lkml.org 
[lkml]   [2016]   [Aug]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: Entropy sources (was: /dev/random - a new approach)
On Thu, Aug 25, 2016 at 5:30 PM, H. Peter Anvin <hpa@zytor.com> wrote:

> The network stack is a good source of entropy, *once it is online*.
> However, the most serious case is while the machine is still booting,
> when the network will not have enabled yet.
>
> -hpa

One possible solution is at:
https://github.com/sandy-harris/maxwell

A small (< 700 lines) daemon that gets entropy from timer imprecision
and variations in time for arithmetic (cache misses, interrupts, etc.)
and pumps it into /dev/random. Make it the first userspace program
started and all should be covered. Directory above includes a PDF doc
with detailed rationale and some discussion of alternate solutions.

Of course if you are dealing with a system-on-a-chip or low-end
embedded CPU & the timer is really inadequate, this will not work
well. Conceivably well enough, but we could not know that without
detailed analysis for each chip in question.

\
 
 \ /
  Last update: 2016-09-17 09:57    [W:0.056 / U:0.756 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site