[tor-bugs] #6232 [Analysis]: Make entropy-over-time graph

Tor Bug Tracker & Wiki torproject-admin at torproject.org
Tue Jul 10 12:56:02 UTC 2012


#6232: Make entropy-over-time graph
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 Reporter:  arma         |          Owner:                   
     Type:  enhancement  |         Status:  needs_information
 Priority:  normal       |      Milestone:                   
Component:  Analysis     |        Version:                   
 Keywords:               |         Parent:                   
   Points:               |   Actualpoints:                   
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Comment(by robgjansen):

 Replying to [comment:19 robgjansen]:

 > Replying to [comment:18 gsathya]:
 >
 > > I also have Rob's entropy calculation based on the probability that a
 country might be chosen(bw of all relays in a particular country/total bw
 of all relays of all countries), but I have no idea what to call it. Also,
 should this be 1 value per consensus or 1 value per country per consensus?
 > >

 Sorry, I need to start doing preview before submitting my comments. I've
 corrected my comment below.

 > Let b_i be the bw of all relays in country i
 > Let s be the total bandwidth of all relays
 Let p_i be b_i / s (i.e. the probability that a selected relay belongs to
 country i)

 > Compute this for all countries i
 >
 > The entropy of this particular consensus is then computed as:
 > - ( sum_(all i) p_i log_2 (p_i) )
 >
 > [note there is a negative sign in front of the sum]
 >
 > You could call this the diversity of a consensus in the face of a
 national level adversary. Does this make sense?

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6232#comment:20>
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