Test OpenSSL Speeds

Feb 10, 2015 How To


I was recently benchmarking to use of 4096-bit RSA certificates for some secure host communications. One of the servers was a raspberry pi, (lol) and the other was a beast of a machine with 128GB of RAM and 24 cores. Both of these devices would be communicating with each other as clients and servers, so they would each need to verify SSL certs.


Noticing that there was significant lag on the Pi, I wanted to run some benchmarking. Up my sleeve I have a cool trick, which is the openssl speed command:

You can pass your bit length to the rsa so it appears as rsa4096 if you don’t want to test all possible lengths.

Interpreting the Results

If you take a look at the results, they provide some very useful results:


As you can see above, we can sustain the signing of 4096-bit rsa’s at 44.2 a second. Since this box does not actively sign or serve as a CA, and will only be verifying the certs, let’s look at the verify metric. On our current hardware, miraculously, we can verify 2916.7 certs a second signed with rsa4096. This is more than acceptable, since we won’t be making more than 1 HTTP request a second.

I’ll be posting another article soon about stress testing nginx and SSL offloading.

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