[tor-dev] New tech report: Counting daily bridge users

[Karsten Loesing]

Hi everyone,

I just finished a new tech report titled "Counting daily bridge users":

https://research.torproject.org/techreports/counting-daily-bridge-users-2012-10-24.pdf

>From the abstract: "As part of the Tor Metrics Project, we want to learn
how many people use the Tor network on a daily basis.  Counting users in
an anonymity network is, obviously, a difficult task for which we cannot
collect too sensitive usage data.  We came up with a privacy-preserving
approach for estimating directly connecting user numbers by counting
requests to the directory mirrors and deriving approximate user numbers
from there.  In this report we describe a modified approach for
estimating the number of users connecting via bridges by evaluating
directory requests made to bridges.  We compare this new approach to our
current approach that estimates bridge user numbers from total unique IP
addresses seen at bridges.  We think that results from the new approach
are closer to reality, even though that means there are significantly
fewer daily bridge users than originally expected."

Feedback is much appreciated and could influence our implementation of
user number estimates in the future (#7154).

Thanks,
Karsten