questions about RNGs and FIPS 140
John Denker
jsd at av8n.com
Fri Aug 27 13:05:50 EDT 2010
On 08/26/2010 11:34 PM, Thomas wrote:
> Luckily /dev/random is re-seeded during run-time.
I would have said something different: *IF* you are
lucky, then /dev/random gets reseeded during run time.
> So even if you do
> a roll-back of a system and the new input it non-deterministic it will
> generate different output immediately.
Depending on details of the system, there is no guarantee
that /dev/random gets reseeded at all, much less reseeded
"immediately".
There exist lots of small and/or embedded and/or virtual
Linux systems that have no useful sources of entropy.
The kernel attempts to collect entropy, but there are no
positive lower bounds on the effectiveness of the built-in
measures.
You could always add a source, but that is a topic for a
whole new discussion. For more on this, see
http://www.av8n.com/turbid/
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