Re: Problem with random.c and PPC

Remco Post
2002-08-22T17:21:31Z

On donderdag, augustus 22, 2002, at 03:19 , David Wagner wrote:

> Chris Friesen wrote:
>> The problem is this. If you have an embedded system that is headless,
>> diskless, keyboardless, and
>> mouseless, then your only remaining source of any interrupt-based
>> entropy is the network.
>
> Try replacing "network" with "/dev/zero" to see how your sentence
> sounds, and then maybe the flaw in your reasoning will become apparent.
>
> "If you have an embedded system that is headless, etc., then your
> only remaining source of entropy is /dev/zero."
>
> Well, sometimes there is just no reliable entropy source on hand.
> Maybe it's better to admit that than to fool ourselves.

And how would you see this. On a diskless/headless system, you'll be
sure to find more than one NIC, making it IMHO very unlikely for one
attacker to be able to generate so much traffic on all of those that all
NICs are continuesly generating interrupts. Granted, it's not the best
source of entropy, but it's guanranteed to be more that /dev/zero.
Having your network cards in your entropy pool, is not really bad, and
is a lot better than not being able to generate session keys at all for
your ssh connection.

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---
Met vriendelijke groeten,

Remco Post

SARA - Stichting Academisch Rekencentrum Amsterdam http://www.sara.nl
High Performance Computing Tel. +31 20 592 8008 Fax. +31 20 668 3167

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