Dagster: Censorship-Resistant Publishing Without Replication

Abstract

In this paper we present Dagster, a new censorship-resistant publishing scheme. Unlike previous censorship-resistant schemes, Dagster does not rely on the widespread replication of data and can even be used in a single server setting. It accomplishes this by ``intertwining'' legitimate and illegitimate data, so that a censor can not remove objectionable content without simultaneously removing legally protected content. The Dagster system was designed to be as simple and efficient as possible. It increases required network traffic by a constant (but tunable) factor, but otherwise has a very low cost for both clients and servers, making it easy to scale.