Riposte: An Anonymous Messaging System Handling Millions of Users
This addresses the need for scalable and secure anonymous communication for applications like Twitter or Wikileaks, representing a significant advancement rather than an incremental improvement.
The paper tackles the problem of building an anonymous broadcast messaging system that scales to millions of users while protecting against traffic analysis and denial-of-service attacks, achieving an anonymity set of 2,895,216 users in 32 hours with a three-server cluster.
This paper presents Riposte, a new system for anonymous broadcast messaging. Riposte is the first such system, to our knowledge, that simultaneously protects against traffic-analysis attacks, prevents anonymous denial-of-service by malicious clients, and scales to million-user anonymity sets. To achieve these properties, Riposte makes novel use of techniques used in systems for private information retrieval and secure multi-party computation. For latency-tolerant workloads with many more readers than writers (e.g. Twitter, Wikileaks), we demonstrate that a three-server Riposte cluster can build an anonymity set of 2,895,216 users in 32 hours.