On Mon, Sep 09, 2002 at 02:57:34PM -0500, Oliver Xymoron wrote:
> > Why not use the power-on state of DRAM as a source of initial pool
> > entropy?
>
> There's actually not a lot there, and what is there is not random, but
> rather a rapidly fading "ghost" of what was there last.
Which means it is not completely predictable, which means there is
going to be some entropy in there...
> And for most folks, this gets wiped by POST or the kernel long
> before the RNG gets its hands on it.
Well now, *that's* a pain.
But for us embedded folks who control our boot ROM there is the
potential to grab some entropy from that melting ghost.
> Nonetheless, there's no reason not to take whatever state we get
> when we allocate our pool. Amusingly, the current code needlessly
> zeroes out its pool before using it - twice! I've already fixed this
> in my patches.
Perfect! So if some embedded-types do manage to dig up some entropy
from the end/beginning of the world, we will have a place to put it
where it will be put to use. Cool.
Thanks,
-kb, the Kent who suggests a comment left in that code might prevent
someone from "fixing" it at a later date.
-
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