Making Peer-to-Peer Anonymous Routing Resilient to Failures

One hurdle to using peer-to-peer networks as anonymizing networks is churn. Node churn makes anonymous paths fragile and short-lived: failures of a relay node disrupt the path, resulting in message loss and communication failures. To make anonymous routing resilient to node failures, we take two steps: (1) we use a simple yet powerful idea based on message redundancy by erasure coding and path redundancy to mask node failures; (2) we base mix choices of a path on node lifetime prediction and choose stable nodes as relay nodes, thereby prolonging single path durability. We present an allocation of erasure-coded message segments among multiple paths that provides a guideline on how to maximize routing resilience upon different node availabilities in real-world systems. Via detailed simulations, we compare routing resilience of our approach and existing anonymity protocols, showing that our approach greatly improves routing resilience while consuming modest bandwidth.