[DragonFlyBSD - Bug #1358] Random number generator

[bugtracker-admin at leaf.dragonflybsd.org]

Issue #1358 has been updated by alexh.


This has never been relevant. The only way to ensure the system starts up with (enough) entropy is to save some on shutdown. See ceccfc6bc7912b64fce4d4cd929eaf9346d00d53 for more details.


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Bug #1358: Random number generator
http://bugs.dragonflybsd.org/issues/1358#change-12460

* Author: robin.carey1
* Status: Feedback
* Priority: Low
* Assignee: 
* Category: Crypto
* Target version: 4.2.x
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---------- Forwarded message ----------
From: Robin Carey <robin.carey1 at googlemail.com>
Date: 2009/5/8
Subject: Random number generator
To: submit-request at lists.dragonflybsd.org

I had an idea about how to improve the random number generator in
DragonFlyBSD which I would like to share.

There is a bootstrapping problem where it is difficult to get enough
"entropy" at boot to ensure the random number generator is fully seeded and
completely unpredictable immediately after the system has booted.

Currently the random number generator seeds itself from nanotime() and
nanouptime() which introduces a small degree of entropy, but probably not
enough to ensure the above requirement is met.

So a possible improvement could be made by introducing more "entropy" at
initialisation from a high resolution timer like the TSC - rdtsc() (which is
also used in the random number generator - NANOUP_EVENT() - courtesy of
Matthew Dillon). That is my suggestion: Use rdtsc() aswell as nanotime() and
nanouptime() to ensure the random number generator has enough "entropy" at
boot to ensure it is fully seeded and completely unpredictable. If this were
done (and true) then you would not need the current ability of the random
number generator being able to be seeded from a file - an ability which
Matthew Dillon implemented to solve the boot-seeding problem.

I am wondering if there are any other high resolution timers available .....

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