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Re: Anonymity easily thwarted by flooding network with relays?
On 11/18/2010 11:03 PM, Roger Dingledine wrote:
attack, which doesn't care how many hops your path has (as long
as it's at least two). You can read more about it from the various
freehaven.net/anonbib/ links in this blog post about a related topic:
https://blog.torproject.org/blog/one-cell-enough
--Roger
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Roger,
I'm not sure as a career sys admin that I am qualified to really
comment on this. But in order for this attack to work, you have to
correlate the input data to the entry node to the output data to the
exit node (as you have said). That can be done by measuring timing and
size of the data.
Getting around this seems to me to be easy. All that has to happen
is the addition of garbage data from the client which is then stripped
out on the exit node. That way the data going into the network has a
false size, always larger than what is actually being transported, this
happens in the first layer of the "onion". So the data in, never equals
the data out and vice versa.
At that point *timing* is the only correlating factor. And with the
latency of the tor network, that would be very hard to track, with the
perceived security going up on busier guard and exit nodes. Also, some
slight random latency could be introduced (smallish factor, 1 to 10 ms)
for all middle nodes, muddying the waters even more.
Like I mentioned before, I'm not really qualified to comment on
this. I use tor as an IT tool for security and offsite testing.
--
Michael Cozzi
cozzi@xxxxxxxxxxxxxxxxxxx
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