Collecting entropy from device_attach() times.

[Pawel Jakub Dawidek]

On Sun, Sep 23, 2012 at 02:37:48AM +0200, Mariusz Gromada wrote:
> W dniu 2012-09-22 21:53, Pawel Jakub Dawidek pisze:
> > Mariusz, can you confirm my findings? 
> 
> Pawel,
> 
> Your conclusions can be easily confirmed by shape analysis of the EDF. 
> Usually maximum quantile difference (called D-statistic) gives you a 
> kind of overview, function shape gives you a strong feeling, p-value 
> gives you a formal proof.
> D-statistic values (your data):
> 
>   6bit:   0.33%
>   7bit:   0.29%
>   8bit:   0.27%
>   9bit:   0.21%
> 10bit:   6.34%
> 11bit:  19.07%
> 12bit:  54.80%
> 
> What I would say: increasing the number of bits from 6 to 9 does not 
> affect distribution "uniformity", reaching the tenth bit results in 
> sudden increase in the difference measure -  the more bits, the more 
> difference is observed. Distribution shape analysis for the 10th bit 
> shows non-linear function. Lack of "randomness" in the quntile 
> difference curve - chart  shows completely lack of noise (pure 
> functional relation).  These are very strong indicators that starting 
> from 10th bit distribution was changed and is no longer uniform.
> 
> To formally confirm above conclusion for i.e. 5% significance level, 
> which means that confidence level is 95%, I need some extra data 
> regarding sample sizes. Please pass to me number of collected 
> observations in each 6-12 bit experiment.

Total number of observations was 162833.

-- 
Pawel Jakub Dawidek                       http://www.wheelsystems.com
FreeBSD committer                         http://www.FreeBSD.org
Am I Evil? Yes, I Am!                     http://tupytaj.pl
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 196 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-security/attachments/20120923/d3fc7f89/attachment.pgp