[PracticalSecurity] Anonymity - great technology but hardly used

Ben Laurie ben at algroup.co.uk
Wed Oct 26 18:34:14 EDT 2005

Travis H. wrote:
> Part of the problem is using a packet-switched network; if we had
> circuit-based, then thwarting traffic analysis is easy; you just fill
> the link with random garbage when not transmitting packets.  I
> considered doing this with SLIP back before broadband (back when my
> friend was my ISP).  There are two problems with this; one, getting
> enough random data, and two, distinguishing the padding from the real
> data in a computationally efficient manner on the remote side without
> giving away anything to someone analyzing your traffic.  I guess both
> problems could be solved
> by using synchronized PRNGs on both ends to generate the chaff.  The
> two sides getting desynchronzied would be problematic.  Please CC me
> with any ideas you might have on doing something like this, perhaps it
> will become useful again one day.

But this is trivial. Since the traffic is encrypted, you just have a bit
that says "this is garbage" or "this is traffic".

OTOH, this can leave you open to traffic marking attacks. George Danezis
and I wrote a paper on a protocol (Minx) designed to avoid marking
attacks by making all packets meaningful. You can find it here:



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