Date Added: Feb 2010
The authors present Drac, a system designed to provide anonymity and unobservability for real-time instant messaging and Voice-over-IP communications against a global passive adversary. The system uses a relay based anonymization mechanism where circuits are routed over a social network in a peer-to-peer fashion, using full padding strategies and separate epochs to hide connection and disconnection events. Unlike established systems, Drac gives away the identity of a user's friends to guarantee the unobservability of actual calls, while still providing anonymity when talking to untrusted third parties. They present the core design and components of Drac, they discuss the key ways in which it challenges their current concepts of anonymity and provide an initial simulation-based security analysis.