[ECOS] Entropy gathering?

[ECOS] Entropy gathering?

[Grant Edwards]

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.)?

-- 
Grant Edwards                   grante             Yow! If I pull this SWITCH
                                  at               I'll be RITA HAYWORTH!!
                               visi.com            Or a SCIENTOLOGIST!


-- 
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss

[ECOS] Re: Entropy gathering?

[Grant Edwards]

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            


-- 
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss