Fingerprinting child abuse images
Massive internet companies like Google, Facebook and Twitter will able to easily remove child abuse images from their services using a unique digital fingerprintWikimedia Commons

Child abuse images will be digitally fingerprinted to prevent paedophiles sharing them online in a new initiative which hopes to eradicate millions of indecent images from the web. In a partnership that is a first of its kind, the UK's Internet Watch Foundation (IWF) is teaming up with Google, Facebook, and Twitter to help prevent abusive images from being uploaded to their services.

The IWF, which scours the internet to find and remove abusive images, allocates each image a unique identifier called a hash - sometimes referred to as a digital fingerprint - which it will now begin to share with the world's biggest internet companies. "There are billions of images on the internet and by creating a digital fingerprint of a single image, you can pluck it out, like finding a needle in a haystack," the IWF said in a statement.

The charity said that it will automatically begin creating three types of hashes to meet the needs of the online industry which are PhotoDNA, MD5, and SHA-1 hashes. Google, Facebook and Twitter already made great efforts to prevent such images being stored and shared on their respective networks but considering the vast number of people using their services, it can be a difficult task.

While big name companies will grab the headlines, the IWF says the technology can be used by any online service including those involved in the upload, storage, or search of images, such as filtering services, hosting services, social media and chat services, data centres and connectivity services.

IWF CEO Susie Hargreaves said the technology could be "a game-changer" in the fight against child sexual abuse images online: "This is something we have worked on with our Members since the Prime Ministers' #WePROTECT summit last December. We'll soon be able to offer the hash list to all IWF Members, who are based around the world. It means victims' images can be identified and removed more quickly, and we can prevent known child sexual abuse images from being uploaded to the internet in the first place."

Last year David Cameron called child abuse a "national threat" and vowed to fight back. The IWF's analysts remove up to 500 web addresses containing child abuse images every single day, with each URL potentially containing thousands of images.

"By hashing all the child sexual abuse images found on each URL, the size of the hash list will increase significantly every day. It has the potential to reach millions of hashes of images. The more hashes given to the online industry, the greater the protection offered on companies' online services," said Hargreaves.

Dark web

What is the dark web?

The dark web is a section of the internet that requires specialist software tools to access, such as the Tor browser. Originally designed to protect privacy, it is also associated with illicit activities.

It is often confused with the deep web, which is a vast section of the open internet not indexed by search engines such as Google. The deep web comprises around 95% of the internet.

While the move will help prevent the spread of abusive images on mainstream services like Google and Facebook, the problem of the dark net remains, and this is where the vast majority of the world's child abuse images are stored, shared, and sold.

In 2013 GCHQ and NSA announced they would join forces to track down and unmask paedophiles by using specialist code-breakers to attempt to crack the encrypted messages sent by the people sharing these images on the anonymous Tor network. However, industry experts believe that despite the attempts of the UK government and the Internet Watch Foundation, the scale of the issue means it will make little difference.

"Despite Cameron's comments on the 'national threat' of child sexual abuse, and a renewed commitment to tackling it, there is still a fundamental misunderstanding of the scope of this problem and the means by which it can be tackled. The number of people and volume of material involved in child sexual abuse crimes is overwhelming. British, and international law enforcement simply doesn't have the numbers to deal with this on a case-by-case basis. It requires the action of millions, to protect communities and the refusal to stand idly by," said Christian Berg, CEO and founder of NetClean, which provides tools to help detect abusive images online.