We discuss problems and trade-offs with systems providing anonymity
for web browsing (or more generally any communication system that requireslow
latency interaction). We focus on two main systems: the Freedom network [12]
and PipeNet [8]. Although Freedom is efficient and reasonably secure against denial of service attacks, it is vulnerable to some generic traffic analysis attacks,
which we describe. On the other hand, we look at PipeNet, a simple theoretical
model which protects against the traffic analysis attacks we point out, but is vulnerable to denial of services attacks and has efficiency problems. In light of these
observations, we discuss the trade-offs that one faces when trying to construct an
efficient low latency communication system that protects users anonymity.