The Wisdom of Crowds: Attacks and Optimal Constructions

We present a traffic analysis of the ADU anonymity scheme presented at ESORICS 2008, and the related RADU scheme. We show that optimal attacks are able to de-anonymize messages more effectively than believed before. Our analysis applies to single messages as well as long term observations using multiple messages. The search of a "better" scheme is bound to fail, since we prove that the original Crowds anonymity system provides the best security for any given mean messaging latency. Finally we present D-Crowds, a scheme that supports any path length distribution, while leaking the least possible information, and quantify the optimal attacks against it.

• Type: Conference
• Year: 2009
• Where: ESORICS
• Authors: Carmela Troncoso, Claudia Díaz, Emilia Käsper, George Danezis
• Keywords: ADU Anonymity Scheme, ESORICS 2009, Original Crowds Anonymity, RADU Scheme, Security Privacy