Speaker: Fengjun Li
Title: CAT: a node-failure-resilient anonymous communication protocol

Abstract:

The goal of anonymous communication is to hide the identity of a
communication participant (the initiator/recipient or their
association) from being known by its partner and other third parties.
Most of existing anonymous communication approaches rely on a relative
small set of pre-selected relay servers to redirect the messages. The
pre-selection approaches provide good anonymity, but suffer from node
failures and scalability problem. To provide better resilience to node
failures, we present CAT, a node-failure-resilient anonymous
communication protocol. In this protocol, the initiator of a
connection selects a set of relay groups, instead of relay servers, to
set up anonymous paths. A valid path consists of relay servers, at
least one from every selected relay group. The initiator negotiates
commutative path keys with the relay servers so that the relative
positions of relay servers in the path are commutative. Therefore,
multiple anonymous yet commutative paths form an anonymous tunnel to
mark single node failure through "path hopping" - whenever a
connection encounters a node failure, it can quickly switch to a
nearest backup path.