Privacy-preserving Ways to Estimate the Number of Tor Users

[Karsten Loesing <karsten.loesing@xxxxxxx>]

Hello everyone,

Sebastian and I just finished our tech report on "Privacy-preserving
Ways to Estimate the Number of Tor Users" which is available here:

  https://metrics.torproject.org/papers.html

  https://metrics.torproject.org/papers/countingusers-2010-11-24.pdf

From the Introduction:

"The Tor network allows hundreds of thousands of users every day to stay
anonymous online and enables another tens of thousands of people in
oppressed countries to circumvent local censorship. At least, these are
the orders of magnitude of Tor usage that we assume at the time of
writing this report. Estimating the number of users in an anonymity
network is a hard problem. On the one hand, it's important to learn
something about the users of a network to improve its service. But on
the other hand, the users of an anonymity network have a high demand for
privacy, which prohibits collecting sensitive information that is
necessary to obtain exact usage statistics. In this report we describe
our approaches to collect aggregated usage data and derive user number
estimates from them."

The new user number estimate described in Section 4 is available here:

  https://metrics.torproject.org/users.html

As always, feedback is highly appreciated!

Best,
Karsten