Efficient Unobservable Anonymous Reporting against Strong Adversaries

We present DURP, a decentralized protocol for unobservable, anonymous reporting to an untrusted destination, with low latency and overhead. DURP provably ensures strong anonymity properties, as required for some applications (and not provided by existing systems and practical designs, e.g., Tor), specifically: − Provable unobservability against global eavesdropper and malicious participants. − Provable source anonymity against a malicious destination. − Probable-innocence against a malicious destination which is also a global eavesdropper. DURP design is a modular combination of two modules: a queuing module, ensuring fixed rates for certain events, together with an anonymization module, which can use either OnionRouting (DURP) or Crowds (DURP). We present analysis, backed by simulation results, of the network properties and performance of DURP, and show it has reasonable overhead. We also use the analysis results to create an optimized version of DURP.