNA is used in
computer systems such as Facebook, it can search the system for images that contain the hash and
identify the child pornography. 136
Microsoft donated the system to NCMEC. 137 NCMEC is able to distribute updated hash
information to the technology companies using PhotoDNA without providing images to the
companies. 138 The International Centre for Missing and Exploited Children (“ICMEC”) has a
similar system that can identify up to eighty-five percent of images seized on a hard drive,
enabling law enforcement to focus its labor primarily on the remaining fifteen percent. 139 Google
has also been using “hash” technology since 2008 to identify images that would not normally be
Additional efforts are still needed to combat the vast amount of child pornography online.
More webpages must be searched. For example, Google searches approximately fifteen billion
pages, merely a fraction of the Internet. 141 Google and other search engines are only able to report
child pornography and block it from appearing in a search result. 142 While this reduces the
number of offenders, it does not permanently eradicate the child pornography, which law
enforcement may use to identify and prosecute offenders. 143 Additionally, it is unknown how
many sex abuse images are contained in the various databases because of the number of
government entities around the globe maintaining these databases. 144 Thus, more collaboration
between victims, law enforcement, private industry, NCMEC, and their international counterparts
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133 Charles Arthur, Twitter to Introduce PhotoDNA System to Block Child Abuse Images, THE GUARDIAN (July 22, 2013, 5:39 AM),
http://www.theguardian.com/technology/2013/jul/22/twitter-photodna-child-abuse; see also Our Continued Commitment to
Combatting Child Exploitation Online, GOOGLE OFFICIAL BLOG (June 15, 2013), http://googleblog.blogspot.com/2013/06/our-
continued-commitment-to combating.html (explaining the technology used by Google to combat child pornography).
134 Zack Whittaker, Microsoft Develops Image DNA Technology for Fighting Child Porn, ZDNET BLOG (Dec. 17, 2009, 6:07 PM),
http://www.zdnet.com/blog/igeneration/microsoft-develops-image-dna-technology-for-fighting-child-porn/3655. The hash resolves
privacy concerns for victims by only providing companies a unique signature of the image that is reported to authorities. Authorities
have access to the child pornography images and are able to determine who the victim is from the unique hash. The company does not
receive the victim’s personal information. Adi Robertson, Microsoft Gives PhotoDNA Matching Software to Police to Help Find Child
Pornography, THE VERGE (Mar. 20, 2012. 9:51 AM), http://www.theverge.com/2012/3/20/2886999/microsoft-licensing-photodna-
135 PhotoDNA Press Materials are Now on the Microsoft Digital Crimes Unit Newsroom, MICROSOFT,
https://www.microsoft.com/en-us/news/presskits/photodna/ (last visited Feb. 1, 2015); Robertson, supra note 134.
136 Arthur, supra note 133.
137 PhotoDNA Press Materials are Now on the Microsoft Digital Crimes Unit Newsroom, supra note 135.
138 18 U.S.C. § 2258C (2012) (requiring NCMEC to partner with technology companies to reduce the sharing of child pornography);
Voluntary Industry Initiatives, NAT’L CTR. FOR MISSING & EXPLOITED CHILDREN,
https://secure.missingkids.com/Exploitation/Industry (last visited Feb. 1, 2015). In addition to PhotoDNA, NCMEC has a URL
initiative that reports child pornography websites to electronic service providers for takedown. Id. A Hash Value Sharing Initiative,
similar to PhotoDNA, provides electronic service providers with “hash” values of the “worst of the worst” images. Id. In 2011,
NCMEC reviewed 17.3 million images and videos of suspected child sexual abuse through both public and private efforts. Our
Continued Commitment to Combatting Child Exploitation Online, supra note 133.
139 Int’l Ctr. for Missing & Exploited Children, Video Fingerprinting Technology Removes Child Pornography Online, DFI NEWS
(May 1, 2014, 3:25 PM), http://www.dfinews.com/news/2014/05/video-fingerprinting-technology-removes-child-pornography-online.
140 Our Continued Commitment to Combatting Child Exploitation Online, supra note 133.
141 Tim Worstall, I’m Not Sure that Google’s New Child Pornography Database Is Going to Work, FORBES (June 17, 2013, 6:06 AM),
142 See id.
143 There is an argument to be made that victims should be given the absolute right to order their sex abuse images destroyed either
before or after it comes into the control of law enforcement, but unfortunately, a discussion of that right is beyond the scope of this
Article. At a minimum, victims should have the same right to access their sex abuse images as defendants.
144 Arthur, supra note 133 (noting that a small portion of child pornography images are actually given a hash); see also Gillespie,
supra note 21, at 295 (noting Interpol’s duty to coordinate the “many countries” with child pornography databases).