john-users - Re: Real c/s Explaination

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Date: Wed, 22 Aug 2012 21:41:52 -0700 (PDT)
From: NeonFlash <psykosonik_frequenz@...oo.com>
To: "john-users@...ts.openwall.com" <john-users@...ts.openwall.com>
Subject: Re: Real c/s Explaination

Hi can anyone look into the below question and provide some details?

Thank you.



________________________________
 From: NeonFlash <psykosonik_frequenz@...oo.com>
To: "john-users@...ts.openwall.com" <john-users@...ts.openwall.com> 
Sent: Wednesday, August 22, 2012 6:40 AM
Subject: [john-users] Real c/s Explaination
 
Hi,

I wanted to understand in depth the meaning of the c/s speed displayed while running an attack using JtR on a cryptographic hashing algorithm.

For instance, if we run:

./john -fo=DES --test

For me it would show something like, 2300K c/s

My understanding is that my processor can perform 2300K DES Encryptions using descrypt of the candidate passwords in 1 second. However, I think this is not an accurate description. I would appreciate it if someone can elaborate over this (Solar Desginer especially :D )

Also, how is it related to the clock cycle and clock speed of a Processor?

For instance, if I am comparing the benchmark for the same hashing algorithm using the same version, build of JtR on two different processor, how accurate is the comparison in terms in efficiency?

I guess, cycles per byte need to be calculated for that but for this I need to understand the meaning of c/s in more detail.

I love JtR and I would like to understand in much more depth at code level.

Thank you.