In this blog post I present a secure and privacy friendly asynchronous point-to-point message exchange protocol using a public bulletin board that makes individual send or receive events unlinkable to one another. While the clients must securely run in the user’s endpoint device, the bulletin board can be hosted on an arbitrary public cloud at no additional risk. In fact the protocol provides the same unlinkability guarantees as the underlying mixing network thus also protecting the social graph. The protocol is efficient, and the central bulletin board can adaptively be scaled and distributed depending on the load.
This blog post describes the details of the design of the Burnrchat app that was the result of a design sprint I previously discussed on this blog.