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Re: [tor-talk] Tor Survey

The posted script uses the "openssl speed" command to evaluate the node's encryption performance. This command iterates through every algorithm OpenSSL supports, most of which Tor doesn't use. There is also a bug in OpenSSL where the speed command alone does not utilize encryption accelerators, so the output of this part of the script is completely useless to the study anyway. To get the actual performance Tor sees you have to test each algorithm Tor uses independently with "-evp". For example, on one of my Tor nodes "openssl speed" gives me: 
type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 
bytes
aes-256 cbc      66979.82k    72147.67k    75580.48k    72884.57k 
72832.34k

while "openssl speed -evp aes-256-cbc" gives:


aes-256-cbc     442163.07k   472286.16k   477768.11k   485609.13k 
484977.32k

So Tor actually has available to it over 6x the performance for this 
algorithm of what the script will show.  No idea which algorithms Tor 
actually uses though.

-Pascal


On 1/11/2012 4:47 AM, Marco Valerio Barbera wrote:

Dear Tor Relay Administrator,

my name is Marco Valerio Barbera, I am a PhD student in Computer Science at La Sapienza University of Rome and I am currently doing a research study on the security of the Tor Network in collaboration with Angelos Keromytis, head of the Network Security Lab at Columbia University.

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