[Dtls-iot] Reference to Heninger Paper

[Hannes Tschofenig <[e-mail]>]

Stephen wrote:

(7) 14: Doesn't [Heninger] really cause many devices to use one RSA
prime factor? That's not the same as "same keys again and again" and in
any case you're not recommending RSA keys on challenged nodes here.
Shouldn't you do the analysis of the impact of a dodgy PRNG on
populations of devices that follow these profiles and not something else?


Heninger did an analysis of the deploy infrastructure of that time and
RSA is in widespread use. Hence, her analysis focuses on the problems
with RSA keys.

However, her observations are general in the sense that a non-existent
or bad random number generator will lead to output that is predictable
or the same with a number of devices. This is essentially what I write.

Copy-and-paste from the text:

---
   Special care has to
   be taken when generating random numbers in embedded systems as many
   entropy sources available on desktop operating systems or mobile
   devices might be missing, as described in [Heninger].  Consequently,
   if not enough time is given during system start time to fill the
   entropy pool then the output might be predictable and repeatable, for
   example leading to the same keys generated again and again.
---