Digital fingerprints of a million child abuse images made

Image credit: BBC

According to the Internet Watch Foundation, digital fingerprints of a million images of child sexual assault have been created.

The fingerprints, known as hashes, will assist companies and police in identifying copies of the photographs, according to the UK organisation responsible for finding and removing such material online.

It is intended that this will prevent the photographs from being reused.

The photos are from the Child Abuse Image Database, which is maintained by the government.

The database contains some of the most heinous online materials, referred to as category A and B stuff.

The hashes are an algorithm-generated identifying code that acts as a fingerprint for each image or video.

Many computer companies compare hashes of photographs to lists of hashes provided by organisations like the IWF to search for child abuse content on their systems.

However, the system is not without flaws. Changes to images can alter the hash value, allowing an image to elude detection. However, the IWF claims that the technology it employs allows an image to be resized, cropped, or have its colours changed without changing the hash value.

Lists of hashes cannot be used to identify encrypted images.

A human assessor will determine which category unlawful material fits into before making hashes, according to UK law.

The charity also creates metadata that reveals the specific nature of the abuse being perpetrated on the child, with the goal of speeding up enforcement action.

The IWF’s chief executive, Susie Hargreaves, said in a statement that the nature of the material required analysts to work four-hour shifts with regular breaks and have access to the best counselling and support.

According to the organisation, it has assisted in the removal of an unprecedented amount of material.

It claims that in 2021, it took action to remove 252,000 web pages that it determined contained photographs or videos of minors who had been sexually abused – a record number.