Re: regarding the changes to kernel entropy gathering

[RVP <rvp%SDF.ORG@localhost>]

On Tue, 6 Apr 2021, Taylor R Campbell wrote:

> Why do you say that?  We do incorporate many sources that are not
> well-studied -- every keystroke, for example, and the CPU cycle
> counter at the time of the keystroke, affects the output of
> /dev/urandom.

Is the output of /dev/random also influenced like this?

> What do you mean by `things like timing jitter have been pooh-poohed
> in the literature'?  Timing jitter in ring oscillators arising from
> thermal noise in the silicon is the main source of entropy in most
> on-die hardware RNGs on the market that I'm aware of.  This design is
> reasonably well-studied in the literature.

I should've been more precise :(. Back in the beginning of the year
when a related discussion re: initial seeding on devices w/o usable
audio devices got stuck, I said that when all else fails the user
can be asked to mash on the keyboard and jiggle the mouse. To which
nia@ responded that those old-fashioned methods weren't considered
good enough nowadays, and linked to a paper which discussed this.

I had in mind that (and similar stuff) when I wrote what I did--not
well-studied physical processes like jitter derived from comparing
a pair of free-running oscillators.

-RVP