Whitepaper: https://www.coverdrop.org/coverdrop_guardian_implementation_june_2025.pdf
Source code: GitHub - guardian/coverdrop: Blowing the whistle through a news app
A team at the University of Cambridge and The Guardian developed CoverDrop: a secure, anonymous, and usable method of establishing initial contact between journalists and sources embedded in a set of extensions to a typical news app.
Confidential
All messages between sources and journalists are end-to-end encrypted.
Ease-of-use
Included in the news reader app for every user: no technical wizardry needed.
Anonymous
Real messages hide among the cover traffic sent by all app users: CoverDrop protects metadata.
Plausible deniability
Sources can plausibly deny that they have used CoverDrop: even when asked to unlock the device.
Real world
The Guardian deployed CoverDrop to millions of news reader installations in 2025.
Research project
CoverDrop started as an academic project and remains an active research area at the University of Cambridge.