As encryption is becomming a common feature of on line communication quite a few copmmentators predicted that individuals will at last be able to effectivelly protect their privacy. In this workshop we will see that not only the content but also the shape of the traffic, and other traffic data, can reveal a great deal of information about a users private patterns of behaviour. We will present practical ways one could use to extract information from these patters and techniques that have to be used in order to fool this type of traffic analysis.