How a secure whistleblower technology moved from the research lab to the newsroom

In a functioning democracy, a free press plays a vital role in holding powerful institutions to account. But for journalism to thrive, citizens must be able to contact reporters securely – especially when revealing sensitive or controversial information.

This is particularly challenging in an era of pervasive surveillance, where even the act of communication can raise suspicion.

So say speakers Dr Daniel Hugenroth (above) and Professor Alastair Beresford (below) who, at our Wednesday Seminar on Wednesday 12 November, will present their work on CoverDrop. This is a secure communication system that is now deployed within The Guardian's news app, designed to help whistleblowers reach journalists without revealing their identity.

Unlike traditional secure messaging tools, CoverDrop hides not just the content of messages, but the very existence of communication. It achieves this by sending regular, encrypted, fixed-size blocks of data to a central server and then on to journalists – whether or not a real message is present. This strategy ensures that observers, including network operators or state-level adversaries, cannot distinguish between genuine and dummy traffic.

The speakers will trace CoverDrop's full five-year journey from research to real-world deployment. Starting with workshops with journalists to understand their needs, they'll share insights from user studies that shaped the design – some of which challenged conventional assumptions.

They'll explore the technical hurdles of implementing metadata privacy on modern smartphones, and the protocol design choices needed to support plausible deniability and high-latency communication. Finally, they'll discuss the engineering work required to integrate CoverDrop into a production news app used by millions, highlighting lessons learned that go beyond academic prototypes.

This talk is a case study in how cryptography, usability, and systems engineering can come together to support press freedom in practice. Those who would like to join the talk online can do so via this link.