* [ECOS] Entropy gathering?
@ 2008-04-03 19:18 Grant Edwards
2008-04-03 19:29 ` [ECOS] " Grant Edwards
0 siblings, 1 reply; 2+ messages in thread
From: Grant Edwards @ 2008-04-03 19:18 UTC (permalink / raw)
To: ecos-discuss
I'm working on adding some secure protocol support (ssl/ssh) to
an eCos app, and the libraries implmenting the protocols need a
source of cryptologically secure random bits. I've been
searching through the eCos source tree, and there don't appear
to be any sort entropy gathering hooks anywhere.
The BSD stacks appear to use an aRC4 keystream for "random"
data. The stream uses a constant seed and then mixes in the
system clock value. It could be worse, but it's not great
either.
Has any thought been given to providing a mechanism to gather
some entropy from the timing of interrupts generated externally
(network, serial ports, etc.)?
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at I'll be RITA HAYWORTH!!
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^ permalink raw reply [flat|nested] 2+ messages in thread
* [ECOS] Re: Entropy gathering?
2008-04-03 19:18 [ECOS] Entropy gathering? Grant Edwards
@ 2008-04-03 19:29 ` Grant Edwards
0 siblings, 0 replies; 2+ messages in thread
From: Grant Edwards @ 2008-04-03 19:29 UTC (permalink / raw)
To: ecos-discuss
On 2008-04-03, Grant Edwards <grante@visi.com> wrote:
> The BSD stacks appear to use an aRC4 keystream for "random"
> data. The stream uses a constant seed and then mixes in the
> system clock value. It could be worse, but it's not great
> either.
Upon reading the above statement, I think I should clarify that
the "system time" that's mixed in is the HAL's hardware counter
value and not the system tick count time. The hardware counter
is changing much faster (a good thing), but it provides
relatively few bits (on my targets, it ranges from 14-18).
--
Grant Edwards grante Yow! My mind is making
at ashtrays in Dayton ...
visi.com
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2008-04-03 19:18 [ECOS] Entropy gathering? Grant Edwards
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