[tor-dev] Running doctor's sybil checker over archived consensuses

Philipp Winter phw at nymity.ch
Mon Jan 19 16:47:26 UTC 2015


On Thu, Jan 15, 2015 at 06:11:25PM -0500, grarpamp wrote:
> On Thu, Jan 15, 2015 at 10:25 AM, Philipp Winter <phw at nymity.ch> wrote:
> > The median amount of new fingerprints in a consensus is six.  The
> > Here are some preliminary notes about the most significant spikes.  I'll
> 
> > 2008-10-25: Missing consensuses.
> 
> FYI, between here there was thread tor-talk 'many new relays' of possible
> event around end 2009-06 to begining 2009-07. Along with usual posts
> of people about potential things to detect.

Interesting, thanks for pointing this out.  This event is visible in
the diagram but not as a sudden spike but more as a temporary increase
in the base rate:
<http://www.nymity.ch/new_fingerprints/2009_new_fingerprints.png>

This event also shows why a simple threshold-based detection mechanism
is insufficient: Sybils can be added slowly over several hours or days
in order to stay under the threshold.

Cheers,
Philipp


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