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@martin.kleppmann.com

Congratulations @lambda.bsky.social! Today @theguardian.com is launching a new way for whistleblowers to anonymously contact journalists, based on years-long research by Daniel and other colleagues. www.theguardian.com/gnm-press-of...

theguardian.comThe Guardian launches Secure Messaging, a world-first from a media organisation, in collaboration with the University of CambridgeSecure Messaging is a new innovation for confidential story-sharing and source protection, underpinning the Guardian’s commitment to investigative journalism. The Guardian has published the open sourc...

9/6/25, 12:29 pm151 reposts395 likes

Martin Kleppmann

@martin.kleppmann.com

9 June 2025

This system is baked into the Guardian's news app that millions of people have installed. Every regular user of the app generates cover traffic, and an attacker monitoring the network cannot distinguish someone using the secure messaging feature from a regular user.

Martin Kleppmann

@martin.kleppmann.com

9 June 2025

Technical details in the white paper: www.coverdrop.org/coverdrop_gu... and the original (2022) research paper on which it is based: petsymposium.org/popets/2022/... Our lab's announcement: www.cst.cam.ac.uk/news/guardia... So excited that this is now out!

coverdrop.orgcoverdrop.org

Daniel Hugenroth

@lambda.bsky.social

9 June 2025

Thank you so much @martin.kleppmann.com for all your help, guidance, and feedback during this project! Especially with the tricky bits around key rotation and concurrency. And glad that we were able to distill some insights from the production world already into our P79 course.

Nabil

@nabilf.bsky.social

9 June 2025

Lovely!!! Hoping for the success of this initiative