[cryptography] Quality of HAVEGE algorithm for entropy?

Stephan Mueller smueller at chronox.de
Fri Nov 29 05:55:41 EST 2013


Am Freitag, 29. November 2013, 11:22:29 schrieb Joachim Strömbergson:

Hi Joachim,

> 
> Very cool. How does [1] compare functionally to jytter?
> http://jytter.blogspot.se/

I very briefly checked, but it seems that the author's consideration takes 
interrupts and the like as the basis for the entropy. In addition, he 
assumes that the prediction of some events cannot be done with a good 
resolution. However, none of these considerations apply.

My RNG is:

rdtsc
<some small code>
rdtsc

==> now you simply measure the execution time of the code. That time shows 
variances. And I just pick them up and magnify them.

The key is that you always have these varations on all kinds of CPUs. And as 
mentioned before, I think the key reason is that the clock cycles of the CPU 
mismatch with the RAM / Cache clock cycles.

Ciao
Stephan
-- 
| Cui bono? |


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