[liberationtech] Jacob Appelbaum's Ultrasurf Report

[Rohan Dixit]

This seems like an ideal application of information theoretic tricks for
quantifying the amount of information in a signal. It reminds me of the
search for the crack to the Enigma machine of the German military in World
War II, somehow


> ..which reminds me: there may be merit to an architecture that uses a
> relatively constant, quantized bandwidth to mask traffic.  So for
> instance, if you have 12kBps of peak outbound requests (as measured over
> the last minute, say, you send a steady stream of 10kBps (mostly noise)
> to your entry point so that no one can correlate your inbound requests
> with traffic leaving the entry point or arriving at end point. This rate
> can be pushed up in fixed increments that disguise actual throughput but
> never fall below a minimum that disguises small transactions like IMAP
> and XMPP.
>
> Providing cover for bursty traffic like web browsing in the reverse
> direction is trickier, but is equally doable, provided you can budget
> for the bandwidth and/or buffering at the entry points.
>


I guess then one partial solution to masking even low-latency Tor data is
to simply wait until network speeds increase a couple orders of magnitude.
There's likely a practical upper limit on how much information a human
being can absorb in a given day, and as networking protocols are optimized
and infrastructure supporting increased bandwidth is laid, the overhead of
dummy packets (perhaps statistically generated based on current traffic in
the network a la [Wang, 4]) is a vanishing cost.


[ 4 ] Timing analysis in low-latency mix networks:
attacks and defenses [Wang et al]
http://www.cs.utexas.edu/~shmat/shmat_esorics06.pdf

--
Rohan Dixit
rohandixit86 at gmail.com
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