  Traffic analysis is a type of attack on secure communications systems, in
which the adversary extracts useful patterns and information from the observed
traffic. This paper improves and extends an efficient traffic analysis attack,
called "statistical disclosure attack." Moreover, we propose a solution to
defend against the improved (and, a fortiori, the original) statistical
disclosure attack. Our solution delays the attacker considerably, meaning that
he should gather significantly more observations to be able to deduce
meaningful information from the traffic.
