[ECOS] Re: Entropy gathering?

Grant Edwards grante@visi.com
Thu Apr 3 19:29:00 GMT 2008


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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