[viff-devel] How to avoid the boring math

Marcel Keller mkeller at cs.au.dk
Fri Apr 24 05:18:29 PDT 2009


Hi friends of VIFF,

I've now played a little bit with artificial bandwidth limits and 
artificial delays in order to be able to better analyze protocols. 
(Actually, my motivation was to get the running time for AES matching my 
analysis. It worked.)

I found out that setting a delay of 1 second for every packet gives a 
running time matching the number of rounds quite well. On the other 
hand, limiting the bandwidth gives at least a qualitative impression of 
the number of elementary operations. Another observation is that one 
could also have a look at the TCP sequence numbers to get an impression 
of the number of elementary operations.

I've included to shell scripts for Linux: One delays the network traffic 
to a given address space by 1 second, the other limits the traffic to 
15kbit/s.  They must be run as root.

If adding a delay, one should also apply the attached patch to avoid 
strange results (longer running times for less traffic).

Best regards,
Marcel

Disclaimer: Hereby I reject to encourage anyone to replace serious 
protocol analysis by heuristics.


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