PrivacyWeek 2021

Building an end-to-end encrypted social network
2021-10-30, 20:00–20:45 (Europe/Vienna), Stream
Language: English

Circles is a new E2E encrypted social networking app that I built to share baby photos with my close friends and family. I will talk about why I wanted a new kind of sharing app, and how Circles builds on Matrix to provide a private and convenient way to keep in touch.


Everyone wants to do better at keeping in touch with close friends and family. In a recent survey, 95% of respondents told us that they wished they could share more often than they do. We asked why people don't share more with the people closest to them, and two responses dominated the answers: (1) Concern over who can see what they share, and (2) Not wanting to inconvenience the receiving party.

These answers reflect the limitations of our current tools. We can either have security and privacy, as with encrypted messengers like Signal and Element/Matrix, or we can have the convenience of the big social platforms like Facebook and Instagram. I wanted both, so I built something new.

My new app is called Circles, and it's built on the Matrix platform for end-to-end encrypted messaging. It uses Matrix's encrypted chat rooms behind the scenes to recreate the social structures and user interface of a typical social networking app. I'll talk about how we use Matrix to implement two types of social structures in an E2E encrypted, privacy preserving way: private groups and social circles.

Dr. Wright is the founder of Kombucha Digital Privacy Systems LLC, where he focuses on building tools to help people keep their family's data safe online. In his "other life" he is an associate professor of Computer Science at a large public university in Portland, Oregon. Prior to that, he was a member of the technical staff at MIT Lincoln Laboratory.

Dr. Wright's publications include research on the privacy of conversations in encrypted voice-over-IP; on the security of encrypted databases; and on providing privacy for photos on cloud services like Google Photos.