Image Hash List - new breakthrough technology

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Awarded ‘Innovation of the Year’ by Cloud Hosting Magazine.

You can now prevent anyone from uploading, downloading, viewing or hosting images of child sexual abuse on your services.

The IWF Image Hash List is the most up to date and effective way to protect your customers, colleagues, and services from online child sexual abuse images.

Watch our video:

IWF Image Hash List video 

Image Hash List film available here with Spanish subtitles.

Image Hash List film available here with French subtitles.


Why do I need it?

If people can upload, download, view or host images on your services, you could benefit from the IWF Image Hash List.

By using our List you'll be able to prevent:

  • The upload of a child sexual abuse image on your system;
  • The sharing of an image through your services;
  • The use of your hosting services by a child sexual abuse website.

Using the IWF Image Hash List will:

  • Make your network safer;
  • Protect your customers;
  • Save your employees time and distress;
  • Protect the victims from re-victimisation.

Digital fingerprints

We turn child sexual abuse images into unique codes (hashes) - think of it as a digital fingerprint - every day to help you keep your services free from these images. We do this using Microsoft PhotoDNA. Using our List you'll be able to automatically match known images before they appear on your services. You'll have access to a daily updated list of IWF hashes to carry out automated checks.

Cloud solution

The IWF and Microsoft have teamed up to make it easy for companies to use the IWF Image Hash List.

The Microsoft and IWF collaboration has enabled a cloud-based delivery solution.

Companies can compare anything from a single image to the millions of images uploaded through their platforms daily, using the cloud solution. For most companies, it’s not possible to manually scan every image which is uploaded onto their platforms as the numbers are too high. So the IWF Image Hash List, deployed through the cloud solution, can do it for you.

You can do all of this without affecting the users’ experience due to the speed and efficiency of the cloud solution. Any IWF member can integrate the cloud solution into their platform and be proactive in monitoring against the distribution of online child sexual abuse material.

Corporate Vice President, Microsoft EMEA, Michel Van Der Bel says: “The impact of IWF’s work has been profound. They have made great progress, but there is more to be done. This is a journey."

"Microsoft was delighted to be able to employ the technology of our cloud based service to support IWF’s Image Hash List. It’s great work and we are very happy to be involved.”

IWF Deputy CEO, Fred Langford says: “The collaboration with Microsoft and our access to the police database makes this development unparalleled globally. For us, this development could revolutionise the way we work and give peace of mind to the thousands of children, whose images have been shared again and again. We currently have more than 125,000 hashes on the list but we’re looking at potentially millions.”

Enhanced quality checks

Each child sexual abuse image is assessed manually by two expert IWF analysts. These enhanced quality checks are designed to ensure that each image is categorised accurately before it reaches your systems.

International Deployment

Our image hashes are categorised to support international use. So whether your services focuses on a single country, or a multi-national platform, we can tailor the List to what you need.

Better than traditional hashes

We need to help you keep up with the criminals. Unlike traditional hashing technology, an image can be resized, cropped or colours changed and our hashes will still find a match to the original image.

How is the IWF Image Hash List different?

  • The images on our List come from:
  • Public reports;
  • IWF Analysts actively searching for them;
  • The UK Home Office’s Child Abuse Image Database (incl. images that aren’t yet online).
  • International companies trust the IWF Hash List and use it with legal confidence.
  • Thousands of images are added each week.

Why choose the IWF Image Hash List

  • Security: You can access the Image Image Hash List through our cloud solution or you can download it as a CSV file or via an API, avoiding the need for additional, external hardware. This direct data feed offers enhanced security assurance and flexibility.
  • Quality assurance: All IWF hashes come from images that have been assessed and categorised by our analysts. We want you to be 100% confident in the content of our list.
  • Daily updates: The IWF Hash List is updated daily as hashes of new images are constantly being added by the team here.
  • Global: All images are graded according to the UK Sentencing Council and are categorised to support greater international use.
  • Two hash versions available: We provide both PhotoDNA and MD5 versions of the hashes. We recommend PhotoDNA.
  • Continual improvement: We are always investigating new technologies to improve the effectiveness of our Image Hash List.
  • Actively searching: We are the only Hotline in the world who is actively seeking images so we are finding more content than anyone else and therefore creating more hashes. We also conduct research to further develop our expertise.
  • Funding the solution: We are a not for profit organisation working to remove child sexual abuse content from the internet. Join a global network of industry partners to fund the solution.

Contact us

Contact us today to discuss your IWF Image Hash List requirements: Email or call +44 (0)1223 20 30 30.

Co-funded by the European Union Safer Internet Thinkuknow INHOPE UK Council for Child Internet Safety Investors In People Child rights Connect Nominet European Financial Coalition