I'm so sorry, something went terribly wrong with gmail/thunderbird :-( 2013/2/22 Nick Kossifidis <mickflemm@xxxxxxxxx>: > Hello all, > > It's nice to see there is still discussion on the matter of using cpu > timings for entropy. In general using cpu timings for gathering entropy is a > nice idea but it's not that unpredictable. If someone can profile the system > he/she can get enough infos to predict (to some point) the generator's > outcome, especially during boot/reboot. You might pass the tests on a single > run but if you try to compare the runs e.g. when booting the system multiple > times you'll see they are correlated. > > Take a look at this: > > http://dl.dropbox.com/u/11670313/runtime-data.tar.bz2 > > It's the output of this patch, before passing data to the entropy pool (btw > did anyone review this patch or should I resend it ?): > > https://patchwork.kernel.org/patch/1759821/ > > If you plot the datasets you'll see e.g. that across reboots you get a very > similar distribution. It is somehow different across boots but still there > is some correlation there too, notice the difference when fsck runs, still > not much. > > The distribution is good in general, for mixing it with the rest in the > system's entropy pool, but on its own I don't think it's enough, especially > without crypto post-processing. -- GPG ID: 0xEE878588 As you read this post global entropy rises. Have Fun ;-) Nick -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
