This project targets an important aspect of online privacy by giving users the ability to hide their communication patterns through anonymous communication. Anonymous communication mitigates the "dossier effect," where third parties can accumulate enough information about users to construct a detailed profile, regardless of the use of encryption. This project addresses two key research issues in anonymous communication: scale and performance. To support large user bases, it is necessary to redesign the current centralized architecture of anonymous communication systems and replace it with a peer-to-peer one. The project studies the myriad security, privacy, and performance issues introduced by such a change. Better performance will improve the usability of anonymous communication to make it a reasonable option for routine Internet use. The ultimate goal is to make anonymity technology accessible to all people for appropriate uses and to integrate it into basic Internet protocols.