Microsoft has developed a technology PhotoDNA which creates signatures of images that can be used in matching without being able to recreate the image from the signature. It is in use on Microsoft's Bing, as well as Twitter, Facebook and Google's Gmail, primarily for identifying child abuse imagery.
UK indecent image databases
- Childbase ceased to be active in 2011
- An interim National Hash Set Database (HSD) was created by National Policing Improvement Agency, Home Office Scientific Development Branch, Association of Chief Police Officers Digital Forensics Triage groupby amalgamating the hash databases of abuse imagery held by police forces in North West England with those held by CEOP, By May 2013 the database held over 200 million unique hashes.
- A national Child Abuse Image Database (CAID) was announced in March 2014 replacing the HSD, which will allow law enforcement to "support analysis by police of devices seized during investigations; to support victim identification; and to provide hash set data to the internet industry". It became operational in December 2014.
- Hansard, 2014-10-22
- Hansard, 2014-11-06
- Police Central e-Crime Unit Financial Harm Reduction and Performance Report, Oct 2012 - Sep 2013
- Hansard, 2014-03-05 "We will create a new child abuse image database that will hold a national record of the images seized by the police."
- Hansard, 2014-10-29
- Hansard, 2016-05-03