It has more to do with the structure of the public internet. A fully passive observer in a few key locations has a surprisingly high probability of being able t

It has more to do with the structure of the public internet. A fully passive observer in a few key locations has a surprisingly high probability of being able to perform correlation attacks. This is a pretty interesting "where do I start?" paper if you want to know more but don't have much background on the subject: http://www.syverson.org/tor-vulnerabilities-iccs.pdf http://www.syverson.org/tor-vulnerabilities-iccs.pdf