Cashmere: Resilient Anonymous Routing
Li Zhuang
Feng Zhou
Ben Y. Zhao
Antony Rowstron
ACM/USENIX 2nd Symposium on Networked Systems Design and Implementation (NSDI 2005)
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Paper Abstract
Anonymous routing protects user communication from identification by
third-party observers. Existing anonymous routing layers utilize
Chaum-Mixes for anonymity by relaying traffic through relay nodes called
mixes. The source defines a static forwarding path through which traffic is
relayed to the destination. The resulting path is fragile and shortlived:
failure of one mix in the path breaks the forwarding path and results in data
loss and jitter before a new path is constructed. In this paper, we
propose Cashmere, a resilient anonymous routing layer built on a structured
peer-to-peer overlay. Instead of single-node mixes, Cashmere selects regions
in the overlay namespace as mixes. Any node in a region can act as the MIX,
drastically reducing the probability of a mix failure. We analyze Cashmere's
anonymity and measure its performance through simulation and measurements,
and show that it maintains high anonymity while providing orders of magnitude
improvement in resilience to network dynamics and node failures.