How we engineered a way to restrict child sexual abuse material without looking at your data

Our new partnership with the Internet Watch Foundation (IWF) proves that strong encryption and targeted CSAM prevention can coexist through careful DNS engineering.

For years, the fundamental operating principle of the VPN industry has been absolute neutrality. We built our infrastructure to move encrypted data securely from one point to another without looking inside the packets or logging user activity. That strict adherence to a neutral network has been essential for protecting dissidents, journalists, and everyday internet users from mass surveillance. However, we recognized that our commitment to privacy doesn’t require us to turn a blind eye to the specific distribution of child sexual abuse material. We realized we could engineer a way to actively reject these dedicated CSAM domains while keeping our foundational promises of encryption and anonymity completely intact.

Today, we’re proud to announce a major step forward in this mission with the launch of our “Not on My Network” initiative. We’ve partnered closely with the nonprofit Internet Watch Foundation (IWF) to systematically restrict access to all known dedicated CSAM domains across our entire global server network. This project represents a maturation of our security philosophy, proving that a privacy company can take a definitive stance against the worst network abuse. We’re drawing a hard line to ensure that our infrastructure is never used to facilitate or access dedicated exploitation material identified by IWF.

Engineering a solution with OpenBoundary

The engine driving this new initiative is a server-level technology we developed called OpenBoundary. Rather than relying on client-side scanning, OpenBoundary operates entirely at the DNS level. When a connection request is made, our secure resolvers check the domain against a verified, highly targeted list provided by the experts at the IWF. If the requested destination is flagged as a dedicated CSAM domain, the connection is instantly dropped at the network boundary. This precise mechanism means we never break your encryption, we never perform deep packet inspection, and our strict no-logs policy remains completely uncompromised.

Breaking the false binary of privacy

This deployment strikes at the heart of a long-standing debate within the cybersecurity community. Pete Membrey, our Chief Research Officer, has been a driving force behind this architectural shift. “The privacy debate has been falsely framed as a binary choice between protecting encryption and weakening it for safety,” Membrey explains. “Privacy infrastructure does not have to carry everything indiscriminately. With careful engineering, protection and privacy can actually reinforce one another.” His core thesis proves that we can build robust user protection without sacrificing absolute network confidentiality.

The experts leading the fight against digital exploitation agree that this technical approach represents a vital breakthrough. Kerry Smith, the CEO of the IWF, directly challenges the assumption that safety must come at the expense of anonymity. “This innovative approach shows it’s possible for ExpressVPN to balance its commitment to online child safety and online privacy,” Smith explains. By collaborating to build these precise DNS-level guardrails, we’re demonstrating that a secure internet can also be a fundamentally responsible one.

Open source and industry collaboration

We firmly believe that protecting the internet from abuse should never be treated as a proprietary competitive advantage. To that end, we will be open-sourcing the underlying code for OpenBoundary alongside a comprehensive technical whitepaper that details its network architecture. We’re actively inviting other VPN providers, internet service providers, and cloud platforms to adopt this technology and join the “Not on My Network” initiative. We’re thrilled that CyberGhost VPN and Private Internet Access have already stepped forward to join us in this critical industry-wide effort.