The Internet Watch Foundation (IWF) has announced a new tool, Image Intercept, designed to help smaller platforms detect and block known child sexual abuse material (CSAM). This development is particularly relevant to Fediverse operators, many of whom have asked how they can take proportionate steps to protect their users and comply with legal obligations, including under the UK Online Safety Act.
What Is Image Intercept?
Image Intercept is a lightweight hash-matching tool that checks image and video uploads against IWF’s trusted and regularly updated database of known CSAM. If a match is detected, the content is blocked before it is uploaded, stored, or shared.
The tool uses a combination of Microsoft’s PhotoDNA, cryptographic hash matching, and other detection methods. It is intended for websites and digital services with limited technical resources, and is specifically targeted at startups and smaller-scale providers that may not have existing moderation infrastructure.
Why This Matters for Fediverse Administrators
Most Fediverse instances are low-risk, community-run, and not targeted by people distributing CSAM. However, even a single known CSAM image hosted or shared on your platform can cause further harm to victims, put your service and volunteers at legal risk, and undermine your community’s safety.
The UK Online Safety Act and other regulations include duties for services to assess and mitigate risks associated with illegal harms, including CSAM. While small services are not expected to conduct proactive scanning, choosing to use a tool like Image Intercept shows clear intent to protect users and meet a proportionate standard of care.
As a reminder, our recent study demonstrated a higher than expected rate of known CSAM on the network. This is not a hypothetical future problem, this is an issue today.
Next Steps
IFTAS supports approaches that help decentralised platforms respond to serious harms responsibly and proportionately. Image Intercept may offer a practical option for smaller Fediverse services, if it can be implemented in a way that aligns with privacy, decentralised technology, and the needs of volunteer-run platforms.
IFTAS is currently exploring the practical implementation of Image Intercept across Fediverse platforms, including:
- Whether it is compatible with services like Mastodon, Pixelfed, Misskey, Peertube, and others,
- The technical effort required to deploy it effectively,
- Whether data handling practices align with privacy-respecting infrastructure,
- How eligibility and cost affect small and volunteer-led services.
We encourage Fediverse administrators, especially UK-based or with significant UK audience, to register interest with IWF if they think this tool may be appropriate for their platform:
A Need for Proactive, Community-Focused Tools
CSAM is among the most serious forms of online harm, and every responsible service operator should be prepared to address it. However, any safety solution must be proportionate, workable, and respectful of the values of decentralised communities.
IFTAS will continue to communicate with IWF and other child safety organisations to assess whether Image Intercept is a suitable option for the broader Fediverse. We will share updates and technical guidance in the IFTAS Connect library and community forum.
If you are experimenting with the tool, or have concerns or questions about its use, please let us know. We want to ensure that the Fediverse can protect its users and uphold community safety values, while maintaining its independence and user-focused principles.
This is not just about technology. It is about protecting people, maintaining trust, and doing our part to stop the circulation of known child sexual abuse imagery.
IFTAS Connect Member Discussion: https://connect.iftas.org/forums/discussion/label-discussion-child-safety-csea-csam/
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